No 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

An extensive investigation on the input, formation and fate of PCDD/Fs in a pulp mill using reeds as raw materials in China was carried out. The main PCDD/Fs input in the production process came from reeds, which may be contaminated by PCDD/Fs from sodium pentachlorophenate to control snailborne schistosomiasis. High levels of I-TEQ in the products were observed. Ó