Ppm Polychlorinated Biphenyls Research Articles

Isolation and Characterization of Different Bacterial Strains from Soils, With the Potential of Degrading Polychlorinated Biphenyls (PCBs) Under Aerobic Conditions

Polychlorinated biphenyl (PCBs) are persistent organic compounds used between 1930 and 1970 as thermal insulators in electrical equipment such as transformers, electrical condensers, heat exchangers, and hydraulic systems. Currently, this xenobiotic is a potential source of pollution to soil and water resources. This research aimed to isolate and characterize bacteria strains possessing a high potential to degrade PCBs contained in used dielectric oils. The bacteria strains were isolated from a soil sample taken from “Alao” Hydroelectric Power Center. Four culture media were used for the soil sample culturing: Agar for Standard Methods Medium (STD), Phosphorus, Ammonium, and Salts Medium (PAS), Minimum Medium (Mm), and Minimum Medium (Mm) supplemented with 25 µL of oil contaminated with 43,6 ppm of PCBs. The isolation, screening, and stabilization process were carried out using three culture media: STD, PAS, and Mm, each supplemented with 25 µL of oil contaminated with 43,6 ppm of PCBs. Nineteen bacterial colonies were isolated and exposed to a higher concentration of PCBs. Eighteen colonies could tolerate 250 µL of oil contaminated with 500 ppm of PCBs. Once stabilized and purified these bacteria strains, were characterized according to their microscopic and macroscopic characteristics and tolerance to heavy metals. Through biochemical tests, 18 strains were identified belonging to Providencia alcalifaciens, Proteus mirabillis, Providencia rettgeri, Providencia stuartii, Pseudomona alcaligenes, Morganella morganii, and Shigella disenteriae

Polychlorinated biphenyls induce oxidative stress and metabolic responses in astrocytes

Exposure to environmental toxicants is prevalent, hazardous and linked to varied detrimental health outcomes and disease. Polychlorinated biphenyls (PCBs), a class of hazardous organic chlorines once widely used for industrial purposes, are associated with neurodegenerative disease and oxidative stress in both in vitro and in vivo models. Here, we investigated the impact of Aroclor 1254, a commercially available PCB mixture, on primary murine astrocytes to determine the response to this once ubiquitously used toxicant on the most numerous cells of the central nervous system (CNS). Astrocytes are a critical component of homeostasis throughout the CNS, including at the blood-brain barrier, where they serve as the primary defense against xenobiotics entering the CNS, and at the synapse, where they are closely coupled to neurons through several metabolic pathways. We hypothesized that PCBs cause astrocytic oxidative stress and related dysfunction including altered metabolism. We exposed primary murine cortical astrocytes to PCBs and report an increased expression of antioxidant genes (Prdx1, Gsta2, Gfap, Amigo2) in response to oxidative stress. Our data show increased ATP production and spare respiratory capacity in astrocytes exposed to 10 μM (∼ 3 ppm) PCBs. This dose also causes an increase in glucose uptake that is not seen at a higher dose (50 μM) suggesting that, at a lower dose, astrocytes are able to engage compensatory mechanisms to promote survival. Together, these data suggest that exposure to PCBs impact astrocytic metabolism, which is important to consider both in the context of human health and disease and in in vitro and in vivo disease models.

Potentiality of Native Ascomycete Strains in Bioremediation of Highly Polychlorinated Biphenyl Contaminated Soils.

Polychlorinated biphenyls (PCBs) are organic pollutants that are harmful to environment and toxic to humans. Numerous studies, based on basidiomycete strains, have reported unsatisfactory results in the mycoremediation of PCB-contaminated soils mainly due to the non-telluric origin of these strains. The abilities of a five-Ascomycete-strain consortium in the mycoremediation of PCB-polluted soils and its performance to restore their sound functioning were investigated using mesocosm experiments associated with chromatography gas analysis and enzymatic activity assays. With the soil H containing 850 ppm PCB from which the strains had been isolated, a significant PCB depletion of 29% after three months of treatment was obtained. This led to an important decrease of PCBs from 850 to 604 ppm. With the soil L containing 36 ppm PCB, biodegradation did not occur. In both soils, the fungal biomass quantified by the ergosterol assay, did not increase at the end of the treatment. Biodegradation evidenced in the soil H resulted in a significantly improved stoichiometry of N and P acquiring enzymatic activities. This unprecedented study demonstrates that the native Ascomycetes display remarkable properties for remediation and restoration of functioning of the soil they originated from paving the way for greater consideration of these strains in mycoremediation.

