Pollution of HCHs,DDTs and PCBs in tidal flat of Hangzhou Bay 2009–2013

The concentration and distribution of three persistent organic pollutants （hexachlorocyclohexanes （HCHs）, dichlorodiphenyltrichloroethanes （DDTs） and polyehlorinated biphenyls （PCBs）） was assessed in tidal fiat sediments collected from the south bank of Hangzhou Bay, China from 2009 to 2013. Gas chromatography coupled to triple quadrupole mass spectrometry （GC-MS/MS） was used for analysis, based on United States Environmental Protection Agency methods EPAS080A, EPA8081B, and EPA3550B. The results showed that the levels of HCHs, DDTs and PCBs decreased in the order of DDTs 〉 HCHs 〉 PCBs, and their mass fractions ranged from 0.29-32.91, 0.09-13.19 and 0.16-4.10 ktg/kg （dry mass）, respectively. The levels of HCHs, DDTs and PCBs decreased slowly from 2009 to 2013, with considerably greater concentrations in winter than in spring and summer. In this study area, the concentrations of DDTs and HCHs decreased gradually towards the mouth of Hangzhou Bay, while the concentrations of PCBs were related to changes in the local economy. In addition, the sources of HCHs and DDTs were identified as atmospheric precipitation and historical residues, Finally, we predicted that PCBs pollution primarily originated from Aroclor 1254（Lot A4）, which might root in the illegal demolition and stacking of abandoned paint, transformer or electronic equipment in the south bank of Hangzhou Bay.

Distribution and health risk assessment of organochlorine pesticides(OCPs) in industrial site soils:A case study of urban renewal in Beijing,China

A field survey was conducted in a contaminated industrial site of southern Beijing, China to investigate the contents and distribution of the organochlorine pesticides （α-, β-, y-, δ-HCH, p,p＇-DDT, p,p＇-DDE, p,p＇-DDD and o,p＇-DDT） in the profiles of soil, and a health risk assessment was carded out with CalTOX multimedia exposure model. Results showed that mean concentrations of total hexachlorocyclohexane isomers （HCHs） and total dichlorodiphenyltrichloroethane isomers （DDXs） in soils were in the range of 13.20- 148.71 mg/kg, and 3.02-67.43 mg/kg, respectively. Organochlorine pesticides （OCPs） content peaked in the surface and declined in soil profile with depth. The amounts of HCHs in three profiles of soil were larger than DDXs. Composition analysis indicated that there was a trend of degradation of OCPs in the site, but the mean of HCHs and DDXs concentration were over the state warning standard limit （HCHs, 0.50 mg/kg; DDXs, 0.50 mg/kg）. According to current land use development, health risk assessment with CalTOX and Monte Carlo analysis showed that health risks mainly came from two exposure pathways： dermal uptake and inhalation, and the total risk values all exceeded the general acceptable health risk value （10-6）. The sensitivity analysis indicated that five parameters significantly contributed to total risk.

Response of testicular antioxidant enzymes to hexachlorocy clohexane is species specific

Aim: To find out whether the response of testicular oxidative stress parameters to hexachlorocyclohexane (HCH) is species specific. Methods: In rats and mice (n=5 in each group), HCH was administered at a dose of 20 mg/kg/day intraperitoneally for 30 days in 0.1 ml of refined groundnut oil. The control groups received equal volume of the vehicle. Animals were sacrificed 24 hours after the last injection and various oxidative stress parameters were measured immediately. Results: The level of both endogenous as well as FeSO_4 and ascorbic acid-stimulated lipid peroxidation was increased significantly in the HCH-treated rats, whereas the pattern was just the reverse in case of mice. Although the level of H_2O_2 content increased in response to HCH in both groups, a totally different trend was observed for the activity of the principal H_2O_2-metabolising enzyme, catalase. In case of rats, a significant decline in the activity of catalase was recorded in response to HCH whereas a sharp augmentation in the enzyme activity was noticed in mice. Similarly, the decreased activity of superoxide dismutase observed in rats remained unaltered in mice. Conclusion: HCH induces oxidative stress in the testis of both rats and mice. However, the pattern of response of testicular oxidative stress parameters seems to be species specific.

