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Chapter Four

Pollution Characteristics of Industrial Construction and Demolition Waste

Abstract

Different types of industrial construction and demolition wastes in various places were collected. The mercury content varies much overall, whereas the wastes from the chemical industry contain most due to the mercury-containing raw materials used. Waste from the light industry poses a high risk of Cd. Residential wastes and recycled aggregates exhibit a low ecological risk. The mobility fractions of heavy metals can be very high; most anthropogenic polluted metals bind loosely with minerals in construction waste. The metals easiest to be leached are Zn and Cu, whereas Cd is the hardest. A high Cd content exists in pesticide manufacturing factory, mainly coming from phosphorus rocks. These wastes are also severely contaminated by organophosphorus, intermediates, and pyrethroid pesticide. Pesticides spread all over the plant both in enclosed workshops and in residues, in which bricks and coatings contain the most. Centralized collection for disposal of wastes can only eliminate part of the contaminated waste. Risk assessment indicates that highly noncarcinogenic risks exist, especially in dermal contact and oral ingestion. Industrial construction and demolition waste generated in a fire/explosion accident may be hazardous and cause spread of pollution with explosion shock waves.

Keywords

Heavy metal; Organic pollutant; Pollution characteristic; Risk assessment code; Spatial distribution

4.1. Mercury and Its Distribution in Construction and Demolition Waste

Different types of industrial construction and demolition (C&D) wastes in various places were collected and analyzed in detail. The coverage of investigation is shown in Table 4.1.

4.1.1. Distribution Characteristics of Mercury

Mercury contents of C&D waste from five different sources varied much overall, in which the maximum amount of 1542.83 μg/kg was 178.5 times the minimum amount of 6.46 μg/kg. The average amount of 164.97 μg/kg was 1.1 times the value of soil natural background limit of 150 μg/kg, taking Chinese standard of environmental quality for soils (GB15168-1995) as a comparison. It was indicated that the average mercury content of C&D waste in chemical industry (CI) was the highest among all. The waste with higher mercury contents in CI were, respectively, listed as follows, with the wall sample where cranes were used from a chemical plant in Wuxi (1215.47 μg/kg), concrete blocks from the wall of processing workshop (1542.83 μg/kg), concrete blocks from copper plating workshop of a electroplating factory in Shenzhen (1141.69 μg/kg), and bricks from a nickel plating workshop (1028.43 μg/kg). The average amount of mercury content in metallurgical industry (MI) C&D waste was 61.37 μg/kg, and the average amount of a zinc smelting factory in Yunnan (180.84 μg/kg) > a steel mill in Nanjing (93.69 μg/kg) > a steel mill in Shanghai (50.37 μg/kg) > firebrick in Baogang (21.34 μg/kg). The overall content was not high, and except for a zinc smelting factory in Yunnan, mercury content of the other waste was below first-level standard threshold (150 μg/kg) of soil. The maximum value of mercury content in metallurgical C&D waste present in the inner wall of the chimney from a steel mill was 620.52 μg/kg. Besides, the scraping from the outer wall of chimney (178.04 μg/kg) was far higher than other sampling points (<80 μg/kg). Mercury pollution of the steel mills mainly appeared in the chimney, which might be associated with the use of high mercury-content coal.

Table 4.1

Brief Description of the Samples Involved in This Section

Type	Name	Environment
Chemical industry	Chemical industry	Wall, coatings in workshops
	Electroplating factory	Workshops
	Paint factory	Wall, floor in workshops
	Glaze Technology Co., Ltd.	Wall, floor in workshops
	Incineration plant for hazardous waste	Wall, floor in workshops
Metallurgical industry	Zinc smelting plant	Electrolysis, cleaning workshops
	Abandoned steel mill	Boiler workshops
	Steel plant	Walls in workshops
	Steel plant	Boiler workshops
Light industry	Rubber factory	Workshops
Light industry	Light industry base	Walls in workshops
Pesticide industry	Pesticide manufacturing plant	Warehouses, workshops
Fire/explosion	Fire and explosion scene	Floor waste
Residential aggregates	University canteen	Bricks, wall
Residential aggregates	Temporary dump sites	Bricks, wall
Recycled aggregates	Building materials company	Concrete, clay
Recycled aggregates	Earthquake C&D waste	Coarse and fine aggregate

The main reason why CI and MI contributed to high mercury content was that, in the industries such as electroplating factory, mercury-containing raw materials were used in the production process and some dripped on the floor or wall in the operation process. Pipeline aging and leakage of corrosive liquid caused damages of metope and ground, thus creating mercury-containing C&D waste through adsorption and entrainment. Material stock workshop, filling workshop, production workshop, demolition and maintenance, etc., also caused a mixed accumulation of much mercury-contained waste with general C&D waste. Furthermore, iron and steel industries needed to burn a lot of coal, and mercury escaped into the flue gas with coal combustion, resulting in generation of Hg-polluted wastes.

The average mercury content of C&D waste in light industry (LI) was 112.16 μg/kg, with the highest content of 506.44 μg/kg present in the insulation sandwich of wall rubber, compared with 75.97 μg/kg in living quarters, 78.90 μg/kg in the regeneration product, and 46.67 μg/kg in the renovation wastes of a college canteen. The highest mercury content was nearly 100 times the lowest in CI or metallurgy industry, which had something to do with the use of raw materials and processing. Most Hg presenting in C&D wastes should come from the raw materials used in the production processes. The appearance of sampling spots is shown in Fig. 4.1.

Figure 4.1 Real appearance of sampling point in a zinc smelting factory in Yunnan.

4.1.2. Single Factor Evaluation of Mercury Pollution

There is no relevant standard about heavy metal contents yet in building materials industry, so the secondary standard for soil was adopted as the environmental safety threshold for reference. Five different sources were analyzed using single factor index evaluation method of mercury pollution for the level of C&D waste pollution, and its computation formula was as follows: P = C/S, where P is the mercury pollution index of C&D waste, C is the real average mercury contents of C&D waste (μg/kg), and S is the secondary standard threshold for soil mercury evaluation. The secondary standard was a limit to guarantee agricultural production and keep human body healthy, and S = 300 μg/kg if referring to the secondary standard of environmental quality standard for soils (GB15168-1995). p < 1 was no contamination, 1 ≤ p < 2 was mild contamination, 2 ≤ p < 3 was moderate pollution, p > 3 was heavy pollution. Single factor evaluation results of mercury pollution degree of C&D waste are shown in Table 4.2.

Referring to environmental quality standard for soils (GB15168-1995), the first-level standard is 150 μg/kg, the second-level standard 300 μg/kg, and the third-level standard 1500 μg/kg. Results of the single factor evaluation showed that mercury pollution of C&D waste in CI was more serious than others, and the average content of mercury was up to 669.27 μg/kg. Mercury content of seven samples were over secondary standard threshold of mercury for soils, and one sample was more than third standard threshold of mercury for soils, contamination index was 2.23, i.e., moderate pollution, whereas mercury pollution index of C&D waste from other four sources was less than 1. One sample of MI and LI separately was more than the second-level standard threshold of mercury for soils, and mercury contents of recycled aggregates (RC) and residential wastes were less than secondary standard threshold of mercury for soils.

Table 4.2

Statistical Characteristics of Mercury Contents of C&D Wastes From Different Sources

Industry	Sampling Number	Maximum (μg/kg)	Minimum (μg/kg)	Mean (μg/kg)	Standard Deviation	Contamination Index
CI	10	1542.83	16.88	669.27	525.77	2.23
MI	38	620.52	6.84	61.37	110.91	0.20
LI	6	506.44	6.46	112.16	194.51	0.37
RS	5	156.73	24.59	75.97	50.95	0.25
RC	4	179.11	23.52	78.90	70.57	0.26
Total	63	1542.83	6.46	164.97	316.09	0.55

4.2. Characterization of Cu/Zn/Pb/Cr/Cd/Ni in Industrial C&D Waste

Sixty three C&D waste samples from different sources have been collected. The concentration analysis and risk assessments have also been carried out.

4.2.1. Total Concentrations of Heavy Metals in C&D Waste

The total heavy metal concentrations of C&D waste samples are summarized in Table 4.3. The threshold values of heavy metals (TVHMs) of the environmental quality standard for soils in China are also shown. In this standard, Level-I value is the upper limit for soil environmental background, Level-II is the upper limit to guarantee agriculture and human health, Level-III is the threshold value to maintain regular growth in plants. Cd was not detected in most of the samples. The average contents of Pb, Cd, and Ni were lower than the TVHM^e3 (Level-III), whereas Cu, Zn, and Cr are 1–4 times higher. However, the maximum of each element was far above the TVHM^e3 (Level-III).

Table 4.3

Total Heavy Metal Concentrations in C&D Waste Samples From Five Sources

	Heavy Metal (mg/kg)
Sample	Cu	Zn	Pb	Cr	Cd	Ni
CI	6310 ± 18,700^a	911 ± 969	82 ± 129	943 ± 912	2.24 ± 0.22	573 ± 843
CI	(296%)^b	(106%)	(159%)	(97%)	(10%)	(147%)
MI	204 ± 602	3340 ± 5710	201 ± 318	232 ± 222	6.3 ± 4.8	54.2 ± 49.4
MI	(296%)	(171%)	(158%)	(95%)	(76%)	(91%)
LI	50.7 ± 35.2	128 ± 53	20.5 ± 9.2	95.5 ± 67.5	1.18 ± 1.01	31.9 ± 29.7
LI	(69%)	(41%)	(45%)	(71%)	(86%)	(93%)
RS	35.9 ± 9.3	704 ± 289	23.7 ± 8.3	95.0 ± 91.3	ND^c	18.0 ± 11.0
RS	(26%)	(41%)	(35%)	(96%)	ND^c	(61%)
RC	24.6 ± 2.9	906 ± 538	23.3 ± 3.8	70.7 ± 12.8	ND	21.3 ± 1.8
RC	(12%)	(59%)	(16%)	(18%)	ND	(8.6%)
Average	1130 ± 7490	2280 ± 4520	141 ± 265	311 ± 406	5.28 ± 4.67	131 ± 380
Max	59,400	49,300	1260	7510	15.4	2870
Min	4.43	17.7	ND	10.1	ND	5.29
De/An^d	63/63	63/63	59/63	63/63	14/63	63/63
TVHM^e	35	100	35	90	0.2	40
TVHM^f	100	250	300	200	0.6	60
TVHM^g	400	500	500	300	1	200

To visualize the evaluation of each heavy metal, six graphs are presented in Fig. 4.2. The severely contaminated samples were mainly contained in the CI and MI categories. Generally, low degrees of the heavy metal contents were present in the LI, residential aggregates (RS), and RC samples. In the case of Zn, three of five RS samples and three of four RC samples exceeded the TVHM^e3 (Level-III), with mean concentrations up to 704 and 906 mg/kg, respectively; simultaneously, low concentration existed in the LI samples, with 128 mg/kg on average. This phenomenon might be caused by the slathering of the walls and furniture with zinc-rich paint during interior renovation.

Considerable hazard was posed in various workplaces of CI and MI according to Fig. 4.2. For almost every graph, no significant differences were found between LI, RS, and RC, but the dots representing CI and MI protruded obviously from the others. For Cu, the most seriously polluted sample was CI8 (59,400 mg/kg) from a copper electroplating workshop, which exceeded the TVHM^e3 (Level-III) by 150 times. CI10 (3190 mg/kg) from a nickel plating workshop came from the same plant. Other seriously polluted samples included MI1 and MI2 from the electrolysis workshop and clean workshop, respectively, in the zinc smelting plant (Fig. 4.2A).

