Household herbicide use as a source of simazine contamination in urban surface waters

Jackie H Myers; Gavin Rose; Erica Odell; Pei Zhang; AnhDuyen Bui; Vincent Pettigrove

doi:10.1016/j.envpol.2022.118868

Household herbicide use as a source of simazine contamination in urban surface waters

Environ Pollut. 2022 Apr 15:299:118868. doi: 10.1016/j.envpol.2022.118868. Epub 2022 Jan 18.

Authors

Jackie H Myers¹, Gavin Rose², Erica Odell³, Pei Zhang⁴, AnhDuyen Bui⁵, Vincent Pettigrove⁶

Affiliations

¹ Aquatic Environmental Stress Research Group, RMIT University, PO Box 71, Bundoora, Victoria, 3083, Australia. Electronic address: jackie.myers@rmit.edu.au.
² Aquatic Environmental Stress Research Group, RMIT University, PO Box 71, Bundoora, Victoria, 3083, Australia.
³ Aquatic Environmental Stress Research Group, RMIT University, PO Box 71, Bundoora, Victoria, 3083, Australia. Electronic address: erica.odell@rmit.edu.au.
⁴ Department of Economic Development, Jobs, Transport and Resources, MacLeod, Victoria, 3085, Australia. Electronic address: pei.zhang@ecodev.vic.gov.au.
⁵ Department of Economic Development, Jobs, Transport and Resources, MacLeod, Victoria, 3085, Australia. Electronic address: anhduyen.bui@ecodev.vic.gov.au.
⁶ Aquatic Environmental Stress Research Group, RMIT University, PO Box 71, Bundoora, Victoria, 3083, Australia. Electronic address: vincent.pettigrove@rmit.edu.au.

PMID: 35063546
DOI: 10.1016/j.envpol.2022.118868

Abstract

Contamination of urban surface waters by herbicides is an increasing concern; however, sources of contamination are poorly understood, hindering the development of mitigation and regulatory strategies. Impervious surfaces, such as concrete in driveways and paths are considered an important facilitator for herbicide runoff to urban surface waters following applications by residential homeowners. This study assessed the transferability of a herbicide from concrete pavers treated with an off-the-shelf product, containing simazine as the active herbicide, marketed for residential homeowner application to impervious surfaces. Commercially available pavers were treated according to label directions and the effects of exposure time prior to irrigation, repeated irrigations, and dry time between irrigations on transferability of simazine to runoff were assessed. Simazine transferability was greatest when receiving an initial irrigation 1 h after application, with concentrations in runoff reduced by half when exposure times prior to the first irrigation were >2 days. Concentrations remained stable for repeated irrigations up to 320 days and exposures to outdoor conditions of 180 days prior to a first irrigation. Dry time between irrigations significantly influenced simazine transfer to runoff. Dry periods of 140 days resulted in approximately a 4-times increase in simazine transferability to runoff. These results suggest that herbicides used by homeowners, or any other users, on impervious surfaces are available to contaminate runoff for prolonged time periods following application at concentrations that may pose risks to aquatic life and for reuse of harvested runoff on parks and gardens. Regulators should consider the potential of hard surfaces to act as reservoirs for herbicides when developing policies and labelling products.

Keywords: Herbicides; Homeowner herbicide application; Impervious surfaces; Simazine; Urban runoff.

MeSH terms

Herbicides* / analysis
Simazine / analysis
Water Pollutants, Chemical* / analysis

Substances

Herbicides
Water Pollutants, Chemical
Simazine