Primary emissions or environmental persistence contribute to the present DDTs: Evidence from sediment records in Tibetan lakes

Jun Li; Ruwen Chang; Xiyu Ban; Guo-Li Yuan; Jie Wang

doi:10.1016/j.jhazmat.2023.132342

Primary emissions or environmental persistence contribute to the present DDTs: Evidence from sediment records in Tibetan lakes

J Hazard Mater. 2023 Oct 5:459:132342. doi: 10.1016/j.jhazmat.2023.132342. Epub 2023 Aug 18.

Authors

Jun Li¹, Ruwen Chang², Xiyu Ban², Guo-Li Yuan³, Jie Wang⁴

Affiliations

¹ State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China; School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China. Electronic address: junli@cugb.edu.cn.
² School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China.
³ State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China; School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China.
⁴ College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China. Electronic address: jiewangcau@cau.edu.cn.

PMID: 37598514
DOI: 10.1016/j.jhazmat.2023.132342

Abstract

Dichlorodiphenyltrichloroethane (DDT) compounds are still circulating the global environment even though the technical DDT has been restricted in agriculture since the last century. The persistent presence of DDTs worldwide remains uncertain, as it is unclear whether their existence is primarily due to ongoing use or the prolonged persistence in soils and sediments that result in continuous reemission into the atmosphere. The present study applied a sequential extraction procedure to determine the DDT concentrations in rapid desorption, slow desorption, and bound residue fractions in the dated sediment cores from distinct regions of Tibet. The temporal variation of total DDTs (sum of three fractions) in sediments from southern and eastern Tibet respectively revealed the different DDT usage histories in India and China mainland. Nevertheless, the current application volumes of DDT-containing products in these regions were found to decrease significantly. The reversible transformations among three fractions of DDTs with aging time was observed along sediment profile, including the back conversion from bound residue. This process may be the key driver to prolong the half-life of sediment p,p'-DDT, resulting in the persistence of secondary sources of this persistent organic pollutant in the global environment for a longer duration than previously expected.

Keywords: DDT; Fraction transformation; Half-life; Sediment record; Tibetan Plateau.