For Zn, about half of the CI samples and one-third of the MI samples exceeded the TVHM^e3 (Level-III). In MI, the most polluted sample was MI1 (49,300 mg/kg) from a zinc smelting electrolysis workshop, and it was more than 100 times higher than the TVHM^e3 (Level-III). The severely polluted samples mainly came from the two MI plants, the zinc smelting plant and a Shanghai steel plant (Fig. 4.2B).

For Pb, almost all the LI, RS, and RC samples were below the TVHM^e1 (Level-I), and all the CI samples were lower than the TVHM^e3 (Level-III). Most of the MI samples met the TVHM^e3 (Level-III) except MI2 (879 mg/kg) from a cleaning workshop in the zinc smelting plant, MI20 (766 mg/kg) and MI24 (1260 mg/kg) from a Shanghai steel plant, and MI29 (1050 mg/kg) from another Shanghai steel plant (Fig. 4.2C).

The Cr concentrations of the LI, RS, and RC samples were all below the TVHM^e3 (Level-III). Among the CI samples, CI5 (701 mg/kg) from the CI corporation, CI9 (7510 mg/kg) from a chrome plating workshop in the electroplating factory, and CI10 (306 mg/kg) from a nickel plating workshop in the same plant exceeded the TVHM^e3 (Level-III). Among the MI samples, almost all the severely contaminated ones came from Shanghai steel plants (Fig. 4.2D).

Cd was not detected in the majority of the samples. There were 11 samples exceeding the TVHM^e3 (Level-III), among which 9 samples were from MI. MI1-2 were from Electrolysis & Clean workshop in zinc smelting plant, and MI7, MI9-10, and MI13 were collected from chimney and boiler workshop in the abandoned steel mill. MI14 was from Shanghai steel plant. MI37-38 was collected from the boiler workshop in steel plants. The other two samples surpassing Level-III were CI8 from electroplating factory and LI6 from LI bases (Table 4.3 and Fig. 4.2E).

Figure 4.2 Concentrations of Cu (A), Zn (B), Pb (C), Cr (D), Cd (E), and Ni (F) in construction and demolition waste from five sources in China (n = 63). CI, chemical industry; Level-I, the first-level standard; Level-II, the second-level standard; Level-III, the third-level standard [environmental quality standard for soils in China (CEPA, GB 15618-1995)]; LI, light industry; MI, metallurgical industry; RC, recycled aggregates; RS, residential aggregates.

The mean concentration of Ni in the CI samples (573 mg/kg) was much higher than those of MI, LI, RS, and RC (54.2, 31.8, 18.0, and 21.3 mg/kg, respectively). Almost all the CI samples were higher than the TVHM^e3 (Level-III), of which there is a maximum of 2870 mg/kg in CI10 from a nickel plating workshop in the electroplating factory. Five of six samples from the CI corporation posed a high risk (Fig. 4.2F).

4.2.2. X-Ray Fluorescence Analysis of Heavy Metals in C&D Waste

Due to the large number of samples, the six most polluted samples were selected as representative for X-ray fluorescence (XRF) analysis of heavy metals in C&D wastes, among which four samples (CI7−CI10) came from electroplating plants, and the other two (MI1-MI2) came from the zinc smelter plants (Table 4.4).

Table 4.4

Main Mineral Constituent of C&D Waste Samples According to the Xrf Analysis Presented as % W/W Content of Mineral Oxides

Sample	SiO₂	Al₂O₃	Fe₂O₃	MgO	CaO	K₂O	Na₂O
CI-7	60.491	18.865	7.638	1.398	1.122	2.521	1.321
CI-8	30.162	4.563	1.528	0.712	14.039	0.701	0.074
CI-9	48.307	6.521	1.745	0.456	15.091	1.047	0.601
CI-10	49.552	7.137	1.678	0.389	11.107	2.191	0.858
MI-1	2.985	1.865	0.981	0.219	1.878	1.993	76.451
MI-2	2.359	1.227	2.385	0.133	1.184	2.142	73.901

XRF was performed to investigate the chemical elemental composition. The details are shown in Table 4.4. As can be seen, electroplating factory C&D waste samples CI7−CI10 were mainly SiO₂ (30.2–60.5%), Al₂O₃ (4.6–18.9%), and CaO (1.1–15.1%), which were common composition in bricks, suggesting relatively slight corrosion. In contrast, zinc smelting plant samples MI1-2 were mainly Na₂O (73.9–76.5%). The high content of sodium meant that severe corrosion could have occurred in these floor bricks and also indicated frequent contact with sodium salts.

4.2.3. X-Ray Diffraction Analysis of Heavy Metals in C&D Waste

The crystalline phases of the six samples were analyzed by X-ray diffraction (Fig. 4.3). The main mineralogical compositions of the four CI samples were common brick compositions like quartz, silicon oxide, gypsum, and a small amount of berlinite, which was in good correspondence to the XRF results. Although the concentration of Pb was under THVM Level-II according to the Inductive Coupled Plasma results, lead arsenate, a highly toxic substance extensively used as an insecticide, was present in samples CI7 and CI8 in small quantities. There was also another toxic substance, potassium chromium oxide, in CI8. According to the figure, the Cr concentration in CI8 was the lowest among CI7−CI10, however, the chromium crystallization was not detected in the other three samples. This meant large quantities of Cr appeared to be noncrystal forms existing in the samples.

Obviously, much more complex patterns in MI samples were posed as the result of deposition and erosion on the workshop floor in zinc smelter plants. Combined with the XRF results, it can be found that above 70% (w/w) of them were mainly composed of sodium salts such as sodium silver chloride, halite, and nitrite. Moreover, peaks of copper chloride bromide were obvious. In view of the easy solubility of such toxic substances, it may pose a high danger as the high concentration of Cu (476–3740 mg/kg). A series of zinc-bearing minerals, such as zinc, zinc oxide, barium zinc oxide, and zincite, showed the extremely serious contamination in line with the total concentrations of Zn. The crystalline phases of chromium were identified in both MI1 and MI2. As carriers of heavy metals, the mineral phases especially for zinc and copper minerals were easily mobilized under acid condition, which meant a potential risk in natural environment.

Figure 4.3 X-ray diffraction of six most polluted construction and demolition waste samples from the electroplating factory and zinc smelter in China. Electroplating factory samples (CI-7, galvanizing workshop; CI-8, copper plating workshop; CI-9, chrome plating workshop; CI-10, nickel plating workshop). Zinc smelter samples (MI-1, electrolysis workshop; MI-2, cleaning workshop).

4.2.4. Chemical Speciation of Heavy Metals in C&D Waste

The potential mobility, bioavailability, and toxicity of heavy metals in C&D waste are not only associated with their total concentration levels but also their chemical speciations. To evaluate bioavailability and environmental risk more accurately, a modified European Communities Bureau of Reference (BCR) sequential extraction was utilized. The results are shown in Table 4.5 and Fig. 4.4. The acid soluble/exchangeable fraction (F1) presented high bioavailability of the metals; meanwhile, metals associated with the reducible fraction (F2) could remain available under anoxic conditions. The oxidizable fraction (F3) was easily mobilized and transformed into F1 or F2 in oxidizing conditions. The residual fraction (F4) might hold metals within the crystal structure of its constituents and was identified as a stable fraction.

A verification of the results of the BCR sequential extraction procedure was performed by comparing the sum of the four fractions (F1, F2, F3, and F4) with the total digestion concentrations of heavy metals from the HNO₃ digestion procedure. The detailed calculation was expressed as follows:

$Recovery (%) = (F 1 + F 2 + F 3 + F 4) / Total digestion \times 100 %$ $Recovery (%) = (F 1 + F 2 + F 3 + F 4) / Total digestion \times 100 %$

The recovery rates are listed in Table 4.5 and were in good agreement with the total heavy metal concentrations, with satisfactory recovery rates ranging from 89.7% to 111%. This indicated that this modified BCR sequential extraction method was reliable.

Proportions of each chemical fraction are presented in Fig. 4.4. For the CI7 sample from the galvanizing workshop, Cu, Pb, Cr, and Ni mainly existed in the residual fraction, whereas their total concentrations were all under TVHM-II. But the acid extractable fraction of Pb contained the toxic substance lead arsenate. Zn mainly existed in the acid extractable fraction. The mobility fraction of Zn [(F1 + F2 + F3)/Total] in the CI7 sample was over 93%, with a very high total concentration of 2120 mg/kg.

Table 4.5

Content Distributions of Each Fraction of Heavy Metals in Construction and Demolition Waste Samples (mg/kg)

Sample	Element	F1	F2	F3	F4	∑F	Total^a	Recovery (%)^b	RAC (%)^c
CI-7	As	ND^d	ND	ND	29.66 ± 2.21	29.66 ± 2.48	30.80 ± 2.75	96.29	ND
	Fe	550.76 ± 35. 56	619.08 ± 45.24	137.23 ± 12.27	17,448.72 ± 1310.83	18,755.77 ± 1648.63	17,945.38 ± 1361.5	104.52	2.94
	Mn	16.43 ± 1.15	4.50 ± 0.29	ND	875.40 ± 72.28	896.33 ± 72.64	878.69 ± 71.96	102.01	1.83
CI-8	As	ND	76.83 ± 6.36	30.17 ± 2.37	29.41 ± 2.74	136.42 ± 11.34	132.50 ± 12.23	102.96	ND
	Fe	364.15 ± 28.14	5993.08 ± 464.29	707.79 ± 67.39	3883.30 ± 261.97	10,948.31 ± 998.92	12,278.84 ± 1196.4	89.16	3.33
	Mn	51.48 ± 4.06	30.65 ± 2.91	2.73 ± 0.19	89.49 ± 7.29	174.35 ± 14.59	167.46 ± 14.64	104.11	29.53
CI-9	As	ND	ND	ND	18.81 ± 1.65	18.81 ± 1.65	18.84 ± 1.56	99.86	ND
	Fe	451.19 ± 32.16	4881.86 ± 354.29	864.36 ± 76.10	5370.45 ± 478.93	11,567.86 ± 1030.29	10,847.08 ± 988.33	106.64	3.90
	Mn	15.88 ± 1.06	91.18 ± 8.38	15.99 ± 1.43	166.28 ± 14.21	289.34 ± 23.68	292.23 ± 22.79	99.01	5.49
CI-10	As	ND	ND	ND	17.46 ± 1.42	17.46 ± 1.42	17.21 ± 1.38	101.50	ND
	Fe	1654.47 ± 117.25	4951.48 ± 378.35	421.76 ± 31.38	4767.28 ± 387.41	11,794.99 ± 931.29	11,098.99 ± 878.94	106.27	14.03
	Mn	136.50 ± 10.03	101.40 ± 9.32	0.74 ± 0.05	163.22 ± 14.01	401.85 ± 34.72	423.93 ± 41.34	94.79	33.97
MI-1	As	4.61 ± 0.26	29.30 ± 2.39	53.07 ± 4.93	63.38 ± 5.32	150.36 ± 13.97	155.09 ± 12.19	96.95	3.06
	Fe	31.57 ± 2.37	584.19 ± 32.91	595.30 ± 46.09	3696.13 ± 268.36	4907.18 ± 489.78	5288.42 ± 469.35	92.79	0.64
	Mn	46.58 ± 3.96	76.57 ± 5.97	38.70 ± 2.72	46.65 ± 3.96	208.50 ± 18.93	214.04 ± 19.17	97.41	22.34
MI-2	As	33.33 ± 2.12	34.99 ± 2.87	0.58 ± 0.07	138.75 ± 12.27	207.65 ± 16.26	232.31 ± 21.82	89.39	16.05
	Fe	65.97 ± 4.09	727.70 ± 36.47	395.31 ± 29.26	9696.55 ± 876.21	10,885.53 ± 983.02	11,962.41 ± 864.38	91.00	0.61
	Mn	ND	62.50 ± 4.27	13.75 ± 1.25	81.04 ± 6.09	157.28 ± 12.33	166.17 ± 15.19	94.65	ND

Figure 4.4 Chemical fraction profiles of Cu, Zn, Pb, Cr, Cd, and Ni in the six most polluted construction and demolition waste samples from the electroplating factory and zinc smelter in China. Electroplating factory samples (CI-7, galvanizing workshop; CI-8, copper plating workshop; CI-9, chrome plating workshop; CI-10, nickel plating workshop). Zinc smelter samples (MI-1, electrolysis workshop; MI-2, cleaning workshop).

