Bioconcentration of Polychlorinated Norbornene and Norbornadiene

Heptachloronorbornene (l,2,3,4,5,7,8-heptachlorobicyclo[2,2,l]hept-2-ene) is produced by the Diels-Alder reaction by addition of vinylchloride to cyclopen-tadiene. This product is converted by dehydrochlorination to hexachloronor-bornadiene (l,2,3,4,7,7-hexachlorobicyclo[2,2,l]hepta-2,5-diene) which is an intermediate in the syntheses of the stable chlorinated cyclodiene insecticides. Hexachloronorbornadiene (HCND) and heptachloronorbornene are very hydrophobic chemical intermediates with very high log Kqw values of 5.15 

Spehar et al. [231] investigated the bioconcentration potential of hexachloro-norbornadiene and heptachloronorbornene using 30-day flow-through test with early juvenile fathead minnows Pimephales promelas) with a body weight of 0.12 g and 4% lipid content. The measured mean concentrations of hexa-chloronorbornadiene (HCND) in water was 20.0 3.9 pg and the water concentration of heptachloronorbornene (HepCNB) was 25.9 3.4 pg b. The bioconcentration factors on a wet weight basis after 30 days in this fish species were 6,400 and 11,200, respectively. The bio concentration factors on a lipid basis (BCFl) of HCND and HepCNB after 30 days were 160,000 and 280,000, respectively (see Table 13). 

---