SYNOPSIS. Current risk assessment techniques for almost all chemicals involve establishing a threshold dose, or the dose below which no adverse effects are seen. But threshold doses may not apply in situations where the chemical mimics the actions of an endogenous compound—such as a steroid hormone—that is important to development. In such cases, any exposure may exceed the threshold. Recent st...

This article demonstrates the feasibility of a novel process concept for the remediation of PCB contaminated soil. The proposed process consists of PCB extraction from soil using solid polymer beads, followed by biodegradation of the extracted PCBs in a solid-liquid two-phase partitioning bioreactor (TPPB), where PCBs are delivered from the polymer beads to the degrading organisms. The commerci...

The purpose of this experiment was to determine the effects of Aroclor 1242, a mixture of polychlorinated biphenyls (PCBs), on plumage characteristics and molt in the American kestrel, Falco sparverius. Several characteristics of plumage, including color and molt schedule, are modulated by hormonal signals and hence may be modified by endocrine-active contaminants. If so, the functions of pluma...

Psychrotolerant polychlorinated biphenyl (PCB)-degrading bacteria were isolated at 7 degreesC from PCB-contaminated Arctic soil by using biphenyl as the sole organic carbon source. These isolates were distinguished from each other by differences in substrates that supported growth and substrates that were oxidized. 16S ribosomal DNA sequences suggest that these isolates are most closely related...

The possibilities and limitations of analyses of polychlorinated biphenyls (PCBPs) by capillary gas chromatography and capillary gas chromatography-mass spectrometry have been investigated. Metal capillary columns (WCOT) coated with Apiezon L and OV-101 were not suitable for PCB analyses. Good results were obtained in the separation of model mixtures of PCBs and of Aroclor 1242 on a glass capil...

The Mongol invasion of Eastern Europe, and especially its sudden withdrawal from Hungary in 1242 CE, has generated much speculation and an array of controversial theories. None of them, however, considered multifaceted environmental drivers and the coupled analysis of historical reports and natural archives. Here we investigate annually resolved, absolutely dated and spatially explicit paleocli...

Microprobe two-step laser desorption/laser ionization mass spectrometry (μLMS) is used as a new analytical technique for the detection of polychlorinated biphenyls (PCBs). Three standard Aroclor solutions (Aroclor 1232, 1242, and 1262) and three samples of activated carbon spiked with Aroclor 1242 are examined. All the PCBs present in the Aroclor solutions are clearly identified using μLMS. The...

Xenobiotics suspected of being estrogenic-the PCB aroclor 1242 and the pesticides toxaphene, dieldrin, p,p'-DDD, cis-Nonachlor, trans-Nonachlor, p,p'-DDE, and chlordane-were examined for their ability to override a male-producing incubation temperature and result in female hatchlings in the red-eared slider, a turtle with temperature-dependent sex determination. Compounds were assayed in the en...