Toxic Dust Emission from Drought-Exposed Lakebeds – A New Air Pollution Threat from Dried Lakes

Abstract. A large number of lakes worldwide are shrinking rapidly due to climate change and human activities. Pollutants accumulated in dried lakebed sediments may be released into the atmosphere as dust aerosols. However, whether lakebed dust carry sufficient toxic materials and exceeds threshold atmospheric concentrations to pose a significant health risk is currently unknown. Recently, Poyang Lake and Dongting Lake, 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 lakebed dust from these lakes could contribute maximum daily PM₁₀ concentrations up to 637.5 μg/m³. Critically, for the first time, we show that the dust generated from lakebeds 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 lakebed dust could have a greater impact on human health as climate change leads to more extreme drought conditions in the future.