In the CI8 sample, the mobility fractions of Cu and Zn were both over 99%, and that of Ni was over 86%. The concentrations of Cu, Zn, and Ni far surpassed TVHM-III. Pb, Cr, and Cd mainly existed in the residual fraction, but small quantities of lead arsenate and potassium chromium oxide existed in the mobility fraction.

The proportions of the mobility fractions of Cu, Zn, and Cr in the CI9 sample were 94.4, 89.9, and 94.3%, respectively. The total concentrations of Cu and Zn were below TVHM-II; however, the concentration was extremely high for Cr (7510 mg/kg), and mainly existed in the acid extractable fraction. As no chromium crystallization was detected, Cr could be existing in amorphous forms in this sample. Pb mainly existed in the reducible fraction, and Ni mainly existed in the residual fraction. Both their total concentrations were below TVHM-II.

The proportions of the mobility fractions of Cu, Zn, Pb, and Ni in the CI10 sample were all over 83%, with total concentration of Cu and Ni surpassing TVHM-III. Although Cr surpassed TVHM-III, it mainly existed in the residual fraction.

The proportions of the mobility fractions of Cu, Zn, and Pb in the MI-1 sample were all over 88%, with concentrations of Cu and Zn above TVHM-III and Pb above TVHM-II. Large quantities of Cu existed as copper halide and most of the Zn appeared to be zinc, zinc oxide, barium zinc oxide, and zincite. Cr and Ni mainly existed in the residual and oxidizable fractions. But there is barium chromate in the mobility fraction. Although the total concentration was high above TVHM-III, Cd mainly existed in the residual fraction and was over 95%.

In the MI-2 sample, the proportions of the mobility fractions of Cu, Zn, Pb, and Cd were over 83%, and all of them exceeded TVHM-III. Cu mainly existed in the reducible and oxidizable fractions as copper halide. Cd mainly existed in the reducible fraction and was over 89.5%. Cr and Ni mainly existed in the residual fraction and were over 65%; both were below TVHM-I.

The higher the proportion of heavy metals in the mobility fraction, the greater the potential for transfer ability will be exerted. These results suggested that Zn, Cu, Pb, and Ni had higher transfer ability and reflected that most heavy metals bound loosely with minerals in the form of mobility fractions. Therefore it was difficult to ensure the stabilities of these heavy metals by means of only a simple landfill or random stacking.

In another study, No. 1–4 samples were C&D waste from chemical industry and No. 5–6 were from metallurgical industry, No. 7 was the reference sample simulated in the laboratory. Speciation analysis of Cr, Cu, Ni, Pb, and Zn is listed in Table 4.6.

The acid extractable fraction, reducible fraction, and oxidizable fraction of Zn and Cu in C&D waste in Zn, Cu workshops from an electroplating factory and the electrolysis and cleaning section of zinc manufacturing factory were high in amount, whereas the residual fraction was low. The Zn and Cu in C&D waste in Zn, Cu workshops from an electroplating factory had strong mobility and would cause high environmental risks.

4.2.5. Risk Assessment Code of Heavy Metals in Most Polluted Waste

Compared with other chemical fractions, it is much easier for the acid extractable fraction to transform and migrate into the environment. Hence, the risk assessment code (RAC) is defined as the proportion of acid extractable elements in the total species distribution (%F1 for BCR), which is used to evaluate the environmental risk levels of metals in the ecosystem. A proportion of 1–10% reflects a low risk, 11–30% a medium risk, 31–50% a high risk, and above 50% poses a very high risk and is considered dangerous. The RAC values are presented in Table 4.5. Specific results and evaluation criteria are shown in Fig. 4.5.

Table 4.6

Speciation Analysis of Heavy Metals in Construction and Demolition Waste

Sample	Speciation	Zn (mg/kg)	Cu (mg/kg)	Cr (mg/kg)	Ni (mg/kg)	Pb (mg/kg)
1. Zn workshop from an electroplating factory	Acid extractable fraction	1568.57	14.15	–	–	–
	Reducible fraction	289.79	–	–	–	–
	Oxidizable fraction	313.10	3.99	–	–	–
	Residual fraction	13.79	5.24	12.44	3.75	3.63
	Total	2185.26	23.38	12.44	3.75	3.63
2. Cu workshop from an electroplating factory	Acid extractable fraction	3014.30	31,720.20	–	255.17	–
	Reducible fraction	799.28	15,473.30	6.11	180.49	–
	Oxidizable fraction	112.68	356.12	4.29	129.67	–
	Residual fraction	2.84	3.52	8.46	8.54	0.69
	Total	3929.10	47,553.14	18.87	573.87	0.69
3. Cr workshop from an electroplating factory	Acid extractable fraction	133.42	155.57	5424.78	–	–
	Reducible fraction	151.38	164.02	1064.09	–	46.28
	Oxidizable fraction	1.33	–	565.11	–	–
	Residual fraction	3.20	1.90	40.93	1.023	1.74
	Total	289.33	321.49	7094.91	1.023	48.02
4. Ni workshop from an electroplating factory	Acid extractable fraction	192.72	983.35	70.08	648.16	–
	Reducible fraction	93.61	1047.95	38.63	1818.15	52.65
	Oxidizable fraction	31.64	1019.50	28.30	164.01	–
	Residual fraction	2.74	7.74	21.01	3.85	1.07
	Total	320.71	3058.54	158.02	2634.17	53.72
5. Electrolysis section in a zinc factory	Acid extractable fraction	17,133.68	290.02	–	–	21.24
	Reducible fraction	20,194.2	1063.25	1.67	6.57	156.98
	Oxidizable fraction	17,588.25	1200.81	44.41	44.71	218.20
	Residual fraction	79.35	6.45	4.04	2.25	4.54
	Total	54,995.48	2560.53	50.12	53.53	400.96
Table Continued

Sample	Speciation	Zn (mg/kg)	Cu (mg/kg)	Cr (mg/kg)	Ni (mg/kg)	Pb (mg/kg)
6. Cleaning section in a zinc factory	Acid extractable fraction	13,353.54	28.34	–	–	53.98
	Reducible fraction	17,563.98	317.78	–	–	451.95
	Oxidizable fraction	1842.60	97.62	12.57	–	244.23
	Residual fraction	53.89	5.11	1.93	0.61	13.79
	Total	32,814.01	448.85	14.50	0.61	763.95
7. Laboratory simulation	Acid extractable fraction	103.03	514.07	242.69	–	501.58
	Reducible fraction	12.53	55.53	162.26	–	131.96
	Oxidizable fraction	13.62	–	343.45	–	–
	Residual fraction	4.85	2.53	27.06	1.77	0.78
	Total	134.03	572.13	775.46	1.77	634.32

According to the RAC classification, the results presented in Fig. 4.5 suggested that Cd presented a low risk in almost all samples. Pb presented a medium risk in the CI8 sample and a low risk in the remaining samples. Ni, Cr, and Cu had different potential risks in different samples. Ni presented a high risk in the CI-8 sample, Cr a very high risk in the CI-9 sample, Cu a high risk in the CI-9 and CI-10 samples and a very high risk in the CI-8 sample. Meanwhile, Zn presented the highest potential risk overall. It presented a high risk in the CI-9, MI-1, and MI-2 samples and a very high risk in the CI-7, CI-8, and CI-10 samples. The environmental risk based on the average RAC in all samples was roughly sequenced as: Zn > Cu > Cr > Ni > Pb > Cd. The results indicated that much more attention should be paid to Zn, Cu, Cr, and Ni in C&D waste.

Issues such as increasing C&D waste disposal costs and the recycling potential of the many components in the C&D waste stream have resulted in the evolution of the recycling of C&D waste into a growing industry in China in recent years. In China, residential C&D wastes are the main raw material for recycled products because there are generally considered not to be environmental hazards. The recycling process of C&D waste includes three main steps: screening, drying, and crushing. Drying under 500°C can help remove organic pollutants, but incapable for heavy metal pollution. The third-level standard limit values (CEPA, GB 15618-1995) were exceeded for zinc in residential C&D waste, which may come from pigments, paints, lacquers, manganese batteries, and wood preservative coatings, and hence the removal of surface materials is necessary before recycling.

Figure 4.5 Risk assessment code (RAC) of Cu, Zn, Pb, Cr, Cd, and Ni in the six most polluted construction and demolition waste samples from the electroplating factory and zinc smelter in China. Electroplating factory samples (CI-7, galvanizing workshop; CI-8, copper plating workshop; CI-9, chrome plating workshop; CI-10, nickel plating workshop). Zinc smelter samples (MI-1, electrolysis workshop; MI-2, cleaning workshop).

The contents of heavy metals at a chemical group were not as serious as other CI and MI plants, with only a relatively high risk of zinc and nickel. The company used to produce hydrochloric acid, caustic soda, zinc oxide, synthesis resins, pesticide, emulsifier, etc. By contrast, the three steel plants were extremely vulnerable to zinc, lead, chromium, and cadmium pollution. It was found that the presence of zinc, lead, and cadmium was mainly from steel-smelting activities. The lead pollution was mainly from the floor surface of the processing plant and transport workshop, probably due to the splash of lead-based gasoline during the transport process. The high concentrations of these chromium and cadmium hazardous compounds were found principally in the chimney affected directly by coal-burning flue gas. Thus it needed selective deconstruction for chimneys and workshop floors during building demolition to allow the wastes to be recycled.

The highest environmental risks of these pollutants were found to be present in the electroplating factories (galvanizing, copper plating, chrome plating, and nickel plating workshops) and zinc smelting plants (electrolysis and clean workshops). Zinc, copper, chromium, and nickel mainly existed in the mobility fraction, and lead and cadmium mainly existed in the residual fraction. It was proved that pH was the most relevant factor in the leaching methods of C&D waste due to its strong control of the heavy metals released. The frequent incidences of acid rain in China suggest that these pollutants can generate high potential mobility risks and ecological hazards in the case of a deposit in an unlined landfill or random stacking and recycling. Thus environmentally friendly processes, such as elution or immobilization, are required to remediate these contaminated C&D waste.

