Organochlorine pesticides in the air around the Taihu Lake, China

Organochlorine (OC) pesticides have been used broadly in China's past, yet very little is known about their atmospheric concentrations and transport. In this work, air samples were collected in the Taihu Lake Region, China, from July 23 to August 11, 2002, to measure concentrations of OC pesticides in air. The average concentrations of alpha and gamma- hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), heptachlor (HEPT), alpha-endosulfan, p,p'-DDT, p,p'-DDE, p,p'-DDD, and o,p'-DDT in the air were 74 and 46, 47, 53, 307, 124, 212, 36, and 767 pg m(-3), respectively. It was interesting to note that the concentrations of p,p'-DDT, p,p'-DDE, and o,p'-DDT were all very high, even though the use of technical DDT has been banned in China since 1983. Moreover, the average concentration ratios of o,p'-DDT/p,p'-DDT and p,p'-DDE/p,p'-DDT were as high as 6.3 and 1.8. This suggested that there could be an unknown source of DDT-related compounds (DDTs), especially o,p'-DDT and p,p'-DDE. It is very likely that this unknown source was the application of dicofol, an acaricide manufactured from technical DDT and used mainly on cotton fields to treat mites in China. Backward trajectory analysis also provided consistent evidence that the high air concentrations of DDTs were related to trajectories from the area north of the Yangtze River, where cotton fields account for a significant fraction of land use.     

Air-water gas exchange of organochlorine pesticides in Taihu Lake, China

Previous research in the Taihu Lake Region (TLR) of China found high levels of atmospheric organochlorine pesticides (OCPs). To understand the sources and the environmental behaviors of these OCPs in the TLR, research on air-water gas exchange was performed in 2004. Hexachlorocyclohexanes (HCHs), DDT related compounds (DDTs), cis-chlordane (CC), trans-chlordane (TC), heptachlor (HEPT), and alpha-endosulfan in both air and water samples were analyzed, and air-water gas exchange fluxes of these compounds were calculated. The net volatilization flux of alpha-HCH was 58 ng m(-2) day(-1), suggesting that the residue of technical HCH in the lake sediment might have been an important source of alpha-HCH to the air of this region after the ban of technical HCH two decades ago. The main components of technical chlordane, TC, CC, and HEPT, each had net volatilization fluxes >230 ng m(-2) day(-1), suggesting that waste discharge from manufacturing plants in the upper region was the main source of chlordane to the lake. Unlike alpha-HCH and chlordane, o,p'-DDT and alpha-endosulfan had net deposition fluxes, suggesting that these compounds were transported through the atmosphere from land sources and then deposited into the lake. The correlation between air concentrations and ambient air temperature indicated that the current sources of o,p'-DDT and alpha-endosulfan were from land; alpha-HCH and chlordane were mainly from the lake.     

Organochlorine pesticides and polychlorinated biphenyls in flatfish from the southern Baltic, 1983

Hexachlorobenzene (HCB), alpha-, beta-, gamma- and delta-benzenehexachloride (BHC; HCH), p,p'-DDE, o,p'-DDD, o,p'-DDT, p,p'-DDD and p,p'-DDT (espilon DDT) and polychlorinated biphenlys (PCBs) levels have been determined in muscle tissue of 37 turbots Psetta maxima, 27 plaices Pleuronectes platessa and 106 flounders Platichthys flesus netted during 1983 in a different regions in the southern part of the Baltic Sea. The mean levels found for flatfish muscle tissue related to wet weight were: 0.7, 0.88 and 1.1 microgram/kg HCB; 1.3, 2.6 and 3.0 micrograms/kg alpha-BHC; 11, 10 and 11 micrograms/kg beta-BHC; 4.4, 4.9 and 5.5 micrograms/kg gamma-BHC; delta-BHC remained undetected; 17, 18 and 20 micrograms/kg epsilon BHC; 5.1, 5.2 and 8.7 micrograms/kg p,p'-DDE; o,p'-DDD remained undetected; o,p'-DDT was detected in 10 of 106 samples of the muscle tissue of flounder at the mean level of 17 micrograms/kg; 4.6, 5.0 and 7.6 micrograms/kg p,p'-DDD; 3.1, 4.0 and 11 micrograms/kg p,p'-DDT; 13, 14 and 29 micrograms/kg epsilon DDT and 71, 66 and 94 micrograms/kg PCBs for turbot, plaice and flounder, respectively. Generally, the levels of organochlorine pesticides and PCBs in wet muscle tissue of fish followed the increased lipids content of muscles. Some local differences in pollution pattern of organochlorines have occurred. The results are compared with levels found in flatfish collected in a different regions of the Baltic Sea during 1966-1981, and reported previously by other authors.     

