Hair mercury levels and dietary exposure of mercury in relation to fish consumption among coastal population in Negombo, Sri Lanka

Abstract

Consumption of contaminated fish is the major source of the human exposure to total mercury (T-Hg) and methyl mercury. This study reports the fish consumption habits of three groups based on the age category and their occupation; “Children” (age 9-20 years) and two groups of “Adults” (age above 21 years) based on their occupation; “Adults-Fishermen” (fishermen) and “Adults-Other”. Hair T-Hg levels were measured from 30 individuals (age 9-48 years) from Negombo area in Sri Lanka. All individuals in this survey consumed fish at least six servings per week, which belongs to the high fish consumer category (> 3 servings/week) according to World Health Organization (WHO) guidelines. The main fish groups consumed by the respondents were mainly yellow-fin tuna (YFT), skipjack tuna (SKT), kawakawa and frigate tuna and small fish such as sardines (spotted sardines, goldstripe sardine, other sardines, scads and trevallies). The majority consumed an equal amount of big fish and small fish. The average weekly fish consumption per individual varied depending on the test group (Children; 1270 g/week per person, Adults-other; 1078 g/week per person and Adults-fishermen 1852 g/week per person) which exceeded United States Food & Drug Administration (USFDA) recommended level of 340 g/ week of seafood containing low concentration of Hg. The mean hair T-Hg of respondents of Negombo population was 4.89±3.23 µg/g (range 1.60-13.38 µg/g), which exceeded the United States Environmental Protection Agency (USEPA) reference dose (1 µg/g) for T-Hg level of hair. The total hair mercury in three respondent groups (Children 3.33±1.36 µg/g, Adults-other 2.89±1.26 µg/g and Adults-Fishermen 6.08±3.62 µg/g), were not significantly different (p>0.05) from each other. Real exposure value of three respondent groups were not significantly different (p>0.05). There was a low strength positive correlation (r=0.353, p>0.05) between hair T-Hg levels with the weekly large fish consumption.