The samples from the zinc smelting plant and electroplating factory, in which the copper and zinc contents reached up to 5% of the total weight, could be a new resource to extract metals. Now there were two methods, thermal and hydrometallurgical methods, to recover the heavy metals from the solid phase. The combination of alkaline–acidic leaching enhanced the removal of Zn, Cr, and Ni, whereas thermal treatment can destroy persistent organic compounds and remove easily volatile heavy metals, such as Pb, Cd, and Cu.

4.3. Leaching Toxicity of C&D Waste From Different Sources

Results of the leaching experiment are shown in Table 4.7 and Fig. 4.6. In general, the leaching toxicity of C&D waste from chemical and metallurgical industries was the highest, followed by residual C&D waste, whereas that of C&D waste from LI and RC was the lowest. Different heavy metals showed different leaching tendency. The metals easiest to be leached was Zn (22 of 62 samples) and Cu (21 of 62 samples), then it was Ni (12 of 62 samples) and Cr (9 of 62 samples), whereas Cd (2 of 62 samples) was the hardest to be leached.

4.4. Characteristics of Organic Pollutants in Multicontaminated Industrial C&D Waste

Transfer of pollutants in industrial C&D waste exists between the atmosphere, water, and soil system. Industrial C&D waste from pesticide manufacturing plants pose an extreme threat to the environment due to the multiple contaminations (organic and inorganic pollutants). Meanwhile, it has been several decades since the production of a series of highly toxic pesticides like phorate (cynamid-3911) was banned. These plants have to be abandoned and have not been demolished until recently to meet the demand for urbanization and industrialization, with a huge amount of hazardous industrial C&D waste produced. Despite severe pollution, industrial C&D waste has not been listed as the focus of government administration due to its miscellaneous generation source and immature source separation technology.

Heavy metals broadly existed in the C&D waste of chemical and metallurgical factory. Floor wastes endured the most serious pollution of copper, lead, zinc, and chromium, whose maximum concentration reached 59,400, 1260, 49,300 and 7510 mg/kg, respectively. Among organic pollutants in soil and water around chemical factories, Persistent Organic Pollutants (typically polycyclic aromatic hydrocarbons (PAHs), Polychlorinated biphenyl, and organochlorine pesticide), pyrethroids, and organophosphorus residues attached to soil by means of absorption. Multiple contaminations of cadmium, lead, and pesticide existed in several fertilizers and insecticides, which may be under risk of exposure in some workplaces. PAHs and PCBs had been found in C&D waste. This section demonstrates the systematic pollution characteristics of heavy metals and organic pesticide in industrial C&D waste of an abandoned pesticide manufacturing plant. Industrial C&D waste had been taken from different spots throughout the factory and 20 of them were analyzed. Qualification and quantification of heavy metals and organic pollutants in industrial C&D waste were obtained. This section elucidated characterization of industrial C&D waste in pesticide manufacturing plant thus providing a basic reference of source determination, separation, and management for industrial C&D waste.

Table 4.7

Leaching Toxicity of Heavy Metals in C&D Waste From Different Industries

	Heavy metal (mg/L)
Sample	Cu	Zn	Pb	Cr	Cd	Ni	As
CI	0.48 ± 1.31^a (273%)^b	0.82 ± 1.81 (221%)	ND^c	45.54 ± 142.16 (312%)	ND	0.18 ± 0.57 (317%)	0.01 ± 0.03 (300%)
MI	0.16 ± 0.30 (188%)	3.15 ± 6.34 (201%)	0.34 ± 1.56 (459%)	0.01 ± 0.04 (400%)	0.02 ± 0.11 (550%)	0.07 ± 0.18 (257%)	0.11 ± 0.53 (482%)
LI	ND	ND	ND	ND	ND	ND	ND
RS	ND	ND	ND	0.07 ± 0.15 (214%)	ND	ND	0.01 ± 0.03 (300%)
RC	ND	ND	ND	ND	ND	ND	ND
Average	0.17 ± 0.57	1.97 ± 5.06	0.2 ± 1.19	7.36 ± 57.15	0.01 ± 0.09	0.08 ± 0.28	0.07 ± 0.41
Max	4.19	27.84	9.18	450.10	0.67	1.80	3.09
Min	ND	ND	ND	ND	ND	ND	ND
De/An^d	22/62	23/62	6/62	9/62	2/62	13/62	5/62
Standards for drinking water quality^e	1.0	1.0	0.01	0.05	0.005	0.02	0.05
Environmental quality standards for surface water (Level-III)^f	1.0	1.0	0.05	0.05	0.005	–	0.05
Integrated wastewater discharge standard^g	2.0	5.0	1.0	1.5	0.1	1.0	0.5
Standard for pollution control on the security landfill site for hazardous wastes^h	75	75	5	12	0.5	15	2.5
Identification standards for hazardous wastesⁱ	100	100	5	15	1	5	5

Figure 4.6 Concentrations of heavy metals in construction and demolition waste leachate from different sources. (A) Cu, (B) Cd, (C) Cr, (D) Ni, (E) As, (F) Pb, (G) Zn.

4.4.1. PAH Existence and Its Distribution

Main specific pollutants including oil, PAHs, pesticides, and the intermediates existed in industrial C&D waste of pesticide manufacturing plants, mostly concentrating in particle and powder waste. The most severely contaminated industrial C&D waste were those around the tanks, of which the potential risk was the leakage through the cracks on the tank surface. Its production process should be focused on while the establishment of management and disposal of industrial C&D waste was performed. In situ reduction or source separation should be carried out.

Polycyclic aromatic hydrocarbons (PAHs) are primarily generated during industrial processes including the processing, burning, or use of organic matters. The scattering, spilling, or volatilization of chemical materials or pesticides would be a great pollution risk in the industrial C&D waste and soil systems.

It was found that PAHs and pyrethroids as well as their intermediates could be detected in C&D waste in some chemical and pesticide factories, among which 13 kinds of PAHs were detected. Deltamethrin and cypermethrin were found in a few samples. The highest concentration of cypermethrin was 53 mg/kg. Intermediates such as permethric acid ethyl ester were found in various samples. Distribution of PAHs in industrial C&D waste is listed in Table 4.8.

In C&D waste with a better ventilation condition, the degree of contamination by organic pollutants was relatively lower, including the wall waste of large open workshops and warehouses, or the external wall surface of the workshops. Moderate contamination existed in the surface plates of the raw materials and solvent transferring pipelines and the nearby ground waste. The degree of contamination was affected by the pipeline corrosion, weather conditions, and the specific process. There could be obvious pollution risks in the coatings and ground waste of enclosed workshops and warehouses. The pollution conditions were relatively complex in these regions, as gaseous, liquid, and solid-phase contaminants could coexist with absorption, permeation, diffusion, etc. The most seriously contaminated areas were the waste container, wrapping materials of tanks, and the ground waste nearby. These wastes contained huge amounts of pollutants and were no doubt hazardous wastes, which were not yet clearly defined and classified.

Table 4.8

Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Industrial Construction and Demolition Waste, mg/kg

PAHs	Waste 1	Waste 2	Waste 3	Waste 4	Waste 5	Waste 6
Naphthalene	0.08	0.07	–	0.71	0.01	0
Acenaphthylene	0.04	0.13	0.02	–	0.03	0.14
Acenaphthene	–	–	–	–	–	0.04
Fluorene	0.08	0.18	0.13	–	0.05	0.53
Philippines	0.82	2.38	1.26	13.29	0.91	5.25
Anthracene	0.08	0.25	–	12.76	0.10	0.74
Fluoranthene	0.68	3.08	0.74	3.55	0.70	10.26
Pyrene	–	1.91	–	–	–	7.57
Benzo(a)anthracene	0.36	0.863	0.36	0.34	0.43	3.72
Chrysene	3.25	1.67	0.32	0.14	0.41	5.43
Benzo(j)fluoranthene	1.34	1.43	1.20	–	1.17	2.35
Benzo(e)pyrene	2.09	0.59	0.54	0.56	0.62	4.74
Benzo(b)fluoranthene	0.68	0.52	0.52	0.98	0.58	4.70

Therefore the disposal of organic pollutants-contaminated C&D waste should be based on the industrial manufacturing process. C&D waste with high pollution risks should be determined at first and source reduction should be carried out.

4.4.2. Existence of Volatile Organic Compounds in Industrial Waste From Pesticide Manufacturing Plants

Volatile organic compounds (VOCs) (not including pesticides) were detected in C&D waste from pesticide manufacturing plants and smelting plants. The results are shown in Table 4.9. Only those with high concentrations are listed.

Seventeen kinds of VOC pollutants were detected, but the concentrations were not high. The highest amount of C29-C36 was 513 mg/kg, whereas that of 1,2-dichloroethane was 64.2 mg/kg, which made them the two most severe pollutants. Except for the PAHs and pesticides, the risk of organic pollutants was low and specific disposal was not necessary.

4.4.3. A Comprehensive Study on Characterization of Organophosphorus Pesticides-Contaminated Waste

C&D wastes characterized in this section were obtained in an abandoned pesticide manufacturing plant in north China. Geological conditions and processing line of this plant are introduced as follows. Products of this plant mainly consisted of organophosphorus and pyrethroid pesticide. The sampling map along with a simplified version of the general layout in which the sample was drawn is given in Fig. 4.7. The general layout only reserved the main workshops, fields, and other buildings relative to sampling, some buildings were shifted together. C&D waste from different workshops, warehouses, and other buildings throughout the plant were collected.

Table 4.9

Existence of Volatile Organic Compounds (VOCs) in Industrial Construction and Demolition Waste

VOCs	Unit	Detection Limit	Waste 1	Waste 2	Waste 3	Waste 4
Total Petroleum Hydrocarbon
C6-C9	mg/kg	0.5	–	–	85.2	–
C10-C14		10	16	–	44	15
C15-C28		20	276	53	477	451
C29-C36		20	130	55	451	513
Substitutes
Toluene-d8	mg/kg	–	97	98	98	96
4-Bromo-fluorobenzene		–	96	99	88	98
Dichlorofluoromethane		–	116	113	111	118
p-Terphenyld14		–	120	92	100	73
Monocyclic Aromatic Hydrocarbons
Benzene	mg/kg	0.05	–	–	0.39	–
Toluene		0.05	–	–	0.07	–
p-Xylene		0.05	0.13	–
o-Xylene		0.05	0.08	–
Chlorinated Aliphatic Hydrocarbons
1,1-Dichloroethane	mg/kg	0.05	–	–	0.34	–
1,2-Dichloroethane		0.05	–	0.13	64.2	0.08
1,1,2-Trichloroethane		0.05	–	–	0.39	–
Halogenated Aromatic Hydrocarbons
Chlorobenzene	mg/kg	0.05	–	–	3.06	–
Dichlorotoluene	mg/kg	0.05	–	–	0.23	–

Although it was a decade since this plant was abandoned, extreme odor pervaded most parts of the plant. C&D waste from the workshops, facilities, tanks, and tubes was randomly discarded in residue. This was mainly because manufacture of phorate was banned along with the severe deficit around 2004. Two burning tanks were located in the east of the sampling range, which were used for the incineration of polluted substances. The concrete, bricks wrapped around the towel and pond, and the solution were collected in neutralization process. A relatively small stacking field with tanks spread in disorder vertically connected the neutralization process and a much larger open field with piles of C&D waste randomly discarded in stack. An open warehouse made of wood was located at the end of the field. Three parallel enclosed workshops lay in the central district of the sampling map. A long field with three open workshops and several tanks was located a block away from the three workshops. A small pool had been generated naturally due to rainfall not far from the workshops. A large, round cultivation pond was under demolition. C&D waste and gas sample at the external edge of this field were obtained.