Isolation of Organochlorine Pesticide from Ginseng with Supercritical CO_2

The feasibility of removal of the organochlorine pesticides residues of hexachlorocyclohexane(BHC) from radix ginseng with supercritical CO2 was explored. Some factors, such as extraction pressure, extraction temperature, and kinds of co-solvents were investigated. The experimental results indicate that it is possible to reduce BHC residues in radix ginseng to the level of 0.1 × 10^-6 with supercritical CO2 in the presence of suitable amount of co-solvent, such as water.

Influence of Phenobarbital and Carbon tetrachloride on the Modulation of Tissue Retention Profile of Hexachlorocyclohexane in Rats

The study was designed to investigate the role of hepatic metabolic activity on body burden of HCH residue. Male albino rats were orally administered 0, 5, and 10 mg/kg HCH for 90 days, followed by either sodium phenobarbital or carbon tetrachloride treatment for 0, 15 and 30 days after withdrawal of their respective HCH administration. The liver weight was significantly increased at 30 days after the administration of phenobarbital and carbon tetrachloride in both 5 mg and 10 mg/kg HCH withdrawal groups when compared to control. HCH residue was maximun in fat followed by adrenal>thymus>liver>kidney>spleen>testes>brain>plasma. Carbon tetrachloride caused an accumul-ation of HCH residues in the liver 15 and 30 days after administration of both doses of HCH. Phenobarbital did not show significant variation in HCH residues in hepatic tissue. Phenobarbital treatment caused significant induction of hepatic RED, APD, AHH, GST and QR activities. Significant decreases in activities were observed by carbon tetrachloride when compared to animals treated with HCH alone. The overall results clearly suggest the role of P450 protein on the body burden of HCH residues.

介绍六六六γ-异性体(Gammexane;Gamma Isomer of Hexachlorocyclohexane)之测定法

六六六之合成原料为苯及氯气,在国内均可购置;其制造手续较D.D.T.为简便,效用较D.D.T.为优胜,因其非但可作喷射剂,并可作蒸熏剂,其所须之浓度较D.D.T.小,时间亦较短。就苍蝇而论,0.01%之六六六γ-异性体可以杀死73%,而0.02%之D.D.T.仅能杀死51%,对人类之接触迄令亦尚未发现任何损害。国内药厂颇可大量制造,目前则尚在小规模之试制中。六六六之有效成份为其γ-异性体(白色粉末熔点112.0-112.8℃)。

Chlorobenzenes and organochlorinated pesticides in vegetable soils from an industrial site, China

Organochlorinated compounds are ubiquitous contaminants in the environment, especially in industrial sites. The objective of the work was to investigate whether a vegetable field near an industrial site is safe for vegetable production. The residues of chlorobenzenes （CBs）, hexachlorocyclohexanes （HCHs） and dichlorodiphenyltrichloroethanes （DDTs） in a vegetable field which was near a chemical plant in China were characterized. Point estimate quotient was used for ecological risk assessment of the investigated site. The results showed that all CBs except monochlorobenzene （MCB） were detected in soils. The total concentrations of ∑ CBs ranged from 71.06 to 716.57 ng/g, with a mean concentration of 434.93 ng/g. The main components of CBs in soil samples were dichlorobenzenes （DCBs）, trichlorobenzenes （TCBs） and tetrachlorobenzenes （TeCBs）, while for single congeners, 1,2,4-TCB had the highest concentration, which ranged from 13.21 to 210.35 ng/g with a mean concentration of 111.89 ng/g. Residues of hexachlorobenzene （HCB） in soil samples ranged from 0.9 to 11.79 ng/g, significantly lower than ∑ DCB, ∑ TCB and ∑ TeCB. Concentrations of ∑ HCHs and ∑ DDTs in soils ranged from 11.32 to 55.24 ng/g and from 195.63 to 465.58 ng/g, respectively, of which the main components were α-HCH and p,p＇-dichlorodiphenyldichloroethylene （p,p＇-DDE）. Ecological risk assessment for the investigated site showed that the most potential risks were from TCBs and TeCBs, based on the hazard quotients. The higher residues of CBs and DDTs compared to the target values and the higher than 1 hazard quotients indicated that this area is not safe for vegetable production and thus soil remediation is needed.

