The pollution and ecological risk of endosulfan in soil of Huai'an city, China.

Endosulfan, a persistent organic pollutant newly listed under the Stockholm Convention, is currently widely produced and used as a pesticide in China. Concentrations of endosulfans (including α-, ß-isomers, and their metabolite endosulfan sulfate) were determined in surface soil collected from Huai'an city, where the largest endosulfan producer is located. The concentrations of Σendosulfan (sum of α-endosulfan, ß-endosulfan, and endosulfan sulfate) at all sites ranged from 0.28 to 44.81 ng/g dry weight (dw), following a lognormal distribution. The geometric mean was 1.09 ng/g dw, and the geometric standard deviation was 3.02. The ß-endosulfan levels were consistently greater than those of α-isomer. The concentration ratios of α-endosulfan to ß-endosulfan ranged from 0.03 to 0.70, which were much lower than the commercial endosulfan mixture. This is because that α-endosulfan is more volatile and degrades faster than ß-endosulfan in soil. The contour map of Σendosulfan levels in soil indicates that the factory was the point pollution source with the highest endosulfan level in its surrounding area, especially the southern area. However, the non-point agricultural sources are more important. Based on Monte Carlo simulation, the Σendosulfan inventory in soil in Huai'an is estimated to be 0.8-3.0 tons. In order to understand the potential ecological risk of endosulfan, the Monte Carlo-based hazard quotient distribution was estimated and showed that Σendosulfan posed a potentially high risk to soil organisms. To our knowledge, this study is the first that reports soil pollution and risk of endosulfan around the manufacturer in China. This study will help China's implementation of Stockholm Convention for the reduction and elimination of endosulfan in future.

Dechlorane Plus pollution and inventory in soil of Huai'an City, China.

Dechlorane Plus (DP) has been used as a highly chlorinated flame retardant substituting those that are now internationally regulated under the Stockholm Convention. Nevertheless DP's environmental behavior has seldom been studied in China. There is only one DP manufacturer producing DP since 2005, which is located in Huai'an, Jiangsu Province. The DP levels in 21 soil samples that were taken from Huai'an in October 2009 and determined by gas chromatography/electron-capture negative ion-mass spectrometry (GC/ECNI-MS) method ranged from 0.83 to 1.2 x 10(3) ng g(-1), following a lognormal distribution. The geometric mean was 5.1 ng g(-1) dry weight (dw) and the geometric standard deviation was 4.6. Sampled soils had f(anti)[C(anti)(-DP)/(C(syn)(-DP)+C(anti)(-DP))] values of 0.67-0.85, with the average value of 0.79, which are close to the values in DP commercial products. This suggests that the main DP pollution source is the commercial DP product. The contour map of DP levels in soil indicated that the factory was the point pollution source with the highest DP level in its surrounding area, especially the southern area. A Monte Carlo based inventory estimation was conducted. The DP inventory in Huai'an is estimated to be 4-31 tons. To our knowledge, this study is the first that reports soil pollution by DP.

Toxic emissions from open burning.

This review compiled the data from recent actual and simulation studies on toxic emissions from open burning and categorized into sources, broadly as biomass and anthropogenic fuels. Emission factors, in mass of pollutant per mass of material being burned, and actual concentrations, in mass of pollutant per unit volume have been compared based on source classifications. In addition to gaseous emissions, this review presents the updated data on emissions to air in the form of particulate matter, and emissions to soil and water environment. Data from forest fires, accidental fires such as vehicle fires, house fires, and unintentional landfill fires are included in this review as well as combustion involving traditional and recreational activities.

HRGC/HRMS analysis of mirex in soil of Liyang and preliminary assessment of mirex pollution in China.

China is a country with the most severe termite damage in the world. Mirex is one of the two effective orgochlorine pesticides used in China for termite control. A high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) was employed for mirex analysis in soil samples from Liyang city, which once was an important mirex production base in China. The detected mirex levels in soil in Liyang were 2.9-4300pgg(-1)dw (dry weight), with the geometric mean 26.83pgg(-1)dw and the geometric standard deviation 5.02. The highest level occurred at the site near the Liyang Guanghua Chemical Factory. It implies the contribution of industrial activities to the mirex pollution in the surrounding environment. However, the factory only influenced very limited adjacent areas. A Level III fugacity model was developed to study the mirex pollution in Chinese provinces. The results show that the highest concentration occurred in Jiangxi Province, which has the largest consumption of mirex among Chinese provinces. On a regional scale, the calculated concentrations of mirex in the environment are generally so low that it indicates no harm to human and organisms. The total amount of mirex in the environment in China was estimated to be about 25.12tons, most of which exists in soil.

