[Spatial Distribution and Risk Assessment of Heavy Metals in Soils from a Typical Urbanized Area].

With the rapid urbanization in China, soil environments are facing high risks. Taking a typical urbanized area as a case study, a total of 106 surface soil samples (0-20 cm) and 96 subsurface soil samples (20-40 cm) were collected to determine the concentrations of heavy metals, and then, the Nemerow index and Hankson index methods were used to evaluate their degrees of ecological risk. The spatial distributions of ecological risks were also explored. Experimental results showed that the concentrations of Cr, Ni, Cu, Zn, As, Cd, Pb, and Hg in surface soil samples were 2.87-84.64, 1.40-56.00, 2.75-125.05, 15.05-201.39, 1.46-89.92, 0.001-0.92, 15.29-160.07, and 0.006-0.52 mg·kg-1, respectively, and those in subsurface soil samples were 3.56-75.14, 1.65-71.58, 3.28-290.04, 17.99-296.94, 3.07-65.67, 0.02-1.00, 11.10-97.59, and 0.01-0.41 mg·kg-1, respectively. According to the risk control standards for soil contamination of agricultural land, approximately 71.70%, 40.57%, 4.72%, 3.77%, and 0.94% of Cd, Cu, Pb, As, and Zn, respectively, in the surface soil samples exceeded the standards, while 72.92%, 39.58%, 6.25%, 3.13%, 3.13%, and 1.04% of Cd, Cu, As, Zn, Pb, and Ni, respectively, in the subsurface soil samples exceeded the standards. Obviously, the pollution by Cd and Cu was the most severe in the research area, and the main contaminated areas were distributed in the northern part of the land. The soil environmental quality pollution assessment illustrated that high risk areas were distributed in the northern part of the research area too. The risk assessment results indicated that the main pollution factor was Cd, which is accordance with the serious pollution findings for Cd. In response to these results, effective management and remediation methods should be taken to control the soil environment pollution in this typical urbanized area.

[Spatial Distribution and Potential Ecological Risk Assessment of Heavy Metals in Soils and Sediments in Shunde Waterway, Southern China].

Environmental quality of soils and sediments around water source area can influence the safety of potable water of rivers. In order to study the pollution characteristics, the sources and ecological risks of heavy metals Zn, Cr, Pb, Cu, Ni and Cd in water source area, surface soils around the waterway and sediments in the estuary of main tributaries were collected in Shunde, and ecological risks of heavy metals were assessed by two methods of potential ecological risk assessment. The mean contents of Zn, Cr, Pb, Cu, Ni and Cd in the surface soils were 186.80, 65.88, 54.56, 32.47, 22.65 and 0.86 mg · kg⁻¹ respectively, and they were higher than their soil background values except those of Cu and Ni. The mean concentrations of Zn, Cr, Pb, Cu, Ni and Cd in the sediments were 312.11, 111.41, 97.87, 92.32, 29.89 and 1.72 mg · kg⁻¹ respectively, and they were higher than their soil background values except that of Ni. The results of principal component analysis illustrated that the main source of Cr and Ni in soils was soil parent materials, and Zn, Pb, Cu and Cd in soils mainly came from wastewater discharge of local manufacturing industry. The six heavy metals in sediments mainly originated from industry emissions around the Shunde waterway. The results of potential ecological risk assessment integrating environmental bioavailability of heavy metals showed that Zn, Cu, Pb and Ni had a slight potential ecological risk. Cd had a slight potential ecological risk in surface soils, but a moderate potential ecological risk in surfaces sediments. Because the potential ecological risk assessment integrating environmental bioavailability of heavy metals took the soil properties and heavy metal forms into account, its results of risks were lower than those of Hakanson methods, and it could avoid overestimating the potential risks of heavy metals.

[Risk Assessment and Risk Management of Chemicals in China].

Risk assessment and risk management have been increasingly approved as an effective approach for appropriate disposal and scientific management of chemicals. This study systematically analyzed the risk assessment methods of chemicals from three aspects including health risk, ecological risk and regional risk. Based on the current situation of classification and management towards chemicals in China, a specific framework of risk management on chemicals was proposed by selecting target chemicals, predominant industries and related stakeholders as the objects. The results of the present study will provide scientific support for improving risk assessment and reasonable management of chemicals in China.

[Assessment of Emission and Co-Reduction of PCDD/Fs and PCNs in the Secondary Copper Production Sector].

Polychlorinated naphthalenes (PCNs) could he generated and discharged unintentionally in the secondary copper production industry with similar mechanisms as PCDD/Fs during high-temperature industrial processes. Therefore, measures that reduce the release of PCDD/Fs will also reduce PCNs emissions. Analysis of the technical process and correlation with their emissions will provide theoretical basis for co-mitigation of PCNs and PCDD/Fs. The production process of secondary copper was analyzed, with key production stages of discharge identified through monitoring the emissions of two kinds of pollutants. Co-reduction technologies were screened and specified. Three recommendations on co-mitigation of the two pollutants were provided to support the implementation of Stockholm Convention and UPOPs reduction in the secondary copper production sector in China. Key words:secondary copper industry; smelting; PCNs; PCDD/Fs; co-mitigation

[Risk assessment and countermeasures of BTEX contamination in soils of typical pesticide factory].