Figure 4.7 Sampling information. (Bottom) Dot map of actual sampling. (Top left) Simplified layout of the plant: (A) burning tank, (B) enclosed centralized stacking field of polluted construction and demolition waste, (C) sewage treatment facility, (D) neutralization process, (E) random stacking field, (F) tank, (G) stacking field with tanks, (H) small pool, (I) cultivation pool under demolition, (J) open warehouse, (K) enclosed workshop I, (L) enclosed workshop II, (M) enclosed workshop III, (N) open workshop I, (O) open workshop II, (P) open workshop III.

A total of 32 different types of C&D waste were collected, among which bricks were collected as major components of C&D waste, along with floated coating, concrete, rocks, detritus, and wood, in which 20 were detected as containing pollutants and are listed in Table 4.10. A trowel and chisel were used for the detachment of C&D waste from the external surface of the wall, floor, and tank. Each sampling was conducted in triplicate and the samples were stored in dark, and pretreated 7 days after sampling.

A detailed mean concentration (±standard deviation) of organic pollutants is listed in Table 4.11. Six kinds of pesticide intermediates were detected, among which dichlorovinyl ethyl chrysanthemate, for instance, existing in most wastes, could not be quantified due to lack of standards or products. Eleven organophosphorus pesticides and their metabolites were determined. One kind of pyrethroids, namely, cypermethrin, was also obtained.

Results showed that a large amount of pesticide intermediate compounds existed in most C&D waste. Existence of O,O′-diethyl dithiophosphate component was astonishing as the maximum concentration reached 18,749 mg/kg with an average of 3254 mg/kg. As for organophosphorus pesticides, phorate had the highest concentration in almost all the C&D waste with an average of 16,868 mg/kg. The peak of concentration of phorate reached an absolutely high level of 82,327 mg/kg. Four more C&D waste contained more than 10,000 mg/kg phorate, with a concentration of 73,057, 69,734, 20,207, and 76,196 mg/kg, respectively. Concentration of parathion was 6521 mg/kg in average, and the highest was 67,807 mg/kg. Results showed that parathion was also a severe pollutant in this plant. Fluxes of terbufos, ethion, and sulfotep were 0–1933, 0–585.2, and 0–383.9 mg/kg with a mean concentration of 170.0, 53.3, and 80.8 mg/kg, respectively. Two C&D wastes containing chlorpyrifos seemed to be polluted severely, with a concentration of 1431 and 1919 mg/kg, respectively. Phorate sulfone, a common metabolite of phorate, had an average and maximum concentration of 111.3 and 3163 mg/kg, respectively. Cypermethrin, a kind of pyrethroid pesticide, did not exist in most C&D wastes, but the maximum content was extremely high (2865 mg/kg). Accumulation of each pesticide component among different C&D wastes is demonstrated in Fig. 4.8.

Concentration data were log-transformed in this figure to reduce the influence of extremely high components like phorate. Results showed that GT-1 contained the most organic pollutants, whereas WS-4 contained the least. Mass concentration of organic pollutants did not absolutely correspond to the types of pollutants contained, indicating that complex and extreme pollution existed in most C&D wastes.

Table 4.10

Sources and Brief Properties of Construction and Demolition Waste

Item	Material	Location	Property	Odor
WS-1	Coatings	Workshop	Flat block	Extreme
WS-2	Coatings	Workshop	Flat block (larger)	Extreme
WS-3	Concrete, coatings	Workshop	Flat block	Mild
WS-4	Concrete	Workshop	Flat block	Mild
BK-1	Brick	Centralized stack field	Block	Strong
BK-2	Brick	Centralized stack field	Block	Strong
BK-3	Brick	Random stack field	Large block (wrapped by clay)	Strong
BK-4	Brick	Workshop, stack	Large block	Extreme
BK-5	Brick	Workshop, stack	Large block	Mild
BK-6	Brick	Workshop, stack	Large block	Strong
BK-7	Brick, detritus	Random stack field	Block	Mild
BK-8	Brick, detritus	Near pool	Block	Strong
WD-1	Wood	Warehouse	Large block	Mild
DS-1	Detritus	Random stack field	Small block, loose	None
DS-2	Concrete, brick, detritus	Workshop	Block	Strong
DS-3	Detritus, concrete	Random stack field	Small block	Mild
DS-4	Detritus	Neutralization department	Block, brittle	None
DS-5	Concrete, brick	Absorption tank	Moist, solid	None
DS-6	Detritus	Workshop, stack	Block	Strong
GT-1	Detritus, stone	Tank	Moist, hard block	Strong

4.4.4. Existence of Organophosphorus Pesticides in C&D Waste From Exterior Plant

The existence of organophosphorus pesticides in C&D waste outside the plant and their concentrations are listed in Table 4.12.

Evidently, new organophosphorus pollutants were found in C&D waste outside the plant, including cyanthoate, synergistic phosphorus, and dichlorvos. The concentration of dichlorvos reached up to 1000 mg/kg, which was no doubt serious contamination.

Table 4.11

Mean (±Standard Deviation) Concentration of Pesticide Pollutants (mg/kg) in Construction and Demolition Waste From the Pesticide Manufacturing Plant

Samples	Organophosphorus Pesticide										Pyrethroid
Samples	O,O,O-Triethyl Phosphorothioate	O,O'-Diethyl Dithiophosphate	Phorate	Parathion	Terbufos	Ethion	Chlorpyrifos	Sulfotep	Cholrmephos	Phorate Sulfone	Cypermethrin
WS-1	32.4 ± 1.6	163.2 ± 28.7	1221 ± 92	46.5 ± 33.4	5.7 ± 0.5	7.3 ± 0.4	Undetected (UD)	0.7 ± 1.3	UD	20.3 ± 1.0	UD
WS-2	574.1 ± 35.9	2578 ± 156	1886 ± 139	966.4 ± 86.9	349.2 ± 17.8	13.9 ± 1.4	UD	UD	UD	17.2 ± 0.3	UD
WS-3	424.3 ± 53.5	5705 ± 150	73,057 ± 23,819	35,098 ± 2403	UD	120.9 ± 4.2	UD	383.3 ± 42.5	UD	UD	139.3 ± 35.4
WS-4	7.2 ± 0.7	47.1 ± 4.4	386.5 ± 44.9	21.8 ± 1.9	4.6 ± 0.1	UD	UD	UD	UD	UD	UD
BK-1	215.0 ± 10.4	3053 ± 187	69,734 ± 1718	153.1 ± 36.7	37.9 ± 0.8	88.0 ± 1.5	1431 ± 111	154.2 ± 9.2	UD	71.6 ± 4.7	169.8 ± 64.9
BK-2	489.5 ± 47.0	4515 ± 435	82,327 ± 10,457	UD	UD	197.2 ± 81.7	1919 ± 486	178.6 ± 20.8	UD	171.3 ± 19.2	385.0 ± 142.2
BK-3	2764 ± 713	11,699 ± 2548	20,207 ± 4368	8544 ± 2442	1933 ± 359	UD	UD	374.4 ± 56.3	UD	UD	UD
BK-4	0.6 ± 0.6	4126 ± 2287	790.4 ± 371.1	67,807 ± 39,114	448.4 ± 251.2	UD	UD	265.6 ± 153.3	UD	UD	UD
BK-5	10.0 ± 1.5	200.3 ± 17.0	112.9 ± 5.8	105.6 ± 21.7	8.7 ± 0.3	UD	UD	4.3 ± 0.4	UD	UD	UD
BK-6	26.8 ± 18.6	380.7 ± 164.6	1102 ± 729	233.0 ± 47.6	42.9 ± 18.2	UD	UD	8.4 ± 3.2	UD	UD	UD
BK-7	377.3 ± 36.9	18,749 ± 3315	2582 ± 422	12,003 ± 4413	UD	20.5 ± 0.4	UD	173.5 ± 27.9	UD	UD	UD
BK-8	8.9 ± 7.2	668.1 ± 344.4	261.9 ± 28.6	3849 ± 2163	6.1 ± 4.7	UD	UD	25.5 ± 26.7	UD	UD	UD
WD-1	64.7 ± 9.9	237.7 ± 27.2	352.5 ± 169.8	106.7 ± 50.8	23.5 ± 2.8	UD	UD	UD	UD	UD	UD
DS-1	162.3 ± 9.2	438.5 ± 41.7	734.6 ± 30.5	462.5 ± 78.6	60.9 ± 5.9	7.8 ± 1.0	UD	10.3 ± 0.8	UD	16.5 ± 0.2	29.5 ± 14.7
DS-2	16.3 ± 6.2	153.7 ± 14.3	890.0 ± 70.7	50.3 ± 1.7	15.2 ± 0.1	UD	UD	UD	UD	54.7 ± 1.1	2865 ± 251
DS-3	UD	166.4 ± 7.9	152.1 ± 13.3	64.5 ± 9.0	18.1 ± 8.1	UD	UD	UD	UD	UD	UD
DS-4	176.5 ± 29.6	379.8 ± 49.4	380.5 ± 49.2	69.7 ± 25.1	16.9 ± 1.4	UD	UD	UD	UD	UD	UD
DS-5	0.8 ± 1.4	116.9 ± 4.7	514.4 ± 56.2	118.1 ± 7.2	22.5 ± 0.8	UD	UD	3.4 ± 3.0	UD	UD	UD
DS-6	82.3 ± 8.4	886.9 ± 51.4	4473 ± 211	158.7 ± 14.4	17.9 ± 0.8	25.0 ± 2.4	UD	3.6 ± 3.1	UD	UD	UD
GT-1	336.7 ± 78.6	10,834 ± 3084	76,196 ± 15,701	575.3 ± 581.1	387.5 ± 9.8	584.6 ± 32.1	UD	108.4 ± 39.2	579.4 ± 134.2	1875 ± 1133	UD
Average	288.5	3254	16,868	6521	170.0	53.3	167.5	80.8	29.0	111.3	179.4
Maximum	2764	18,749	82,327	67,807	1933	585.2	1919	383.9	692.1	3163	3155
Minimum	UD	47.1	112.9	UD	UD	UD	UD	UD	UD	UD	UD

Figure 4.8 Log-transformed concentrations of organic pollutants in different samples.

4.4.5. Distribution and Possible Sources of Organic Pollutants Based on Practical and Statistical Analysis

Distribution of some typical organic pollutants was demonstrated in a spatial sampling map (Fig. 4.9). Three worst contaminated C&D wastes were obtained in the centralized stacking field of polluted C&D waste (BK-2), abandoned tank (GT-1), and enclosed workshop II (WS-3), respectively. C&D waste in the centralized stacking field reflected the most severely polluted C&D waste across the plant. Numerous tanks were discarded in the stack randomly, which were not washed off thoroughly before abandoning based on this section. WS-3 was taken from a packaging workshop. The bad contamination suggested that during package line, which was highly complex in process objects or machines, spilling or leakage of intermediates and products existed despite the wrapped around protection sleeve. BK-4, which was derived from where sulfur, industrial materials, and C&D waste was mixed, was highly contaminated. Muddy industrial materials, bricks, and concrete were stacked or compacted for years to form stratiform steady blocks hard to separate.

