Biological effects of high molecular weight lignin derivatives.

A number of high molecular weight (HMW) lignin derivatives possessing varied chemical properties were screened for their biological effects in order to obtain more information on the possible structural features of HMW lignin-related effects. The studied compounds were both commercial and in-house extracted lignin derivatives. Bioassays used include reverse electron transport (RET), Vibrio fischeri, Daphnia magna, and juvenile rainbow trout (Oncorhynchus mykiss) hepatocytes.

In vivo and in vitro toxicity of decabromodiphenyl ethane, a flame retardant.

Toxicity of a relative new flame retardant, namely decabromodiphenyl ethane (DBDPE), marketed as an alternative to decabromodiphenyl ether (BDE-209) was assessed both in vivo and in vitro using the freshly separated fish hepatocyte assay and standardized water flea and zebrafish egg-larvae tests. The fish hepatocyte assay, based on the synthesis and secretion of vitellogenin from isolated male liver cells produced a clear dose-response curve in the presence of DBDPE. DBDPE induced the induction of hepatic ethoxyresorufin-O-deethylase (EROD) activity at low test concentrations, but started to inhibit the activity at higher concentrations.

Comparison of toxicity of congener-153 of PCB, PBB, and PBDE to Daphnia magna.

Acute and reproductive toxicity tests were performed to assess the effects of two polybrominated flame retardants, polybrominated biphenyl (PBB)-153, polybrominated diphenyl ether (PBDE)-153, and polychlorinated biphenyl (PCB)-153 on Daphnia magna. According to the 24-h acute toxicity test, up to concentration of 210 microg/L, these chemicals were not toxic to Daphnia. In the reproductive tests, we used concentrations of 12.

Strain difference in sensitivity to 3,4-dichloroaniline and insect growth regulator, fenoxycarb, in Daphnia magna.

Acute and reproductive toxicity tests were conducted on seven strains of Daphnia magna from six laboratories in five countries. 3,4-Dichloroaniline (DCA) and fenoxycarb were used as test chemicals. Acute toxicity tests revealed that estimated EC(50) (50% effective concentration) values for DCA varied by a factor of 2.

In vitro estrogenicity of polybrominated flame retardants.

Estrogenicity of five brominated flame retardants (BFRs), namely BDE-47, BDE-99, BDE-205, PBB-153 and technical Firemaster BP-6, were assessed by in vitro assays developed to detect chemicals with estrogenic properties. Recombinant yeast cells containing a human estrogen receptor gene failed to give any response to the chemicals tested. However, the positive control compound, estradiol-17beta, showed that the yeast cell assays had worked properly.

Estrogenicity of phytosterols evaluated in vitro and in vivo.

The estrogenic activity of two phytosterol preparations was evaluated in vitro and in vivo. For the in vitro evaluation, freshly separated hepatocytes of rainbow trout were used. By contrast, the in vivo evaluation was performed by injecting the phytosterols intraperitoneally into juvenile rainbow trout.

Evaluation of wastewater effluents by small-scale biotests and a fractionation procedure.

Municipal and industrial effluents were screened with a battery of biotests and with a modified toxicity identification evaluation Phase I procedure. The acute toxicities of the effluent samples were low and the submitochondrial reverse electron-transport (RET) test was the most sensitive toxicity test. Estrogenic effects were found in almost all effluent samples, and genotoxicity was detected in one concentrated effluent sample.

Estrogenicity of municipal effluents assessed in vivo and in vitro.

The estrogenic potency of municipal sewage treatment plant effluents was studied by comparing in vitro and in vivo test methods. The egg yolk protein precursor vitellogenin was used as a biological indicator of estrogenicity. The in vitro screening technique, based on the synthesis and secretion of vitellogenin from isolated rainbow trout liver cells and performed in the presence of estrogenic effluents, produced a dose-response curve.

Thermal and metabolic factors affecting bioaccumulation of triazine herbicides by rainbow trout (Oncorhynchus mykiss).

The bioaccumulation of the triazine herbicides terbutryn and terbuthylazine in rainbow trout was investigated at water temperatures of 4 degrees C, 10 degrees C, and 17 degrees C. The synergetic effect of water temperature and herbicide on fish liver detoxification metabolism was also studied by measuring liver ethoxyresorufin-O-deethylase (EROD) and UDP-glucuronosyltransferase (UDPGT) activities. The bioaccumulation of terbutryn increased significantly with increasing water temperature.

Effects of phytosterols on zebrafish reproduction in multigeneration test.

Zebrafish from mixed sex populations were exposed continuously across three generations to two phytosterol preparations both containing -sitosterol. The phytosterols were isolated from wood and soy beans. Blood vitellogenin levels and sex ratio changes were used as intermediate indicators of the reproduction failures.