Soil samples around three representative pesticide factories were collected in Zhangjiakou City, Hebei Province, and analyzed to identify their pollution characteristics and health risk of BTEX by purge-and trap and gas chromatography/mass spectroscopy method. Total concentrations of BTEX in soils in Plant A, B and C ranged from 673.50 to 32 363.50 ng x g(-1), nd to 6 461.80 ng x g(-1) and 461.70 to 8 740.80 ng x g(-1), respectively. Concentrations of detected toluene (4 619.50-7 234.30 ng x g(-1)) and ethylbenzene (364.60-7 944.60 ng x g(-1)) had exceeded the Canadian guidelines for industrial land (370 ng x g(-1) and 82 ng x g(-1)), and concentration of xylene (19 799.40 ng x g(-1)) in dust in production area of Plant A was larger than the Dutch soil intervention value (17 000 ng x g(-1)). While concentrationsn of BTEX around Plant A (Region I ) and Plant B and C (Region II) ranged from nd to 645.81 ng x g(-1), and nd to 309.13 ng x g(-1), respectively, which were below the Canadian guidelines for agricultural land. The non-carcinogenic risk of BTEX in Plant A (2.90E-06 -1.32E-04), B (nd -4.30E-05) and C (1.29E-06 -5.64E-05) were all below 1, which suggested that no obvious health risk existed in each plant. The non-carcinogenic risks in Region I (nd -2.02E-06) and Region II (nd -1.10E-06) were below than 1, and also lower than those in factories. High risk areas were mainly concentrated in the downwind, moreover, soils around villages and towns were also with higher risk. In conclusion, soils and dusts in each factory had been polluted and the quality of agricultural land had been partly deteriorated. Finally, environmental management and occupational protection countermeasures were proposed based on the research results.

[Risk assessment and countermeasures of heavy metals pollution in Wanquan segment of Yanghe River].

In order to investigate heavy metals contamination status in Wanquan segment of Yanghe River, Zhangjiakou, 9 water and sediments samples were collected respectively for analyzing Cu, Ni, Cd, Zn, Cr, Pb, Hg and As, with water quality indicators determined at the same time. The potential ecological risk index (PERI) was then employed to evaluate potential ecological risk of heavy metals in sediments. Results indicated that the concentrations of Cu, Ni, Cd, Zn, Cr, Pb, Hg and As in water samples ranged from 1.28-24.13, 1.13-16.84, 0.08-0.11, 1.80-10.65, 1.40-19.12, 0.13-2.05, 0.06-0.99, 0.46-4.22 microg x L(-1), respectively, which are all below the national water quality standard for the demands of industrial use and agricultural irrigation. Principal component analysis (PCA) was conducted to reveal the relationship between water quality indicators and heavy metals pollution in water samples. Concentrations of Cu, Ni, Cd, Zn, Cr, Pb, Hg and As in sediments ranged from 5.90-110.11, 17.34-56.04, 0.07-0.31, 38.71-116.74, 40.39-85.77, 18.65-22.74, nd-0.047, 0.85-9.98 mg x kg(-1), respectively. The descending order of potential ecological risk intensity caused by different heavy metals was: Cd > Cu > Hg > Ni > As > Pb > Cr > Zn, and the average value of each heavy metal was low, while middle-grade risk level of Cd and Hg were also found in several sites. Among all monitoring sites, the descending order of PERI of all target heavy metals was: YH-07 > YH-03 > YH-09 > YH-02 > YH-06 > YH-04 > YH-05 > YH-01, and the average value reached slight grade, while middle-grade risk level was detected in YH-07. Sampling locations in YH-02-YH-03 and YH-07-YH-09 were found with relatively high ecological risk level because of agricultural and anthropogenic activities, respectively. Finally, three risk management regions were figured out and corresponding countermeasures for improving the environmental quality of the watershed were proposed based on the research results.

[Risk assessment and countermeasure of BTEX in pesticide factory].

BTEX are important environmental pollutants, harmful to human through respiratory inhalation, digestive tract and skin contact, and also have teratogenic, mutagenic and carcinogenic effects. BTEX were detected in multi-media to identify their distributions and assess their human health risk in a pesticide factory in Hebei province. Purge and trap GC-MS, adsorption/thermal desorption GC chromatography and the health risk assessment model were applied, and corresponding management measures were proposed. The results showed that BTEX existed in soil, dust, air, groundwater and wastewater. The concentration of BTEX in dust of the production area was 7.33 mg x kg(-1), in particular the concentration of toluene was 5.64 mg x kg(-1), exceeding the Canadian industrial land standard. Building three scenarios for working more than 10 years, 20 years and 30 years, the total non-carcinogens index was 4.19 x10(-3), 8.25 x 10(-3) and 1.22 x 10(-2), respectively, all lower than 1; the carcinogens index of benzene was 1.70 x 10(-7), 3.34 x 10(-7) and 4.92 x 10(-7), respectively, all lower than 10(-6). It indicated that there was no significant non-carcinogens and carcinogens hazard to workers inside the factory, but they might be exposed to more health risks if their work experience increase. Finally, recommendations for improving the environmental quality and personnel security in the factory were proposed based on the research results.

