Soil-Air Partition Coefficients of Persistent Organic Pollutants Decline from Climate Warming: a Case Study in Yantai County, Shandong Province, China

Abstract

Recognizing the kinetics of the soil-air partition coefficients (Ksoil-air) of persistent organic pollutants (POPs) under distinct scenarios of changing climate conditions is crucial for well understanding the response of POPs exchange process across the air-soil interface to climate warming. Taking Yantai County, Shandong Province, China, as a case study, the Ksoil-air values of HCH, DDE, DDD, and DDT in cropland soil under two levels of soil organic matter (SOM) (0.5% and 1.7%) were projected under future climate scenarios by employing representative concentration pathway (RCP) climate scenarios and a multiple linear model of the Ksoil-air of POPs. Compared to baseline conditions, future climate conditions would shift substantially, and daily Ksoil-air values of HCH, DDE, DDD, and DDT under future climate scenarios would decline by approximately 23–91 (× 105), 5,542–21,703 (× 105), 78–309 (× 105), and 18,986–74,133 (× 105), respectively, under future climate scenarios than under baseline conditions when the SOM content was 0.5% or by approximately 9,167–360,45 (× 105), 128,533–508,592 (× 105), 31,513–123,038 (× 105), and 444,513–1738,367 (× 105), respectively, when the SOM level was 1.7%, or by approximately 2–13% under two levels of SOM. Annual Ksoil-air values of HCH, DDE, DDD, and DDT would decline by approximately 3.51–7.54 (× 105), 842.06–1,806.46 (× 105), 11.83–25.66 (× 105), and 2,840.13–6,153.16 (× 105), respectively, when the SOM content was 0.5%, or by approximately 1,397.47–2,997.98 (× 105), 19,739.82–42,347.56 (× 105), 4,713.44–10,211.70 (× 105), and 66,579.06–144,244.10 (× 105), respectively, when the SOM content was 1.7%, or by approximately 8–18% under two levels of SOM. Moreover, Ksoil-air showed daily, monthly, and seasonal temporal changes within whole years and high temporal yearly fluctuation. Daily and annual Ksoil-air values were lower under 0.5% SOM content than under 1.7% SOM content. The results suggested that the adsorbing capacity of soil to POPs would decrease, and many more POPs in the soil would volatilize to the atmosphere from climate warming.