Change in levels of persistent organic pollutants in human plasma after consumption of a traditional northern Norwegian fish dish-mølje (cod, cod liver, cod liver oil and hard roe)

Predicting human plasma concentrations of persistent organic pollutants from dietary intake and socio-demographic information in the Norwegian Women and Cancer study

BACKGROUND

Concentrations of persistent organic pollutants (POPs) in humans are influenced by a large number of factors including birth year, reproductive history and diet. Accordingly, information on dietary habits and socio-demographic variables may predict plasma concentrations of POPs, thus enabling studies on health effects in large epidemiological studies, without performing time consuming and expensive chemical analyses on entire cohorts.

AIMS

To develop and evaluate statistical models for predicting concentrations of POPs in participants of the Norwegian Women and Cancer (NOWAC) study, using questionnaire information and measured plasma POP concentrations.

MATERIALS AND METHODS

Information on estimated dietary intakes and socio-demographic variables from four different questionnaires (in 1991, 1994, 2004 and 2005) were obtained from participants in the NOWAC study. We measured POP concentrations in a total of 367 blood samples from 2005 and built multivariable linear regression models for p,p'-DDE, PCB-118, -138, -153, -180 and summed PCB concentrations in one subsample (N = 259) and evaluated the models in another subsample (N = 108). Measured and predicted values were compared using correlation coefficients and inter-method agreement was evaluated using weighted Cohen's κ for tertile categorization.

RESULTS

Median POP concentrations in the population ranged from 13 ng/g lipid to 162 ng/g lipid (lowest for PCB-118 and highest for p,p'-DDE). Common predictors for all POPs were birth year, breastfeeding and the weight-related variables (BMI or weight change), whereas influential dietary variables differed and were of varying importance. The predicted plasma concentrations were significantly correlated with the measured values (r_s = 0.24, 0.33, 0.41, 0.50, 0.56, and 0.54 for p,p'-DDE, PCB-118, -138, 153, -180 and summed PCBs, respectively). Tertiles of predicted plasma concentrations displayed significant, but varying agreement with measured concentrations (Weighted Cohen's κ = 0.19, 0.22, 0.33, 0.42, 0.45, and 0.50 respectively).

CONCLUSION

Predicted plasma concentrations of certain PCBs showed good precision (Kw > 0.4) when compared to measured concentrations. Thus, the models can be used to classify NOWAC participants into high, medium and low PCB exposure groups.

Change in potato consumption among Norwegian women 1998-2005-The Norwegian Women and Cancer study (NOWAC)

Studies have shown that potato consumption in Norway have been on the decline in recent years. Increase in income and the association of potato consumption with weight gain and chronic diseases like type 2 diabetes have been identified as some of the factors responsible for the change. The aim of this study was to describe the change in potato consumption within persons and how non-dietary variables influenced that change among participants in the Norwegian Women and Cancer study (NOWAC). A prospective analysis was performed in the NOWAC cohort using linear regression. Data on dietary, lifestyle, socioeconomic and health-related factors were collected by mailed questionnaires. The change in potato consumption among 38,820 women aged 41–70 years was investigated using two measurements taken at intervals of 4–6 years. At baseline, mean intake was 112g per day; this had decreased to 94.5g per day at the second measurement. Results showed that the percentage of women who reported that they ate less than 1 potato a day increased from 24.6% at baseline to 35.5% at the second measurement. Those who reported that they ate more than 3 potatoes a day had decreased from 20.2% of the participants at baseline to 12.1% at the second measurement. Multivariable adjusted results show that geography was an important predictor of potato consumption at second measurement. Living in the north compared to Oslo (the capital) was associated with higher intake of potato at second measurement (B: 0.60, 95% CI: 0.55–0.65). Compared to women living with a partner, living alone was associated with lower potato intake at second measurement (B: -0.13, 95% CI: -0.17 –-0.09) while living with children tended to be associated with higher potato intake at second measurement (B: 0.01, 95% CI: -0.02–0.04). Younger age, more years of education, higher income or BMI was associated with a lower potato intake at second measurement. Smoking was associated with a higher intake of potato at second measurement (B: 0.03, 95% CI: 0.00–0.06 for smokers compared to non-smokers). Having diabetes at baseline was associated with lower intake of potato at second measurement (B: -0.04, 95% CI: -0.14 –-0.06 for non-diabetics compared to diabetics). Potato consumption among women in the NOWAC study showed a decline over the period studied. Change in the consumption was found to be influenced by age, education, income, household structure, region of residence as well as health-related factors like smoking and diabetes. The use of repeated measures is necessary to continue the monitoring and also to understand the stability and direction of the possible change in diet of a population.

