# Occurrence, composition, sources, and ecological-health risk assessment of polycyclic aromatic hydrocarbons in Chinese water bodies: a review

## TL;DR

This paper reviews PAH contamination in Chinese water bodies, highlighting pollution levels, sources, and risks to ecosystems and human health.

## Contribution

A comprehensive synthesis of PAH data from 69 study areas in China with spatiotemporal and source-specific risk assessments.

## Key findings

- PAH concentrations in Chinese water bodies ranged from 17.4 to 3,856.68 ng/L, with highest levels in northern and eastern regions.
- Low-molecular-weight PAHs dominated, but high-molecular-weight compounds were more prevalent in industrial zones and deltas.
- Ecological and health risks were high, with some areas exceeding acceptable cancer risk levels by orders of magnitude.

## Abstract

Polycyclic aromatic hydrocarbons (PAHs) pose significant threats to aquatic ecosystems globally. This study conducted a comprehensive literature search (2015–2025) across Web of Science, ScienceDirect, and China National Knowledge Infrastructure (CNKI) databases to evaluate PAH contamination in diverse water bodies in China. Through an analysis of data from 69 distinct study areas, we synthesized concentration distributions, compositional profiles, pollution sources, and associated ecological and health risks. The results revealed significant spatiotemporal variations in PAH contamination across Chinese water bodies, with mean concentrations ranging from 17.4 to 3,856.68 ng/L, and an arithmetic mean of 498.3 ng/L. Northern industrial regions, eastern estuarine and coastal areas exhibited the highest pollution levels, while western remote areas remained less contaminated. Rivers showed the highest mean PAH concentrations, followed by lakes/reservoirs, coastal waters, and estuaries. Low-molecular-weight (LMW) PAHs dominated, accounting for 74.5–82.2% of total PAHs, though high-molecular-weight (HMW) compounds were enriched in industrial zones and deltas. Source apportionment indicated mixed contributions from fossil fuel combustion, petroleum spills, and traffic emissions, with distinct seasonal patterns: coal heating dominated in winter, while runoff inputs were major contributors in summer. Ecological risk assessment indicated high risk was prevalent, with risk quotient (RQ) values greatly exceeding 1 in severely polluted areas such as river basins and estuaries. Health risk evaluation showed that incremental lifetime cancer risk (ILCR) values in certain areas reach ed 4.6 × 10−3, exceeding the acceptable level (10−6) by orders of magnitude. These findings provide a scientific basis for formulating targeted PAH control strategies to better protect aquatic ecosystems and public health in China.