Acute toxicity and toxicokinetics of chlorinated diphenyl ethers in trout

Abstract

1. The LC50 and the uptake and elimination kinetics of 4-chlorodiphenyl ether (4-CDE), 2,4-dichlorodiphenyl ether (2,4-diCDE), 2,4,4'-trichlorodiphenyl ether (2,4,4'-triCDE) and 2,4,5,4'-tetrachlorodiphenyl ether (2,4,5,4'-tetraCDE) were examined in brook trout (Salvelinus fontinalis). The chlorinated diphenyl ethers (CDE) were administered in the water. 2. The 96 h LC50 of 4-CDE and 2,4-diCDE were 0.73 and 0.66 mg/l, respectively. The LC50 of 2,4,4'-triCDE and 2,4,5,4'-tetraCDE could not be determined since they were greater than the water solubilities of these chemicals. 3. Uptake of the CDE by trout was rapid; the uptake rate ranged between 2.4 and 48.9 micrograms/day. However, CDE uptake by trout did not reach a steady state at the conclusion of a 7 day exposure. In contrast, depuration of the CDE from trout was slow; the depuration half-lives of the CDE ranged between 3.9 and 63 days. 4. The toxicokinetics of the CDE in trout could be described by a one-compartment open model with zero-order absorption and first-order elimination. The CDE were taken up initially into the blood and liver of trout before they were redistributed to adipose tissue and muscle. 5. CDE are significantly bioaccumulated by fish from water; the model-predicted maximum body burdens of trout exposed to 100 micrograms/l CDE in water are 146, 316, 1381, and 930 micrograms/g for 4-CDE, 2,4-CDE, 2,4,4'-triCDE and 2,4,5,4'-tetraCDE, respectively.

Ethoxyresorufin‐O‐deethylase induction potency of polychlorinated diphenyl ethers in H4IIE rat hepatoma cells

“…The acute toxicity of these PCDEs to trout occurred at about 1 mg/L [22]. In rats, 2,2Ј,4,4Ј-tetrachlorinated diphenyl ether (PCDE 47), 2,2Ј,4,4Ј,5,5Ј-hexachlorinated diphenyl ether (PCDE 153), and 2,2Ј,3,4,4Ј,6,6Ј-heptachlorinated diphenyl ether (PCDE 184) caused increased liver weights at 500 mg/kg [23].…”

“…The toxicity of a small number of PCDEs has been studied in trout and rat [22,23]. The acute toxicity of these PCDEs to trout occurred at about 1 mg/L [22].…”

Polychlorinated diphenyl ethers—A review

“…Radioactivity was found in all rat tissue examined with the greatest concentration in adipose tissue > skin > liver > kidney > muscle. 24 Chu et al 28 ' 29 also investigated the uptake and distribution of PCDE congeners in the rat. The results, which are consistent with those of Newsome et al, 21 showed that level of PCDEs deposited in liver and adipose tissue were dose dependent with adipose tissue having ten times the PCDE accumulation when compared to liver.…”

“…The PCDEs are rapidly taken up by trout, whereas their rate of elimination is slow and is related to their lipophilicity and biotransformation rates. 24 As noted for the PCBs, food and environmental samples will retain PCDE residues long after initial exposure. 27 The results of distribution and excretion studies conducted by Newsome et al 21 also indicated that the higher chlorinated PCDEs were expected to show an accumulation and tissue distribution pattern similar to that reported for PCBs.…”

“…Accumulation coefficients were concentration-dependent and did not show a trend relative to the number of chlorines. 26 Chui et al 24 demonstrated that PCDEs are significantly bioaccumulated by fish from their aqueous environment. Their studies showed that 4-chlorodiphenyl ether and 2,4-dichlorodiphenyl ether were more toxic to trout than 2,4,4'-trichlorodiphenyl ether and 2,4,4',5-tetrachlorodiphenyl ether.…”