Activated carbon mitigates mercury and methylmercury bioavailability in contaminated sediments.
Environ Sci Technol
; 47(22): 13001-10, 2013 Nov 19.
Article
em En
| MEDLINE
| ID: mdl-24156748
ABSTRACT
There are few available in situ remediation options for Hg contaminated sediments, short of capping. Here we present the first tests of activated carbon and other sorbents as potential in situ amendments for remediation of mercury and methylmercury (MeHg), using a study design that combined 2 L sediment/water microcosms with 14 day bioaccumulation assays. Our key end points were pore water concentrations, and bioaccumulation of total Hg and MeHg by a deposit-feeding oligochaete Lumbriculus variegatus. Four amendments were tested an activated carbon (AC); CETCO Organoclay MRM (MRM); Thiol-SAMMS (TS), a thiol-functionalized mesoporous silica; and AMBERSEP GT74, an ion-exchange resin. Amendments were tested in four separate microcosm assays using Hg-contaminated sediments from two freshwater and two estuarine sites. AC and TS amendments, added at 2-7% of the dry weight of sediments significantly reduced both MeHg concentrations in pore waters, relative to unamended controls (by 45-95%) and bioaccumulation of MeHg by Lumbriculus (by between 30 and 90%). Both amendments had only small impacts on microcosm surface water, sediment and pore water chemistry, with the exception of significant reductions in pore water dissolved organic matter. The effectiveness of amendments in reducing bioaccumulation was well-correlated with their effectiveness in increasing sedimentwater partitioning, especially of MeHg. Sediments with low native sedimentwater MeHg partition coefficients were most effectively treated. Thus, in situ sediment sorbent amendments may be able to reduce the risk of biotic Hg and MeHg uptake in contaminated sediments, and subsequent contamination of food webs.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Poluentes do Solo
/
Carvão Vegetal
/
Sedimentos Geológicos
/
Mercúrio
/
Compostos de Metilmercúrio
Limite:
Animals
Idioma:
En
Revista:
Environ Sci Technol
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Estados Unidos