Arsenic drinking water regulations in developing countries with extensive exposure.

Area of Science:

• Environmental Health
• Toxicology
• Public Health Policy

Background:

• Historical drinking water standards for arsenic have evolved, with the World Health Organization Guideline set at 10 microg/l in 1992.
• Epidemiological studies link long-term exposure to 500 microg/l arsenic in drinking water with increased cancer mortality, notably lung cancer.

Purpose of the Study:

• To evaluate the complexities of setting drinking water arsenic standards, particularly in developing countries.
• To consider factors influencing arsenic risk, such as malnutrition and smoking, and their impact on public health strategies.

Main Methods:

• Review of historical drinking water standards and epidemiological data on arsenic exposure and health outcomes.
• Analysis of synergistic effects between smoking and arsenic exposure on lung cancer incidence.
• Consideration of socio-economic factors and practical limitations in implementing water quality standards.

Main Results:

• A concentration of 500 microg/l arsenic in drinking water is associated with a significant risk of fatal internal cancers.
• Malnutrition and smoking may exacerbate arsenic-related health risks, particularly lung cancer.
• Stringent arsenic standards may hinder immediate solutions like shallow dugwells in developing nations.

Conclusions:

• A prudent public health approach necessitates reducing permissible arsenic concentrations in drinking water.
• Developing countries with high arsenic exposure may benefit from maintaining a 50 microg/l standard as an interim measure.
• Addressing co-factors like malnutrition and promoting smoking cessation are vital components of a comprehensive arsenic mitigation strategy.