Menstrual cycle perturbation by organohalogens and elements in the Cree of James Bay, Canada

Persistent organohalogens (POHs) and metals have been linked to alterations in menstrual cycle function and fertility in humans. The Cree First Nations people living near James Bay in Ontario and Quebec, Canada, have elevated levels of POHs, mercury and lead compared to other Canadians. The present study examines the interrelationships between selected POHs and elements on menstrual cycle function in these Cree women. Menstrual cycle characteristics were derived from structured daily diaries and endocrine measurements from daily urine samples collected during one cycle for 42 women age 19-42. We measured 31 POHs in blood plasma and 18 elements in whole blood, for 31 of the participants. POHs and elements detected in ≥ 70% of the participants were transformed by principal component (PC) analysis to reduce the contaminant exposure data to fewer, uncorrelated PCA variables. Multiple regression analysis revealed that, after adjusting for confounders, PC-3 values showed significant negative association with cycle length, after adjusting for confounders (p = 0.002). PC-3 accounted for 9.2% of the variance and shows positive loadings for cadmium, selenium, and PBDE congeners 47 and 153, and a negative loading for copper. Sensitivity analysis of the model to quantify likely effect sizes showed a range of menstrual cycle length from 25.3 to 28.3 days using the lower and upper 95% confidence limits of mean measured contaminant concentrations to predict cycle length. Our observations support the hypothesis that the menstrual cycle function of these women may be altered by exposure to POHs and elements from their environment.

Persistent organic pollutants are related to the change in circulating lipid levels during a 5 year follow-up

When reporting circulating levels of persistent organic pollutants (POPs), usually lipid-normalized values are given. However, animal experiments and some human data indicate that exposure to POPs may change lipid values. The aim of the present study is to investigate if POP levels can predict future changes in levels of circulating lipids. In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, lipids were measured at age 70 and at age 75 in 598 subjects without lipid-lowering medication. Twenty-three different POPs, including 16 polychlorinated biphenyls (PCBs), five organochlorine pesticides, one dioxin (OCDD) and one flame retardant brominated compound (BDE47) were analyzed by high-resolution chromatography coupled to high-resolution mass spectrometry (HRGC/HRMS) at age 70. Strong relationships were seen among the baseline levels of the non-dioxin-like PCBs 194, 206 and 209 and the degree of increase in total serum cholesterol and LDL-cholesterol during the 5 year follow-up. These relationships were generally stronger when lipid-normalized levels were used compared to wet-weight based levels. On the contrary, for two of the pesticides, hexachlorobenzene and trans-nonachlordane, levels were inversely related to the change in LDL-cholesterol, with strongest associations found using wet-weight based levels. PCBs 194, 206 and 209 were inversely related to the change in HDL-cholesterol, in particular for wet-weight based levels. However, these relationships were only significant for wet-weight PCB 194 following adjustment for multiple testing. None of the POPs was related to the change in serum triglycerides. When investigating the association between the change in total serum cholesterol and LDL-cholesterol across different categories of change in BMI, we noted robust results especially in the group with stable BMI, suggesting that the observed relationships were not due to fluctuations in BMI over time. In conclusion, POPs are related to the change in lipids over time, especially LDL-cholesterol. This may explain why POP exposure previously has been linked to atherosclerosis and cardiovascular disease.

Persistent organic pollutants in Norwegian men from 1979 to 2007: intraindividual changes, age-period-cohort effects, and model predictions

BACKGROUND

Longitudinal monitoring studies of persistent organic pollutants (POPs) in human populations are important to better understand changes with time and age, and for future predictions.

OBJECTIVES

We sought to describe serum POP time trends on an individual level, investigate age-period-cohort effects, and compare predicted polychlorinated biphenyl (PCB) concentrations to measured values.

