Blood Levels Of Persistent Organic Pollutants Research Articles

Blood screening for heavy metals and organic pollutants in cancer patients exposed to toxic waste in southern Italy: A pilot study.

In Italy, in the eastern area of the Campania region, the illegal dumping and burning of waste have been documented, which could potentially affect the local population's health. In particular, toxic waste exposure has been suggested to associate with increased cancer development/mortality in these areas, although a causal link has not yet been established. In this pilot study, we evaluated blood levels of toxic heavy metals and persistent organic pollutants (POPs) in 95 patients with different cancer types residing in this area and in 27 healthy individuals. While we did not find any significant correlation between the blood levels of POPs and the provenance of the patients, we did observe high blood concentrations of heavy metals in some municipalities, including Giugliano, where many illegal waste disposal sites have previously been documented. Our results showed that patients with different cancer types from Giugliano had higher blood levels of heavy metals than healthy controls. Despite the obvious limitations of this exploratory study, our preliminary observations encourage further research assessing the possible association between exposure to hazardous waste, increased blood metals, and increased risk of cancer.

Trunk fat and persistent organic pollutants.

Individuals with obesity, especially those who display excess visceral fat, are known to be more prone to metabolic, ergonomic, and psychosocial problems. In the context of the obesity epidemic, this observation is largely used to justify interventions aimed at a negative energy/fat balance and long-term body fat loss. On the other hand, it is frequently forgotten that adipose tissue has some utilities including the production of molecules, e.g., leptin and adiponectin, that contribute to metabolic regulation. Adipose tissue is also the main site of storage of lipid-soluble persistent organic pollutants (POPs) for which the body load is increased in individuals with obesity (1) and is strongly related to the risk of developing the metabolic syndrome (2). In this issue, Zong et al. (3) extend knowledge on this topic by using NHANES data that offer sufficient statistical power to evaluate the preferential relationship between POPs circulating levels and fat accumulation in specific fat depots. The main finding of their study was the demonstration of stronger associations between POPs and trunk fat mass (FM) percent compared to leg fat. They explained this phenomenon by a possibly more important role of trunk fat in the pharmacokinetics of POPs or a stronger effect of POPs as hormone disruptors on trunk fat metabolism. Since upper body fat deposition is related to metabolic complications, they also raised the possibility that POPs may partly explain the association between upper body fat accumulation and metabolic abnormalities. The study of Zong et al. also included age-stratified analysis which showed stronger inverse correlations between POPs and trunk FM percent in adults < 40 years. This is compatible with the protective role of adipose tissue where its storage of POPs attenuates the exposure of non-adipose organs to these compounds and their detrimental effects. Conversely, stronger positive correlations between POPs and trunk FM percent compared to leg fat were observed in older individuals. This indicates that for a given increase in trunk fat, POPs blood levels unfavorably change in elderly people. This also emphasizes the relevance of further investigations of this issue to verify whether the capacity of adipose tissue to dilute POPs decreases with aging. The results of this study also raised concerns about weight loss in the elderly. Indeed, since a decrease in body fat promotes a significant increase in adipose tissue and blood levels of POPs (4), it would be interesting to determine the impact of fat loss on the POPs–trunk fat relationship, particularly in older individuals. Globally, the study of Zong et al. offers an interesting conceptual contribution and also permits addressing questions that give promising perspectives to this field which deserves more attention from scientists involved in obesity research.

DNA double-strand breaks in relation to persistent organic pollutants in a fasting seabird

Lipophilic persistent organic pollutants (POPs) are released from fat reserves during fasting, causing increased blood concentrations. Thus, POPs represent a potential anthropogenic stressor during fasting periods. We analysed the blood of female common eiders (Somateria mollissima) by using agarose gel electrophoresis and image data analysis to quantify the DNA-fraction, of total DNA, that migrated into the gel (DNA-FTM) as a relative measure of DNA double strand-breaks (DSBs) during the fasting incubation period in the high arctic. In 2008 and in 2009 blood samples were obtained for analysis of 9 POPs and DNA-FTM at day 5 of the incubation period, and then in the same individuals at day 20. This unique study design gave us the opportunity to analyse the same individuals throughout two points in time, with low and high stress burdens. During the incubation period the body mass (BM) decreased by 21–24%, whereas the POP levels increased by 148–639%. The DNA-FTM increased by 61–67% (being proportional to the increase in DSBs). At day 5, but not day 20, DNA-FTM was positively correlated with most analysed POPs. The increase in DNA-FTM was positively correlated with the decrease in BM (g) during incubation. Thus, we suggest that fasting stress (BM loss) decreases DNA integrity and that stress caused by fasting on BM loss appeared to override the additional stress caused by concurrent increase in levels of the analysed POPs in the eiders. Blood levels of POPs in the eiders in Svalbard were relatively low, and additive and/or synergistic genotoxic effects of fasting stress and POP exposure may occur in populations with higher POP levels.

