31-14 Groundwater to the Human Gut: Arsenic Exposure and H. pylori Infection Prevalence

Session: Environmental Geochemistry and Health (Posters)

Poster Booth No.: 40

Presenting Author:

Christabel Obi

Authors:

Obi, Christabel Ifechukwu¹, McIntosh, Jennifer C², Brown, Heidi E³

(1) Hydrology and Atmospheric Sciences, The University of Arizona, Tucson, AZ, USA, (2) Hydrology and Atmospheric Sciences, The University of Arizona, Tucson, AZ, USA, (3) Mel & Enid Zuckerman College of Public Health, The University of Arizona, Tucson, AZ, USA,

Abstract:

Geogenic arsenic (As), an IARC Group 1 carcinogen, is a widespread contaminant of surface water and groundwater, mobilized from documented sources such as volcanoclastic sediments, geothermal fluids, felsic rocks, and basin-fill deposits. Although the U.S. drinking water maximum contaminant level (MCL) for arsenic is 10 ppb, some epidemiological studies suggest that chronic exposure to the far more widespread low-range concentrations (1-5 ppb) may still lead to adverse health outcomes. In the arid southwestern U.S., arsenic is a particular concern for private well owners whose water is not federally regulated and may often exceed drinking water limits. Northern Arizona illustrates the severity: aquifers there show documented arsenic exceedances with reported groundwater concentrations up to 190 ppb.

Helicobacter pylori, another IARC Group 1 carcinogen, is one of the most common bacterial infections worldwide and is a known risk factor for chronic gastritis (stomach inflammation), peptic ulcers, and gastric cancer. Some research works hypothesize an association between arsenic exposure from well water and susceptibility to H. pylori infection heightens gastric cancer development risk; because both arsenic and H. pylori damage the stomach lining cells, thus, their co-occurrence may accelerate progression from chronic gastritis to malignancy. 

This study integrates hydrogeochemical and epidemiological datasets to map the geographic distribution of arsenic exposure in groundwater and H. pylori infection nationwide and to evaluate them as co-located risk factors for gastric cancer. Preliminary results from an ongoing systematic scoping review of published H. pylori seroprevalence (past exposure to the pathogen) and demographic data reveal geographic and demographic heterogeneity: U.S. seroprevalence ranges from 30 – 36% nationally (our work has found 30.7% in southern Arizona to 56.4% in northern Arizona), with American Indian/Alaska Native, Black, and Hispanic populations bearing the highest infection burden. As H. pylori and arsenic mapping proceeds, overlaying these datasets will help pinpoint where geologic and infectious cancer risks converge, guiding targeted screening and future well water testing.

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