It was hypothesized that alterations in plasma concentrations of corticosterone (CS) and prolactin (PRL) may be at least partially responsible for polychlorinated biphenyl (PCB)-induced immunosuppression. A 2 by 2 factorial experiment examined the interactions of PCB and P815, an allogeneic tumor, on plasma concentrations of CS and PRL, and on body, spleen, and thymus weights. The PCB dosage used (10 mg/kg) was previously shown to suppress immune response to the tumor. The four study groups were: Group A (vehicle control), Group B (tumor only), Group C (PCB only), and Group D (tumor plus PCB). Mice received one dose of PCB (Groups C and D) or carrier (Groups A and B) on day -1; tumor (Groups B and D) or carrier (Groups A and C) was injected intraperitoneally on day 0. In Experiment 1, animals were killed on days -1, -0.6, 0 through 10, 21, 42, and 84. Body, spleen, and thymus weights were measured. Plasma samples were obtained for CS and PRL measurements. In Experiment 2, the study was repeated with samples obtained only on days 3 and 10. Group A body weights increased steadily throughout Experiment 1. Relative to Group A, the weight gain in Group B was significantly (p < 0.05) higher. Group C lost weight on days 0 through 6, and gained significantly (p < 0.05) less weight than Group A. Group D gained significantly (p < 0.05) less weight than Groups A, B, and C. As a percent of body weight, spleen weight remained constant over 21 days in Experiment 1 in both Groups A and D. Compared to Group A, Group B showed significantly (p < 0.05) increased spleen percent body weight while Group C showed significantly (p < 0.05) decreased spleen percent body weight. As a percent of body weight, thymus weight remained constant for 21 days in Experiment 1 in Group A. Groups Band C were similar (p > 0.05) and showed a decreased thymus percent body weight compared to Group A. Group D showed significantly (p < 0.05) decreased thymus percent body weight relative to the other three groups. Mean CS concentrations in Experiment 1 in Groups A and B were similar (p < 0.05). Relative to Groups A and B, Group C CS concentrations were elevated, with a peak of 126.1 ng/ml on day 4. Group D CS concentrations were higher than the other three groups, peaking at 294.1 ng/ml on day 10. There was no significant difference in PRL concentrations in Groups A, B, and C in Experiment 1 (p > 0.05). Mean PRL concentration in Group D was significantly (p < 0.05) lower than in the other three groups. The results of Experiment 2 validated those of Experiment 1. Although absolute values differed, the pattern of changes seen in body and organ weights and in CS and PRL concentrations was similar. An acute exposure to PCB and tumor resulted in an increase in circulating CS concentration and a decrease in circulating PRL concentrations. These changes may contribute to PCB-induced immunosuppressioin. / Graduation date:1992

Persistent Organic Pollutants (POPs), such as Polychlorinated Biphenyls (PCBs) or Hexachlorobenzene (HCB), released into water system. They will adsorb to particles, and incorporate into sediments. Thus the concentrations of PCBs and HCB in surface sediments provide information on recent contaminations. Besides, organisms in marine environment are influenced by the concentration in sediments, and so as the food chain. This study investigated the concentrations and characteristics of PCBs and HCB in surficial sediments of Kao-Ping Chi Estuary and nearby areas. The concentrations of PCBs and HCB in sediments were ranged from 1.432 to 6.681 (ng/g dry wt), and from 0.151 to 8.109 (ng/g dry wt¡^¡Awith an average of 3.219 and 1.978, respectively. Both of PCBs and HCB did not exceed the concentrations suggested by several sediment quality guidelines (SQGs). Compared with studies in other countries, the sediments in Kao-Ping coastal areas were more polluted by HCB. Neither PCBs nor HCB could correlate well with mean particle size or total organic carbon (TOC). The Toxic equivalents (TEQ) of dioxin-like PCBs and HCB were ranged from 0.014 to 0.061 pg-TEQ/g, and from 0.015 to 0.811 pg-TEQ/g, respectively. Using Principal Component Analysis, four possible principal components were found. These four principal components could account for 89.29% of the total variance. The first principal component was composed of highly chlorinated PCBs. The second principal component was composed of particle mean size and TOC. And the third and the fourth principal component were composed of di-, tri- PCBs and HCB. According to the factor score plot, the sample stations in this study could be divided into four groups. The first group was the stations that near the shore. The second group which contained stations were 4Km offshore. The third group contained stations with highly chlorinated PCBs. And the fourth group only contained one stations, D16. It was possible that there were other sources influenced station D16. In conclusion, the pollution in the surficial sediments was influenced by the distances from the pollutant sources and the particle size affected by tidal effect.