METHODS

Serum was sampled in 1979, 1986, 1994, 2001, and 2007 from a cohort of 53 men in Northern Norway and analyzed for 41 POPs. Time period, age, and birth cohort effects were assessed by graphical analyses and mixed-effect models. We derived the predicted concentrations of four PCBs for each sampling year using the CoZMoMAN model.

RESULTS

The median decreases in summed serum POP concentrations (lipid-adjusted) in 1986, 1994, 2001, and 2007 relative to 1979 were -22%, -52%, -54%, and -68%, respectively. We observed substantial declines in all POP groups with the exception of chlordanes. Time period (reflected by sampling year) was the strongest descriptor of changes in PCB-153 concentrations. Predicted PCB-153 concentrations were consistent with measured concentrations in the study population.

CONCLUSIONS

Our results suggest substantial intraindividual declines in serum concentrations of legacy POPs from 1979 to 2007 in men from Northern Norway. These changes are consistent with reduced environmental exposure during these 30 years and highlight the relation between historic emissions and POP concentrations measured in humans. Observed data and interpretations are supported by estimates from the CoZMoMAN emission-based model. A longitudinal decrease in concentrations with age was evident for all birth cohorts. Overall, our findings support the relevance of age-period-cohort effects to human biomonitoring of environmental contaminants.

Maternal exposure to organochlorine pesticides in Western Australia

BACKGROUND

Organochlorine pesticides (OCPs) persist over long periods of time. Little is known about levels of OCPs in the plasma of non smoking pregnant women in Western Australia. The aim of this study was to (1) determine exposure concentrations in a sample of pregnant women in Western Australia; (2) to determine the significant environmental, lifestyle and activity contributors to maternal exposure concentrations of OCPs and (3) to compare the measured maternal exposure concentrations with those measured in other countries.

METHODS

In a cross-sectional survey, 167 pregnant women located in rural and urban Western Australia provided plasma and answered questionnaires seeking information on lifestyle, demographics and the determinants of exposure to OCPs.

RESULTS

Of the 10 OCPs examined only HCB, β-HCH and p,p'DDE had concentrations above the limit of detection for more than 50% of samples. The mean level of HCB was 0.08 μg/L (range 0.005-2.0 μg/L), β-HCH 0.18 μg/L (range 0.04-3.16 μg/L) and p,p'DDE 1.05 μg/L, (range 0.03-17.04 μg/L). HCB concentrations were higher in women who ate seafood during pregnancy and who were older and lower among those with a history of breastfeeding. Concentrations of β-HCH were higher among women with a household income<$80,000 and lower among those with a history of breastfeeding. Concentrations of p,p'DDE were higher among women who lived within 1 km of industry and lower among those with a history of breastfeeding.

CONCLUSIONS

Concentrations of pesticides were low in Western Australian mothers compared with international studies.

Prenatal exposure to DDT in malaria endemic region following indoor residual spraying and in non-malaria coastal regions of South Africa

Exemption was granted by the Stockholm Convention in 2004 for use of DDT by indoor residual spraying (IRS) as a malaria vector control. South Africa endorsed the use of DDT in its Malaria Control Programmes in malaria endemic regions and IRS remains a primary method of controlling malaria transmitting mosquitoes in this country. This study examines the impact of IRS on the levels of DDT and its metabolites in maternal blood of delivering women as a measure of prenatal exposure. We report on the concentrations of DDT and its metabolites (p,p'- DDE, p,p'-DDT, o,p'-DDE, o,p'-DDD, p,p'-DDD, and o,p'-DDT) in maternal plasma of 255 delivering women residing in three sites along Indian Ocean, namely in malaria endemic where IRS takes place, low risk and non-malaria sites. Concentrations of measured compounds were found to be significantly higher in the malaria endemic site (p=0.0001): the geometric mean concentration (95% confidence intervals; n=91) for o,p'-DDE was 9 ng/g lipids (7-10); for p,p'-DDE, 3840 ng/g lipids (3008-4902); for o,p'-DDD, 8 ng/g lipids (6-9); for p,p'-DDD, 26 ng/g lipids (20-32); for o,p'-DDT, 168 ng/g lipids (127-221) and for p,p'-DDT, 2194 ng/g lipids (1706-2823). These compounds were also detected in women residing in other sites but in lower concentrations. The maternal characteristics, age, IRS, number of children and breastfeeding were significantly associated for both p,p'-DDE and p,p'-DDT levels in the malaria area where exposure through IRS is predominant. There was no association between maternal characteristics and DDT levels in the low risk and non-malaria area. Results presented are of particular value to the policy decision makers and regulatory toxicology organizations as they characterise the extent of controlled exposure to DDT used exclusively for IRS purposes. Furthermore, findings of this study will form a base for further investigation of foetal exposure to pollutants.

