Bioaccumulation concentration factors

TABLE 24. Bioaccumulation (pgPbg 1 dry weight), concentration factor and biological half-time (/ 2- day) for lead uptake in three different trophic levels of organisms (modified from Reference 134)... 

Food Chain Bioaccumulation. Bioconcentration factors have been determined for algae, shellfish, and fish and exhibit a wide range (29-17,000) (ERA 1976 Oliver and Niimi 1983 Pearson and McConnell 1975). This wide range may be explained in part by species differences in metabolism or differences in concentrations tested. Studies also indicate that hexachlorobutadiene preferentially accumulates in the livers of fish. Further studies which might explain the wide range of BCF values would be helpful. No information was located regarding the bioaccumulation of hexachlorobutadiene in plants or aquatic organisms. More information is needed to determine the importance of terrestrial/aquatic food chain bioaccumulation as a potential human exposure pathway. 

Table III shows the levels of aminocarb present in mayfly nymphs sampled from Portage Brook following the 1st application. Aminocarb concentrations found in insects were not high and no breakdown products of the insecticides were found. The peak concentration detected is only 20 ppb (1 h post-application) exposed to a maximum of 2.26 ppb aminocarb in water, representing a concentration factor of oa 9. Residues declined to below detection limits ( < 20 ppb) rapidly afterwards coinciding with the disappearance of residues in stream water indicating that the uptake and bioconcentration potential by the insects for aminocarb were not high. Further work is necessary to confirm this observation since Penny (16) reported that the other insecticide, fenitrothion, is readily bioaccumulated by aquatic insects yielding a concentration factor of about 60.

For measuring the bioaccumulation of " Tc in fishes and snails a small experimental freshwater pond was spiked with " I c. The concentration factors based on the calculated body burden (fresh wt) for carps Caprinus carpio), mosquitofishes Gam-busia affinis). and snails (Helisoma sp.) were 11, 75, and 121, respectively. ITic effective biological half-lives were 2,5,4.3 and 21.3 d. respectively [69]. 

Endosulfan does not bioaccumulate to high concentrations in terrestrial or aquatic ecosystems. In aquatic ecosystems, residue levels in fish generally peak within 7 days to 2 weeks of continuous exposure to endosulfan. Maximum bioconcentration factors (BCFs) are usually less than 3,000, and residues are eliminated within 2 weeks of transfer to clean water (NRCC 1975). A maximum BCE of 600 was reported for a-endosulfan in mussel tissue (Ernst 1977). In a similar study, endosulfan, isomers not specified, had a measured BCE of 22.5 in mussel tissue (Roberts 1972). Tissue concentrations of a-endosulfan fell rapidly upon transfer of the organisms to fresh seawater for example, a depuration half-life of 34 hours (Ernst 1977). Higher BCFs were reported for whole-body and edible tissues of striped mullet (maximum BCF=2,755) after 28 days of exposure to endosulfan in seawater (Schimmel et al. 1977). However, tissue concentrations decreased to undetectable levels 48 hours after the organisms were transferred to uncontaminated seawater. Similarly, a BCE of 2,650 was obtained for zebra fish exposed to 0.3 pg/L of endosulfan for 21 days in a flow-through aquarium (Toledo and Jonsson 1992). It was noted that endosulfan depuration by fish was rapid, with approximately 81% total endosulfan eliminated within 120 hours when the fish were placed in a tank of water containing no endosulfan. 

Bioaccumulation factor (BAF) Concentration of a chemical in an animal, or concentration of the same chemical in its food. 

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