Health Risk Assessment of Heavy Metal Contamination in Drinking Water

Heavy metal contamination of drinking water poses a persistent global threat to human health, arising from natural leaching, industrial discharge, agricultural runoff and ageing distribution infrastructure. Health risk assessment provides a systematic framework to quantify both non-carcinogenic and carcinogenic hazards associated with metals such as arsenic, cadmium, chromium, lead and mercury. Standard metrics include chronic daily intake, hazard quotient, hazard index and lifetime cancer risk, often complemented by probabilistic approaches to account for parameter uncertainty. Recent advances integrate water quality indices and Monte Carlo simulation to refine exposure estimates and sensitivity analyses, while burden-of-disease metrics such as disability-adjusted life years translate exposure into public health impacts. Findings guide regulatory compliance with WHO and national guidelines, inform treatment and monitoring strategies, and underpin evidence-based interventions to protect vulnerable groups, especially children, who exhibit higher intake per body weight and elevated susceptibility to metal toxicity.

Research from Nature Portfolio

Recent studies have applied comprehensive water quality indices alongside deterministic and probabilistic risk assessments to characterise heavy metal hazards in residential aquifers. One investigation evaluated eighty groundwater samples across wet and dry seasons, employing indices such as the heavy metals evaluation index, pollution index, contamination degree and metal index. Deterministic risk metrics (chronic daily intake, hazard quotient and hazard index) were bolstered by Monte Carlo simulation, revealing that chromium posed the greatest non-carcinogenic risk to children and adults, zinc dominated seasonal concentrations and that ingestion rates and metal levels were the primary sensitivity drivers. A separate analysis extended conventional hazard assessment by estimating years of life lost, years lived with disability and disability-adjusted life years due to arsenic, cadmium, chromium and lead exposures. Non-carcinogenic risk remained below critical thresholds, yet calculated excess lifetime cancer risk for arsenic indicated a measurable burden of skin, lung and kidney cancers, emphasising the need for region-specific mitigation strategies.

Health Risk Assessment of Heavy Metal Contamination in Drinking Water publication trend

The graph below shows the total number of articles in health risk assessment of heavy metal contamination in drinking water across all publications each year (not limited to Nature Index journals).

Technical terms

Chronic Daily Intake (CDI): Estimated daily intake of a substance per unit body weight, accounting for concentration, ingestion rate, exposure frequency and duration.

Hazard Quotient (HQ): Ratio of estimated exposure to a reference dose; HQ < 1 indicates exposure below the level likely to cause adverse effects.

Hazard Index (HI): Sum of hazard quotients for multiple substances or pathways; HI < 1 denotes acceptable overall non-carcinogenic risk.

Lifetime Cancer Risk (CR or ILCR): Probability of an individual developing cancer over a lifetime due to exposure to a carcinogen via a specified route.

Monte Carlo Simulation: Statistical technique that uses repeated random sampling to quantify uncertainty and variability in risk assessment outputs.

Disability-Adjusted Life Years (DALY): Composite measure of disease burden combining years of life lost due to premature mortality and years lived with disability.

References

1. Seasonal variations of potentially toxic elements (PTEs) in drinking water and health risk assessment via Monte Carlo simulation and Sobol sensitivity analysis in southern Iran's largest city. Applied Water Science (2023).
2. Health risk assessments of arsenic and toxic heavy metal exposure in drinking water in northeast Iran. Environmental Health and Preventive Medicine (2019).
3. Comprehensive health risk analysis of heavy metal pollution using water quality indices and Monte Carlo simulation in R software. Scientific Reports (2023).
4. Human health risk assessment of heavy metals in drinking water sources in three senatorial districts of Anambra State, Nigeria. Toxicology Reports (2022).
5. Prediction of human health risk and disability-adjusted life years induced by heavy metals exposure through drinking water in Fars Province, Iran. Scientific Reports (2023).