The Expert: Dr. David Carpenter, Director of the Institute for Health and the Environment and an expert on PCBs, testifies for the plaintiffs and details research on the effect PCBs have on the brain.
Dr. David Carpenter, Harvard trained physician and Director of the Institute for Health and the Environment and an expert on Polychlorinated Biphenols [PCB’s], testifies for the plaintiffs in Erickson v. Monsanto, a 2021 Washington state court trial over PCB exposure at a school that plaintiffs claim left them with brain damage.
The doctor initially addresses the question of what concentration of PCBs in the brain would cause damage to brain function. First qualifying his answer to say that these studies have not been done [because this would not be an ethical study], he states that PCBs at any level are not good for the brain. Furthermore, since brain cells have minimal capacity to regenerate as other organs in the body such as the liver can, any damage as a result of PCB exposure is likely to be permanent in the brain. A child that is exposed to chemicals such as lead that result in a detrimental effect on IQ, never reaches the same cognitive function as a child never exposed. This implies permanence in the effect. Although this permanence has yet to be absolutely proven after exposure to PCBs, the implication is strong.
The expert has been involved in studies looking at rates of hospitalization for various diseases in relation to the proximity to living near toxic waste sites that contain PCBs. These studies found significant increases in heart disease, diabetes, thyroid disease, infections, hypertension, asthma, and chronic pulmonary disease. Although the blood levels of PCBs were not examined, the air levels of PCBs were. The concentration of PCB air contaminants found to be significantly associated with these diseases was 4-6 ng/cm3. This is “two orders of magnitude lower than those presumed at Sky Valley,” the school under examination in this case. By comparison, concentrations of PCBs in the air in areas remote from toxic sites average 0.8ng/cm3.
Carpenter cites a study of people living near a Monsanto plant in Alabama that makes PCBs. This study exposed a strong relationship between PCB levels and hypertension, a disease physicians don’t usually associate with toxin exposure. Similarly, a study of the Native Americans living near PCB contaminated sites found increased incidences of diabetes. The St. Lawrence River where three aluminum foundries leak PCBs into the river from the hydraulic fluids they use, had significant contamination of soil and air. The study of those living near this river looked at the different types of PCBs and found an association of one class with the development of diabetes. Thus for hypertension and diabetes, the strongest association was with the class of lower chlorinated PCBs while high cholesterol, high triglycerides, and obesity were associated with the higher chlorinated PCBs. This latter association is felt to be related to food consumption whereas the former was more related to breathing contaminated air.
In answer to questioning by the plaintiff’s lawyer, the expert testifies that the PCBs by themselves are stable, but once inhaled, the body has enzymes to destroy them. This is more easily accomplished with congeners containing lower amounts of chlorine making them more readily metabolized than PCB congeners with a lot of chlorines.
The response to another question regarding whether the PCB molecule stays in the brain once it gets there, indicated that the brain is much less capable of degrading the molecule like the liver can, but since the molecule is fat soluble, it does get washed out into other areas of the body. Monkey studies indicated that there was an accumulation of PCBs over time in certain parts of the brain.
Finally, questioning about whether the deleterious effects of PCBs persist even when the blood levels diminish, Carpenter reiterates that despite having no studies that have definitively proven this, his experience is that once the brain is damaged in this way, it remains a permanent problem.
This extremely authoritative testimony was crucial. The judgment was for the plaintiff for $185.15 million.
Gary Gansar, MD, is residency-trained in general surgery. He served as Chief of Surgery and Staff at Elmwood Medical Center and on the Medical Executive Committee at Touro Infirmary and Mercy Hospital in New Orleans, LA. Dr. Gansar was Board Certified in general surgery while in active practice. He joined AMFS in 2015 as a Physician Medical Director.
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