James J. Pagano

Cognitive development in preschool children prenatally exposed to PCBs and MeHg.

A number of epidemiological studies have shown predictive relationships between prenatal exposure to polychlorinated biphenyls (PCBs) and subtle deficits in cognitive development in infancy through the preschool years [Child Dev. 56 (1985) 853; J. Pediatr. 116 (1990) 38; J. Pediatr. 134 (1999) 33; Toxicol. Lett. 102-103 (1998) 423; Neurotox. 21 (6) (2000) 1029-1038]. However, since not all studies have demonstrated these relationships (J. Pediatr. 119 (1991) 58-63), debate regarding the role of prenatal PCB exposure in cognitive development continues. The current study was designed to provide additional data to assist in resolving this question. Two hundred twelve children enrolled in the Oswego Newborn and Infant Development Project were assessed using the McCarthy Scales of Childrens Abilities at 38 months of age, followed by a reassessment at 54 months of age. The relationship between prenatal exposure to PCBs (cord blood PCBs) and McCarthy performance was assessed at both ages after first controlling for a wide range of important predictors of cognitive development, including socioeconomic status (SES), maternal IQ, maternal education, home environment, cigarette smoking, and many others. Cord blood PCBs were statistically significant predictors of small but measurable deficits in McCarthy performance at 38 months of age. Moreover, a significant interaction between cord blood PCBs and maternal hair mercury (MeHg) was found, such that negative associations between prenatal MeHg exposure and McCarthy performance were found in subjects with higher levels of prenatal PCB exposure. No relationship between PCBs and/or MeHg and McCarthy performance was observed when the children were reassessed almost 1.5 years later (54 months of age). Inspection of the age-related trajectory of McCarthy performance revealed that the more highly exposed children caught up with the least exposed children by 54 months. Although the current data partially replicate the findings of Jacobson et al., Patandin et al., and Walkowiak et al. [J. Pediatr. 116 (1990) 38; J. Pediatr. 134 (1999) 33; Lancet 358 (2001) 1602], results reported here suggest that functional recovery may occur. Moreover, the interaction between PCB and MeHg cannot be considered conclusive until it has been replicated in subsequent investigations.

Prenatal PCB exposure and neonatal behavioral assessment scale (NBAS) performance

We examined the relationship between prenatal (cord blood) polychlorinated biphenyls (PCBs) and Neonatal Behavioral Assessment Scale (NBAS) performance in babies born to women who consumed contaminated Lake Ontario fish. Cord blood PCBs, DDE, HCB, Mirex, lead, and hair mercury levels were determined for 152 women who reported never consuming Lake Ontario fish and 141 women who reported consuming at least 40 PCB-equivalent lbs. of Lake Ontario fish over their lifetime. Earlier work demonstrated that the newborns of fish eaters are exposed to a more heavily chlorinated distribution of PCB congeners, and that highly chlorinated PCBs (hepta-, octa-, and nonachlorinated biphenyls) are most strongly correlated with breast milk levels, perhaps providing the best index of PCB exposure in the Oswego cohort. Given the above, one would predict that these PCBs would be related to impaired performance on those NBAS clusters associated with fish consumption: namely Habituation, Autonomic, and Reflex clusters of the NBAS. Excepting the Relex cluster, these predictions were confirmed. Results revealed significant linear relationships between the most heavily chlorinated PCBs and performance impairments on the Habituation and Autonomic clusters of the NBAS at 25-48 h after birth. Additionally, higher prenatal PCB exposure was associated with a nonspecific performance impairment on the NBAS as evidenced by a significantly greater proportion of NBAS scales in which poor performance was exhibited (more than 1 standard deviation below the mean) in the most highly exposed neonates. Moreover, PCBs of lighter chlorination were unrelated to NBAS performance, as were DDE, Mirex, HCB, lead, and mercury. These results corroborate our earlier findings linking Lake Ontario fish consumption to the most heavily chlorinated PCB congeners, and suggest that the chlorination and persistence of PCBs may be an important factor both for exposure assessment and for determining relationships with neurobehavioral functions.

The Relationship between Prenatal PCB Exposure and Intelligence (IQ) in 9-Year-Old Children