Table 4.12

Existence of Organic Pesticides in Construction and Demolition (C&D) Waste From the Exterior Plant (mg/kg)

Organic Pollutants	C&D Waste 1	C&D Waste 2	C&D Waste 3	C&D Waste 4
Parathion	<0.01	<0.01	<0.01	<0.01
Terbufos	<0.01	4.17	2.39	<0.01
Phorate	82.3	<0.01	<0.01	54.8
Phorate sulfone	<0.01	<0.01	<0.01	<0.01
Phorate sulfoxide	<0.005	<0.005	<0.005	<0.005
Cyanthoate	<0.01	<0.01	0.04	0.25
Sulfotep	<0.01	0.54	0.75	<0.01
Ethion	<0.01	<0.01	<0.01	<0.01
Fenthion	<0.005	<0.005	<0.005	<0.005
Synergistic phosphorus	9.17	17.22	10.59	34.17
Dichlorvos	1074	839	947	1059
Triethyl phosphorothioate	<0.01	<0.01	<0.01	<0.01

The two C&D wastes containing 10,000–50,000 mg/kg pollutants were both derived from the open stacking field, indicating that despite being exposed to sun and rain for decades, C&D waste still posed a tremendous risk to the environment. The low background organic content of C&D waste led to very slight absorption of organic pollutants. Nevertheless, Organophosphorus pesticides(OPPs) permeated into the surface of C&D waste and formed a relatively stable phase with time.

The slightest contamination level appeared in C&D waste from neutralization process (DS-4, DS-5), pool bank (BK-8), cultivation pool (DS-3), open warehouse (WD-1), and enclosed workshop III (DS-2,WS-4), respectively, most of which were reasonable. Neutralization process was mainly used for the addition of alkali to maintain the pH of incineration gas. OPPs in C&D waste immersed under water were largely dissolved into the pool when the surface fluctuated. The concentration of phorate in the water sample from the pool was 2.57 mg/L, five times that of the limit in the industrial effluent level III (GB8978-1996) (Fig. 4.10). The open warehouse was slightly contaminated, which can be resulted from the strict management and enclosed packaging and sealing of products. The low concentration of pesticide in DS-3 around the cultivation pool was an exception because it was merely on the external part as no admission was accessed under demolition. Based on the gas obtained (Fig. 4.10), this place was severely contaminated (Table 4.13).

Intermediates, mainly O,O'-diethyl dithiophosphate, shared most distribution features with phorate in C&D waste. Pesticide intermediates were not disposed of appropriately, which was due to the lack of knowledge or management of intermediates, whereas phorate was well recognized for its high toxicity. Actually, O,O'-diethyl dithiophosphate was highly corrosive and highly soluble in water. Pearson correlations were calculated for each pollutant to analyze its possible source, which are listed in Table 4.14. The two intermediates correlated well with each other (r² = 0.29, p = .015) as they were close in structure and usage. The remarkable difference of treatment and regulation between phorate and intermediate largely reduced their correlation in concentration (r² = 0.11, p = .161), although they were similarly used. Parathion was another severe pollutant that was not under strict regulation either. Furthermore, the low level of parathion in tanks was likely due to its distinguishing mixture or loading process. Correlation analysis showed no strong correlation of parathion concentration with other pesticides (r² < 0.14, p > .81).

Figure 4.9 Spatial distribution of some typical organic pollutants throughout pesticide manufacturing plant.

Figure 4.10 Sampling information including gaseous and water samples.

Table 4.13

Concentration of Phorate in Gaseous and Water Samples

Samples	Gas Sample (μg/m³)						Water Sample (mg/L)
Samples	GS-1	GS-2	GS-3	GS-4	GS-5	GS-6	WT-1	WT-2
Phorate	UD	1.07	0.25	UD	0.41	3.65	UD	2.57 ± 0.74

The concentration of phorate sulfone had a strong correlation with phorate (r² = 0.34, p = .007), as it was metabolized from phorate. The maximum content of phorate sulfone, labeled as highly dangerous, in GT-1 was 3163 mg/kg; it was also detected elsewhere. A high concentration (71.3 mg/kg) in BK-2 suggested that a methodical execution of phorate disposal might largely decrease the risk of phorate sulfone. Transition from phorate to phorate sulfone was partly related to microbial activity and chemical oxidation. DS-2 was probably in close contact with microbes in soil compared with brick wall wastes, which accelerated the metabolization of phorate.

Table 4.14

Pearson Correlations (r) and the Associated p Values for Organic Pollutants

	O,O,O-Triethyl Phosphorothioate	O,O'-Diethyl Dithiophosphate	Phorate	Parathion	Terbufos	Ethion	Chlorpyrifos	Sulfotep	Cholrmephos	Phorate Sulfone
O,O′-Diethyl dithiophosphate	0.535
O,O′-Diethyl dithiophosphate	0.015
Phorate	0.106	0.326
Phorate	0.658	0.161
Parathion	−0.096	0.064	−0.078
Parathion	0.686	0.789	0.745
Terbufos	0.928	0.447	−0.031	0.155
Terbufos	0.000	0.048	0.896	0.513
Ethion	0.048	0.399	0.793	−0.089	0.049
Ethion	0.840	0.081	0.000	0.709	0.839
Chlorpyrifos	0.046	0.043	0.457	−0.083	−0.119	0.243
Chlorpyrifos	0.846	0.858	0.043	0.729	0.618	0.302
Sulfotep	0.627	0.642	0.472	0.370	0.566	0.218	0.220
Sulfotep	0.003	0.002	0.036	0.108	0.009	0.355	0.351
Cholrmephos	0.019	0.354	0.536	−0.057	0.117	0.925	−0.076	0.043
Cholrmephos	0.938	0.125	0.015	0.812	0.623	0.000	0.751	0.856
Phorate sulfone	0.021	0.354	0.585	−0.068	0.103	0.950	0.014	0.056	0.995
Phorate sulfone	0.930	0.126	0.007	0.776	0.664	0.000	0.953	0.816	0.000
Cypermethrin	−0.094	−0.134	0.000	−0.070	−0.105	−0.051	0.060	−0.100	−0.066	−0.032
Cypermethrin	0.693	0.574	0.999	0.770	0.660	0.832	0.801	0.676	0.782	0.892

Enclosed workshop III was a former cypermethrin workshop. Cypermethrin contained no phosphorus so the processing line ought to be different. That led to the unusually high content of pyrethroid pesticide (PPs) but low content of OPPs pollutants. This was also reflected by the irrelevance between cypermethrin and OPPs. Packaging in enclosed workshop II involved PPs along with OPP products, resulting in PP residue. Meanwhile, the demolition or other activities transferred a small part of PP-polluted C&D waste from the workshop onto open fields, mixed with other randomly stacked C&D waste. A larger part was centralizedly collected in an enclosed field. However, most part of the PP-polluted C&D waste could not be effectively recognized and remained in the residue.

4.4.6. Factors Affecting Concentration of Pollutants Among C&D Waste

Concentrations of organic and metal pollutants in C&D waste of different exposure conditions, locations, materials, and with different odor levels were analyzed. As shown in Fig. 4.11, C&D waste abandoned in an enclosed place underwent a heavier contamination. Exception occurring in some C&D waste suggested that some organophosphorus pesticides like parathion might not be so vulnerable under exposure. C&D waste abandoned in stack field had a slightly higher concentration of OPPs than that in workshop, which indicated that environmental pollution risk was not constrained in workshops, but scattered throughout the plant if C&D waste was not properly disposed.

Distribution of OPPs in different types of C&D wastes (brick, wood, etc.) is introduced in this section. Based on Fig. 4.11, most pollutants existed in rocks. Extreme contamination occurred in bricks and coatings, which were the main components of walls. Detritus, representative of ground C&D waste, was not severely polluted relatively due to accelerated degradation by microbes attached to soil with detritus. Meanwhile, the much larger organic content of soil than C&D waste might cause the absorption of OPPs. Contrary to the OPPs, heavy metals tended to accumulate in detritus, whereas those in bricks and coatings were not especially high. The odor emitted from OPP-contaminated C&D waste could partly tell the pollution level. C&D waste without odor was most slightly polluted in Fig. 4.11, but that with mild or strong odor might contain a high level of OPPs, despite of the pungent odor of phorate. It could result from some combination between C&D waste and OPPs.

Figure 4.11 Pollutant content of construction and demolition waste under various conditions.

4.4.7. Hierarchical Cluster Analysis

Hierarchical cluster analysis was carried out based on the practical sampling so as to further demonstrate the correlation among C&D waste. The dendrogram of different sampling sites are demonstrated in Fig. 4.12 as four groups were identified. Most C&D waste formed group 1, which showed complex distribution of pollutants due to the diversified processing line of this plant along with the reaction with surroundings in multiphase. BK-1, BK-2, and WS-3, which belonged to group 2, were highly correlated with the mixture of organic pesticide pollutants and could reflect the entire processing operation of the whole plant. Group 3 contained BK-4, BK-7, and BK-3, also showing a highly confounding contamination pattern. Whether the admixture of pollutants was deliberated probably made a distinction between group 2 and group 3. Based on the sampling, C&D waste from group 2 was either centralizedly collected with soil after demolition, or assembled together before packaging during manufacturing. C&D waste from group 3 was mainly stacked randomly in disorder. GT-1 contained the most kinds of pollutants and the unique existence in tanks compared with other C&D waste made it an independent group. Results of the cluster analysis emphasized the importance for the regulated disposal of polluted C&D waste.

Figure 4.12 Dendrogram of sampling sites by means of Ward's method.

4.4.8. Principal Component Analysis

Principal component analysis (PCA) is a statistical procedure that uses an orthogonal transformation to convert a set of observations of possibly correlated variables into a set of values of linearly uncorrelated variables called principal components. The results of PCA using SPSS 20.0 are listed in Tables 4.15 and 4.16, and Fig. 4.13.

The first four principal components variance summed up a contribution rate of 85%, the first five of 93%, among which the first principal component variance had a contribution of 36%. In factor 1, ethion, chlormethylfos, and phorate sulfone had relatively large contributions. In factor 2, O,O,O-triethylphosphorothioate and terbufos had large contributions.

4.5. Environmental Risk of Industrial C&D Waste in Organophosphorus Pesticide Manufacturing Plant

Industrial C&D waste, especially that contaminated by organophosphorus pesticides had great potential environmental risks even after decades of exposure under the nature. Environmental Risk Assessment is a process for estimating the likelihood or probability of an adverse outcome or event to the human health and ecosystem resulting from the hazardous pollutants. It can be divided into human health risk assessment and ecological risk assessment. Currently, the risk assessment of contaminated site is generally based on principles of human health risk assessment, and is an extremely complex project, including the analysis of potential harm and degree to exposed human health due to the contaminated waste (industrial C&D waste in this book), air, dust, water, food, and other factors. According to the results of the risk assessment, the target value for the site remediation is proposed.