Bioremediation trial on aged PCB-polluted soils—a bench study in Iceland

Polychlorinated biphenyls (PCBs) pose a threat to the environment due to their high adsorption capacity to soil organic matter, stability and low reactivity, low water solubility, toxicity and ability to bioaccumulate. With Icelandic soils, research on contamination issues has been very limited and no data has been reported either on PCB degradation potential or rate. The goals of this research were to assess the bioavailability of aged PCBs in the soils of the old North Atlantic Treaty Organization facility in Keflavík, Iceland and to find the best biostimulation method to decrease the pollution. The effectiveness of different biostimulation additives (N fertiliser, white clover and pine needles) at different temperatures (10 and 30 °C) and oxygen levels (aerobic and anaerobic) were tested. PCB bioavailability to soil fauna was assessed with earthworms (Eisenia foetida). PCBs were bioavailable to earthworms (bioaccumulation factor 0.89 and 0.82 for earthworms in 12.5 ppm PCB soil and in 25 ppm PCB soil, respectively), with less chlorinated congeners showing higher bioaccumulation factors than highly chlorinated congeners. Biostimulation with pine needles at 10 °C under aerobic conditions resulted in nearly 38 % degradation of total PCBs after 2 months of incubation. Detection of the aerobic PCB degrading bphA gene supports the indigenous capability of the soils to aerobically degrade PCBs. Further research on field scale biostimulation trials with pine needles in cold environments is recommended in order to optimise the method for onsite remediation.

Dechlorination of polychlorinated biphenyls in transformer oil using UV and visible light

A study on dechlorination of PCB138 in transformer oil (TO) and 2-propanol (IPA) using 254 nm ultraviolet (UV) light as well as dye sensitized visible light has been conducted. Studies on dechlorination of polychlorinated biphenyls (PCBs) in TO using visible light in the presence of methylene blue (MB) and triethylamine (TEA) (providing a ‘photocatalytic’ cycle) in both deaerated and aerated conditions have been conducted to determine effects of TO, MB and TEA on reaction rates. The results show that photolytic methods are effective in treating PCBs in TO, and that the oil plays a limited adverse role. Under UV irradiation, PCB 138 can be >99% dechlorinated in the presence 0.06% (w/w) TO in IPA within 1 h with a rate constant of 0.0853 min−1, while 47% of PCB138 can be dechlorinated in 92.1% (w/w) TO in IPA within 2 h with a rate constant of 0.0051 min−1. In the ‘photocatalytic’ system, 94% reduction of PCB 138 was achieved within 30 min with a rate constant of 0.0968 min−1 when the solvent was 60.70% (w/w) TO in IPA, while 71% dechlorination of PCB138 was achieved within 30 min with a rate constant of 0.0382 min−1 when 81.62% (w/w) TO was present. In treatment of 30–73 ppm PCBs in TO, the optimal concentration of MB and TEA were found to be 0.5 g/L and 58.08 g/L respectively. Because of quenching by oxygen, deaeration of the solution is necessary for an efficient reaction. The photocatalytic system is especially adapted for treating lower concentration of PCBs in TO.

Study on the plasma treatment of waste oil containing PCB

The paper presents the results of treatment of transformer oil containing less than 2 ppm polychlorinated biphenyls (PCB) in a plant of high-temperature plasma melting of ash residues after the municipal waste incineration. The content of undecomposed PCBs, dioxins, and other hazardous waste in all secondary products of treatment (off gases; slag; secondary fly ash; process water used for slag granulation) was analyzed by different methods. Performed analytical investigations showed high ecological degree of PCB decomposition in the plant of plasma-thermal treatment of ashes after incinerators.