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Environmental Sciences." Includes bibliographical references (p. 190-192).

Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains ix, 74 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 64-74).

Thesis (Ph. D.)--University of Kentucky, 2002. / Title from document title page. Document formatted into pages; contains vii, 158 p. : ill. Includes abstract. Includes bibliographical references (p. 128-155).

Endocrine-disrupting chemicals (EDCs) are environmental pollutants known to perturb hormone systems and interfere with normal endocrine function. Exposure to EDCs during hormone-sensitive developmental periods can result in profound dysfunction in reproductive physiology and behavior. In this dissertation, effects of gestational exposure to a class of EDCs called polychlorinated biphenyls (PCBs) were examined in the developing hypothalamus, which is known to control reproductive physiology and behavior in vertebrates. The specific hypothesis was that PCBs caused changes in sexually dimorphic hypothalamic nuclei, resulting in perturbation of adult sociosexual behaviors and alteration of neural networks with changes in expression of microRNAs and genes during development and in adulthood. This research focused on two brain areas relevant to understanding the PCB effects on the developing hypothalamus: 1) microRNA and related target gene expression during postnatal development, 2) adult sociosexual behaviors and gene expression. In both sections, molecular changes were examined in two sexually dimorphic hypothalamic nuclei, medial preoptic nucleus (MPN) and ventromedial nucleus (VMN), known for their role in regulation of sociosexual behavior. In the first section of the dissertation, the effects of PCBs were examined on the expression of microRNAs and target genes at four ages during postnatal [P] development (P15, P30, P45, and P90). Age and sex specific effects were observed in both MPN and VMN, with greater effects in the MPN. The second research section of the dissertation explored whether sociosexual behaviors, namely ultrasonic vocalizations and sociosexual preference behaviors, were altered by gestational PCBs. Expression of forty-eight neuroendocrine candidate genes was also examined in the MPN and VMN of the same animals. Several sociosexual behaviors were affected, including number and acoustic properties of ultrasonic vocalizations, and nose-touching with opposite-sex animals. Gene expression was altered in sex and region-specific manner in the brains of behaviorally affected rats. Taken together, these findings suggest that gestational PCBs have lasting effects on molecular mechanisms during postnatal development and in adulthood, and could result in altered sociosexual behavior. These results have implications for human health and disease, as early life exposures to EDCs have been linked to reproductive decline in humans. / text

Endocrine disrupting chemicals (EDCs) are a class of environmental toxicants, of both natural and synthetic origin, that interfere with normal endocrine function. Exposure to EDCs during susceptible periods of development, particularly embryogenesis, can result in profound neurological and reproductive deficits. While the impact of developmental exposure to EDCs on reproductive function and behavior has been much studied, the underlying mechanisms responsible for these observed effects are not well understood. The goal of the research detailed in this dissertation is to elucidate the cellular and molecular targets by which a representative class of EDCs, polychlorinated biphenyls (PCBs), disrupts normal reproductive neuroendocrine function. My specific hypothesis is that PCBs cause changes in sexually dimorphic brain regions underlying sex-specific reproductive physiology and behavior through the perturbation of normal developmental apoptosis, with long-term consequences for reproductive success. The studies detailed herein focus on three areas which contribute to an understanding of the effects of PCBs on neuroendocrine reproductive function: (1) the in vitro effects of PCBs on a neuroendocrine cell line, (2) developmental effects of PCBs on the gestationally exposed F1 generation, and (3) the physiological consequences of these developmental alterations for adult reproductive function. In the first section of this dissertation, the neurotoxic and endocrine disrupting effects of PCBs on a representative developing neuroendocrine cell model, the GT1-7 GnRH cell line, are investigated in time- and dose-response experiments. Treatment and dose-dependent effects are observed for GnRH peptide concentrations, cell viability, apoptotic and necrotic cell death, and caspase activation. In general, GnRH peptide levels are suppressed by high doses and longer durations of PCBs, and elevated at low doses and shorter time points. The suppression of GnRH peptide levels was partially reversed in cultures co-treated with the estrogen receptor antagonist ICI 182,780. All PCBs tested reduced viability and increased both apoptotic and necrotic cell death. The second section of this dissertation examines whether prenatal PCB exposure alters normal neuroendocrine development in the F1 generation, including sexual differentiation of the brain. Disruption of hypothalamic development is detectable as early as the day after birth (postnatal day (P) 1), as indicated by abnormal programmed cell death, and alterations in neuroendocrine gene and protein expression. The third section discusses the physiological impact of developmental PCB exposure on reproductive maturation and adult neuroendocrine function. Pubertal onset is advanced and estrous cyclicity irregular in PCB endocrine-disrupted females. Furthermore, sexual differentiation of female neuroendocrine systems is masculinized/defeminized. Collectively, these results suggest that the disrupted sexual differentiation of the POA can be detected as early as the day after birth, effects that may underlie the adult reproductive phenotype. / text

