Data from: Littoral sediment arsenic concentrations predict arsenic trophic transfer and human health risk in contaminated lakes

Lake sediments store metal contaminants from historic pesticide and
herbicide use and mining operations. Historical regional smelter
operations in the Puget Sound lowlands have resulted in arsenic
concentrations exceeding 200 μg As g-1 in urban lake sediments. Prior
research has elucidated how sediment oxygen demand, warmer sediment
temperatures, and alternating stratification and convective mixing in
shallow lakes result in higher concentrations of arsenic in aquatic
organisms when compared to deeper, seasonally stratified lakes with
similar levels of arsenic pollution in profundal sediments. In this study
we examine the trophic pathways for arsenic transfer through the aquatic
food web of urban lakes in the Puget Sound lowlands, measuring C and N
isotopes – to determine resource usage and trophic level – and total and
inorganic arsenic in primary producers and primary and secondary
consumers. Our results show higher levels of arsenic in periphyton than in
other primary producers, and higher concentrations in snails than in
zooplankton or insect macroinvertebrates. In shallow lakes arsenic
concentrations in littoral sediment are similar to deep profundal
sediments due to arsenic remobilization, mixing, and redeposition,
resulting in direct arsenic exposure to littoral benthic organisms such as
periphyton and snails. The influence of littoral sediment on determining
arsenic trophic transfer is evidenced by our results which show
significant correlations between total arsenic in littoral sediment and
total arsenic in periphyton, phytoplankton, zooplankton, snails, and fish
across multiple lakes. We also found a consistent relationship between the
percent inorganic arsenic and trophic level (determined by δ15N) in lakes
with different depths and mixing regimes. Cumulatively, these results
combine to provide a strong empirical relationship between littoral
sediment arsenic levels and inorganic arsenic in edible species that can
be used to screen lakes for potential human health risk using an easy,
inexpensive sampling and analysis method.