Organochlorine pesticides and polychlorinated biphenyls in cod from the southern Baltic, 1983

Hexachlorobenzene (HCB), alpha-, beta-, gamma- and delta-benzenehexachloride (BHC; HCH), p,p'-DDE, o,p'-DDD, o,p'-DDT, p,p'-DDD and p,p'-DDT (sigma DDT) and polychlorinated biphenyls (PCB) levels have been determined in muscle tissue of 207 cod (Gadus morhua) netted during 1983 in different regions in the southern part of the Baltic Sea. The mean levels found for cod muscle tissue (microgram/kg) related to wet weight were: 0.65 HCB, 1.2 alpha-BHC, 9.0 beta-BHC, 2.8 gamma-BHC, delta-BHC remained undetected, 13 sigma BHC, 4.4 p,p'-DDE, o,p'-DDD and o,p'-DDT remained undetected, 4.0 p,p'-DDD, 1.8 p,p'-DDT, 10 sigma DDT and 55 PCBs. The results are compared with levels found in cod caught in different regions of the Baltic Sea during 1967-1983, and reported previously by other authors.     

Organochlorine pesticides and polychlorinated biphenyls in livers of cod from the southern Baltic, 1983

Hexachlorobenzene (HCB), alpha-, beta-, gamma- and delta-benzenehexachloride (BHC; HCH), p,p'-DDE, o,p'-DDD, o,p'-DDT, p,p'-DDD and p,p'-DDT (sigma DDT) and polychlorinated biphenyls (PCB) levels have been determined in livers of 210 cod (Gadus morhua) netted during 1983 in a different regions in the southern part of the Baltic Sea. The mean levels found for cod livers related to wet weight (mg/kg) were: 0.096 HCB, 0.15 alpha-BHC, beta-BHC was found in trace amounts, 0.098 gamma-BHC, delta-BHC remained undetected, 0.26 sigma BHC, 1.1 p,p'-DDE, o,p'-DDD and o,p'-DDT remained undetected, 1.1 p,p'-DDD, 0.39 p,p'-DDT, 2.6 sigma DDT and 7.2 PCB. The levels of sigma DDT, sigma BHC and HCB found are comparable with those noted in livers taken from cod of the same length class and netted in 1981, whilst-for PCB somewhat lower levels were found. Because of heavy contamination with PCBs, sigma DDT, sigma BHC and HCB the livers of cod caught in Baltic Sea still remain insuitable for human consumption.     

Organochlorine pesticides and polychlorinated biphenyls in sprats from the southern Baltic, 1983

Hexachlorobenzene (HCB), alpha-, beta-, gamma-, and delta-benzenehexachloride (BHC; HCH), p,p'-DDE, o,p'-DDD, o,p'-DDT, p,p'-DDD and p,p'-DDT (sigma DDT) and polychlorinated biphenyls (PCB) levels have been determined in muscle tissue of 214 sprats (Sprattus sprattus) netted during 1983 in a different regions in the southern part of the Baltic Sea. The mean levels found for sprats muscle tissue related to wet weight were: 17 micrograms HCB/kg, 33 micrograms alpha-BHC/kg, 52 micrograms beta-BHC/kg, 33 micrograms gamma-BHC/kg, delta-BHC remained undetected, 120 micrograms sigma BHC/kg, 110 micrograms p,p'-DDE/kg, o,p'-DDD remained undetected, o,p'-DDT was detected in 2 of 214 samples at the mean level 24 micrograms/kg, 94 micrograms p,p'-DDD/kg, 115 micrograms p,p'-DDT/kg, 320 micrograms sigma DDT/kg and 800 micrograms PCB/kg. The levels of organochlorine pesticides reported are two to three times higher than those reported for wet muscles of sprats sampled in the same area two years before, whilst for PCB the levels differ slightly. When based on light-petroleum extractable lipids, the corresponding levels of organochlorine pesticides were also higher and for PCB the residue levels dropped. The results are compared with levels found in sprats collected in a different regions of the Baltic Sea during 1969-1983, and reported previously by other authors.     