Levels of selected persistent organic pollutants in blood from delivering women in seven selected areas of São Paulo State, Brazil

Persistent organic pollutants (POPs) present in the living environment are thought to have detrimental health effects on the population, with pregnant women and the developing foetus being at highest risk. We report on the levels of selected POPs in maternal blood of 155 delivering women residing in seven regions within the São Paulo State, Brazil. The following selected POPs were measured in the maternal whole blood: 12 polychlorinated biphenyls (PCBs) congeners (IUPAC Nos. 99, 101, 118, 138, 153, 156, 163, 170, 180, 183, 187, 194); dichlordiphenyltrichloroethane p,p'-DDT, diphenyldichloroethylene p,p'-DDE and other pesticides such as hexachlorocyclohexanes (α-HCH, β-HCH, γ-HCH), hexachlorobenzene (HCB), chlordane derivatives cis-chlordane, trans-chlordane, oxy-chlordane, cis-nonachlor and trans-nonachlor. Statistical comparisons between regions were performed only on compounds having concentrations above LOD in 70% of the samples. PCB118 congener was found to be highest in the industrial site (mean 4.97 ng/g lipids); PCB138 congener concentration was highest in the Urban 3 site (mean 4.27 ng/g lipids) and congener PCB153 was highest in the industrial and Urban 3 sites with mean concentration of 7.2 ng/g lipids and 5.89ng/g lipids respectively. Large differences in levels of p,p'-DDE between regions were observed with the Urban 3 and industrial sites having the highest concentrations of 645 ng/g lipids and 417 ng/g lipids, respectively; β-HCH was found to be highest in the Rural 1 site; the γ-HCH in Rural 1 and industrial; the HCB in the Rural 1 and industrial sites and oxy-chlordane and t-NC in the Rural 2 sites. An association between levels of some contaminants and maternal age and parity was also found.

In vitro steroidogenic effects of mixtures of persistent organic pollutants (POPs) extracted from burbot (Lota lota) caught in two Norwegian lakes

This study investigated the effects of two mixtures of persistent organic pollutants (POPs) on steroidogenesis in the H295R cell line. The two mixtures were obtained from the livers of burbot (Lota lota) caught in two Norwegian lakes (Mjøsa and Losna) with different contaminant profiles. Steroid hormone levels in the cell culture medium and mRNA levels of 16 genes involved in steroidogenesis were investigated. The crude Lake Mjøsa extract had to be diluted ten times more than the Lake Losna extract in order to prevent cytotoxicity. The ten times diluted Lake Mjøsa mixture had higher levels of DDT and derivates (∑DDTs, 1.7 times) and brominated flame retardants (∑BDEs and HBCD, 15-25 times) than the Lake Losna mixture, which, on the other hand, had higher concentrations of ∑PCBs (1.5 times higher) and also of HCB, ∑HCH isomers and ∑chlordane isomers (5-20 times higher). In the cell culture media, only cortisol levels were increased at the highest exposure concentration to the Lake Mjøsa mixture, while both cortisol and estradiol levels were increased following exposure to the two highest Lake Losna mixture exposure concentrations. Testosterone levels decreased only at the highest exposure concentration of the Lake Losna mixture. Multivariate models suggested that ∑PCBs, and to a lesser extent ∑DDTs, were responsible for the cortisol responses, while estradiol and testosterone alterations were best explained by HCB and ∑PCBs, respectively. Exposure to the mixtures generally increased mRNA levels, with smaller effects exerted by the Lake Mjøsa mixture than the Lake Losna mixture. It was concluded that both mixtures affected steroidogenesis in the H295R cells. Small differences in mixture composition, rather than the high content of brominated flame retardants in the Lake Mjøsa mixture, were suggested to be the most probable reason for the apparent differences in potencies of the two mixtures.

