Sampling of total mercury in sand on Sydney beaches and assessment of risk of exposure to children

Abstract

Accumulation of anthropogenic mercury (Hg) onto coastal environments is potentially putting children playing in these areas, particularly beaches, at risk of exposure to mercury through the ingestion of sand. Samples were collected along 11 of Sydney's beaches and two Newcastle beaches where children may be exposed and analysed using a Direct Mercury Analyser (DMA-80). Risk of exposure was assessed based on Health Canada's exposure threshold for the ingestion of total mercury of 105ng Hg kg-1 BW d-1 and USEPA published values of daily ingestion rates by children (0.2g soil d-1 and 1.75g soil d-1). Concentrations of total mercury in beach sand ranged from 0.0035 to 57.89µg kg-1. Beaches with the highest Hg concentration were found to be located in close proximity to potential mercury sources. The highest daily intake calculated was 7.132ng Hg kg-1 BW d-1, well below the daily intake threshold, indicating children have a minimal exposure risk.