Foodweb modeling for polychlorinated biphenyls (PCBs) in the Twelvemile Creek Arm of Lake Hartwell, South Carolina, USA

PCBs from the Sangamo-Weston Superfund Site near Clemson, South Carolina, USA, were released into the Twelvemile Creek Arm of Lake Hartwell until the early 1990s. Monitoring data have shown that while PCB concentration in sediments declined since 1995, PCB concentrations in fish have remained elevated, e.g., largemouth bass ( Micropterus salmoides) concentrations have ranged from 5 to 10 ppm. The EPA aquatic ecosystem model AQUATOX was applied to this system to better characterize foodweb dynamics that lead to biomagnification of PCBs. The model was calibrated with observed fish biomass data. Simulated PCB loading over a 12-year period provided a reasonable fit to observed PCB data in fish. The model demonstrated that contaminated labile detritus loaded to the system was incorporated into the foodweb rather than deposited, thereby maintaining the PCB concentrations in fish while concentrations in the sediment declined. A dominant PCB pathway was from detritus to daphnia to shad to largemouth bass. Fish PCB concentrations showed moderate sensitivity to toxicant parameters; model runs incorporating uncertainty in these parameters predicted recovery (<2 ppm PCB) for all species in the range of years from 2008 to 2013. The high sensitivity of the model to parameters related to growth strongly affected PCB concentrations in fish and should be considered in future AQUATOX applications.

Performance of a Semi-Industrial Scale Gasification Process for the Destruction of Polychlorinated Biphenyls

A semi-industrial scale test was conducted to thermally treat mixtures of spent oil and askarels at a concentration of 50,000 ppm and 100,000 ppm of polychlorinated biphenyls (PCBs) under a reductive atmosphere. In average, the dry-basis composition of the synthesis gas (syngas) obtained from the gasification process was: hydrogen 46%, CO 34%, CO2 18%, and CH4 0.8%. PCBs, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans (PCDDs/PCDFs) in the gas stream were analyzed by high-resolution gas chromatography (GC)-mass spec-trometry. The coplanar PCBs congeners 77, 105, 118, 156/157, and 167 were detected in the syngas at concentrations <2 ×10−7 mg/m3 (at 298 K, 1 atm, dry basis, 7% O2). The chlorine released in the destruction of the PCBs was transformed to hydrogen chloride and separated from the gas by an alkaline wet scrubber. The concentration of PCBs in the water leaving the scrubber was below the detection limit of 0.002 mg/L, whereas the destruction and removal efficiency was >99.9999% for both tests conducted. The concentration of PCDDs/PCDFs in the syngas were 8.1 ×10−6 ng-toxic equivalent (TEQ)/m3 and 7.1 × 10−6 ng-TEQ/m3 (at 298 K, 1 atm, dry basis, 7% O2) for the tests at 50,000 ppm and 100,000 ppm PCBs, respectively. The only PCDD/F congener detected in the gas was the octachloro-dibenzo-p-dioxin, which has a toxic equivalent factor of 0.001. The results obtained for other pollutants (e.g., metals and particulate matter) meet the maximum allowed emission limits according to Mexican, U.S., and European regulations for the thermal treatment of hazardous waste (excluding CO, which is a major component of the syngas, and total hydrocarbons, which mainly represent the presence of CH4).

Degradation of Polychlorinated Biphenyls (PCBs) in Water Matrix Using UV/H202 Efect Of Initial PCB Concentration and Analysis of Reaction Product

