| Aquatic products like fish and shellfish contain high-quality protein and other essential nutrients thus are common in human diets. However, they are polluted by Hg and other compounds from industrial pollution and other sources. MeHg is a highly neurotoxic pollutant which can accumulate within the bodies of aquatic organisms and transfer through the food chain, and ultimately cause damage to human being consuming these foods.This essay studies the content of THg and MeHg in 12 species of commercial origin and 4 species of fish from local fishermen, and makes surveys on the amount of fish residents typically eat and their living habits to perform statistical analysis. The study results discuss the amount of dietary exposure and exposure risk of residents living in the Pearl River Delta, and suggest some preventive measures and dietary recommendations. Specific contents are as follows:1,Analysis of methylmercury automatic analysis system optimized experimental conditions;The experimental results show that when the N2 purge time is set to 5min, the flow rate of N2 and Ar were 344 mL/min and 34 mL/min respectively. Hg0, MeHg and ethyl Hg have the best separation and speed when the GC is at 40℃. Within the normal range of MeHg analysis curve, the best dosage of reagent ethyl is 40μL; using KOH solution or KOH/CH3OH solution digesting the reference material DORM-3, the results showed high accuracy and precision.2,Typical consumption of fish in the Pearl River Delta region containing THg and MeHg and calculation and risk assessment of external exposure of human:This study evaluates the content and distribution of THg and MeHg in commercial fish in 4 representative cities in the Pearl River Delta (zhanjiang,guangzho,shenzhen,zhuhai), and assesses the human THg and MeHg exposure level in the region using relevant internationally recognized standard of THg and MeHg on fish-eating exposure. The results show that MeHg of fish muscle is in the range of 2.39～349μg·kg-1,,with an average concentration of 43.4μg·kg-1. MeHg contents of fish of different feeding habits are:carnivorous>omnivorous>herbivorous, in concert with these segments of the food chain as an explanation of the difference in mercury content in these fishes. In terms of growth environment, marine fish muscle contains higher MeHg concentration than that of freshwater fish. Comparing fish from various regions, fish from Guangzhou city contain similar MeHg levels to fish from other regions in China, but significantly lower than that of wild fish. MeHg intake by fish-eating residents of the range of 0.035～0.087μg·(kg-d)-1(bw), mean 0.050μg·(kg·d)-1(bw), which is well below the U.S.EPA guideline for MeHg exposure reference dose(RfD)value(1.1μg·(kg·d)-1), and also lower than the WHO/FAO formulated to withstand temporary weekly intake(PTWI)(1.6μg·kg-1). The results show that MeHg exposure of Guangzhou residents from eating fish is small, but attention should be directed to children and other sensitive group in terms of both frequency and specific amount of fish consumption.3,Pearl river delta region within the human body THg and MeHg exposure and risk assessment;The content of marine fish in the range of 27～362μg/kg in a Zhanjiang fishing village, the average content of 90μg/kg, the overall low. Because diet habits are unique, local residents still have a high content of human hair MeHg in the range of 190～3323μg/kg, the average concentration of 929μg/kg. According to different diet habits, different gender, different age groups hair THg and MeHg concentration level of the Pearl river delta region to determine the main source of human MeHg, assess their risk of exposure, MeHg content and THg, the relationship between age of Zhanjiang city, Guangzhou, Shenzhen, Zhuhai city four levels of human hair at a low level of MeHg.
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