Typical pesticides diffuse loading and degradation pattern differences under the impacts of climate and land-use variations

Wei Ouyang; Xin Hao; Mats Tysklind; Wanxin Yang; Chunye Lin; Aihua Wang

doi:10.1016/j.envint.2020.105717

Typical pesticides diffuse loading and degradation pattern differences under the impacts of climate and land-use variations

Environ Int. 2020 Jun:139:105717. doi: 10.1016/j.envint.2020.105717. Epub 2020 Apr 10.

Authors

Wei Ouyang¹, Xin Hao², Mats Tysklind³, Wanxin Yang², Chunye Lin², Aihua Wang²

Affiliations

¹ State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China. Electronic address: wei@itc.nl.
² State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
³ Environmental Chemistry, Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden.

PMID: 32283357
DOI: 10.1016/j.envint.2020.105717

Abstract

Riverine sediment can reconstruct the history of organic pollution loads and can provide reliable temporal information for pesticide metabolite dynamics in watershed. Sediment core samples were collected from two riverine sections of a cold watershed base in the presence land use change under agricultural development, and the vertical concentrations of four pesticides (atrazine, prometryn, isoprothiolane, and oxadiazon) and two atrazine metabolites (deisopropyl-atrazine and deethyl-atrazine) were determined by gas chromatography-mass spectrometry. The presence of pesticides and metabolites was detected at different depths (11-17 cm) at 1-cm intervals along the two sediment cores, and the flux was calculated with a constant rate of supply model based on the observed concentrations and ²¹⁰Pb isotope radioactivity chronology. By comparing the concentrations and fluxes of pesticides between the two sediment sections, significant differences in accumulation under different land-use patterns were found. Redundancy analysis further indicated that temporal watershed farmland variance was the dominant factor for pesticide loading. The lower concentration of atrazine and the higher concentration of the other pesticides in the estuarine sediment was closely related to the decreasing upland in the upstream area and the increase in paddy fields in the downstream area. The analysis of atrazine and the metabolites indicated that atrazine is more likely degraded to deethyl-atrazine and the metabolites have similar migration processes in the sediments, which can easily migrate downward. Moreover, the ratio of metabolites to atrazine showed that atrazine degradation was intensive during the transport process, but the metabolites efficiency was lower in this area due to the cold temperature. The results provide insights for the management of pesticide pollution control in watersheds and the potential effects of low temperature on the degradation of pesticides.

Keywords: Atrazine degradation; Diffuse pollution; Pesticide; Sedimentary pattern; Watershed modeling.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Agriculture
Atrazine*
Environmental Monitoring
Pesticides* / analysis
Water Pollutants, Chemical* / analysis

Substances

Pesticides
Water Pollutants, Chemical
Atrazine