Yajuan Shi

Hexachlorobenzene sources, levels and human exposure in the environment of China

This article summarizes the published scientific data on sources, levels and human exposure of hexachlorobenzene (HCB) in China. Potential sources of unintended HCB emission were assessed by production information, emission factors and environmental policies. HCB was observed in various environmental compartments in China. HCB levels increased from South China to North China in most of environmental compartments (air, soil and mussel). Some hotspots were identified near the factories producing and using HCB. In terms of spatial distribution, HCB concentrations in air and shellfish showed much variation, which indicated some primary emission sources in China. HCB levels in air and human milk in China were relatively higher than those in other countries, but HCB levels in other compartments were similar to those in Europe and other countries in Eastern Asia. In the limited studies on temporal trends of HCB levels in China, HCB concentrations in air, sediment, fish and human milk did not show a consistent downward trend. Although HCB levels in food and human milk does not pose a health risk in China at present, long-term exposure to HCB should not be overlooked.

Polybrominated diphenyl ethers (PBDEs) in China: Policies and recommendations for sound management of plastics from electronic wastes

Polybrominated diphenyl ethers (PBDEs), used as flame retardants (BFRs), are incorporated in plastics of most electronic equipment. Among BFR mixtures, deca-BDE is the most widely used commercial additive in the polymer industry and the use of deca-BDE is currently not subject to any restrictions in China. However, debate over environmental and health risks associated with deca-BDE still remains. Regulatory agencies in developed countries have adopted and/or established environmentally sound strategies for the management of potential threat posed by PBDEs to the environment and human health. No regulations or management policies for PBDEs currently exist in China at either central or provincial government levels. Large amounts of plastics containing PBDEs are still in use and must be disposed of after their lifetimes, creating outdoor reservoirs for the future dispersal of PBDEs into the environment. Concerted action is needed not only to regulate the production and use of PBDEs but also to find ways to effectively manage waste electrical and electronic products that contain PBDEs. This article is the first to investigate the policy issues and current problems related to the use of PBDEs in China. In addition, we estimate the mass flows of PBDEs contained in Waste Electrical and Electronic Equipment (WEEE) in China. We suggest alternatives to PBDEs and sound management of plastics used in electrical and electronic equipment (EEE) that contain PBDEs.

A review of spatial and temporal assessment of PFOS and PFOA contamination in China

The current state of concentrations of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in China is presented. While products that are known to degrade to either PFOS or PFOA have been used in China, concentrations in environmental media have been reported to be relatively low across China. Greater concentrations of PFOS and PFOA were observed in southern and eastern China than in other areas of China. Concentrations of PFOS and PFOA were relatively great in the Huangpu River, with concentrations of 20.5 ng l−1 and 1590 ng l−1, respectively. Surface waters of Dongguan and Shanghai were more contaminated by PFOS and PFOA than that of other cities. Dongguan was the only city in China in which PFOS value in surface water exceeded the water quality criterion, while PFOA concentration in Shanghai was 152 ng l−1. Similar to other contaminants, point-source pollution was also the common pattern of PFOS and PFOA contamination. Concentrations of PFOS in human blood in China were relatively greater in China than other countries, with drinking water contamination given as the most likely source. Concentrations of PFOS in human blood have increased from the 1980s to the 2000s, while such a trend was not observed for PFOA.

Environmental pollution by persistent toxic substances and health risk in an industrial area of China

Soil is an important environmental medium that is closely associated with humans and their health. Despite this, very few studies have measured toxicants in soils, and associated them with health risks in humans. An assessment of health effects from exposure to contaminants in soils surrounding industrial areas of chemical production and storage is important. This article aims at determining pollution characteristics of persistent toxic substances (PTS) in an industrial area in China to unravel the relationship between soil pollution by PTS and human health. One hundred and five soil samples were collected and 742 questionnaires were handed out to residents living in and around an industrial area around Bohai Bay, Tianjin in Northern China. Concentrations of organochlorine pesticides and polycyclic aromatic hydrocarbons (PAHs) were determined in soil. Mann-Whitney U and binary multivariate non-conditional logistic regression models were employed to analyze the relationship between health indicators of local residents and contaminant levels. Odds ratio (OR) and a 95% confidence interval (CI) for health incidences were also calculated. The average concentrations of DDT (73.9 ng/g), HCH (654 ng/g) and PAHs (1225 ng/g) were relatively high in the industrial area. Residents living in the chemical industry parks were exposed to a higher levels of PTS than those living outside the chemical industry parks. This exposure was associated with a higher risk of breast cancer (OR 1.87, 95% CI 0.12-30.06), stomach cancer (OR 1.87, 95% CI 0.26-13.41), dermatitis (OR 1.72, 95% CI 1.05-2.80), gastroenteritis (OR 1.59, 95% CI 0.94-2.68), and pneumonia (OR 1.05, 95% CI 0.58-1.89).

Distribution and availability of arsenic in soils from the industrialized urban area of Beijing, China.

Concentrations of arsenic (As) were determined in soils of 5 industrial sites in an urban area of Beijing, China. Fifty seven typical surface soils were sampled to determine total concentrations of metals, pH and dissolved organic carbon (DOC). One hundred and eight deep soils were submitted to a four-step, sequential extraction to assess the relative mobility and bioavailability of As in the soil profiles. Total concentrations of As in surface soils ranged from 5.7 to 2.3 x 10(1) mg kg(-1), dw with greater concentrations inside the perimeter of the chemical plant which had greater concentrations than did other plants. 75.4% of surface soil samples in the industrial area contained concentrations of As that were greater than was considered to be the background concentration of 7.8 mg kg(-1), dw for the region. The mean concentration (9.9 mg kg(-1), dw) in the industrial soils was greater than that soils from other type of land use. Concentrations of As were significantly and negatively correlated with soil pH and DOC in industrial soils. Although mean concentration of total As in the soils from all sites were less at greater depths, the entire range from 0 to 180 cm (especially 0-80 cm) contained concentrations of As that were greater than background. Sequential extractions of soil indicated that only some surface soils had relatively great amount of extractable fraction of As. Most soils had relatively great amount of residual As. This result suggests that most arsenic in Beijing industrial soils should be immobile and of limited bioavailability.