Risk assessment of short-chain chlorinated paraffins in Japan based on the first market basket study and species sensitivity distributions.

The chemical risks of short-chain chlorinated paraffins (SCCPs) to human health and ecological species in Japan were assessed in this study. SCCPs are used as extreme pressure additives in metal-working fluids and flame retardant agents in plastic materials. The first market basket study with a high resolution gas chromatography and mass spectrometry with electron capture negative ionization is reported. Total daily food intakes for Japanese residents of different ages were estimated using Latin Hypercube simulations, and the highest 95th percentile intake is 6.8 x 10(2) ng/kg/day for a 1-year-old child. Based on the reported no-observed-adverse-effect-level (NOAEL) and the estimated exposure mainly from food, it was concluded thatSCCPs are not posing risks to humans in Japan. Ecological risks to aquatic and sediment organisms were estimated using species sensitivity distributions. The 95th percentiles of the distributions obtained by fitting several environmental SCCP concentration data of river water and sediment were 41.8 ng/L and 558 ng/g wet weight as the possible highest concentrations, respectively. No-observed-effect-concentrations (NOEC) were determined by calculating the fifth percentiles of a species sensitivity distribution, which were 2.2 microg/L for aquatic organisms and 1.7 to 13.5 mg/ kg wet weight for sediment organisms. While it is likely that there is no imminent environmental chemical risk for aquatic organisms at a regional level in Japan, this study concluded that a more detailed risk assessment is necessary for sediment organisms.

Potential role of chlorination pathways in PCDD/F formation in a municipal waste incinerator.

The role of chlorination reactions in the formation of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in a municipal waste incinerator was assessed by comparing predicted chlorination isomer patterns with incinerator flue gas measurements. Complete distributions of PCDD and PCDF congeners were obtained from a stoker-type municipal waste incinerator operated under 13 test conditions. Samples were collected from the flue gas prior to the gas cleaning system. While total PCDD/F yields varied by a factor of 5 to 6, the distributions of congeners were similar. A conditional probability model, dependent only on the observed distribution of monochlorinated isomers, was developed to predictthe distributions of polychlorinated isomers formed by chlorination of dibenzo-p-dioxin (DD) and dibenzofuran (DF). Agreement between predicted and measured PCDF isomer distributions was high for all homologues, supporting the hypothesis that DF chlorination can play an important role in the formation of PCDF byproducts. The PCDD isomer distributions, on the other hand, did not agree well with model predictions, suggesting that DD chlorination was not a dominant PCDD formation mechanism at this incinerator. This work demonstrates the use of PCDD/F isomer patterns for testing formation mechanism hypotheses, and the findings are consistent with those from other municipal waste combustion studies.

Correlations between homologue concentrations of PCDD/Fs and toxic equivalency values in laboratory-, package boiler-, and field-scale incinerators.

The toxic equivalency (TEQ) values of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are predicted with a model based on the homologue concentrations measured from a laboratory-scale reactor (124 data points), a package boiler (61 data points), and operating municipal waste incinerators (114 data points). Regardless of the three scales and types of equipment, the different temperature profiles, sampling emissions and/or solids (fly ash), and the various chemical and physical properties of the fuels, all the PCDF plots showed highly linear correlations (R(2)>0.99). The fitting lines of the reactor and the boiler data were almost linear with slope of unity, whereas the slope of the municipal waste incinerator data was 0.86, which is caused by higher predicted values for samples with high measured TEQ. The strong correlation also implies that each of the 10 toxic PCDF congeners has a constant concentration relative to its respective total homologue concentration despite a wide range of facility types and combustion conditions. The PCDD plots showed significant scatter and poor linearity, which implies that the relative concentration of PCDD TEQ congeners is more sensitive to variations in reaction conditions than that of the PCDF congeners.