Organochlorine pesticides and polychlorinated biphenyls in herring from the southern Baltic, 1983

Hexachlorobenzene (HCB), alpha-, beta-, gamma- and delta-benzenehexachloride (BHC, HCH), p,p'-DDE, o,p'-DDD, o,p'-DDT, p,p'-DDD and p,p'-DDT (sigma DDT) and polychlorinated biphenyls (PCB) levels have been determined in muscle tissue of 187 herring (Clupea harengus) netted during 1983 in a different regions in the southern part of the Baltic Sea. The mean levels found for herring muscle tissue related to wet weight (microgram/kg) were: 14 HCB, 18 alpha-BHC, 23 beta-BHC, 14 gamma-BHC, delta-BHC remained undetected, 56 sigma BHC, 115 p,p'-DDE, o,p'-DDD and o,p'-DDT remained undetected, 84 p,p'-DDD, 51 p,p'-DDT, 250 sigma DDT and 530 PCB. The levels of organochlorine pesticides determined in wet muscles or extractable lipids of herring are nearly 2-3 times as high as those noted in fish sampled in the same area in two years before, whilst for PCBs the wet weight levels were comparable, and when based on a lipid weight are somewhat higher. The results are compared with levels found in herring collected in different regions of the Baltic Sea during 1965-1983, and reported previously by other authors.     

Melting glaciers: a probable source of DDT to the Antarctic marine ecosystem

Persistent organic pollutants reach polar regions by long-range atmospheric transport and biomagnify through the food web accumulating in higher trophic level predators. We analyzed Adélie penguin (Pygoscelis adeliae) samples collected from 2004 to 2006 to evaluate current levels of sigmaDDT (p,p'-DDT + p,p'-DDE) in these birds, which are confined to Antarctica. Ratios of p,p'-DDT to p,p'-DDE in Adélie penguins have declined significantly since 1964 indicating current exposure to old rather than new sources of sigmaDDT. However, sigmaDDT has not declined in Adélie penguins from the Western Antarctic Peninsula for more than 30 years and the presence of p,p'-DDT in these birds indicates that there is a current source of DDT to the Antarctic marine food web. DDT has been banned or severely restricted since peak use in the 1970s, implicating glacier meltwater as a likely source for DDT contamination in coastal Antarctic seas. Our estimates indicate that 1-4 kg x y(-1) sigmaDDT are currently being released into coastal waters along the Western Antarctic Ice Sheet due to glacier ablation.     

Field validation of anaerobic degradation pathways for dichlorodiphenyltrichloroethane (DDT) and 13 metabolites in marine sediment cores from China

Although the production and use of dichlorodiphenyltrichloroethane (DDT), a legacy component of persistent organic pollutants, have been highly restricted worldwide, the environmental fate of DDT has remained a great concern as it is not only ubiquitous and bioaccumulative but can also be degraded to a series of metabolites that may be more hazardous ecologically. The present study, taking advantage of the abundant levels of DDT and its metabolites in a subtropical coastal region of China, investigated into the degradation pathways of DDT in natural coastal sediment. Sediment profiles indicated that degradation of 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane (p,p'-DDT) to 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethane (p,p'-DDD) mainly occurred in sediment of the top 20 cm layer. 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethylene (p,p'-DDE), aerobically transformed from p,p'-DDT prior to sedimentation, was likely to degrade to 1-chloro-2,2-bis-(p-chlorophenyl)ethylene (p,p'-DDMU) which was further converted to 2,2-bis(p-chlorophenyl)ethylene (p,p'-DDNU). In addition, p,p'-DDNU could be transformed to 2,2-bis(p-chlorophenyl)ethane (p,p'-DDNS) and other high-order metabolites. On the other hand, the conversions of p,p'-DDD to p,p'-DDMU and 1-chloro-2,2-bis-(p-chlorophenyl)ethane (p,p'-DDMS) to p,p'-DDNU were deemed slow in anaerobic sediment. Therefore, the present study confirmed all the degradation pathways involving reductive dechlorination and p,p'-DDE being a more important precursor for p,p'-DDMU than p,p'-DDD in anaerobic sediment, as proposed previously. On the other hand, the present study suggested that p,p'-DDMU instead of p,p'-DDMS was more likely the precursor for formation of high-order metabolites. Based on the current assessments, use of (DDD+DDE)/DDTs to indicate whether there is fresh DDT input may lead to large uncertainties if the concentrations of high-order metabolites are not negligible. Similarly, ecological risk assessment associated with DDT should be conducted with consideration of high-order DDT metabolites.     

RESIDUES OF p, p'-DDE AND DICOFOL IN MILK OF DAIRY COWS FED COMMERCIALLY PRODUCED APPLE POMACE

Residues of the miticide, dicofol, used in orchards, as well as p,p'-DDE a metabolite of p,p'-DDT present as an impurity in dicofol, were found in each commercial apple pomace sampled at several locations in Central New York. Traces of dicofol and p,p'-DDE were found in milk when cows were experimentally fed one of the pomaces for 9 days. These compounds were also detected in the milk of cows which had been fed by a dairy farmer on a practical basis for several months. It was judged that the milk residues were too low to be of health significance to consumers.