A first evaluation of the usefulness of feathers of nestling predatory birds for non-destructive biomonitoring of persistent organic pollutants

In previous studies, feathers of adult predatory birds have been evaluated as valid non-destructive biomonitor matrices for persistent organic pollutants (POPs). In this study, we assessed for the first time the usefulness of nestling raptor feathers for non-destructive biomonitoring of POPs. For this purpose, we collected body feathers and blood of nestlings from three avian top predators from northern Norway: northern goshawks (Accipiter gentilis), white-tailed eagles (Haliaeetus albicilla) and golden eagles (Aquila chrysaetos). We were able to detect a broad spectrum of legacy POPs in the nestling feathers of all three species (Σ PCBs: 6.78-140ng g(-1); DDE: 3.15-145ng g(-1); Σ PBDEs: 0.538-7.56ng g(-1)). However, these concentrations were lower compared to other studies on raptor species, probably due to the aspect of monitoring of nestlings instead of adults. Besides their analytical suitability, nestling feathers also appear to be biologically informative: concentrations of most POPs in nestling feathers showed strong and significant correlations with blood plasma concentrations in all species (p<0.050; 0.775<r<0.994). In addition, the reported correlations between feathers and blood plasma were much higher than those previously reported for adult individuals. Accumulation profiles and species-specific differences were in accordance with other toxicological studies on avian species and generally in agreement with the specific ecology of the studied species. In summary, our results indicate that the use of nestling feathers of northern raptors may be a valid and promising non-destructive biomonitoring strategy for POPs in their ecosystems.

Levels of organochlorines and lipids across pregnancy, delivery and postpartum periods in women from Northern Norway

The objective of this study was to investigate changes in the levels of common organochlorines (OCs) and lipids in maternal serum during and after pregnancy. A subset of 50 pregnant women from the North Norwegian Mother-and-Child Study was included in this study. Blood samples were collected during the 2(nd) trimester and postpartum (Day 3 and 6 weeks) in different regions of Northern Norway, and were analyzed for the Arctic Monitoring and Assessment Programme (AMAP) suite of OC contaminants. During the gestational period, both lipids and wet-weight OC levels peaked at birth and were the lowest at 6 weeks postpartum. When the OC concentrations were lipid-adjusted, this peaking was no longer evident. Wet-weight concentrations of OCs appear to be driven by the physiological lipid profiles and are interpreted to constitute biomarkers of lipidemia. It is suggested that this observation may have implications for the biomonitoring of individuals at risk of Type 2 diabetes. Both age and parity were strong predictors for the OCs measured, but no consistent association with body mass index (BMI) was evident. Independent of lipid-adjustment, all compounds were positively and significantly correlated with each other (within and across the three collection time periods). The peaking of OCs during pregnancy suggests that the period spanning the last weeks of the 3(rd) trimester and the early postpartum days constitutes an optimum sampling window purely from the analytical perspective.

Maternal levels of organochlorines in two communities in southern Vietnam

Some pesticides and PCBs continue to be reported as environmental problems in some areas of Vietnam. In 2005, a study among delivering women took place in two communities in south-central Vietnam (Khanh Hoa Province), namely the coastal city of Nha Trang and the rural district of Dien Khanh located about 10 km inland. The main findings in plasma (n=189) were relatively high mean concentrations of p,p'-DDE (12.2 microg/l in Nha Trang and 11.4 microg/l in Dien Khanh) and p,p'-DDT (1.2 microg/l in Nha Trang and 1.1 microg/l in Dien Khanh) with no significant community differences. The ratio of p,p'-DDE/p,p'-DDT (11.5 in Nha Trang/12.7 in Dien Khanh) suggests, as in other Vietnamese OCs studies, a relatively recent use of this pesticide. Mean concentrations of PCB 153 (0.15 microg/l in Nha Trang and 0.10 microg/l in Dien Khanh) and other congeners were low in both communities. Age and parity (all compounds), as well as community of residence for PCB 153, were the most important predictors of plasma OCs concentrations.