Regional differences and sources of organochlorine pesticides in soils surrounding chemical industrial parks

Concentrations of organochlorine pesticides (OCPs; dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB)) were investigated in 105 soil samples collected in vicinity of the chemical industrial parks in Tianjin, China. OCP concentrations significantly varied in the study area, high HCH and DDT levels were found close to the chemical industrial parks. The intensity of agricultural activity and distance from the potential OCP emitters have important influences on the OCP residue distributions. Principal component analysis indicates that HCH pollution is a mix of historical technical HCH and current lindane pollution and DDT pollution input is only due to technical DDT sources. The significant correlations of OCP compounds reveal that HCHs, DDTs and HCB could have some similar sources of origin.

Antioxidant and metabolic responses induced by cadmium and pyrene in the earthworm Eisenia fetida in two different systems: contact and soil tests

The effects of cadmium and the polycyclic aromatic hydrocarbon (PAH) pyrene on the earthworm Eisenia fetida were investigated in contact and soil tests. Metabolic (glutathione-S-transferase, GST) and oxidative (catalase, CAT) stress enzymes were studied as biomarkers in earthworms after 48 hours, 14 days and 28 days. Contact test indicated that cadmium had significant effects on survival and enzyme activities while pyrene influenced neither in the studied concentrations. Induction of CAT and GST in earthworms exposed to cadmium and pyrene in the acute soil test (14 d) revealed the metabolism of these chemicals resulting in the production of reactive oxygen species. After a relatively long period of exposure (28 d), earthworms exposed to pyrene failed to handle the high toxicity and were physiologically damaged, while those exposed to cadmium adapted to the disturbed environment through effective metabolism of the chemical and management of the oxidative stress.

Factors Influencing the Spatial Distribution of Organochlorine Pesticides in Soils surrounding Chemical Industrial Parks

Topsoil samples (n = 105) were collected to study the distribution of dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) residues in the vicinity of chemical industrial parks in Tianjin, China. The occurrence and distribution of target organochlorine pesticides (OCPs) were mapped to identify the spatial variation using Geographical Information System (GIS). In general, the concentrations of OCPs were higher in soils near the industrial parks, even some hotspots showed very high OCP contaminations which could cause ecological risk. The relationships between contaminant concentrations and other factors (land use and soil properties) were discussed. Significant correlations (P < 0.01) between TOC contents and the concentrations of DDTs, alpha-HCH, and beta-HCH indicated the effect of organic carbon on OCP distribution. Soil pH levels had no obvious effect on the OCP distributions. Except for the effects of the industrial parks, the capacities of biodegradation and dissipation of soils under different land uses were the important factors that affected the HCH distribution, but the distribution of DDTs was mainly influenced by the TOC levels. The results of this study can provide some evidences and data on the long term effects of industrial activities in the environment even after the cease of operations for a long time.

Effects of Environmental Factors on Organochlorine Pesticide Residues in Soils of the Guanting Reservoir Area, China

Topsoil samples from 56 sites around the Guanting Reservoir, China, were measured for HCH and DDT concentrations. The total soil HCH content (including α -, β -, γ -, and δ - isomers) in these soil samples ranged from 0 to 7.33 ng.g− 1, with a mean of 0.69 ng.g− 1. These levels were considerably lower than those of the total DDT soil contents (including pp′-DDE, pp′-DDD, op′-DDT, and pp′-DDT), which ranged from 0 to 76.01 ng.g− 1, with a mean of 9.46 ng.g− 1. DDT was also found to be the major pollutant in the soil samples, accounting for ∼ 93% of the total organochlorine pesticide (OCP) contents. Several environmental factors including land use, soil texture, soil taxonomy, and microbial biomass were considered to be responsible for the OCP levels observed. The data provide some insight into the effects of environmental conditions such as soil formation, agricultural cultivation, nutrient enrichment, and other anthropogenic activities on the degradation of OCPs in soils. Although the OCP residues currently are below the maximum limits set for use on agricultural land in China, and only rarely would such levels pose significant ecological concern, OCPs are highly persistent in soil and bioaccumulative. The data provided in this study are considered crucial for reservoir remediation, especially since the Guanting Reservoir will serve as one of the main drinking water sources for Beijing in the foreseeable future.

Factors affecting HCH and DDT in soils around watersheds of Beijing reservoirs, China.

The factors that influence the dynamics of hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT) in soils around the watersheds of Beijing reservoirs were examined. Compared with other studies on HCH and DDT in soils and established reference values, the concentrations of HCH and DDT in soils around our study area were relatively low. The relationships between HCH and DDT concentrations and land use, soil texture, and soil properties were discussed. HCH and DDT concentrations were higher in arable soils than those in uncultivated fallow soils. Although land use was the most important factor affecting HCH and DDT residues, additional factors such as soil texture and soil total organic carbon were also involved in pesticide retention in soils. The results indicated that the historical agricultural applications of HCH and DDT were the major source of their residues. Atmospheric deposition, as well as long-distance transportation and inputs from surrounding weathered agricultural soils may also serve as important sources of HCH and DDT residues in the watersheds.