Triazine and other herbicides in sediments of lower Laurentian Great Lakes – pre- and post-depositional mobility and in-situ degradation

Authors

• Shanshan Zhou, University of Illinois at Chicago
• Huan He, University of Illinois at Chicago
• Tian Lin, University of Illinois at Chicago
• Jiehong Guo, Michigan Technological UniversityFollow
• Xiusen Yang, Michigan Technological UniversityFollow
• Xinyue Jia, Zhejiang University of Technology
• Neil C. Sturchio, College of Earth, Ocean and Environment
• Karl J. Rockne, College of Engineering
• John P. Giesy, University of Saskatchewan
• An Li, University of Illinois at Chicago

Document Type

Article

Publication Date

10-1-2026

Department

Department of Civil, Environmental, and Geospatial Engineering

Abstract

Triazine and other herbicides have been heavily used in the corn belt of North America, however, little is known about their occurrence, transport, and fate in sediments of the Laurentian Great Lakes. In this work, 12 cores plus >70 surface grab samples of sediments were collected from Lakes Erie and Ontario, and analyzed for atrazine, simazine, alachlor, and des-ethyl atrazine (DEA). When combined with the data for Lakes Michigan, Superior, and Huron, region-wide predictive models were developed by multivariate regressions to describe spatial distributions of accumulation and recent flux of herbicides to sediments. Longitudinal trends of accumulation and recent flux of atrazine within Lakes Erie and Ontario were identified, which reflect its pre-depositional mobility with water propelled by continued input over the past decades. The vertical profiles of atrazine and alachlor in cores deviate from their time records of usage, which is likely attributable to post-depositional downward mobility and may compromise the accuracy of using sediment to describe the history of contamination by these herbicides in Lakes Erie and Ontario. The ratio of DEA to atrazine concentrations increased exponentially with increasing core depth and time elapsed, with log-linear regression coefficient (r²) ranging 0.61-0.95 (p <  0.02) for most cases. DEA found in deeper sediment was likely due to leaching from overlying upper sediment layers.

Publication Title

Environmental Pollution

Recommended Citation

Zhou, S., He, H., Lin, T., Guo, J., Yang, X., Jia, X., Sturchio, N., Rockne, K., Giesy, J., & Li, A. (2026). Triazine and other herbicides in sediments of lower Laurentian Great Lakes – pre- and post-depositional mobility and in-situ degradation. Environmental Pollution, 406. http://doi.org/10.1016/j.envpol.2026.128635
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p2/2723