5.2.1 Labeling 5.2.2 Inspection

Polychlorinated biphenyls (PCBs) are most commonly found in electrical equipment such as transformers, klystrons, capacitors, and fluorescent light ballasts that were manufactured before 1979. PCBs are a diminishing hazard at SLAC because PCB-containing equipment is maintained in a manner that reduces PCB contamination, and in many cases such equipment has been replaced. As of 2004, approximately 24 pounds of the material remains in transformers, and systematic replacement of equipment will eventually eliminate PCBs from other sources completely. PCB-containing equipment or PCB-contaminated material is strictly regulated under the Toxic Substances Control Act (TSCA) and it must be handled and disposed of in accordance with the requirements described in this chapter. 1.1 Hazards/Impacts PCBs are known to cause chronic reproductive effects, gastric disorders, and skin lesions in laboratory animals, and the US Environmental Protection Agency (EPA) has identified PCBs as probable human carcinogens. In humans and animals, PCBs accumulate in fatty tissues. In the environment, PCBs degrade very slowly, so they pose a risk to animals all along a food chain because they bio-accumulate. At SLAC hazards associated with PCBs include Exposure. If PCB-containing oil or material leaks or is accidentally released or spilled, workers may be exposed through skin contact or by accidental ingestion. Exposure to PCBs and toxic by-products due to fire or explosion. PCBs and highly toxic dioxin may be inhaled when PCB-contaminated oil or equipment burns. Slippery surfaces. Oil leaking from electrical equipment containing PCBs could cause slips or falls. Typical PCB-containing items at SLAC ar

Prepared under a Cooperative Agreement with the

A health consultation is a verbal or written response from ATSDR or ATSDR’s Cooperative Agreement Partners to a specific request for information about health risks related to a specific site, a chemical release, or the presence of hazardous material. In order to prevent or mitigate exposures, a consultation may lead to specific actions, such as restricting use of or replacing water supplies; intensifying environmental sampling; restricting site access; or removing the contaminated material. In addition, consultations may recommend additional public health actions, such as conducting health surveillance activities to evaluate exposure or trends in adverse health outcomes; conducting biological indicators of exposure studies to assess exposure; and providing health education for health care providers and community members. This concludes the health consultation process for this site, unless additional information is obtained by ATSDR or ATSDR’s Cooperative Agreement Partner which, in the Agency’s opinion, indicates a need to revise or append the conclusions previously issued

DOI: 10.1093/toxsci/kfg209 Inhibition of Gap Junctional Intercellular Communication by

Polychlorinated biphenyls (PCBs), a structurally diverse group of environmental pollutants, are effective promoters in two-stage cancer models, which implies that epigenetic mechanisms are involved. Inhibition of gap junctional intercellular communication (GJIC) belongs among critical epigenetic events of tumor promotion. We determined the relative potencies of a series of environmentally relevant PCB congeners to inhibit GJIC in vitro in a rat liver epithelial cell line with pluripotent oval cell characteristics. The nonplanar PCBs were potent inhibitors of GJIC, whereas the coplanar PCBs did not inhibit GJIC. We then compared the effects of the coplanar PCB 126 (3,3�,4,4�,5-pentachlorobiphenyl) and the noncoplanar PCB 153 (2,2�,4,4�,5,5�-hexachlorobiphenyl) with effects of two model GJIC inhibitors, a tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) and epidermal growth factor (EGF). In contrast to TPA or EGF, PCB 153 elicite

Di-n-butylphthalate

Di-n-octylphthalat

P-448 BY MICROSOMAL HEME OXYGENASE, AND THE INHIBITION OF 8-AMINOLEVULINATE DEHYDRATASE BY POLYCHLORINATED BIPHENYLS

Cobalt(ous) ion regulates cellular heme metabolism in the intact animal (1-7) as welt as in cultured hepatocytes 1 through effects on the activities of microsomal heme oxygenase and on the mitochondrial enzyme 8-aminolevulinate synthetase (ALAS)Y The metal effects on the latter enzyme result in an initial inhibition of ALAS activity which is then followed by induction of the enzyme (2, 5). The effect of cobalt on heme oxygenase, the enzyme that catalyzes degradation of heme compounds, is only that of induction (1-7 and footnote 2). In the course of a number of studies we have noted that concomitant with the induction of hepatic heme oxygenase by cobalt there is a marked decrease in microsomal heme and cytochrome P-450 contents and prototypic P-450-dependent drug-metabolizing enzyme activities. These observations have led us to propose that the increased activity of heme oxygenase is responsible for the decrease in the cellular content of cytochrome P-450 and consequently the decrease in drug oxidative activities (3, 6, 8). Studies with the isotopically labeled heme precursor 8-aminolevulinate (ALA) have confirmed this idea, an

Research

Objectives: The objective of this article is to extend our previous studies of persistent organic pollutant (POP) contamination of U.S. food by measuring perfluorinated compounds (PFCs), organochlorine pesticides, and polychlorinated biphenyls (PCBs) in composite food samples. This study is part of a larger study reported in two articles, the other of which reports levels of polybrominated diphenyl ethers and hexabromocyclododecane brominated flame retardants in these composite foods [Schecter et al. 2010. Polybrominated diphenyl ethers (PBDEs) and hexabromocyclodecane (HBCD) in composite U.S. food samples, Environ Health Perspect 118:357–362]. Me t h o d s: In this study we measured concentrations of 32 organochlorine pesticides, 7 PCBs, and 11 PFCs in composite samples of 31 different types of food (310 individual food samples) purchased from supermarkets in Dallas, Texas (USA), in 2009. Dietary intake of these chemicals was calculated for an average American. Re s u l t s: Contamination varied greatly among chemical and food types. The highest level of pesticide contamination was from the dichlorodiphenyltrichloroethane (DDT) metabolite p,p´‑dichlorodiphenyldichloroethylene, which ranged from 0.028 ng/g wet weight (ww) in whole milk yogur

INE PCDD/PCDF: Human Background Data for Germany, a 10-Year Experience

This paper gives an overview of the development of the environmental or background exposure of humans to polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in Germany. To determine the background exposure, adipose tissue, human milk, or blood can be used. The good comparability of the matrices analyzed is demonstrated. The daily consumption of low-level contaminated food, mainly of animal origin, leads to the accumulation of PCDDs/PCDFs in the human adipose reservoir. The influence of factors such as various eating habits, severe weight loss, age, and nursing (women only) on the human body burden is discussed. Because of decreasing humans could emission of PCDDs/PCDFs into the environment, a decline of these components in be observed over a time span of 10 years. Environ Health Perspect 1 06(Suppl 2):723-731 (1998)