Combining data sets of organochlorines (OCs) in human plasma for the Russian Arctic

As part of AMAP's human circumpolar study of POPs, an international effort was initiated to extend coverage to communities across the Russian Arctic. Two additional laboratories were invited to join the analytical component of this effort, resulting in four participating analytical centres. Although quality assurance measures were put in place, and the level of performance of the laboratories was generally acceptable, deficiencies in the analytical protocols used were recognized subsequent to the collection and analyses of the plasma specimens. The current paper describes the criteria employed to critically appraise the four data bases and guide their integration into a single data set. Summary statistics are presented for plasma concentrations of major PCBs, p,p'-DDE, p,p'-DDT, beta-HCH, and HCB for communities/regions across the arctic/subarctic Russian continent, and for one community located in the Aral Sea area of Uzbekistan (a control group). Highly exposed people were identified in the coastal communities of Chukotka, which appears mainly related to marine mammal intake, but recent pesticide use is also suspected. Other communities with intermediate levels of PCBs had relatively elevated beta-HCH, p,p'-DDT and HCB concentrations and low DDE/DDT ratios (<10), suggesting recent pesticide use.

The effect of plasma lipids on the pharmacokinetics of chlorpyrifos and the impact on interpretation of blood biomonitoring data

Lipophilic molecules, like chlorpyrifos (CPF), present a special problem for interpretation of biomonitoring data because both the environmental dose of CPF and the physiological (pregnancy, diet, etc.) or pathological levels of blood lipids will affect the concentrations of CPF measured in blood. The objective of this study was to investigate the distribution of CPF between plasma and tissues when lipid levels are altered in late pregnancy. CPF was sequestered more in the low-density lipid fraction of the blood during the late stages of gestation in the rat and returned to nonpregnant patterns in the dam after birth. Plasma partitioning of CPF increased with increases in plasma lipid levels and the increased partitioning of CPF into plasma lipids resulted in less CPF in other tissue compartments. Gavage dosing with corn oil also increased plasma lipids that led to a moderate increase of CPF partitioning into the plasma. To mechanistically investigate the potential pharmacokinetic effects of blood lipid changes, an existing CPF physiologically based pharmacokinetic/pharmacodynamic model for rats and humans was modified to account for altered lipid-tissue partition coefficients and for major physiological and biochemical changes of pregnancy. The model indicated that plasma CPF levels are expected to be proportional to the well-known changes in plasma lipids during gestation. There is a rapidly growing literature on the relationship of lipid profiles with different disease conditions and on birth outcomes. Increased blood concentrations of lipophilic chemicals like CPF may point to altered lipid status, as well as possibly higher levels of exposure. Thus, proper interpretation of blood biomonitoring data of lipophilic chemicals requires a careful consideration of blood lipids.

Associations between marine food consumption and plasma concentrations of POPs in a Norwegian coastal population

There are strong indications that a moderate intake of fatty fish decreases the risk of cardiovascular diseases due to its content of omega-3 fatty acids. Other studies indicate that fatty fish consumption increase the body burden of Persistent Organic Pollutants (POPs) and may thereby increase the risk of negative health effects. Many of the latter studies are based on POP analysis of fatty fish, from which a recommended daily intake for humans has been calculated based on the no-observed adverse effect level (NOAEL) obtained from animal studies. Studies investigating associations between human plasma concentrations of POPs and intake of marine food show deviating results. In this study we investigated associations between self-reported intake of marine food (fatty fish, fish liver, fish liver oil, seagull eggs and halibut) and plasma concentrations of POPs. The study group consisted of 44 women and 16 men from northern Norway with a marine based diet. In addition to donate blood samples, the participants answered a detailed food frequency questionnaire with special emphasis on marine food consumption. Concentrations of 25 different POPs were measured in plasma. PCB 153 and p'p-DDE were the most ubiquitous PCB and chlorinated pesticide and the geometric mean concentrations were 73 ng/g lipids and 116 ng/g lipids respectively. The main findings in this study were that age, gender and intake of fresh fish liver oil were significant predictors of three of the most common PCBs and trans-Nonachlor in this study group. In addition, intake of seagull eggs influenced the concentration of PCB 180. However, even though the participants had a high intake of marine food they did not have elevated levels of POPs compared to other study groups. Intake of fatty fish did not significantly affect the body burden of POPs in this study group.

