Reproductive risks from contaminants in drinking water

Area of Science:

• Environmental toxicology
• Reproductive health
• Developmental toxicology

Background:

• Reproductive toxicity encompasses a wide range of adverse effects, including functional impairments and chemical secretion, often relevant to chronic low-level exposures.
• Several water contaminants, such as sodium chlorite, chloroacetic acid, and dichloro-/trichloro acetonitrile, require further investigation for their developmental toxicity.
• Existing risk assessments cover pollutants like nitrates/nitrites, fluorides, and lead, but many chemicals lack sufficient data for comprehensive risk evaluation.

Purpose of the Study:

• To highlight the complexity of reproductive toxicity beyond traditional endpoints like birth defects and sterility.
• To identify specific chemical contaminants in water and the environment that pose reproductive and developmental risks.
• To emphasize the need for further research on poorly characterized chemicals, chemical mixtures, and occupational exposures.

Main Methods:

• Literature review and synthesis of existing data on reproductive and developmental toxicity of various chemical agents.
• Analysis of risk assessments performed for known water pollutants.
• Identification of data gaps and areas requiring further scientific investigation.

Main Results:

• High concentrations of sodium chlorite may impair reproduction. Certain water chlorination by-products and pollutants like nitrates/nitrites, fluorides, and lead warrant attention.
• Occupational exposures to herbicides (molinate), nematocides (dibromochloropropane), and halogenated contaminants (ethylene dibromide, epichlorohydrin) show selective male reproductive toxicity.
• Ethylene thiourea is teratogenic in rats, while compounds like TCDD and hexachlorobenzene exhibit significant reproductive toxicity. Data for chemicals like tetrachloroethylene and nickel are insufficient for risk assessment.

Conclusions:

• Reproductive toxicity is a multifaceted issue requiring consideration of subtle, chronic effects. A broader range of chemicals, including environmental metabolites and poorly soluble compounds, must be evaluated.
• Significant data gaps exist for many chemicals, hindering comprehensive risk assessment, especially for substances found in drinking water.
• Further research into the interactive effects of multiple low-level contaminants is crucial for a complete understanding of reproductive health risks.