Water-level fluctuations influence sediment porewater chemistry and methylmercury production in a flood-control reservoir.

ABSTRACT: Reservoirs typically have elevated fish mercury (Hg) levels compared to natural lakes and rivers. A unique feature of reservoirs is water-level management which can result in sediment exposure to the air. The objective of this study is to identify how reservoir water-level fluctuations impact Hg cycling, particularly the formation of the more toxic and bioaccumulative methylmercury (MeHg). Total-Hg (THg), MeHg, stable isotope methylation rates and several ancillary parameters were measured in reservoir sediments (including some in porewater and overlying water) that are seasonally and permanently inundated. The results showed that sediment and porewater MeHg concentrations were over 3-times higher in areas experiencing water-level fluctuations compared to permanently inundated sediments. A

SUBMITTER: Eckley CS 

PROVIDER: S-EPMC6498431 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature