Depuration Study Research Articles

Short‐term tissue distribution, depuration and possible gene expression effects of [3H]TCDD exposure in soft‐shell clams (Mya arenaria)

AbstractA short‐term, waterborne exposure and depuration study of Mya arenaria to [3H]tetrachlorodibenzo‐p‐dioxin([3H]TCDD) was performed. Gill, digestive gland, foot, and gonad were sampled up to 2 weeks after a 24‐h exposure to a low dose (10 parts per trillion [pptr]) or high dose (2,000 pptr) of [3H]TCDD in the water. In the gill, peak concentrations occurred at the beginning of depuration (406 and 8,658 pg/g wet weight, low‐ and high‐dose groups, respectively), whereas peak concentrations in the digestive gland and foot were found 12 to 24 h after exposure (digestive gland, 539 and 9,369 pg/g wet weight; foot, 146 and 2,718 pg/g wet weight; low‐ and high‐dose groups, respectively). In contrast, tissue concentrations in the gonad increased through the post‐exposure period; at 2 weeks after exposure, tissue concentrations were highest in the gonad (243 and 3,012 pg/g wet weight, low‐and high‐dose groups, respectively). Examination of gill and gonad by differential display polymerase chain reaction identified potential alterations in expression of genes that may be associated with increased cell cycling or translation initiation. This study shows that M. arenaria can accumulate TCDD in the gonad from an acute exposure, and it identifies several M. arenaria genes whose expression may be altered by TCDD exposure.

Bioconcentration of linear alkylbenzene sulfonate (LAS) in bluegill ( Lepomis macrochirus)

The potential of the surfactant linear alkylbenzene sulfonate (LAS) to be bioconcentrated in various tissues and organs of bluegill ( Lepomis macrochirus) was determined during a 35 day continuous exposure to a mean measured water concentration of 0.5 (±0.05) mg l −1 14C-ring labelled LAS and during a 14 day depuration study. Based on the assumption that all of the 14C-radioactivity was present as intact LAS, which represents the maximum amount of LAS that could be present, the steady state whole body bioconcentration factor (BCF) was 104 and the muscle BCF was 36. The site of greatest concentration was the gall bladder with a BCF of approx. 5000. The BCF for liver, gills and viscera, remaining carcass, and blood ranged from 64 to 283. Clearance of 14C-activity from the organs and tissues was rapid with half-lives of 2–5 days. These results on LAS were obtained by both the plateau and kinetic methods of data analysis and are similar to other published data on surfactant bioconcentration.