his study investigated the effect of the different initialconcentrations of polychlorinated biphenyls (PCBs) on its degradation in water matrix using UVIHP2 and on the formation of reaction intermediates or products. Simulated PCB-contaminated water solution was subjected to irradiation with 17 W, 254 nm wavelength UV lamp in a batch tubular reactor. The ratio of oxidant to PCBs, in terms of Arodor 1260, was based on 2,800 I!L HP2 isto 40 ppm PCB. Samples were extracted from the matrix by solid-phase extraction (SPE) method using C18 cartridges with hexane and ethyl acetate as solvents. The samples were analyzed using Gas Chromatography-Electron Capture Detector System (GC-ECD) to determine the concentration of PCBs in the samples and pH was monitored every sampling time. The analysis of chloride (CI-)ion concentration in the samples was done using Argentometric titration. Determination of reaction intermediates and products was carried out with 40 ppm PCB concentration using Gas Chromatography-Mass Spectroscopy (GC-MS) system. A decrease in pH in the early stages of degradation was observed and the higher the initial concentration of PCB the greater was the drop in pH. The PCB degradation profile showed that from 1 to 40 ppm initial concentration, the degradation efficiency of UVIHP2 increased with increasing initial PCB concentration. At 80 ppm, however, it was observed that there was a decrease in the efficiency of the system. The inorganic chloride ions produced indicate that dechlorination took place in the system. GC-MS analysis verified the decrease in concentration of PCBs in the solution and showed the preferential attack of the UV/HP2 to PCBs over long chain saturated alkanes or waxes which contained the PCBs.

Biotransformation of PCBs in Contaminated Sludge: Potential for Novel Biological Technologies

In this study, the biological transformation of polychlorinated biphenyls (PCBs) was investigated in sludge from the Ralston Street Lagoon (RSL), a United States Environmental Protection Agency (USEPA) designated Toxic Substances Control Act (TSCA) site, in Gary, IN. A biological tilled soil reactor (BTSR) operating under cycling anaerobic-aerobic conditions and vermicomposting bioreactors (VBs) inoculated with Eisenia foetida earthworms were both systematically investigated. Sludge heavily contaminated with PCBs (> 500 ppm PCB as Aroclor 1248) was loaded into the BTSRs and amended sequentially with PCB-dechlorinating anaerobic sediments and then aerobic PCB biodegrading microbes. The VBs were loaded with sludge mixed in varying ratios with sterile soil and then inoculated with earthworms. Bioreactors were monitored for the duration of the studies (ranging from four to nine months) and samples were regularly removed, extracted and analyzed for PCB congener content. Appropriate biotic and negative abiotic controls were maintained under the various conditions to quantify and measure the biological transformation of the PCB's. All samples were analyzed for PCB congener concentrations by Soxhlet extraction followed by gas chromatography with electron capture detection (ECD). In the BTSRs loaded initially with 500 ppm of PCBs, a 75 % reduction of total PCB was obtained while the BTSR loaded with 140 ppm PCBs revealed only a 25 % reduction in total PCB level. Sample analyses from the VBs demonstrated total PCB reductions ranging from 55 to 66 %, although worm-free control reactors showed PCB attenuations from 48 to 68 %. Analysis of earthworms showed an increase in PCB levels in the earthworm biomass, with concentrations reaching as high as 313 ppm. Mass balance analysis of the VB results demonstrated that most of the PCBs were bioaccumulated, although some PCB elimination was demonstrated. The results from both the anaerobic-aerobic cycling BTSR and VB investigations demonstrate potential for application for site clean-up and possible bioremediation of the Ralston Street Lagoon sludge.

Accumulation of methylmercury or polychlorinated biphenyls in in vitro models of rat neuronal tissue