Background Several epidemiologic studies have demonstrated relationships between prenatal exposure to polychlorinated biphenyls (PCBs) and modest cognitive impairments in infancy and early childhood. However, few studies have followed cohorts of exposed children long enough to examine the possible impact of prenatal PCB exposure on psychometric intelligence in later childhood. Of the few studies that have done so, one in the Great Lakes region of the United States reported impaired IQ in children prenatally exposed to PCBs, whereas another found no association. Objectives This study was designed to determine whether environmental exposure to PCBs predicts lower IQ in school-age children in the Great Lakes region of the northeastern United States. Methods We measured prenatal exposure to PCBs and IQ at 9 years of age in 156 subjects from Oswego, New York. We also measured > 50 potential predictors of intelligence in children, including repeated measures of the home environment [Home Observation for Measurement of the Environment (HOME)], socioeconomic status (SES), parental IQ, alcohol/cigarette use, neonatal risk factors, and nutrition. Results For each 1-ng/g (wet weight) increase in PCBs in placental tissue, Full Scale IQ dropped by three points (p = 0.02), and Verbal IQ dropped by four points (p = 0.003). The median PCB level was 1.50 ng/g, with a lower quartile of 1.00 ng/g and an upper quartile of 2.06 ng/g. Moreover, this association was significant after controlling for many potential confounders, including prenatal exposure to methylmercury, dichlorodiphenyldichloroethylene, hexachlorobenzene, and lead. Conclusions These results, in combination with similar results obtained from a similar study in the Great Lakes conducted 10 years earlier, indicate that prenatal PCB exposure in the Great Lakes region is associated with lower IQ in children.

Response inhibition during Differential Reinforcement of Low Rates (DRL) schedules may be sensitive to low-level polychlorinated biphenyl, methylmercury, and lead exposure in children.

Background Animal studies have shown that exposure to common, low-level environmental contaminants [e.g., polychlorinated biphenyls (PCBs), lead] causes excessive and inappropriate responding on intermittent reinforcement schedules. The Differential Reinforcement of Low Rates task (DRL) has been shown to be especially sensitive to low-level PCB exposure in monkeys. Objectives We investigated the relationships between prenatal PCB and postnatal Pb exposure performance on a DRL schedule in children. We predicted that a) prenatal PCB exposure would reduce interresponse times (IRTs) and reinforcements earned, and b) postnatal Pb exposure would reduce IRTs and reinforcements earned. Methods We tested 167 children on a DRL20 (20 sec) reinforcement schedule, and recorded IRTs and the number of reinforced responses across the session. We measured prenatal PCB exposure (cord blood), methylmercury (MeHg) (maternal hair), and postnatal Pb exposure (venous blood), and > 50 potentially confounding variables. Results Results indicated impaired performance in children exposed to PCBs, MeHg, and Pb. Children prenatally exposed to PCBs responded excessively, with significantly lower IRTs and fewer reinforcers earned across the session. In addition, exposure to either MeHg or Pb predicted statistically significant impairments of a similar magnitude to those for PCBs, and the associated impairments of all three contaminants (PCB, MeHg, and Pb) were statistically independent of one another. Conclusions These results, taken with animal literature, argue the high sensitivity of DRL performance to low-level PCB, MeHg, and Pb exposure. Future research should employ behavioral tasks in children, such as DRL, that have been demonstrably sensitive to low-level PCB, MeHg, and Pb exposure in animals.

Iron-mediated reactions of polychlorinated biphenyls in electrochemical peroxidation process (ECP).

A study was conducted to explore some of the basic processes of polychlorinated biphenyl (PCB) destruction by a new technology termed electrochemical peroxidation process (ECP). ECP represents an enhancement of the classic Fenton reaction (H2O2 + Fe2+) in which iron is electrochemically generated by steel electrodes. Focus was on the extent of adsorption of a mixture of Aroclor 1248 on steel electrodes in comparison to iron filings. Commercially available zero-valent iron filings rapidly adsorbed PCBs from an aqueous solution of Aroclor 1248. Within 4 h, all the PCBs were adsorbed at 1%, 5%, and 10% Fe0 (w/v) concentrations. Little difference in adsorption was found between acidic (2.3) and unamended solutions (pH 5.5), even though significant differences in iron oxidation state and Fe2+ concentrations were measured in solution. PCB adsorption also occurs on steel electrodes regardless of the pH or electric current applied (AC or DC), suggesting the combination of oxidizing (free radical-mediated reactions) and reducing (dechlorination reactions) iron-mediated degradation pathways may be possible. Extraction of the iron powder after 48 h of contact time yielded the progressive recovery of biphenyl with increasing Fe mass(from 0.4% to 3.5%) and changes of the PCB congener-specific pattern as a consequence of dechlorination. A variety of daughter congeners similar to those accumulated during anaerobic microbial dechlorination of Aroclor 1248 in contaminated sediments indicate preferential removal of meta- and para-chlorines.

Temporal trends of polychlorinated biphenyls and organochlorine pesticides in Great Lakes fish, 1999-2009.