Residues of Organochlorine Pesticides(OCPs) in Agricultural Soils of Zhangzhou City,China

A soil survey was conducted in Zhangzhou City, an important agricultural region in south of the Fujian Province, China. 93 surface soil samples were collected in the paddy fields, vegetable lands, orchards and tea plantations from Zhangzhou City. An additional soil profile was sampled in a paddy field as previous research had indicated high concentrations of organochlorine pesticides （OCPs） in the paddy fields. Dichlorodiphenyltrichloroethanes （DDTs） ranged from 0.64 78.07 ng g-1 dry weight and hexachlorocyclohexanes （HCHs） ranged from 0.72-30.16 ng g-1 dry weight in the surface soil of the whole study region. Ratios of a-HCH/-γ-HCH 〈 4 and o,p′-DDT/p,p′-DDT 〉 1 in all soil samples suggested that lindane and dicofol were widely applied in this region in the past. Concentrations of HCHs and DDTs in soils from the four land use types followed the orders： paddy fields 〉 vegetable lands 〉 tea plantations 〉 orchards and tea plantations 〉 orchards 〉 paddy fields 〉 vegetable lands, respectively. Analyses of the data showed no correlation （r 〈 0.1） between elevation and OCPs contents in paddy fields, orchards and vegetable lands, indicated no significantly different features in distribution of HCHs and DDTs in the soils from low lying plains and mountains and the unsystematic usage of OCPs, and highlighted the fragmented nature of agricultural production in Zhangzhou, as well as the reemission of OCPs from the soils, where high OCPs concentrations were found, in Longhai of Zhangzhou. In addition, no obvious relationship between the OCPs and total organic carbon （TOC） （r 〈 0.3） was observed in the soil profile. The mean contribution of dicofol in total DDTs was 66% in the whole Zhangzhou region. The approximate burdens of HCHs and DDTs in the surface layer of 0-20 em were 0.44 and 1.55 t, respectively. The storage of both HCHs and DDTs in soil surface layer （0-20 cm） accounts for 40% burden of the soil layer of 0 50 cm （1.10 t HCHs and 3.87 t DDTs）, in which the highest concentrations of OCPs were observed in soil profile.

Application of sewage sludge and intermittent aeration strategy to the bioremediation of DDT- and HCH-contaminated soil

Adding organic amendments to stimulate the biodegradation of pesticides is a subject of ongoing interest. The effect of sewage sludge on the bioremediation of dichlorodiphenyltrichloroethane（DDT） and hexachlorocyclohexane（HCH） contaminated soil was investigated in bench scale experiments,and intermittent aeration strategy was also used in this study to form an anaerobic–aerobic cycle. Bioremediation of DDT and HCH was enhanced with the addition of sewage sludge and the intermittent aeration. The removal rates of HCH and DDT were raised by 16.8%–80.8% in 10 days. Sewage sludge increased the organic carbon content from 6.2 to218 g/kg,and it could also introduce efficient degradation microbes to soil,including Pseudomonas sp.,Bacillus sp. and Sphingomonas sp. The unaerated phase enhanced the anaerobic dechlorination of DDT and HCH,and anaerobic removal rates of β-HCH,o,p′-DDT and p,p′-DDT accounted for more than 50% of the total removal rates,but the content of α-HCH declined more in the aerobic phase.

Simulating the transfer and fate of hexachlorocyclohexane in recent 50 years in Beijing, China

Taking Beijing as a study area, a dynamic fugacity model was used to simulate the transfer and fate of technical HCHs according to the physic-chemical properties of the studying environment and HCH isomers. Dynamic changes of the transfer fluxes and concentrations of HCH isomers during 1952―2003 were simulated and the model results suggest good agreement between the calculated and measured concentrations of HCH isomers. During 1952―1983, the average input and output amount of HCHs through agricultural application and degradation are 130 t and 150 t respectively. The dominant transfer processes of HCHs in the study area are air-soil deposition, soil erosion and soil-air diffusion, transfer fluxes of these processes are 80 t?a?1, 16 t?a?1 and 11 t?a?1, which account for 92% of total transfer fluxes of HCHs isomers. There were approximately 253t HCHs in all environmental compartments of the study area during this period and 97% of which existed in soil compartment. Air and water advection became the dominant input sources of HCHs after 1984 when the application of technical HCHs was prohib-ited, concentration of HCHs quickly descended to a quite low level in several years. Total amount of HCHs isomers remaining in the study area environment now is less than 5% that before 1983, and this percentage may descend to 0.5% after 20 years by prediction.