In vivo exposure levels for neurotoxicants are often reported in parts per million (ppm) concentration in tissue, whereas exposure levels in experiments utilizing in vitro models are most commonly reported in micromolar (μM) concentration in the exposure solution. The present experiments sought to determine whether or not in vitro solution concentration was an appropriate dose-metric for comparison to in vivo tissue levels for lipophilic compounds. To do so, the accumulation of the polychlorinated biphenyl (PCB) mixture Aroclor 1254 (A1254) or methylmercury (MeHg) was examined in three commonly utilized in vitro neuronal tissue models: nerve growth factor differentiated pheochromocytoma (PC12) cells, primary cultures of rat neocortical cells, and adult rat hippocampal slices. Tissues were exposed to A1254 (0.65 ppm) or to MeHg (0.0033–0.33 ppm) in serum-free media for 1 or 24 h. Total PCB or mercury accumulation was measured by dual column gas chromatography with electron capture detection or by cold vapor atomic absorption, respectively. PC12 cells accumulated 66.7 and 103.8 ppm PCBs after 1 and 24 h exposure to A1254. Neocortical neurons also accumulated significant concentrations of PCBs, but less so than PC12 cells. After 1 h exposure to 0.65 ppm A1254, slices contained 3.46 and 0.81 ppm PCBs when exposed in a static and perfused system, respectively. After 1 h exposure to 0.0033, 0.033, and 0.33 ppm MeHg, PC12 cells contained 0.3, 2.2, and 17.7 ppm mercury, respectively; after 24 h, PC12 cells contained 0.4, 2.8, and 21.9 ppm. Hippocampal slices accumulated 1.7 and 4.8 ppm mercury after 1 and 3 h exposure to 0.33 ppm MeHg. For comparison, mercury accumulation in rat fetal and pup brain tissue after maternal exposure [0, 0.1, 1.0, or 2.0 mg/kg/day MeHg from gestational day (GD) 6–15] ranged from 0.05 to 7.89 ppm in 0.1 mg/kg dose animals on postnatal day 10 and 2.0 mg/kg dose animals on GD16, respectively. These results demonstrate that accumulation of PCBs and MeHg in vitro is tissue-, time-, and concentration-dependent and indicates that tissue levels rather than exposure concentrations are a more appropriate metric for comparison of in vitro to in vivo effects.

Promotion of thyroid tumors in rats by pregnenolone-16alpha-carbonitrile (PCN) and polychlorinated biphenyl (PCB).

Pregnenolone-16alpha-carbonitrile (PCN) and Aroclor 1254 (PCB) both reduce serum thyroid hormone levels in rats, but only PCN consistently produces an increase in serum thyrotropin (TSH). PCN-mediated increases in TSH result in increased thyroid follicular cell proliferation and hyperplasia, which may represent early events on a morphological continuum leading to neoplasia. The purpose of this study was to assess whether PCN, a compound that increases serum TSH, and PCB, which does not increase TSH, promote thyroid tumors in a two-stage carcinogenesis model. Male SD rats were administered the thyroid tumor initiator diisopropanolnitrosamine (2.5 g/kg, sc), and after seven days were fed control diet, diet containing 1000 ppm PCN, or diet containing 100 ppm PCB for 19 weeks. Body weights were unaffected by PCN treatment, but were reduced 21% after 19 weeks of PCB treatment compared to control. PCN treatment significantly reduced serum T4 through week 3 before returning to control concentrations, whereas T4 levels following PCB treatment fell below detection limits by week 3 and remained drastically reduced through week 19. TSH concentrations in PCN-treated rats increased three-fold at week 2, then declined to near control values at week 19. After one week of PCB treatment, TSH concentrations reached nearly twice that of controls, and were sustained until week 6. The incidence of thyroid follicular cell proliferative lesions, including cystic and follicular hyperplasia, cystic and follicular adenoma, and follicular carcinoma, was significantly increased following PCN treatment, but not following PCB treatment. PCB treatment caused an increase in thyroid carcinomas (4 of 22 rats) not associated with the proliferative-type lesions produced by PCN, despite an increase in TSH serum concentrations. In conclusion, PCN appears to promote thyroid tumors in a manner consistent with known effects of excessive TSH stimulation. However, thyroid carcinomas stemming from PCB treatment indicate that separate mechanisms exist for the production of thyroid cancer in rodents by chemicals classically considered microsomal enzyme inducers.

Remediation of former military bases in the Canadian Arctic

This paper describes novel aspects of the remediation of three former military bases in the Canadian Arctic. At Iqaluit, the site has been totally cleaned up. All buildings were demolished, and soils contaminated with metals and polychlorinated biphenyls (PCBs) removed. Soils were excavated and most containerized and shipped south for disposal; soils containing 1–5 ppm PCBs were buried on site along with nonhazardous debris. PCB-contaminated concrete foundations were also investigated and removed. While most contamination was in the surface of the active layer, some migration of PCBs along the surface of the underlying bedrock at greater depth was found. At Sarcpa Lake, a dump leaching PCBs was excavated. Methodology was developed for this investigation and the difficulties of excavation in permafrost are described. The PCBs in the dump were from electrical equipment and/or PCB-containing paint used at this former Distant Early Warning (DEW) Line site. Investigation of the painted material at the site showed PCB levels as high as 7.4% in the paint. Wall swab results show that the repainting of the walls had effectively rendered the PCBs unavailable to solvent washing. At Resolution Island, the extent of contamination is much larger than the other two sites. Interceptor barriers were designed and installed in the leachate pathways carrying PCBs between the site and the ocean. At this site, the presence of petroleum products along the drainage pathway has led to increased transport of PCBs due to their higher solubility in these solvents as compared to water. Current progress at this unique remote site and the options for dealing with the contaminated soil are discussed.

