수은 고노출 지역 초등학생의 수은노출수준과 노출요인 연구

Abstract

Objectives: Blood mercury levels among adults living in certain areas of the Gyeongsang Provinces have beenshown to be very high (Kunwee County 29.6 μg/L, Yeongcheon-city 26.7 μg/L). The purpose of this project wasto determine mercury exposure levels in schoolchildren and factors related with their mercury levels in highmercury exposure areas identifyed by the 2007 Korea National Environmental Health Survey. Methods: From June to September 2010, 1,097 students from grades 3 to 6 at 19 elementary schools participatedin this study, including 294 students from 10 elementary schools in Kunwee County, 529 students fromYeongcheon City, 122 students from two elementary schools in Pohang City, North Gyeongsang Province, and152 students from two elementary schools in Ulsan Metropolitan City. Biological samples from schoolchildren,including whole blood, urine and hair, were collected to measure total mercury at the time of a health check up. Information about children was collected by questionnaire. Total mercury concentrations in blood were measuredusing the Direct Mercury Analyzer 80 with the gold-amalgam collection method. Results: The mean mercury levels were 2.70 μg/L in 1,091 blood samples, 2.25 μg/g-creat. in 820 urinesamples and 1.03 μg/g in 1,064 hair samples. Blood mercury levels in the schoolchildren was slightlyhigher than the result of 2.4 μg/L from a 2006 survey of elementary school children on exposure and healtheffects of mercury by the National Institute of Environmental Research. However, 0.3% and 4.5% ofparticipants exceeded the reference level of blood mercury by CHBMII (15 μg/L) and the US EPA (5.8 μg/L), respectively. The reference level of urine by CHBMII (20 μg/L) was exceeded by 0.4% of participants. As factors, residence period in the study areas, residence type, father’s education level and income allshowed significant associations with mercury level in the biological samples. The number of dentalamalgam sides showed an association with urine mercury. Fish intake preference and fish intake frequencywere important factors in mercury levels. In particular, intake of shark meat and recent intake of shark meatwere associated with higher mercury levels. In this regard, participation in the performance of an ancestralrite showed a relation with higher mercury levels. Conclusion: The intake of shark meat was very important factor to high mercury exposure level. It isrecommended to monitor and manage students with high mercury exposures who exceeded CHBM II and EPAguidelines, and include blood mercury testing in the Children’s Health check up for this province.