Polychlorinated Dibenzo -p- Dioxins and Dibenzofurans in Lake Sediments from Chinese Schistosomiasis Areas

Abstract

Lake D is located in the south of China. The total area of the lake is about 3,000 km 2 . The dimension of the lakeland varies greatly with changing of seasons. It is an important source of grain and freshwater fish in China. However schistosomiasis japonica prevailed in this region for a long time, sodium pentachlorophenate(Na-PCP) has been sprayed since the 1960s to control the spreading of snailborne schistosomiasis. Being contaminants of technical Na-PCP, PCDD/Fs may enter the environment and contribute to human exposure after the treatment. The low water solubilities and high adsorption to sediment of PCDD/Fs do not rule out their movement in the environment. Schecter et al. (1994) compared PCDD/Fs levels in blood and milk in agricultural workers and others following Na-PCP exposure in another schistosomiasis area in China, high levels of PCDD/Fs in exposed persons are evident. But the investigation concerning the contamination of Lake D has not been carried out before this study. M A T E R I A L S A N D M E T H O D SThe samples were taken from eight different locations distributed over the whole lakeland in March 1995 before spraying Na-PCP that year. Sample 1 and Sample 2 were collected in the areas that were covered with water only in the rainy season and exposed directly to the air in the dry season, while other samples are all from sediments under water.Samples are air dried and sieved( φ 2 mm) to eliminate any solid objects.Ten grams of sieved samples are spiked respectively with 3.5 ng each of eight 13 C-labelled 2,3,7,8,-substituted PCDD

Declining polychlorinated dibenzo-p-dioxins and dibenzofurans levels in the sediments from Dongting Lake in China

“…During the 1990s, the sediment in Dongting Lake was recognized to be highly contaminated with PCDD/Fs (Zheng et al, 1997). Total I-TEQ values of PCDD/Fs ranged from 130 to 891 pg g À1 with a mean value of 274 pg g À1 in the sediment samples collected in 1995.…”

“…As one of the by-products of Na-PCP (Bao et al, 1995), PCDD/Fs may enter the environment and contribute to human exposure. The sediment in Dongting Lake was recognized to be highly contaminated with PCDD/Fs in 1995 (Zheng et al, 1997). Concerning the adverse effect of Na-PCP, Na-PCP has been prohibited spraying in this region since 1995.…”

Occurrence of polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls pollution in sediments from the Haihe River and Dagu Drainage River in Tianjin City, China

“…In 1999, about 342 000 tons alkali was produced and the capacity of chloralkali production in Tianjin was the second largest in China (Song, 2000(Song, , 2001. Many studies have reported that PCP production may be a very important source of polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) (Hagenmaier and Hermann, 1987;Rappe et al, 1991;Bao et al, 1995;Zheng et al, 1997;Xu et al, 2000). Endemic chloracne among the workers in a plant located in this chemical industry zone had been noted since 1974 (Cheng et al, 1993).…”

Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans in China and chemometric analysis of potential emission sources

“…Multilayer silica column purification was commonly adopted, but the composition and structure of the column varied between different researchers (Luksemburg et al, 1996;Zheng et al, 1997;Wu et al, 2001a;Chen et al, 2003b;Hu et al, 2005). Water samples were enriched by XAD (Suplco Company), then freeze-dried and extracted by Soxhletapparatus (Wu et al, 2001b).…”