Extractions of polychlorinated biphenyl (PCB) compounds from surfactant suspension/soil extracts with dechlorination on-line.

Polychlorinated biphenyl (PCB) formulation (Aroclor 1242 or 1248)-surfactant (Brij 97 or Triton CF54) emulsions (0.1-1.0%, v/v) were extracted with supercritical carbon dioxide (scCO2). The declinations curve that resulted for each loading of PCB substrate was accurately modelled as a single-exponential decay, and the half-life [t1/2, 10.76 min +/- 2% (Brij 97) or 10.0 min +/- 14% (Triton CF54)] was independent of the level of loading. When the extraction was combined with on-line dechlorination, t1/2 was increased to 17.62 min +/- 6% or 16.46 min +/- 5%, respectively The dechlorination reactor contributed appreciably to the back-pressure of the system so that, under identical scCO2 head pressures, the flow rate at the exit of the system was reduced from 1500 mL min-1 (as decompressed gas) to 900 mL min-1. When corrected for the difference in flow rates, the declination curves in the absence and presence of the reactor became virtually identical. For a surfactant suspension from a soil that was field-burdened with only 6 ppm PCBs, extended operation (extraction-dechlorination) for 15 h, during which the substrate suspension was replaced every 30 min, caused no loss of the dechlorination efficiency; however, for 1% (v/v) Aroclor 1242 or 1248 in surfactant suspension, the reactor gradually lost reactivity over 5 h of continued operation. However, the reactivity could be restored virtually completely by purging the reactor column with scCO2 for 3 h or washing the column at ambient temperature with 30 mL of methanol-water (7 + 3, v/v). Mass spectrometry of the reaction products indicated that the principal products included biphenyl and toluene, but methylated benzenes and phenols were also present.

Dose- and age-dependent alterations in choline acetyltransferase (ChAT) activity, learning and memory, and thyroid hormones in 15- and 30-day old rats exposed to 1.25 or 12.5 ppm polychlorinated biphenyl (PCB) beginning at conception

1. 1. Polychlorinated biphenyls (PCB) were released into the environment through improper disposal for decades, causing widespread contamination. Slow biodegradation and lipophilic properties of PCB caused its persistence and concentration through food webs. Exposure to these environmental contaminants through maternal transfer during early development has been associated with neurological and endocrinological alterations in several different organisms. 2. 2. The present study extended a preliminary investigation which suggested low level exposure to PCB altered acetylcholine biosynthesis enzyme, choline acetyltransferase (ChAT), activity in the hippocampus and basal forebain and caused aberrations in thyroid hormone and behavior. 3. 3. Dietary exposure of 15-day-old animals to 1.25 ppm of Aroclor 1254 ® (LPCB) during gestation and lactation significantly elevated ChAT activity in both areas of the brain. Animals exposed to 12.5 ppm of Aroclor 1254 ® (HPCB) until 15 days of age demonstrated significant elevations of ChAT activity in the basal forebrain. Thyroxine (T 4) concentrations were slightly elevated in 15-day-old LPCB animals and significantly depressed in HPCB exposed pups; triiodothyronine (T 3) concentrations were not altered. 4. 4. At 30 days both LPCB and HPCB treatment groups displayed significantly depressed ChAT activity in both areas of the brain. t 3 and T 4 concentrations were subnormal, although T4 was not significantly depressed in LPCB animals. 5. 5. In the Morris water maze all animals, when tested between 25 and 29 days of age, improved their latency time to the platform over 10 spatial learning trials. However, when combined means of trials 8–10 were compared, HPCB exposed animals had significantly increased latency time to the podium compared to control and LPCB animals.

