David O. Carpenter, MD. Institute for Health and the Environment University at Albany Rensselaer, NY

Transcription

1 Health Effects and Routes of Exposure to Polychlorinated Biphenyls (PCBs) David O. Carpenter, MD Institute for Health and the Environment University at Albany Rensselaer, NY

2 Health Effects of Exposure to PCBs Cancer: PCBs are known human carcinogens. Immune suppression: More frequent and more serious infections. Endocrine effects: Estrogen mimics. Nervous system effects: Reduced IQ and memory. Especially bad in schools. Diabetes: Increased risk. Heart Disease: Elevates lipids and raises blood pressure.

3 Routes of Exposure to PCBs Traditionally most exposure to PCBs has been assumed to be by ingestion, especially of animal fats. The PCBs congeners in animal fats tend to be higher chlorinated and more persistent. PCBs in air are primarily lower chlorinated and less persistent. If PCBs are in construction materials they will volatize. The question is whether these air borne PCBs cause disease.

4 Table 1. Physical characteristics of PCBs by homologue groups at 25º

5 % of Total PCB % of Total PCB Aroclor 1260 liquid PCB congener in elution order Aroclor 1260 vapor PCB congener in elution order Figure 2. The congener patterns in Aroclor 1260 liquid (top) and the congener pattern seen when passing air over the liquid and collecting and analyzing the vapor-phase PCBs

6 Our Studies We have performed two types of studies. The first uses the NYS SPARCS dataset which gives disease diagnosis upon discharge from hospitals. This has large numbers, but no individual exposure assessment beyond the zip code of residence near to waste sites. These are ecologic, hypothesis-generating studies. Exposure is assumed to be primarily by inhalation. The second type of study is of a smaller population with direct measures of exposure and with personal medical and clinical chemistry history.

7 Zip Codes Grouped by Exposure Status

8 PCBs and Diabetes Diabetes has usually been thought to be a lifestyle disease resulting from poor diet, obesity and lack of exercise. While lifestyle is important, it may not be the most important risk factor for developing diabetes. New evidence shows that people with high concentrations of PCBs are more likely to have diabetes.

9 Results of Regression Analysis for Adult Diabetes Discharge Coeffici ent SE RR (CI) P- Value Clean Site (ref) PCB Sites ( ) < Other Waste Site ( ) < Hudson River ( <.000 SE= standard error; RR = rate ratio; CI = 95% confidence interval. 1

10 Diabetes at Akwesasne We studied 601 Mohawks ages years, obtaining fasting glucose, history of diagnosis of diabetes, serum PCBs and 3 pesticides (DDE, HCB, mirex). The prevalence of diabetes was 18.5%. After adjustment for sex, age, BMI, and smoking, the risk ratio (RR) for having diabetes, comparing the highest to lowest quartile was 2.21 for total PCBs and 3.75 for total pesticides. Both results were statistically significant.

11 Association Between Diabetes and Various POPs after Adjustment for all other POPs and Number of Chlorines. Exposure RR p-trend Tri-Tetra Penta-Hexa Hepta Plus HCB DDE Mirex

12 The Significance of These Results These results show that the major association is which the PCBs that have only 3 or 4 chlorines. These are the more volatile and less persistent congeners. Of the pesticides only HCB showed a significant association and it was much less that the low chlorinated PCBs.

13 RRs of PCB Congeners Having No or One Ortho-substituted Chlorine After Adjustment for all Other POPs. RR p-trend All non-mono Dioxin-like Non-dioxin-like

14 Significance of these Results For diabetes the PCB congeners showing strong associations are those with few chlorines lacking dioxin-like activity, and these are the ones that are more volatile. Inhalation is the likely the most important route of exposure leading to development of diabetes. Those who study total PCBs or total pesticides likely miss important associations.

15 The Tragic Story of JM and GM JM was employed as a chemist at a company that dealt with old oils from transformers. He was told to smell the oils to see if they contained PCBs. This he did from 1994 until In 2003 he was found to have thyroid cancer. In 2011 he was diagnosed with malignant melanoma. In 2012 he was diagnosed with lung cancer. He died in GM, wife of JM, was employed as a dish washer and person responsible for dumping used oils. She was told to smell the oils to determine whether they contained PCBs. GM was diagnosed with thyroid cancer in In 2011 she was diagnosed with a severely dysplastic nevus, a precursor to malignant melanoma.

16 PCB concentrations (µg/kg or ppb wet weight) in serum samples from JM and GM (nd = not detected) in relation to those from the National Health and Nutrition Examination Survey random sample of US residents.

17 Inhaled PCBs Caused These Cancers For two individuals who are not blood relatives to develop the same cancers cannot be due to chance. The PCB content in their blood indicates large exposure to volatile PCBs. This is very strong evidence that inhaled PCBs caused JM and GM s cancers.

18 Conclusions These results strongly suggest that inhalation of PCBs can cause diabetes and cancer. It is well known that PCB exposure results in a reduced IQ. Thus PCBs in schools are a major issue. PCBs don t have to be persistent in order to cause disease. PCBs in the air, whether indoor or outdoor, pose serious risks of human disease via inhalation. Volatile PCBs likely cause other adverse health effects as well.