Assessment, Composition and Possible Source of Organochlorine Pesticides in Surface Soils from rmqi, China

Twenty-eight surface soil samples from 5 functional zones （park, traffic roadside, business/residential area, rural area, and industrial area） of Uruimqi, China were collected and analyzed for the concentrations of 14 organochlorine pesticides （OCPs）, such as 3 isomers of hexachlorocyclohexane （HCHs） （α-HCH, β-HCH, and γ-HCH）, 4 dichlorodiphenyltrichloroethanes （DDTs） （p,p′-DDT and its metabolites p, p′-DDD （1,1-dichloro-2,2-bis（p-chlorophenyl）ethane） and p,p′-DDE （1,1-dichloro-2,2-bis（4-chorophenyl）ethylene）, and o, p′-DDT）, and methoxychlor, aiming to survey the residue levels and compositions of these 14 OCPs, to identify possible sources of the OCPs, and to assess their potential risks to human health and the environment in surface soils of Ur/imqi. The concentrations ranged from non-detected to 30.86μg kg^-1 for HCHs （sum of α-, β-, and γ-HCH）, from non-detected to 40.03 μg kg^-1 for DDTs （sum of p, p′-DDT, p, p′-DDD, p, p′-DDE, and o, p′-DDT）, and from non-detected to 11.95 μg kg^-1 for methoxychlor. The total concentrations of the OCPs ranged from 16.40 to 84.86 μg kg^-1, with a mean of 41.89 ± 16.25 μg kg^-1. According to the measured concentrations and occurrence rates of the 14 OCPs, DDTs, HCHs, and methoxychlor were the most dominant compounds. Among the 5 functional zones, the total concentration of OCPs was in the order of rural area 〉 traffic roadside 〉 park 〉 business/residential area 〉 industrial area. The different compositions of DDTs and HCHs indicated that the residues of these compounds in most soil samples originated from historical application, besides slight recent introduction at some sampling sites. The results of Pearson correlation analysis showed that soil total organic carbon played an important role in the residue levels of HCHs, but such relationships were not found with DDTs or other OCPs. The soil quality of Uriimqi was classified as Class I based on the guidelines of the Chinese Environmental Quality Standard for Soil （GB15618-1995）, indicating that the residue levels of OCPs have little risks to the environment and human health in the study area.

Concentrations and classification of HCHs and DDTs in soil from the lower reaches of the Jiulong River, China

Soil is an important source to other environ- mental media and organisms for organochlorine pesticides （OCPs） bioaccumulation. Twenty-four representative sur- face soil samples were collected from the lower reaches of the Jiulong River, China, in 2009. The concentrations of hexachlorocyclohexane isomers （HCHs） ranged from 0.38 to 39.52 ng.g~, with a mean value of 9.51 ng.g-~. The concentrations of dichlorodiphenyltrichloroethanes （DDTs） and their metabolites were within the ranges of 0.94-700.99 ng. gl, with a mean value of 71.17 ng. g-1. The concentrations of HCHs and DDTs in the soil were lower than the first grade level （50 ng. g-a） of the Chinese Environmental Quality Standard （GB 15618-1995）. Hier- archical Cluster Analysis （HCA） and Pearson＇s bivariate Correlations Analysis （PCA） were used to analyse the distribution and contamination levels of OCPs in this region. The results showed that DDTs were the major contaminants and there were no significant correlations between various OCPs concentrations and the total organic carbon （TOC） contents. A significant positive correlation was observed between HCHs and DDTs （p 〈 0.01）, which indicates that HCHs and DDTs may have similar sources and fate in the study area.