multicontaminant

Multicontaminant refers to the presence or potential risk of two or more chemical contaminants in a single environmental sample or exposure pathway. It is used across water, air, soil, food, and consumer products to reflect that real-world hazards rarely involve a single chemical.

In multicontaminant scenarios, the health impact depends on interactions among chemicals, which can be additive, synergistic, or antagonistic. Risk assessment therefore often moves beyond single-chemical hazard identification to consider mixture toxicity, exposure concordance, and cumulative effects across routes of exposure and time.

Measurement and assessment rely on multi-analyte approaches. Sampling protocols are designed to capture representative mixtures, and analytical methods such as gas chromatography–mass spectrometry and liquid chromatography–mass spectrometry enable simultaneous detection of many compounds. Non-target screening and high-throughput toxicology can help identify unexpected or data-poor components. Data interpretation faces challenges like sparse distributions, limited toxicology data for mixtures, and variability in exposure conditions.

Risk assessment frameworks for multicontaminants include methods that sum hazards (hazard quotients), dose-additive models, and more complex approaches such as relative potency factors and cumulative risk assessment. Grouping chemicals by mechanism of action or source can help prioritize priorities for monitoring and mitigation. Regulatory guidance varies but commonly emphasizes protecting vulnerable populations and addressing high-priority mixtures, especially in drinking water, food safety, and environmental remediation.

Practical implications include informing monitoring programs, informing treatment and remediation strategies, and guiding risk communication for communities exposed to multiple contaminants.