Table 4.15

The Variance Contribution Rate for Principal Component Analysis

Component	Sums of Squared Loadings
Component	Total	% of Variance	Cumulative %
1	3.978	36.167	36.167
2	2.657	24.154	60.320
3	1.554	14.126	74.446
4	1.179	10.714	85.161
5	0.950	8.632	93.793
6	0.476	4.324	98.117
7	0.187	1.699	99.816
8	0.014	0.126	99.942
9	0.005	0.045	99.988
10	0.001	0.012	99.999
11	7.246E-005	0.001	100.000

Table 4.16

Factor Loading Matrix for Principal Component Analysis

	Component
	1	2	3	4
O,O,O-Triethyl phosphorothioate	−0.026	0.990	0.080	0.009
O,O-Diethyl dithiophosphate	0.368	0.583	0.119	0.389
Phorate	0.511	0.138	0.800	0.155
Parathion	−0.122	0.023	0.010	0.943
Terbufos	0.034	0.942	−0.122	0.105
Ethion	0.948	0.041	0.296	0.057
Chlorpyrifos	−0.019	−0.020	0.937	−0.153
Sulfotep	0.033	0.591	0.413	0.667
Chlormefos	0.991	0.051	−0.062	0.009
Phorate sulfone	0.991	0.047	0.024	−0.018
Cypermethrin	−0.095	−0.075	0.181	−0.307

Figure 4.13 Loading plot onto plates factor 1 versus factor 2 for principal component analysis.

Due to the lack of risk assessment system for contaminated C&D waste, that for soil system was referred to in this section. The assessment would be performed based on the four procedures below.

1. Pollution identification. Based on the distribution of pollutants, relevant toxicity reports, and information obtained in background research, as well as the total amount of pollutants, combining with the information of the exposed population, a quality control system is established.

2. Exposure assessment. It is the process of estimating or measuring the magnitude, frequency, and duration of exposure to the pollutants, along with the number and characteristics of the population exposed. Generally, the land can be divided into industrial land, agricultural land, and residential land. In this project, the site contaminated by pesticide companies is not likely to be reused as agricultural and residential land. So industrial land is determined as an evaluation criterion.

3. Toxicity assessment is a major procedure in risk assessment. It is a process of the investigation of the potential for a substance to cause harm, and how much causes what kind of harm. All substances are toxic in quantity. The toxicity data mainly include reference dose (RfD), RfC, and slope factor (SF), among which RfD and RfC are the estimated values for the average daily exposure dose or concentration. These three indexes can all be found in database. In addition, toxicity assessment can be divided into noncarcinogenic toxicity and carcinogenicity assessment, which will be described in detail in the example.

4. Risk assessment. It refers to the estimation of the likely health impact or probability on the basis of exposure assessment and toxicity assessment, including uncertainty analysis and risk calculations.

4.5.1. Analysis of Contaminated Industrial C&D Waste and Its Evaluation

The guidance values regulated in “Alberta Tier 1 Soil and groundwater remediation guidelines” is used and the results are listed in Table 4.17. Only those pollutants with existing relevant standards are involved in this evaluation. For other pollutants without standards, it is not possible to be evaluated currently. The calculated excess of pollutants in C&D waste is listed in Table 4.18.

4.5.2. Exposure Pathways and Variables for Industrial C&D Waste

4.5.2.1. Exposure Pathways Analysis

The type of land use has been determined as industrial and commercial sites. The exposed population may be residents and professional workers. In this environment, the exposure pathways under pollutants are listed in Table 4.19.

4.5.2.2. Exposure Quantification

The quantification of the exposure through various pathways is performed using risk-based corrective action model.

a. Oral ingestion

${CDI}_{oral} = \frac{C_{s} ×IR×CF×EF×ED}{BW×AT}$ ${CDI}_{oral} = \frac{C_{s} ×IR×CF×EF×ED}{BW×AT}$

where CDI_oral is the oral ingestion amount [mg/(kg·d)], C_s the concentration of pollutants in waste (soil in the original model, but C&D waste in this section; it would not be mentioned again) (mg/kg), IR the ingestion amount of waste per hour (mg/d), CF the conversion coefficient (10⁻⁶ kg/mg), EF the exposure frequency (d/a), ED the duration of exposure (a), BW the average weight of exposed populations (kg), and AT the averaging time (d). For noncarcinogens, the averaging time (AT) generally consists of a limited exposure duration. For carcinogens (DDVP in this sample), the AT is generally an individual's lifetime, assumed to be 70 years.

Table 4.17

Reference Value for Evaluation

Pollutant	Standards for the Aquatic Environment (μg/L)	Guidance Value of the Highest Concentration of Pollutants in Soil (mg/kg)	Source of Standards
Phorate	2	0.075	Alberta Tier 1 soil and groundwater remediation guidelines
Parathion	0.013	7.2
Terbufos	1	0.08
Chlorpyrifos	0.002	49
Dichlorvos	–	0.1	Allowable soil concentrations in the former Soviet Union

Table 4.18

Calculated Excess of Pollutants

Pollutant	Excess in Aquatic System (%)	Excess in Construction and Demolition Waste (%)
Phorate	50	100
Parathion	/	95
Terbufos	/	85
Chlorpyrifos	/	10
Dichlorvos	/	16.7

b. Inhaled particle:

${CDI}_{inhaled particle} = \frac{- C_{s} \times (\frac{1}{PEF}) \times IR \times EF \times ED}{BW \times AT}$ ${CDI}_{inhaled particle} = \frac{- C_{s} \times (\frac{1}{PEF}) \times IR \times EF \times ED}{BW \times AT}$

Inhaled vapor:

${CDI}_{inhaled vapor} = \frac{C_{a} \times IR \times EF \times ED}{BW×AT}$ ${CDI}_{inhaled vapor} = \frac{C_{a} \times IR \times EF \times ED}{BW×AT}$

where CDI_{inhaled particle} is the concentration of pollutants in the particles inhaled through breathing [mg/(kg·d)], CDI_{inhaled vapor} the concentration of pollutants in the vapor inhaled through breathing [mg/(kg·d)], C_s the concentration of pollutants in the waste (mg/kg), C_a the volatile exposure concentration of pollutants indoor/outdoor (mg/kg), PEF the diffusion coefficient of waste, and IR the breath rate (L/min).

Table 4.19

Exposure Pathways for Industrial and Commercial Sites

Environment	Mechanism	Industrial and Commercial Site
Contaminated C&D waste (less than 1 mm in size)	Direct contact Wind erosion Volatilization Percolation	Direct ingestion Inhalation of particulate matter Inhalation of volatiles Exposure to indoor air Exposure to the underground water contaminated by C&D waste leachate Inhalation of the particulate matter generated by trucks or equipment Skin absorption
Contaminated C&D waste (more than 1 mm in size)	Direct contact Wind erosion Volatilization Percolation	Direct ingestion Skin absorption Inhalation of volatiles Exposure to indoor air Exposure to the underground water contaminated by C&D waste leachate Inhalation of the particulate matter generated by trucks or equipment Skin absorption
Surface water	Run-off Percolation	Ingestion through drinking water Inhalation of volatiles Skin absorption
Underground water	Percolation	Ingestion through drinking water Inhalation of volatiles Skin absorption
Atmosphere	Volatilization	Ingestion though inhalation Skin absorption

c. Ingestion amount through skin contact:

${CDI}_{skin contact} = \frac{C \times CF \times SA \times AF \times ABS \times EF \times ED}{BW \times AT}$ ${CDI}_{skin contact} = \frac{C \times CF \times SA \times AF \times ABS \times EF \times ED}{BW \times AT}$

where CDI_{skin contact} is the ingestion amount through skin contact [mg/(kg·d)], C the concentration of pollutants in the waste (mg/kg), CF the conversion coefficient (10⁻⁶ kg/mg), SA the skin surface area available for contact to C&D waste (cm²), AF the waste to skin adherence factor (mg/cm²), and ABS the absorption factor (dimensionless).

Table 4.20

Features of the Pollutants in Concern

Pollutants	Chemical Abstracts Service	Soil Adsorption Coefficient Log(Koc)	Air Diffusion Coefficient (cm²/s)	Water Diffusion Coefficient (cm²/s)	Solubility in Water 20–25°C (mg/L)	Henry's Constant
Phorate	298-02-2	3.74	0.08	8.0 × 10⁻⁶	44.00	5.0 × 10⁻⁴
Parathion	56-38-2	3.75	0.017	5.8 × 10⁻⁶	11.75	2.37 × 10⁻⁵
Terbufos	13071-79-9	4.14	0.042	5.1 × 10⁻⁶	6.84	0.06827
Chlorpyrifos	2921-88-2	3.70	0.048	5.1 × 10⁻⁶	0.9	1.70 × 10⁻⁴
Dichlorvos	62-73-7	1.70	0.023	7.8 × 10⁻⁶	16,000	3.98 × 10⁻⁵

d. Ingestion through diets

${CDI}_{drinking} = \frac{C_{w} \times IR \times EF \times ED}{BW \times AT}$ ${CDI}_{drinking} = \frac{C_{w} \times IR \times EF \times ED}{BW \times AT}$

${CDI}_{diet} = \frac{C_{F} \times IR \times FI \times EF \times ED}{BW \times AT}$ ${CDI}_{diet} = \frac{C_{F} \times IR \times FI \times EF \times ED}{BW \times AT}$

where CDI_drinking is the ingestion amount through drinking water [mg/(kg·d)], C_w the concentration of pollutants in water (mg/L), C_F the concentration of pollutants in diets (mg/kg), FI the proportion of contaminated diets to all diets (dimensionless), IR the ingestion rate of water/diets (L/d, kg/meal), EF the exposure frequency (d/a, meal/a), and CDI_diet the ingestion amount of pollutants through meals [mg/(kg·d)]. The features of the pollutants in concern are listed in Table 4.20. The selected exposure variables are listed in Table 4.21.

Ingestion amount through the mouth is calculated in Table 4.22.

Ingestion amount through breathing can be divided into two categories, outdoor and indoor ingestion. It is mainly composed of the vapor of pollutants and the particles of contaminated industrial C&D waste. The results are listed in Table 4.23. Ingestion amount through diets is calculated in Table 4.25.

Ingestion amount through the skin is calculated in Table 4.24.

4.5.3. Toxicity Values of Existing Pollutants

The toxicity values of the pollutants in concern are listed in Table 4.26.

