TOXICOLOGICAL SIGNIFICANCE OF NON-ORTHO-SUBSTITUTED, MONO-ORTHO-SUBSTITUTED AND DI-ORTHO-SUBSTITUTED POLYCHLORINATED-BIPHENYLS IN OYSTERS FROM GALVESTON AND TAMPA BAYS
Jl. Sericano et al., TOXICOLOGICAL SIGNIFICANCE OF NON-ORTHO-SUBSTITUTED, MONO-ORTHO-SUBSTITUTED AND DI-ORTHO-SUBSTITUTED POLYCHLORINATED-BIPHENYLS IN OYSTERS FROM GALVESTON AND TAMPA BAYS, Environmental toxicology and chemistry, 13(11), 1994, pp. 1797-1803
Concentrations of non-ortho (77, 126, and 169), mono-ortho (105 and 11
8) and di-ortho (128 and 138) -substituted PCB congeners were measured
in oysters from Galveston and Tampa bays, and reported toxic equivale
nt factors were used to assess their toxicity. Most of the relative to
xicity encountered in the oysters analyzed during this study was due t
o the presence of planar non-ortho-PCBs (53.8-94.3%), particularly con
gener 126. In contrast, the contribution of di-ortho-substituted PCB c
ongeners to the total relative toxicity of the samples was negligible
(<1%). On average, the contribution of each of these non-, mono-, and
di-ortho-substituted PCB congeners to the total toxicity encountered i
n oysters from Galveston and Tampa bays were 126 > 118 greater than or
equal to 169 greater than or equal to 105 > 77 >> 138 > 128 and 126 >
118 > 169 greater than or equal to 77 > 105 >> 138 > 128, respectivel
y. Based on the reported lower clearance rates of non-ortho- and mono-
ortho-substituted PCB congeners compared to other congeners within the
same chlorination level, contaminated oysters that are depurated in c
lean environments will lower their total PCB concentrations, but their
original toxicity may not be proportionally reduced.