Intra- and intercompartmental associations between levels of organochlorines in maternal plasma, cord plasma and breast milk, and lead and cadmium in whole blood, for indigenous peoples of Chukotka, Russia

Long-range transport of pollutants towards circumpolar regions emphasizes the need for up-to-date and reliable biological monitoring data. This paper explores the use, reliability and availability of maternal blood (MB) and plasma (MP), cord blood (CB) and plasma (CP) and mother's milk (MM) in terms of assessing exposure to persistent toxic substances (PTSs). It is concluded that MP has the best combination of availability, sensitivity in terms of number of PTSs, their detection frequency and concentrations, and physiological relevance. The study group consisted of 48 pregnant women of indigenous origin from the Chuchki district in the eastern Russian arctic. Blood, CB and MM specimens were collected from all women and MP, CP and MM were analyzed for the Arctic Monitoring and Assessment Programme (AMAP) suite of organochlorines (OCs) and metals (Pb and Cd in MB and CB). Generally speaking, the levels of PTSs coincided with those indicated in several AMAP publications from Chukotka and other areas of northern Russia. The correlations of PTS concentrations between the three body fluid compartments exceeded the minimum statistical requirements of alpha = 0.05 and beta = 0.20 for most of the compounds, with r > 0.46 except for Cd (r = 0.05); lipid adjustments for the OCs did not affect the r-values to any significant extent. The majority of the inter-OC correlations within compartments also fulfilled the indicated statistical condition. Careful consideration is given to the replacement of concentrations below the detection limit, OC detection frequency, the criteria for log-transformation of the data, analytical uncertainty, and biological variability. Practical implications of the findings are explored.

POP exposure from fish liver consumption and risk of cancer--the Norwegian Women and Cancer Study

The aim of the study was to investigate the hypothesis that consumption of fish liver increases cancer risk in humans due to increased intake of persistent organic pollutants (POPs). This study is based on data from the Norwegian Women and Cancer Study (NOWAC). The study has a prospective cohort design with questionnaire data from 64 285 randomly selected Norwegian women (aged 40-70 at baseline) and linkage to the Norwegian Cancer Registry. Cox proportional hazards regression was used to calculate risk ratios associated with consumption of fish liver and total cancer and cancer in breast, uterus, and colon. Fish liver consumption was, after adjusting for known risk factors, associated with a significant reduced risk for total cancer (RR = 0.92, 95% CI: 0.85, 0.99), and non-significant reduced risk for breast cancer (RR = 0.90, 95% CI: 0.78, 1.04), and colon cancer (RR = 0.82, 95% CI: 0.63, 1.07). Relative risk for uterus cancer was 0.82 (95% CI: 0.61-1.12). No significant dose-response effect was found for frequency of fish liver consumption (when divided into three intake groups) and total cancer, nor for any of the other cancer sites.We have concluded that in Norwegian women, fish liver consumption was not associated with an increased cancer risk in breast, uterus, or colon. In contrast, a decreased risk for total cancer was found.

Abandoned Mid-Canada Radar Line sites in the Western James region of Northern Ontario, Canada: a source of organochlorines for First Nations people?

The potential exists for human exposure to polychlorinated biphenyls (PCBs) and other contaminants originating from abandoned Mid-Canada Radar Line (MCRL) sites in sub-arctic Canada. We examined patterns of differences with respect to body burden of organochlorines (lipid-adjusted) between residents of the Ontario First Nations of Fort Albany (the site of MCRL Site 050) and Kashechewan (no radar base) and Hamilton (an industrial, southern Ontario community) to assess whether the presence of Site 050 influenced organochlorine body burden with respect to the people of Fort Albany. PCBs (Aroclor 1260 and summation operator14 PCBs congeners [CBs]) and DDE in the plasma of Fort Albany and Kashechewan subjects were elevated relative to Hamilton participants. PCB and DDE-plasma levels in First Nation women were of comparable magnitude to those reported for Inuit women living in the west/central Northwest Territories. Significantly lower DDE/DDT ratios observed for Fort Albany indicates exposure to higher levels of DDT compared to Kashechewan. The probable source of DDT exposure for Fort Albany people is the DDT-contaminated soil surrounding buildings of Site 050. The results of the correspondence analysis (CA) indicated that people from Hamilton had relatively higher pesticides and lower CB body burdens, while people from Fort Albany and Kashechewan exhibited relatively higher CBs and lower pesticide levels (CA-1). The separation of Fort Albany and Kashechewan from Hamilton was also clear using questionnaire data (i.e., plotting dietary principal component [PC]-1 scores against PC-2); PC-1 was correlated with the consumption of a traditional diet. Separation of Kashechewan and Albany residents occurred because the people of Kashechewan ate more traditional meats and consumed shorebirds. Only one significant relationship was found between PC analysis and contaminant loadings; PC-1 versus CA-3 for Kashechewan. The presence of Site 050 on Anderson Island appears to have influenced organochlorine body burden of the people of Fort Albany. ANCOVA results revealed that it was not activity on Anderson Island that was important, but activity on Site 050 was the influential variable. When these results are considered with the DDE/DDT ratio data and the CB 187 results (Fort Albany and Kashechewan residents differed significantly), the findings are suggestive that Site 050 did influence organochlorine body burden of people from Fort Albany.

