Arsenic remobilization from sediments contaminated with mine tailings near the Adak mine in Vasterbotten district (northern Sweden)

• Weathering of mine tailings have resulted in high As concentrations in water (up to 2900 mu g 1(-1)) and sediment (up to 900 mg kg(-1)) samples around the Adak mine. Notably, As occurs as As(III) species (15-85%) in the oxic surface and ground water samples, which is not common. Time-series based sediment incubations were set up in the laboratory with contaminated sediments to study the microbial processes involved in transformation and remobilization of As across the sediment-water interface. The microcosm experiments indicate that microorganisms are capable of surviving in As-rich sediments and reduce As(V) to As(III). A decrease in total As concentration in sediments is coupled to an increase in As(Ill) concentration in the aqueous media. In contrast, the controls (treated with HgCl, and formaldehyde) did not show growth, and As(V) concentrations increased steadily in the sediments and aqueous medium. The results imply that active metabolism is necessary for As(V) reduction. These microorganisms possess reduction mechanisms that are not necessarily coupled to respiration, but most likely impart resistance to As toxicity.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Samhällsbyggnadsteknik -- Vattenteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Civil Engineering -- Water Engineering (hsv//eng)

Nyckelord

arsenic

microbes

microcosm

reduction

speciation

mobilization

ars operon homolog

escherichia-coli

west-bengal

reduction

mobilization

speciation

soil

sulfide

water

respiration

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)