Distribution of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in aquatic model ecosystem

Manmade organic compounds in the surface waters of the United States: a review of current understanding

“…They typically found that from 93 to 96 percent of the ~ecovered radioactivity was from the sediment, and speculated that inuch of the remaining TCDD was associated with dissolved organic matter. Similar results also were reported by Isensee and Jones (1975), who observed that from 85 to 99 percent of the TCDD originally added to a model ecosystem remained in the sediment after a 39-day period.…”

“…Thirdly, dissolved organic matter may enhance the solubility of organic compounds which in turn would result in lower apparent BCFs than predicted by a compound's K . Finally, Niimi and McFadden (1982) and Oliver and Niimi (1983) ow I have observed that BCFs increase slightly with increasing solute concentration (although Isensee and Jones (1975) and Canton and others (1977) did not observe variance of BCFs with the solute's aqueous concentration). Despite these possible sources of variation in the prediction of BCFs, consideration of the lipid contents of different aquatic organisms will likely ·result in better comparability of BCFs.…”

“…TCDD appears to be the most toxic of the PCDDs, with an L0 50 of just 2 ~g/kg for guinea pigs. TCDD LD 50 values of 10 ~g/~g for rabbits and 0.6 JJg/kg for guinea pigs have also been documented (Isensee and Jones, 1975).…”

“…By contaminating aquatic microcosms with TCDD sorbed to sediment, Isensee and Jones (1975) found that BCFs for a variety of organisms ranged from 1,000 to 63,300. After 30 days of exposure, equilibrium aqueous concentrations of TCDD as low as 50 pg/L (picograms per liter) caused TCDD concentrations in daphnids to be as great as 2.4 pg/L (corresponding to a BCF of 48,000) .…”

Degradation of 2,7-dichlorodibenzo-p-dioxin by the lignin-degrading basidiomycete Phanerochaete chrysosporium

“…In addition, PCDDs have been identified in paper pulp mill effluents (25) and in ash generated by a variety of combustion processes (40). Since PCDDs are relatively chemically stable and lipophilic in nature (25,40,43), their accumulation in the food chain has been predicted and observed (3,14,29,36). In addition, studies have concluded that these compounds are degraded very slowly by soil bacteria (9,38,41), probably increasing their environmental impact.…”