The international trade in toxic waste: the case of Sihanoukville, Cambodia

Mercury content and consumption risk of 8 species threadfin bream (Nemipterus spp.) caught along the Gulf of Thailand

Total mercury (T-Hg) was examined in 8 threadfin bream species (Nemipterus spp.) caught in the Gulf of Thailand (GoT). The T-Hg contents ranged from 11.3 to 374 μg kg^-1 wet weight, with the lowest in Nemipterus peronii and the highest in Nemipterus nemurus and Nemipterus tambuloides. Accumulation of T-Hg in fish tissue was found to be related to fish size, trophic levels, feeding habits and habitat. Threadfin bream caught in the upper GoT exhibited significantly (p < 0.05) lower T-Hg than those in the middle and lower parts of GoT, which possibly due to local mercury sources e.g., internal anthropogenic activities in the GoT and external from terrestrial input via river discharge. The estimated daily intakes were ranged from 0.03 to 0.07 μg kg^-1 bodyweight day^-1. All threadfin breams in the GoT have HQ <1. To prevent the associated potential risk, the maximum safe daily consumption is recommended at 95.3 g day^-1.

Dietary exposure and risk assessment of mercury via total diet study in Cambodia

To assess the daily intakes of total mercury (THg) and methylmercury (MeHg) and the possible adverse health impacts, different food groups including fish, meat, vegetable and rice were collected from three areas in Cambodia. The concentrations of THg and MeHg ranged from 0.16 to 171 ng g(-1) and not detected (ND) to 82.3 ng g(-1) wet weight (ww), respectively. The concentrations of THg and MeHg in fish were approximately three to four orders of magnitude greater than that in fruit and vegetable. Fish had the highest contribution to the total daily intakes of THg and MeHg. The estimated daily intake (EDI) of THg for the general population in Kampong Cham, Kratie and Kandal was 0.24, 1.38 and 0.22 μg kg(-1) bw d(-1), and 0.11, 0.45 and 0.06 μg kg(-1) bw d(-1) for MeHg, respectively. The dietary daily intakes of MeHg in Kratie and Kampong Cham were greater than the reference dose (RfD) imposed by The United States Environmental Protection Agency (USEPA) and in Kratie was also exceed the provisional tolerable weekly intake (PTWI) imposed by World Health Organization (WHO). To our knowledge, this the first study to evaluate the daily intakes of THg and MeHg in Cambodia.

Mercury contamination in human hair and fish from Cambodia: levels, specific accumulation and risk assessment

Mercury (Hg) concentrations in human hair and fish samples from Phnom Penh, Kien Svay, Tomnup Rolork and Batrong, Cambodia, collected in November 1999 and December 2000 were determined to understand the status of contamination, and age- and sex-dependent accumulation in humans and to assess the intake of mercury via fish consumption. Mercury concentrations in human hair ranged from 0.54 to 190mug/g dry wt. About 3% of the samples contained Hg levels exceeding the no observed adverse effects level (NOAEL) of WHO (50mug/g) and the levels in some hair samples of women also exceeded the NOAEL (10mug/g) associated with fetus neurotoxicity. A weak but significant positive correlation was observed between age and Hg levels in hair of residents. Mercury concentrations in muscle of marine and freshwater fish from Cambodia ranged from <0.01 to 0.96mug/g wet wt. Mercury intake rates were estimated on the basis of the Hg content in fish and daily fish consumption. Three samples of marine fish including sharp-tooth snapper and obtuse barracuda, and one sample of sharp-tooth snapper exceeded the guidelines by US EPA and by Joint FAO/WHO Expert Committee on Food Additives (JECFA), respectively, which indicates that some fish specimens examined (9% and 3% for US EPA and JECFA guidelines, respectively) were hazardous for consumption at the ingestion rate of Cambodian people (32.6g/day). It is suggested that fish is probably the main source of Hg for Cambodian people. However, extremely high Hg concentrations were observed in some individuals and could not be explained by Hg intake from fish consumption, indicating some other contamination sources of Hg in Cambodia.