MULTIGENERATIONAL STUDY OF THE EFFECTS OF CONSUMPTION OF PCB-CONTAMINATED CARP FROM SAGINAW BAY, LAKE HURON, ON MINK. 1. EFFECTS ON MINK REPRODUCTION, KIT GROWTH AND SURVIVAL, AND SELECTED BIOLOGICAL PARAMETERS

This study was conducted to determine the multigenerational effects of consumption of PCB-contaminated carp (Cyprinus carpio) from Saginaw Bay ( Lake Huron) on mink (Mustela vison) reproduction and health and to examine selected biomarkers as potential indicators of polyhalogenated hydrocarbon toxicity in mink. The mink were fed diets formulated to provide 0 (control), 0.25, 0.5, or 1.0 ppm polychlorinated biphenyls (PCBs) through substitution of Saginaw Bay carp for ocean fish in the diets. To determine whether the effects of PCB exposure were permanent, half of the parental (P ) animals 1 were switched from their respective treatment diets to the control diet after whelping the first of two F1 generations. Effects of in utero and lactational exposure to PCBs on subse1 quent reproductive performance of the F1 animals were examined by switching half of the first-year F offspring (kits) to the control diet at weaning, while the other half was continued on their parental diet (continuous exposure). Continuous exposure to 0.25 ppm, or more, of PCBs delayed the onset of estrus (as determined by vulvar swelling and time of mating) and lessened the whelping rate. Litters whelped by females continually exposed to 0.5 ppm, or more, of PCBs had greater mortality and lesser body weights than controls. Continuous exposure to 1.0 ppm PCBs had a variable effect on serum T4 and T3 concentrations. Compared to the controls, there were significant differences in kidney, liver, brain, spleen, heart, and thyroid gland weights of the mink continually exposed to 1.0 ppm PCBs. There was an increase in the incidence of periportal and diffuse vacuolar hepatocellular lipidosis in the P1 mink with continuous exposure to increas1 ing concentrations of PCBs. Plasma and liver PCB concentrations of the adult and kit mink were, in general, directly related to the dietary concentration of PCBs and the duration and time of exposure. Short-term parental exposure to PCBs had detrimental effects on survival of subsequent generations of mink conceived months after the parents were placed on ''clean" feed. The lowest observed adverse effect level (LOAEL) for dietary PCBs in this study was 0.25 ppm.

Effects of dietary PCBs and nonyl-phenol on immune function and CYP1A activity in channel catfish, Ictalurus punctatus

Polychlorinated biphenyls (PCBs) induce CYP1A, modulate immune responses, and may have endocrine disruption properties. Many coastal ecosystems and their tributaries contaminated with PCBs also receive sewage out-fall effluents containing detergents such as nonyl-phenol (NP). Because NP has estrogenic properties and modulates P4501A activity, and because estrogen modulates immune function in a variety of vertebrates, studies to investigate interactions of PCBs and NP are needed. Channel catfish ( Ictalurus punctatus) (25–30 g) were fed seven different diets containing 10 ppm Aroclor 1254 (PCB), 10 ppm NP, Wppm PCB + 10 ppm NP, 100 ppm PCB + 10 ppm NP, 10 ppm PCB + 100 ppm NP, 100 ppm of each, or carrier. After 7 and 21 days of treatment peripheral blood hematocrits, total serum protein and immunoglobulin, antigen-specific antibody, anterior kidney phagocyte oxidative burst, and gut/liver cytochrome P4501A protein/EROD, were evaluated. Phagocyte function was enhanced by low NP on day 7 and low PCB + high NP on day 21. Gut and liver P4501A protein/EROD were greatly induced by combinations of high PCB + high and low NP. Treatments did not effect hematocrits, serum protein or total immunoglobulin on either day or antibody titers on day 21 against formalin-killed Edwardsiella ictualuri (day 14 post sensitization).

