Toxicity of herbicides to cyanobacteria and phytoplankton species of the San Francisco Estuary and Sacramento-San Joaquin River Delta, California, USA. Issue 2 (28th January 2020)

• Record Type: Journal Article
• Authors: Lam, Chelsea H.; Kurobe, Tomofumi; Lehman, Peggy W.; Berg, Mine; Hammock, Bruce G.; Stillway, Marie E.; Pandey, Pramod K.; Teh, Swee J.
• Is Part Of: Journal of environmental science and health. Volume 55:Issue 2(2020)
• Page Start: 107
• Page End: 118
• Publication Date: 2020-01-28
• Subjects: Fluridone -- Imazamox -- Glyphosate -- Microcystis -- Chlamydomonas -- Thalassiosira; Environmental engineering -- Periodicals; Environmental sciences -- Periodicals; Ecology -- periodicals; Hazardous Substances -- periodicals; 628
• DOI: 10.1080/10934529.2019.1672458
• Languages: English
• ISSNs: 1093-4529

Abstract

Abstract: The herbicides glyphosate, imazamox and fluridone are herbicides, with low toxicity towards fish and invertebrates, which are applied to waterways to control invasive aquatic weeds. However, the effects of these herbicides on natural isolates of phytoplankton and cyanobacteria are unknown. Three species of microalgae found in the San Francisco Estuary (SFE)/Sacramento-San Joaquin River Delta (Delta) ( Microcystis aeruginosa, Chlamydomonas debaryana, and Thalassiosira pseudonana ) were exposed to the three herbicides at a range of concentrations in 96-well plates for 5–8 days. All three algal species were the most sensitive to fluridone, with IC50 of 46.9, 21, and 109 µg L −1 for M. aeruginosa, T. pseudonana and C. debaryana, respectively. Imazamox inhibited M. aeruginosa and T. pseudonana growth at 3.6 × 10 4 µg L −1 or higher, and inhibited C. debaryana growth at 1.0 × 10 5 µg L −1 or higher. Glyphosate inhibited growth in all species at ca. 7.0 × 10 4 µg L −1 or higher. Fluridone was the only herbicide that inhibited the microalgae at environmentally relevant concentrations in this study and susceptibility to the herbicide depended on the species. Thus, the application of fluridone may affect cyanobacteria and phytoplankton community composition in water bodies where it is applied.