Toxic dust emission from drought-exposed lake beds – a new air pollution threat from dried lakes

Abstract. Many lakes worldwide are shrinking rapidly due to climate change and human activities. Pollutants accumulated in dried lake bed sediments may be released into the atmosphere as dust aerosols. However, whether lake bed dust carries sufficient toxic materials and exceeds threshold atmospheric concentrations to pose a significant health risk is currently unknown. Recently, Poyang Lake and Dongting Lake, the largest lakes in east China, experienced record-breaking droughts, with 99 % and 88 % areas exposed to the air. Here, we demonstrate, through field sampling, laboratory simulations, and model validation, that lake bed dust from these lakes could contribute maximum daily PM10 concentrations up to 637.5 µg m−3. This study provides new evidence, which we show, that the dust generated from lake beds exceeded regional thresholds for short-term non-carcinogenic risk (HQ = 4.13) and Cr carcinogenic risk (≈2.10 × 10−6). These findings also suggest that lake bed dust could have a greater impact on human health as climate change leads to more extreme drought conditions in the future.