4.5.4. Risk Evaluation of Industrial C&D Waste in Pesticide Manufacturing Plant

The calculation of carcinogenic risk of oral ingestion of single pollutant (DDVP) in C&D waste is performed as:

$R_{oral} = CDI * SF = 8.3 * 10^{- 5} * 0.29 = 2.4 e - 5$ $R_{oral} = CDI * SF = 8.3 * 10^{- 5} * 0.29 = 2.4 e - 5$

Table 4.21

Exposure Variables

Variable	Introduction	Industrial Land (Adult)
BW	Body weight (kg)	60
EF	Exposure frequency (d/a)	261
ED	Exposure duration (a)	30
IR	Inhalation rate of waste (mg/d)	100
SA	Skin surface area available for contact (cm²)	2800
AT	Averaging time (noncarcinogens/carcinogens)	9165/25,550
AF	Waste to skin adherence factor (mg/cm²)	0.2
ABS	Absorption factor	Varies with pollutants
TSP	Total suspended particulate content in air (mg/m³)	0.3
INH	Inhaled amount of air by an adult	15
PIAF	Retention ratio of inhalable waste particles in body	0.75
ET (out)	Proportion of the daily exposure time outdoor	1/3
ET (ind)	Proportion of the daily exposure time indoor	1/3
IR_w	Ingestion rate of underground water (L/d)	1
IR_f	Ingestion rate of food (kg/d)	1.2

Table 4.22

Ingestion Amount Through Mouth

Pollutant	Concentration (mg/kg)	Daily Ingestion Amount (mg/d)	Exposure Time (d)	Averaging Body Weight (kg)	Averaging Time (a)	Ingestion Amount Through The Mouth (mg/kg·d)
Phorate	16,868	100	7830	60	9165	2.4 × 10⁻⁴
Parathion	6521	100				9.0 × 10⁻³
Terbufos	170	100				2.4 × 10⁻⁴
Chlorpyrifos	167.5	100				2.4 × 10⁻⁴
Dichlorvos	163.3	100			25,550	8.3 × 10⁻⁵

Table 4.23

Ingestion Amount Through Breathing

Pollutant	Outdoor Ingestion (mg/kg·d)		Indoor Ingestion (mg/kg·d)
Pollutant	Vapor	Particle	Vapor	Particle
Phorate	1.2 × 10⁻⁴	1.0 × 10⁻⁴	2.5 × 10⁻⁴	1.6 × 10⁻⁴
Parathion	–	6.2 × 10⁻⁵	–	4.0 × 10⁻⁵
Terbufos	–	1.6 × 10⁻⁶	–	1.1 × 10⁻⁶
Chlorpyrifos	–	1.6 × 10⁻⁶	–	1.0 × 10⁻⁶
Dichlorvos	–	3.6 × 10⁻⁷	–	5.6 × 10⁻⁷

Table 4.24

Ingestion Amount Through Skin Contact

Pollutant	Concentration (mg/kg)	Contact Area (cm²)	Skin Contact Coefficient	Exposure Time (d)	Averaging Body Weight (kg)	Averaging Time (a)	Ingestion Amount Through the Skin (mg/kg·d)
Phorate	16,868	2800	0.1	7830	60	9165	1.3 × 10⁻²
Parathion	6521						5.2 × 10⁻³
Terbufos	170						1.4 × 10⁻⁴
Chlorpyrifos	167.5						1.4 × 10⁻⁴
Dichlorvos	163.3					25,550	4.7 × 10⁻⁵

Table 4.25

Ingestion Amount Through Diets

Pollutant	Ingestion Amount Through Drinking Water (mg/kg·d)	Ingestion Amount Through Meals (mg/kg·d)
Phorate	0.018	–
Parathion	–	–
Terbufos	–	–
Chlorpyrifos	–	–
Dichlorvos	–	–

Table 4.26

Toxicity Values of Organic Pollutants

Pollutants	SF_o (mg/kg·d)⁻¹	SF_i (mg/kg·d)⁻¹	SF_d (mg/kg·d)⁻¹	RfD_o (mg/kg·d)	RfD_i (mg/m³)	RfD_d (mg/kg·d)
Phorate	–	–	–	0.0005	–	0.0005
Parathion	–	–	–	0.006	0.0005	0.006
Terbufos	–	–	–	0.000125	–	0.000125
Chlorpyrifos	–	–	–	0.003	–	0.003
Dichlorvos	0.29	–	0.29	0.0005	0.0005	0.0005

The calculation of carcinogenic risk of dermal ingestion of single pollutant (DDVP) in C&D waste is performed as:

$R_{dermal} = CDI * SF = 4.7 * 10^{- 5} * 0.29 = 1.4 e - 5$ $R_{dermal} = CDI * SF = 4.7 * 10^{- 5} * 0.29 = 1.4 e - 5$

The noncarcinogenic value of oral ingested pollutants in C&D waste is listed in Table 4.27. The noncarcinogenic value of dermal ingested pollutants in C&D waste is listed in Table 4.28.

The noncarcinogenic value of inhaled pollutants outdoor in C&D waste is listed in Table 4.29.

The noncarcinogenic value of inhaled pollutants indoor in C&D waste is listed in Table 4.30.

Table 4.27

Noncarcinogenic Value of Oral Ingested Pollutants in C&D Waste

Pollutant	Exposure Amount (mg/kg·d)	Oral Ingested Amount (mg/kg·d)	Noncarcinogenic Value of Single Pollutant
Phorate	2.4 × 10⁻²	0.0005	48.00
Parathion	9.0 × 10⁻³	0.006	1.50
Terbufos	2.4 × 10⁻⁴	0.000125	1.92
Chlorpyrifos	2.4 × 10⁻⁴	0.003	0.08
Noncarcinogenic value of all pollutants			51.5

Table 4.28

Noncarcinogenic Value of Dermal Ingested Pollutants in Construction and Demolition Waste

Pollutant	Exposure Amount (mg/kg·d)	Dermal Ingested Amount (mg/kg·d)	Noncarcinogenic Value of Single Pollutant
Phorate	1.3 × 10⁻²	0.0005	26.00
Parathion	5.2 × 10⁻³	0.006	0.87
Terbufos	1.4 × 10⁻⁴	0.000125	1.12
Chlorpyrifos	1.4 × 10⁻⁴	0.003	0.05
Noncarcinogenic value of all pollutants			28.0

Table 4.29

Noncarcinogenic Value of Inhaled Pollutants Outdoor in Construction and Demolition Waste

Pollutant	Exposure Amount (mg/kg·d)	Inhaled Amount (mg/m³)	Noncarcinogenic Value of Single Pollutant
Phorate	2.2 × 10⁻⁴	–	–
Parathion	6.2 × 10⁻⁵	0.0005	0.124
Terbufos	1.6 × 10⁻⁶	–	–
Chlorpyrifos	1.6 × 10⁻⁶	–	–
Noncarcinogenic value of all pollutants			0.1

Table 4.30

Noncarcinogenic Value of Inhaled Pollutants Indoor in Construction and Demolition Waste

Pollutant	Exposure Amount (mg/kg·d)	Inhaled Amount (mg/m³)	Noncarcinogenic Value of Single Pollutant
Phorate	1.6 × 10⁻⁴	–	–
Parathion	4.0 × 10⁻⁵	0.0005	0.08
Terbufos	1.1 × 10⁻⁶	–	–
Chlorpyrifos	1.0 × 10⁻⁶	–	–
Noncarcinogenic value of all pollutants			0.1

Table 4.31

Noncarcinogenic and Carcinogenic Values and Risks of All Pollutants

	Toxicity Effect			Carcinogenic Risk
Exposure Pathway	Maximum	Total	Whether it Exceeds the Risk Limits or Not	Total	Whether it Exceeds the Risk Limits or Not
Inhaled indoor	0.1	0.1	No	–	No
Inhaled outdoor	0.1	0.1	No	–	No
Dermal ingestion	26	28	Yes	1.4 × 10⁻⁵	No
Ingestion through meals	36	36	Yes	–	No
Oral ingestion	48	52	Yes	2.4 × 10⁻⁵	No

The noncarcinogenic value of ingested pollutants through drinking water in C&D waste is calculated as:

$R_{drinking} = 0.018 / 0.0005 = 36$ $R_{drinking} = 0.018 / 0.0005 = 36$

The noncarcinogenic and carcinogenic values and risks of all pollutants are summed up and listed together in Table 4.31.

As shown in Table 4.31, none of the carcinogenic risks in industrial C&D waste of pesticide manufacturing industry exceeded the limits, but highly noncarcinogenic risks were found, especially in dermal (skin) contact and oral ingestion.

4.6. Cyanide-Contaminated C&D Waste Generated in a Fire/Explosion Accident

Fire and explosion are also an important generation sources of industrial C&D waste. According to statistics in China, 207 accidents happened in factories during Nov. to Dec. in 2011, including mining accidents, traffic accidents, explosion, fire, leakage of poison and toxic materials, and other accidents, among which 7.73% resulted from fire, whereas 6.28% were resulted from explosion. During 2012–15, various notices, regulations, and alarms were issued and put forward by the government including “a notice of the safe production and specific treatment of manufactured aluminum and magnesium products”. However, accidents still happened frequently; large accidents like Tianjin, particularly the serious fire explosion in 2015, caused great damage and resulted in huge casualty. A management program explaining the disposal of C&D waste generated in fire/explosion accidents has been established based on the laboratory simulation experiments and field research experience. In this section, a fire accident that happened in north China is introduced and the C&D waste at the scene is analyzed.

Based on the survey on site, it was found that the C&D waste was piled in a complex way and was of a large amount. Main components of C&D waste were concrete blocks, bricks, muck, scrap metal, etc. The northern part of the explosion spot was stacked mainly of scrap metal, which was once the containers, whereas the southern part of the explosion spot were scattered by C&D waste and muck. The picture of C&D waste debris is shown in Fig. 4.14.

The contamination and diffusion process of C&D waste generated in explosion was that the pollutants (mainly the chemicals in stock, highly contaminated equipment, pipelines, and other industrial waste) and C&D waste experienced a complex reaction of crushing, polymerization, melting, and other physical or chemical mechanism under the condition of highly compressed air flow and high temperature. Then the contaminated waste migrated with the gas diffusion, resulting in the proliferation of pollution. Large blocks of waste would fall earlier before small blocks. The simulation of gas flow and C&D waste is demonstrated in brief in Fig. 4.15. In addition, a large portion of the contaminants may be directly injected downward into the central pit with the explosion shock wave. That meant this part of the contaminated C&D waste was unable to be sampled. According to information obtained, the explosion had covered an area of a radius of about 2 km. The sampling information at about 1–1.5 km around the center of the explosion is shown in Fig. 4.16.

Figure 4.14 Pictures of construction and demolition waste generated in a great fire/explosion accident.

Figure 4.15 Simulation of gas flow and construction and demolition waste in an explosion.

Figure 4.16 Sampling information in a great fire/explosion accident.

After preliminary characterization, the C&D waste collected sent out a strong flavor of almond, which meant cyanide or sulfide might exist. According to the gas chromatography–mass spectrometry analysis, the extracts contained the following substances:

• cumene (an important organic chemical raw material)

• diacetone alcohol

• acetone cyanohydrin (hydrocyanic acid is made of concentrated sulfuric acid and sodium cyanide, whereas the acetone cyanohydrin is produced by acetone and hydrocyanic acid, which is purified by distillation)

• musk xylene (explosive, may cause an explosion in nitration workshops due to high temperature)

• dicyclohexyl disulfide

• p-phenylenediamine

Results of the cyanide analysis are listed in Table 4.32. The rule of waste number could be described using C&D 1 as an example. 1-1 was the muck waste, which was the smallest in size, 1-2 was the particulate waste, 1-3 was the C&D waste in blocks, 1-4 was the stripped waste on the surface of large blocks of C&D waste. As shown in the table, large amounts of contaminated waste that diffused through the gas flow were attached to the C&D waste blocks. C&D waste from chemical, metallurgical, and other industrial enterprises generated in the fire/explosion could be serious secondary pollution sources. Soil was also sampled and detected. It was found that among the solid waste scattered on the ground, the concentration of pollutants in soil was much lower than that on the surface of C&D waste. Overall, the most severely contaminated part of C&D waste came from the small pieces of waste.

Table 4.32

Pollution of the Cyanide-Contaminated Construction and Demolition (C&D) Waste Generated in an Explosion

C&D Waste	Concentration (Cyanide) (mg/kg)
1-1	160
1-2	12.1
1-3	105
1-4	110
2-1	1.53 × 10³
2-2	5.76 × 10³
3-1	3.49 × 10³
3-2	6.10 × 10³
4-1	2.08 × 10³
4-2	5.38 × 10³
5	2.41 × 10³
6	981
7	39.8
8	38.4
9	59.0
10	46.7
11-1	43.7
11-2	33.5
12	195
13	33.3
14	2.62 × 10³

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Table of Contents for Chapter Four. Pollution Characteristics of Industrial Construction and Demolition Waste

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