Temporal trend analysis of the latest Great Lake Fish Monitoring and Surveillance Program (GLFMSP) data showed statistically significant decreases in persistent bioaccumulative and toxic (PBT) contaminant (polychlorinated biphenyls (PCBs), dichloro-diphenyl-trichlorethane and its metabolites (DDTs), dieldrin, cis-chlordane, oxychlordane, cis-nonachlor) concentrations in Lakes Huron, Ontario, and Michigan lake trout over the period of 1999 to 2009. In contrast, for most contaminants, no statistically significant concentration trends were found in top predator fish in Lakes Superior and Erie during the same period. For Lakes Huron, Ontario, and Michigan 5.0 ± 2.6% average annual concentration decreases were found for PCBs, DDTs, dieldrin, and other organochlorine pesticides (OCs) decreased at a faster rate, ranging from 10 ± 4.3% to 20 ± 7.1% per year. For these three lakes, with the exception of PCBs, these current decreases are greater than were shown by an earlier trend analysis that estimated an annual contaminant decrease of about 2-5% for the period of 1980 to 2003. For Lakes Superior and Erie, the finding of no statistically significant trend is in agreement with previously reported results for these lakes.

Photodecomposition of PCBs in aqueous systems using TiO2 as catalyst

Abstract The catalytic decomposition of PCBs promoted by sunlight in an aqueous solution, clay suspension and contaminated sediment is reported. The titanium dioxide catalyzed photolytic process destroyed almost 80% of the total PCBs in an aqueous solution and clay suspension after 4 h of radiation, and 50% of total PCBs were destroyed in sediment suspension within 6 h. It was observed that the lower chlorinated PCB congeners underwent the highest rate of decomposition in the aqueous systems. This preliminary study suggests that photocatalytic processes may be an efficient and low cost technique to remediate PCB-contaminated soils, sediments and waters.

Reductive dechlorination of PCB-contaminated sediments in an anaerobic bioreactor system

An anaerobic bioreactor system was operated in a batch recycle mode to establish the microbial biodegradation of Aroclor 1248-spiked sediment, utilizing sanitary landfill leachate as a novel carbon, nutrient, and/or microbial source. Experiments conducted on two bioreactors confirmed that significant dechlorination of Aroclor 1248-spiked sediments occurred. After 13 weeks of operation, the average total chlorine/biphenyl of the original Aroclor was reduced by 11% and 23%, with the majority of dechlorination occurring within 7 weeks. No dechlorination was observed in the sterilized control reactor. The overall significance is the first reported occurrence of anaerobic dechlorination of a PCB-contaminated sediment in a low-cost laboratory-scale bioreactor system. The environmental significance is the reduction in chlorine content of the original Aroclor, an important component in any environmental bioremediation program. Innovative approaches to laboratory-scale bioreactor monitoring and bioreactor design principles applicable to hazardous waste containment areas are also discussed.

Assessment of Maternal Contaminant Burden by Analysis of Snapping Turtle Eggs

Snapping turtles (Chelydra serpentina serpentina) have been extensively used as an ecosystem and localized indicator of tissue contaminant bioaccumulation, and for monitoring the geographic and temporal trends of contaminants. The purpose of this study was to determine if any relationship exists in the pattern and quantity of select contaminants found in turtle tissues relative to egg contamination. Six gravid snapping turtle females were collected from within and outside the Great Lakes basin and analyzed for congener-specific polychlorinated biphenyls (PCBs), dichlorodiphenyl-dichloroethylene (DDE), mirex and hexachlorobenzene (HCB) distributions in the fat, liver, and eggs. Preliminary data collected from five sites indicates that the pattern of congener-specific PCBs and homologs, average chlorine/biphenyl, and total PCBs are significantly correlated among snapping turtle eggs and tissues. Significant correlations were also observed for DDE, mirex, and HCB. All six turtles in this study revealed a consistent, and enhanced lower-chlorinated PCB pattern in the eggs relative to maternal adipose and liver tissues. Although these preliminary results are based on a relatively small sample size (n = 6), the significance of the relationships observed indicate that the utilization of snapping turtle eggs provides a reliable indicator of maternal contaminant burdens found in the highest environmental trophic levels.

Post-1990 Temporal Trends of PCBs and Organochlorine Pesticides in the Atmosphere and in Fish from Lakes Erie, Michigan, and Superior

We have analyzed concentration data sets covering the period 1992-2010 from the Great Lakes Integrated Atmospheric Deposition Network and from the Great Lakes Fish Monitoring and Surveillance Program to determine and compare pollutant time trends in the atmosphere and in fish. The analytes of interest were polychlorinated biphenyls, DDTs, chlordanes, dieldrin, and α- and γ-hexachlorocyclohexane (HCHs), and the sites of interest were Lakes Erie, Michigan, and Superior. Overall, we found no significant differences between the atmospheric and fish temporal trends for any of these compounds in any of the lakes. Polychlorinated biphenyl concentrations are decreasing in both the atmosphere and in the fish with halving times of 14 ± 2 years. The halving times for DDTs, chlordanes, and dieldrin are 8.7 ± 0.4 years for both the atmosphere and the fish. The most rapid temporal trend was observed for α- and γ-HCH concentrations, which are decreasing in both the atmosphere and in fish with halving times of 3.3 ± 0.4 years. The practical implications of these results are discussed.