This seminar is the second in a three part series that coincides with the Superfund Research Program's 25th Anniversary and the 10th Anniversary of the Superfund Research Program (SRP) Risk e-Learning webinars. The SRP chose this opportunity to highlight the Program's accomplishments in the area of arsenic research. Since its inception, the SRP has funded work to understand the consequences of exposure to arsenic at the molecular and population levels. Equally important, these researchers have developed unique and effective methods to detect arsenic in the environment and to minimize human exposure to arsenic from drinking water and food sources.
Allan H. Smith, M.D., Ph.D.
University of California, Berkeley, School of Public Health
The Astonishing Long-Term Effects of In Utero & Early Childhood Exposure to Arsenic
In this presentation Smith will discuss a unique arsenic exposure scenario that provides a rare opportunity to investigate the long-term mortality impact of early-life arsenic exposure. Smith's research team explored the mortality rates in Antofagasta, Chile, which had a distinct period of very high arsenic exposure from 1958 to 1971 when an arsenic removal plant was installed. The research team compared mortality rates in Antofagasta in the period of 1989-2000 with those of the rest of Chile, focusing on subjects who were born during or just before the peak exposure period and who were 30-49 years of age at the time of death. The results of Smith's research suggest that exposure to arsenic in drinking water during early childhood or in utero has major effects on subsequent mortality in young adults from both malignant (laryngeal cancer, lung cancer and bladder cancer) and nonmalignant (acute myocardial infarction, chronic renal failure and bronchiectasis) causes of death, beyond the effects attributable to any other human environmental exposure.
Joshua W. Hamilton, Ph.D.
Dartmouth College SRP Center
Mouse Models of Human In Utero and Adult Exposures to Low-Dose Arsenic in Drinking Water
During this webinar Dr. Hamilton will discuss his recent research to develop unique mouse models of human fetal and early childhood exposure to arsenic (As) in order to determine both the adverse consequences of these exposures in controlled laboratory experiments and to investigate the underlying mechanisms for these effects. Dr. Hamilton will present the results of two mouse models. In the first model, young adult male and female C57BL6 mice were exposed to inorganic As+3 in drinking water at 10 or 100 parts per billion (ppb) — 10 ppb is the current US EPA Maximum Contaminant Level (MCL) and 100 ppb is twice the previous MCL of 50 ppb. These experiments revealed profound effects on innate immune response of lung to a viral (influenza) infection and on metabolic regulation by liver and adipose tissue. In the second model young adult female mice were exposed to 10 ppb arsenic in drinking water during pregnancy and post-natal nursing, and effects were observed on the mothers and the offspring. This latter model was designed to mimic recent human epidemiology studies from Chile that investigated the long-term consequences of fetal and early childhood exposures to arsenic in drinking water. The results of these mouse experiments demonstrated profound effects on metabolic regulation by the mothers and on growth and development by the offspring. These results support the hypothesis that exposure to arsenic at very low levels equivalent to the US MCL, particularly during pregnancy and during critical windows of fetal and neonatal development, can induce a number of adverse effects both in the adult mothers and their offspring, suggesting that such effects may occur in humans and may contribute to increased disease risks in exposed populations.