MULTIGENERATIONAL STUDY OF THE EFFECTS OF CONSUMPTION OF PCB-CONTAMINATED CARP FROM SAGINAW BAY, LAKE HURON, ON MINK. 2. LIVER PCB CONCENTRATION AND INDUCTION OF HEPATIC CYTOCHROME P-450 ACTIVITY AS A POTENTIAL BIOMARKER FOR PCB EXPOSURE

This study examined the effect of polychlorinated biphenyls (PCBs) from Saginaw Bay (Lake Huron) carp on the hepatic cytochrome P-450 activity in mink (Mustela vison). Hepatic cytochrome P-450 activities are of interest for their possible use as biomarkers to indicate consumption and biological effects of PCBs in the environment. Adult mink were fed diets containing ocean fish (control diet, 0.0 ppm) or Saginaw Bay carp to provide 0.25, 0.5, or 1.0 ppm PCBs. Mink were bred after 3 mo of exposure, and half of the parental mink (P1) and kits (F1-1) previously consuming diets containing Saginaw Bay carp were switched to control diet at weaning of the F1-1 kits. P1 and F1-1 mink were then bred within their age and dietary groups after 15 mo of exposure, to produce the second-year F1(F1-2) and F2 kits. Mink were killed when the new kits were weaned. Transfer of half the animals to the control diet examined whether the effects of the PCB containing diet on hepatic cytochrome P-450 activity were permanent. Continual exposure to diets containing PCBs from Saginaw Bay carp induced cytochrome P-450 activity in a generally dose-dependent manner. Cytochrome P-450 activity was not different from untreated controls in animals switched to the control diet from the PCB-containing diet. The response of cytochrome P-450IA1 (EROD) activity in a dose-dependent manner and the lack of induction after transfer to noncontaminated diets suggest that this hepatic enzyme activity is a potential biomarker for current exposure to PCBs and other similar cytochrome P-450 inducers.

Binding of Polychlorinated Biphenyls to Sediment

Transport, cleanup, and bioremediation properties of polychlorinated biphenyls (PCBs) bound to sediments depend on the specific components to which the PCBs are bound. Analysis of the sediment from Contaminant Cove on the St. Lawrence River by gas chromatography with an electron capture detector shows that the sediment contains 600 ppm PCBs. Previous work showed that there were both weak and strong binding of PCBs to sediment components, but gave no indication of which components were responsible for the binding.2 The average content of PCBs is below the limit of detectability by energy-dispersive x-ray microanalysis (EDX) for CI, but constituents which bind large quantities of PCBs could be detected. Sediment which is not contaminated with PCBs contains no detectable chlorine.EDX analysis was performed on a JEOL JEM-4000FX, using a cryo-stage (operated at -160° C) and a Tracor TN5500 system.

Highly hydrogenated dietary soybean oil modifies the responses to polychlorinated biphenyls in rats.

The effects of dietary highly hydrogenated soybean oil (HSO) upon the changes caused by dietary polychlorinated biphenyls (PCBs) were examined in rats. Six groups of rats were fed the following diets for 30 d: a 20% soybean oil-containing diet (control diet), a diet in which a half of soybean oil was substituted with HSO (HSO-A diet), a diet in which cellulose powder was replaced with HSO (HSO-B diet) and these diets supplemented with 100 ppm PCBs (control + PCBs, HSO-A + PCBs and HSO-B + PCBs diets). Hepatic concentration of PCBs and relative liver weight were markedly decreased in rats fed with the HSO-A + PCBs diet compared with those fed with the other diets containing PCBs. Liver lipids and liver cholesterol were considerably decreased with a reciprocal increase in fecal sterol excretion by rats fed the HSO-A + PCBs and the HSO-B + PCBs diets compared with those fed with the control + PCBs diet. The fatty acid composition in hepatic phospholipids showed an independent increase of the saturated fatty acid content induced by dietary HSO and PCBs. Dietary PCBs also caused decreases in the amounts of monounsaturated and n-3 polyunsaturated fatty acids. These results suggest that dietary HSO prevents accumulation of PCBs in the liver and promotes the excretion of lipids stimulated by PCBs, accompanied by a change in fatty acid metabolism.