WP6 Emerging Pollutants
Wednesday, 16 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(WAN-1117-231323) Assessment of Human Exposure to Microcystin–LR.

Wang, P ¹, Billam, M¹, Tang, L¹, Cai, Q¹, Xu, M², Jiao, J², Lin, Y², Wang, J-S¹, ¹ Department of Toxicology & The Institute of Environmental and Human Health, Texas Tech University, Lubbock, Texas, USA² Wuxi City Center for Disease Control, Wuxi, Jiangsu, China

ABSTRACT- Microcystin–LR (MCLR) is a common hepatotoxic cyanotoxin frequently found in fresh water sources. Its ecotoxic effects were widely reported. MCLR is extremely stable in natural waters, which makes it an emerging pollutant for human exposure through drinking water or recreation activities. To assess the exposure level of human to MCLR, water samples were collected repeatedly in August 2004 from 5 sites along the flowing line of a water treatment plant in Nanquan, located at south of Wuxi City, Jiangsu, China, where heavily cyanobacterial contamination was reported for years. MCLR in water samples was determined with HPLC method. Higher levels of MCLR were found in water samples collected from different sampling sites: averaged 7.13±1.21ppb in sample from nearby the pumping site in Taihu Lake; averaged 5.24±1.66 ppb in samples from the reservoir of the water treatment plant; averaged 1.53±0.14 ppb in water samples collected after the precipitation and filtration in the plant, averaged 1.87±1.40 ppb in water samples collected at output tube post chlorination in the plant, and averaged 2.33±1.92 ppb in tubes distributed water to each household. In addition, averaged 23.90±30.56 ppb MCLR were found in water samples collected from Sanshan, a local water quality monitoring site, and averaged 7.01±4.75 ppb MCLR in water samples from Yutang, a site where fishermen resided. All sampling sites had MCLR levels greater than WHO guideline limit (1ppb). Based on the averaged MCLR level in household water and the daily water consumption recorded from 60 local residents (Male: 3397.02±1391.72 ml/day; Female: 2505.73±801.75 ml/day), a daily exposure to MCLR was estimated: Male, 7.92 g/day and Female, 5.84 g/day. These data provide useful information for future risk assessment, especially for high MCLR contamination sites in the world. (Supported by the research grant, CA94683, from NCI/NIH).

Key words: water pollutant, microcystins, biomonitoring, human exposure