Systematic review of differential inorganic arsenic exposure in minority, low-income, and indigenous populations in the United States.

Inorganic arsenic (iAs) is a human carcinogen and associated with cardiovascular, respiratory, and skin diseases. Natural and anthropogenic sources contribute to low concentrations of iAs in water, food, soil, and air. Differential exposure to environmental hazards in minority, indigenous, and low income populations is considered an environmental justice (EJ) concern, yet it is unclear if higher iAs exposure occurs in these populations. A systematic review was conducted to evaluate evidence for differential iAs exposure in the United States (US). The peer-reviewed literature was searched for studies that (1) estimated iAs exposure based on environmental concentrations of iAs in water, food, soil, or iAs biomarkers and (2) examined iAs exposure in minority, indigenous, and low income US populations. Five studies were identified that estimated exposures and provided demographic information about EJ populations. These studies reported arsenic concentrations in water, soil, or food to estimate exposure, with varied evidence of differential exposure. Additionally, six studies were identified that suggested potential arsenic exposure from environmental sources including soil, rice, private well-water, and fish, but did not report data stratified by demographic information. Evidence across these 11 studies was qualitatively integrated to draw conclusions about differential iAs exposure. The total body of evidence is limited by lack of individual exposure measures, lack of iAs concentration data, and insufficient comparative demographic data. Based upon these data gaps, there is inadequate evidence to conclude whether differential exposure to iAs is an EJ concern in the US.

Workshop overview: arsenic research and risk assessment.

The chronic exposure of humans through consumption of high levels of inorganic arsenic (iAs)-contaminated drinking water is associated with skin lesions, peripheral vascular disease, hypertension, and cancers. Additionally, humans are exposed to organic arsenicals when used as pesticides and herbicides (e.g., monomethylarsonic acid, dimethylarsinic acid (DMA(V)) also known as cacodylic acid). Extensive research has been conducted to characterize the adverse health effects that result from exposure to iAs and its metabolites to describe the biological pathway(s) that lead to adverse health effects. To further this effort, on May 31, 2006, the United States Environmental Protection Agency (USEPA) sponsored a meeting entitled "Workshop on Arsenic Research and Risk Assessment". The invited participants from government agencies, academia, independent research organizations and consultants were asked to present their current research. The overall focus of these research efforts has been to determine the potential human health risks due to environmental exposures to arsenicals. Pursuant in these efforts is the elucidation of a mode of action for arsenicals. This paper provides a brief overview of the workshop goals, regulatory context for arsenical research, mode of action (MOA) analysis in human health risk assessment, and the application of MOA analysis for iAs and DMA(V). Subsequent papers within this issue will present the research discussed at the workshop, ensuing discussions, and conclusions of the workshop.