A Long-Term Risk? Prenatal POPs Exposure and Asthma in Young Adults

Although previous research has suggested that prenatal exposures to persistent organic pollutants (POPs) may be harmful to a child’s developing immune system,1 few studies have investigated long-term outcomes in this regard. Findings reported in this issue of EHP provide evidence that exposure to certain POPs in the womb may be associated with an increased risk of developing asthma that persists into young adulthood.2 “The focus in immunotoxicity studies has often been on immunologic intermediates, such as immune cell counts. This study is unique in that it looks at a long-term clinically relevant outcome,” says Todd Jusko, an environmental epidemiologist at the University of Rochester, who was not involved in the study. Researchers in Denmark assessed the relationship between asthma and prenatal exposure to polychlorinated biphenyls (PCBs), the pesticide hexachlorobenzene (HCB), and dichlorodiphenyldichloroethylene (DDE), a daughter compound of the pesticide DDT. PCBs, HCB, and DDT have been banned or restricted for many years due to concerns over human health effects, but they persist in the environment and the human body. Although levels of these chemicals have been dropping in the human population, diet—especially seafood consumption—remains an important route of exposure.3 Past studies have reported an association between prenatal exposure to DDE and asthma in children at ages 44 and 7–10.5 Prenatal HCB exposure has been associated with airway hyperreactivity in rats.6 Other studies examining prenatal exposure to PCBs and asthma-like symptoms have yielded mixed results; two studies found an association with wheeze in infants7 and allergic sensitivity in children at age 7,8 while another reported an inverse association with allergic disease.9 Children exposed to certain persistant organic pollutants in utero may be at increased risk for asthma that lasts into young adulthood. Divergent findings may be due in part to the fact that previous studies have not followed up past childhood, say the authors of the new study. “A twenty-year follow-up allows us to distinguish between [true] asthma and asthma-like symptoms, such as wheeze, which may resolve in the first six to seven years of life,” says lead author Susanne Hansen, a doctoral candidate in epidemiology at the Statens Serum Institut in Copenhagen. In the current study, the researchers assessed POP levels in blood samples from 872 pregnant Danish women. All samples were collected between 1988 and 1989, during the 30th week of pregnancy. Although blood levels of POPs in the cohort were higher than concentrations found in the general population today, they were average for women of childbearing age in Denmark in the 1980s, according to Hansen. The researchers used registry data and self-reports on asthma diagnosis and medication use since age 6 to identify asthma cases. At age 20, children of mothers with the highest blood HCB concentrations during pregnancy were nearly twice as likely as children of mothers with the lowest concentrations to have been prescribed asthma medication. This is the first study to report an association between developmental HCB exposure and asthma in offspring, according to the researchers. Similarly, children of mothers with the highest blood levels of one particular PCB congener, dioxin-like PCB-118, were nearly twice as likely as children of mothers with the lowest levels to have used asthma medications. The researchers also observed positive associations of HCB and PCBs with self-reported lifetime diagnosis of asthma, and between HCB and clinical diagnosis of asthma, although these associations were not statistically significant. None of the outcomes were associated with maternal DDE. The mechanisms by which HCB and dioxin-like PCBs might influence asthma remain unclear. However, some researchers suspect PCBs and HCB interact with the aryl hydrocarbon receptor—a protein that, when activated in immune cells, may lead to a suppressed immune response.10 “The association between dioxin-like PCB 118 and asthma is an interesting one but not sufficient to suggest a general link between all dioxin-like chemicals and asthma,” says Michele La Merrill, a developmental toxicologist at the University of California, Davis. She says the possibility of such a general link is “a provocative question that would be worth continuing to ask in future studies.” PCBs, HCB, and DDT have been shown to readily cross the placenta, making maternal blood levels during pregnancy a good proxy for fetal exposure. However, the current results are not sufficient for the researchers to make any claims about the relative importance of prenatal versus postnatal exposures. POPs can be transferred via breast milk, and the researchers had no data on breastfeeding habits for the mothers in their study. “Maternal serum levels could also be correlated with postnatal exposure,” Hansen says.