The primary objective of this study was to investigate the use of water table management (WTM) as a microbial delivery system for in-situ bioaugmentation of contaminated soils. In addition, the use of Rhizobium ( R.) for PCB degradation in soils was evaluated. / First, the presence and isolation of a variety of strains of Rhizobium meliloti was demonstrated using plant nodulation tests on alfalfa plants in soils that were contaminated for over 15 years with PCBs, PAHs and heavy metals. Next, R. meliloti, strain A-025, was selected based on its membrane (hydrophobicity, adhesion) characteristics and its potential to transform PCBs. This strain was delivered and implanted in sod columns, 200 mm in diameter x 1000 mm in length, packed with a sandy loam soil, using surface and subirrigation. The results of this study showed that subirrigation led to a higher number and a more uniform distribution of the bacterial cells in the soil at 60, 300, 500, and 700 mm depths, than surface irrigation. / In a different setup, similar column were packed with a PCB contaminated soil. These soil columns were bioaugmented with three bacterial cultures, i.e., R. meliloti (strain A-025), Comomonas testosteroni (strain B-356) and an indigenous bacterial consortium using subirrigation. The results indicated that bioaugmentation of the PCB contaminated soil was possible by using subirrigation. Bioaugmentation with the indigenous culture was observed to be more effective in the biodegradation of PCBs than with A-025 and B-356 cultures at 140 and 340 mm depths. However, at 590 mm depth, bioaugmentation with strain A-025 was observed to be better than the other treatments. Sequential aerobic and anaerobic cycles appear to be of significance for effective dechlorination of PCB congeners to lower chlorinated congeners. / In a separate exploratory study, the rhizospheric effects of alfalfa plants on R. meliloti for PCB depletion were investigated. The results suggest that the growth of alfalfa plants and bioaugmentation of soil with R. meliloti, strain A-025, increased the depletion of PCB congeners in the soil as compared to bioaugmentation alone. In other preliminary studies, the results showed that the presence of PCBs in a sandy loam soil increases the filtration of bacterial cells. Also, soil type and the presence of PCBs affected water infiltration, moisture, and hardness of the soil. Furthermore, water table management system along with bioaugmentation of soil columns with R. meliloti, strain A-025, decreased the concentration of atrazine by 31% during anaerobic and aerobic cycles and reduced the concentration of nitrate by 87% and 78% in the absence and presence of atrazine, respectively, in the drainage water. / The overall results of this work indicate that water table management (subirrigation) can be used for bioaugmentation of contaminated soils. Also, use of R. meliloti may prove to be an interesting option for soils contaminated with PCBs, atrazine and nitrate.

This study determines the effects of variations in suspended biomass, organic carbon, and pH on the time course of 2,2$ sp prime$,4,4$ sp prime$,5,5$ sp prime$-hexachlorobiphenyl uptake by laboratory cultures of Selenastrum capricornutum. Variations in pH had no effect, but uptake was enhanced by higher levels of biomass and depressed by higher levels of organic carbon. The coefficients for these measured effects on hexachlorobiphenyl were combined with existing relations based on molecular connectivity (X) or capacity ratio (K$ sp prime$) to yield semi-empirical equations to predict the instantaneous rate of uptake and bioconcentration factor (BCF) of organic contaminants as: eqalign{& rm Log rate = {-}3.30 + 0.32 X + 1.1 Log biomass {-}0.42 Log Abs cr& rm Log BCF = 4.11 + 0.86 Log K sp prime {-}0.87 Log biomass {-}0.22 Log Abs cr} / The utility of these equations was assessed by comparing time courses of hexachlorobiphenyl uptake predicted from them with time courses observed in water from eleven Quebec lakes.

No description available.