Levels of persistent organic pollutants (POPs) in a coastal northern Norwegian population with high fish-liver intake

Recent research has again raised the issue regarding the potential health effects of long term exposure to persistent organic pollutants (POPs) in the context of a risk-benefit analysis. There remains clear evidence of the beneficial effects of fish consumption on public health and in particular fatty fish with its essential fatty acids. In addition to providing fatty acids, fish fat constitutes an essential source to vitamin D for the northern Norwegian population. Norwegian Food Control Authorities have recommended that children and women of childbearing age should not consume fish liver due to the risk associated with high intake of POPs. The aim of this study was to assess the influence of fish liver intake on the levels of PCBs and chlorinated pesticides in a rural coastal community (n = 31) in northern Norway, applying a cross-sectional design. The geometric mean plasma levels of sum of PCBs (14 congeners) and p,p'-DDE was found to be 558 microg kg(-1) lipids and 179 microg kg(-1) lipids, respectively. These levels were not significantly affected by the reported intake of fish liver, when age and gender were considered. Age in particular, but also gender were significant predictors for most compounds. When merging the dataset with an urban population with considerable lower intake of fish liver, the intake of cod liver still did not significantly affect the levels of PCBs and p,p'-DDE when adjusted for age and gender. Age and gender remain the strongest predictors of plasma levels of POPs in this study whereas fish liver intake was not significantly associated with the POPs.

The Mid-Canada Radar Line and First Nations’ People of the James Bay region, Canada: an evaluation using log-linear contingency modelling to analyze organochlorine frequency data

Abandoned radar line stations in the North American arctic and sub-arctic regions are point sources of contamination, especially for PCBs. Few data exist with respect to human body burden of organochlorines (OCs) in residents of communities located in close proximity to these radar line sites. We compared plasma OC concentration (unadjusted for total lipids) frequency distribution data using log-linear contingency modelling for Fort Albany First Nation, the site of an abandoned Mid-Canada Radar Line station, and two comparison populations (the neighbouring community of Kashechewan First Nation without such a radar installation, and Hamilton, a city in southern Ontario, Canada). This type of analysis is important as it allows for an initial investigation of contaminant data without imputing any values. The two-state log-linear model (employing both non-detectable and detectable concentration frequencies and applicable to PCB congeners 28 and 105 and cis-nonachlor) and the four-state log-linear model (using quartile concentration frequencies for Aroclor 1260, PCB congeners [99,118,138,153,156,170,180,183,187], beta-HCH, p,p'-DDT +p,p'-DDE, HCB, mirex, oxychlordane, and trans-nonachlor) revealed that the effects of subject gender were inconsequential. Significant differences (p < 0.05) between the groups examined were attributable to the effect of location on the frequency of detection of OCs or on their differential distribution among the concentration quartiles. In general, people from Hamilton had higher frequencies of non-detections and of concentrations in the first quartile (p < 0.05) for most OCs compared to people from Fort Albany and Kashechewan (who consume a traditional diet of wild meats that does not include marine mammals). An unexpected finding was that, for Kashechewan males, the frequency of many OCs was significantly higher (p < 0.05) in the 4th concentration quartile than that predicted by the four-state log-linear model, but significantly lower than expected in the 1st quartile for beta-HCH. The levels of PCBs found for women in Fort Albany and Kashechewan were greater than those reported for Dene (First Nation people) and Métis (mixed heritage) of the western Northwest Territories (NWT) who did not consume marine mammals, and for Inuit living in the central NWT (occasional consumers of marine mammals). Moreover, the levels of total p,p'-DDT were greater for Fort Albany and Kashechewan women compared to these same aboriginal groups.