The potential for bioaccumulation of tungsten in earthworms - the effect of legacy lead on biouptake

Abstract

Studies have shown that the metal components in a soil influence the geochemical processes that occur in that soil (McGregor and Blowes 2002; Dermatas 2004; Petrunic and Al 2005). Since tungsten–nylon rounds have been fired on ranges that have historically been used for training using lead rounds, questions have been raised as to the effect that tungsten has on weathered lead and the other constituents in soils. Possible interactions with the various metals in the soil may affect tungsten’s solubility or sorption properties, which may in turn influence its bioavailability. In order to determine the effect of weathered lead on tungsten biouptake, a bioavailability study was conducted using earthworms (Eisenia fetida). This study allowed direct comparison of lead and tungsten biouptake in a variety of soils amended with weathered lead and fired on with tungsten–nylon bullets. The effects of soil aging on biouptake were also studied. Results indicate that changes in earthworm biouptake of lead and tungsten, which resulted from the presence of legacy lead (LL) material in soils, varied and were soil-type dependent. Soil aging generally did not affect the biouptake of lead or tungsten by earthworms.