[Pollution characteristics and health risk assessment of atmospheric volatile organic compounds (VOCs) in pesticide factory].

A method for determining volatile organic compounds (VOCs) in air by summa canister collecting and gas chromatography/ mass spectroscopy detecting was adopted. Pollution condition and characteristics of VOCs were discussed in three representative pesticide factories in Zhangjiakou City, Hebei Province. Meanwhile, an internationally recognized four-step evaluation model of health risk assessment was applied to preliminarily assess the health risk caused by atmospheric VOCs in different exposure ways, inhalation and dermal exposure. Results showed that serious total VOCs pollution existed in all factories. Concentrations of n-hexane (6161.90-6910.00 microg x m(-3)), benzene (126.00-179.30 microg x m(-3)) and 1,3-butadiene (115.00-177.30 microg x m(-3)) exceeded the Chronic Inhalation Reference Concentrations recommended by USEPA, corresponding to 700, 30 and 2 microg x m(-3), respectively. Concentration of dichloromethane (724.00 microg x m(-3)) in factory B was also higher than the reference concentration (600 microg x m(-3)). Results of health risk assessment indicated that non-carcinogenic risk indexes of VOCs ranged from 1.00E-04 to 1.00E + 00 by inhalation exposure, and 1.00E-09 to 1.00E-05 by dermal exposure. Risk indexes of n-hexane and dichloromethane by inhalation exposure in all factories exceeded 1, and risk index of benzene by inhalation in factory B was also higher than 1. Carcinogenic risk indexes exposed to VOCs ranged from 1.00E-08 to 1.00E-03 by inhalation exposure and 1. oo00E -13 to 1.00E-08 by dermal exposure. Cancer risk of 1,3-butadiene by inhalation exceeded 1.0E-04, which lead to definite risk, and those of benzene by inhalation also exceeded the maximum allowable level recommended by International Commission on Radiological Protection (5.0E-05). The risks of dermal exposure presented the same trend as inhalation exposure, but the level was much lower than that of inhalation exposure. Thus, inhalation exposure of atmospheric VOCs was the dominant way of health risk in these factories.

[DDTs and HCHs residues in soils around Guanting Reservoir and related environmental risk assessment].

Surface soil samples around Guanting Reservoir ranging from 2-10 km were measured for pesticide residues (HCHs and DDTs) concentrations in 2009. Occurrences and related environmental risk were analyzed; furthermore, GIS and geostatistical techniques were applied to analyze the spatial variation of organochlorine pesticides. The results show that concentrations of HCHs in soils range from n.d. to 14.97 ng x g(-1) with a mean value of 0.73 ng x g(-1), and DDTs range from n.d. to 64.91 ng x g(-1) with a mean value of 6.46 ng x g(-1). According to the isomers of HCHs and metabolites of DDTs, HCHs and DDTs residues in soils were primarily from historical use. The land use showed great effect on the degradation of HCHs and DDTs, with the residual level sequence of orchard >> crop land > barren land. Based on kriging interpolation, the spatial distribution of HCHs and DDTs around Guanting Reservoir was observed. Spatial variability indicated how HCHs and DDTs had been applied and distributed in the past. Compared with those in other national or international regions, the concentrations of HCHs and DDTs in soils around Guanting Reservoir were very low.

[Assessment on PCBs wastes treatment technologies including incineration, cement kiln and secure landfill].

Analytic hierarchy process and a specialist investigation were applied to value the three PCBs treatment technologies qualitatively and quantitatively, in which the environmental, technological, social and economic factors were considered. The most important factor is thought to be environmental impact. Incineration is proved to be the most suitable technology in this period according to the research. For the high concentration of PCBs pollutants, or the low concentration of PCBs pollutants with good economic performance and large quantity of waste, incineration is considered the best. For the low concentration of PCBs pollutants in the area with bad economic performance and with little quantity of waste, cement kiln and landfill are thought to be suitable. It is also suggested that pollutants be treated at the nearest place. What's more, the measures to improve the three technologies are discussed and the policy comments on PCBs treatment are presented.

Persistent organic pollutants control strategy in China.

The development of Persistent Organic Pollutants (POPs) control policy in China in the context of international concerns on POPs was reviewed. The aspects of the Chinese POPs control strategies were analyzed, and compared with those of developed counterparts (e.g. U.S., E.U., Japan). Currently, while the legal framework on POPs management, which complies with international guidelines has been established, it should be improved in the areas of special POPs management, risk assessment, the precautionary principle, life-cycle management and technical support capacity. The analysis of Chinese POPs policy and suggestions for strengthening the science-based decision making capacity are not only useful for Chinese decision-makers, but also a case study for developing world and make a great contribution for the global elimination of POPs to make a toxic-free future.