Menu
:
:



Arsenic (V) bioconcentration kinetics in freshwater macroinvertebrates and periphyton is influenced by pH

1024 681 Stroud Water Research Center

Lopez, A.R., D.H. Funk, and D.B. Buchwalter. 2017. Environmental Pollution 224:82–88.

doi: 10.1016/j.envpol.2016.12.066

Abstract

Arsenic is an important environmental pollutant whose speciation and mobility in freshwater food webs is complex. Few studies have characterized uptake and efflux rates of arsenic in aquatic benthic invertebrates. Further, we lack a fundamental understanding of how pH influences uptake kinetics in these organisms or how this key environmental variable could alter dietary exposure for primary consumers. Here we used a radiotracer approach to characterize arsenate accumulation dynamics in benthic invertebrates, the influence of pH on uptake in a subset of these organisms, and the influence of pH on uptake of arsenate by periphyton – an important food source at the base of aquatic food webs. Uptake rate constants (Ku) from aqueous exposure were modest, ranging from ∼0.001 L g−1d−1 in three species of mayfly to 0.06 L g−1d−1in Psephenus herricki. Efflux rate constants ranged from ∼0.03 d−1 in Corbicula fluminea to ∼0.3 d−1 in the mayfly Isonychia sp, and were generally high. Arsenate uptake decreased with increasing pH, which may be a function of increased adsorption at lower pHs. A similar but much stronger correlation was observed for periphyton where Ku decreased from ∼3.0 L g−1d−1 at 6.5 pH to ∼0.7 L g−1d−1 at 8.5 pH, suggesting that site specific pH could significantly alter arsenic exposure, particularly for primary consumers. Together, these findings shed light on the complexity of arsenic bioavailability and help explain observed differences reported in the literature.

Give the Gift of Fresh Water

As you give thanks for the gifts in your life, we invite you to give the gift of water. Clean drinking water, good health, happy trout, productive soil, clean air, the simple joys of swimming, boating, fishing — our healthy freshwater ecosystems make these and so many other things possible.

Your donation today will help preserve and protect
the future of fresh water.