A Chinese risk assessment procedure was developed to address active substances used in biologically active (biocidal) antifouling paints. The priority was to promote the use of environmentally friendly, technically and economically viable alternatives to DDT/TBT (dichlorodiphenyltrichloroethane/tributyltin) in the control of marine fouling organisms. The procedure was based upon European Union Biocide Product Directive (EU-BPD) and International Standard Organization (ISO) method for the Environmental risk assessment of antifouling systems. In order to focus on Chinese national conditions, international templates were adapted to address regional differences. In the Chinese method, persistence, bioaccumulation and toxicity information is assessed on a step by step basis, allowing an antifouling substance to be defined as either Risk of high concern or Relatively low risk at the end of the decision making process. 4,5-Dichloro-2-n-Octyl-3-Isothiazolinone (DCOIT, Sea-nine), triphenylborane pyridine (TPBP), 8-methyl-N-vanillyl-6-nonenamide (Capsaicin) and Zinc ethylene (bis) dithiocarbamate (Zineb), popularly used in China as active substance of antifouling paints, were reviewed according to the developed procedure. The preliminary results indicate that Sea-nine use in antifouling products can be considered low risk, whereas TPBP, Capsaicin and Zineb failed the screening procedure on the basis of bioaccumulation potential, persistence and an unacceptable risk ratio, respectively. Data availability was determined to be a critical factor in the assessments due to the application of Safety Factors for data-poor substances.
Nonferrous metal smelting is a potential emission source of trace elements. However, it is vital to identify the dominant factors in determining toxic element (TE) spatial distribution and migration behaviors. We hypothesize that soil clay is the key factor in agricultural land around nonferrous metal smelting areas. Hence, this study focused on Qingyuan Town, a typical nonferrous metal smelting base. From this site, 95 soil samples (0–20 cm) were collected from cultivated land around the nonferrous metal smelters. Eight soil samples were analyzed for TE speciation and clay minerals in hot spot and non-hot spot areas following the TE distribution. A geographical detector (Geodor) showed that the distributions of total and exchangeable TE were affected by multiple factors (clay, CaO, and Fe2O3). X-ray diffraction (XRD) showed that the clay was mainly comprised of an illite and smectite mixed layer (67.13%), illite (15.38%), chlorite (9.25%), and kaolinite (8.25%). Moreover, correlation analysis showed that the exchangeable As was positively correlated with illite (R2 = 0.76, at p < 0.01 level), kaolinite (R2 = 0.43, at p < 0.01 level), and chlorite (R2 = 0.59, at p < 0.01 level) in the hot spot, but negatively correlated with a mixed layer of illite and smectite (R2 = 0.83, at p < 0.01 level). In contrast, the cases of Cd, Cu, Pb, and Zn presented an opposite tread with As. The positive matrix factorization (PMF) results showed that the contribution rate of nonferrous metal smelting to soil As was 42.90% and those of Cd, Cu, Pb, and Zn were 84.90%, 56.40%, 59.90%, and 59.20%, respectively. These results can provide guidance for controlling the TE risk associated with agricultural land management.
Abandoned mining areas can display soil and water pollution and also a high incidence of endemic diseases. Here, based on preliminary results on mental retardation and high incidence rates of cancers, we investigate the contamination status and potential ecological risk at an abandoned pyrite mine located in Xianju village, Hubei province, central China. The study focused on the three potentially toxic metals As, Pb, and Zn and four other common elements, including Ca, Fe, S, and Se. Soil samples were collected from 12 sites and leachate seeping from five sites. Leachates were strongly acidic compared to the soil, with pH values <3.22. Soil As and Se concentrations exceeded the Chinese Grade II standards for soil environmental quality (GB 15618-2009) (30 and 3 mg·kg−1, respectively), ranging from 33.6 ± 0.7 to 78.2 ± 1.0 mg As·kg−1 dry matter (DM) and 5.3 ± 0.8 to 17.1 ± 1.4 mg Se·kg−1 DM. Arsenic, Fe, Se, and S in leachates all exceeded the Chinese Grade III standard for surface water environmental quality (GB 3838-2002) (0.1, 0.3, 0.03, and 1.0 mg·L−1). The potential ecological risks from Pb and Zn in soils were low, but As in soils and leachates represented a moderate or strong risk to children according to the Nemerow index and hazard quotient. Soil replacement combined with further remediation measures is required to remediate the contaminated area.
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