Premium
Effects of four rice paddy herbicides on algal cell viability and the relationship with population recovery
Author(s) -
Nagai Takashi,
Ishihara Satoru,
Yokoyama Atsushi,
Iwafune Takashi
Publication year - 2011
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.582
Subject(s) - population , algae , biology , viability assay , ecotoxicology , toxicity , toxicology , flow cytometry , environmental chemistry , botany , chemistry , cell , biochemistry , medicine , microbiology and biotechnology , environmental health , organic chemistry
Paddy herbicides are a high‐risk concern for aquatic plants, including algae, because they easily flow out from paddy fields into rivers, with toxic effects. The effect on algal population dynamics, including population recovery after timed exposure, must be assessed. Therefore, we demonstrated concentration–response relationships of four paddy herbicides for algal growth inhibition and mortality, and the relationship between the effect on algal cell viability and population recovery following exposure. We used SYTOX Green dye assay and flow cytometry to assess cell viability of the alga Pseudokirchneriella subcapitata . Live cells could be clearly distinguished from dead cells during herbicide exposure. Our results showed that pretilachlor and quinoclamine had both algicidal and algistatic effects, whereas bensulfuron‐methyl only had an algistatic effect, and pentoxazone only had an algicidal effect. Then, a population recovery test following a 72‐h exposure was conducted. The algal population recovered in all tests, but the periods required for recovery differed among exposure concentrations and herbicides. The periods required for recovery were inconsistent with the dead cell ratio at the beginning of the recovery test; that is, population recovery could not be described only by cell viability. Consequently, the temporal effect of herbicides and subsequent recovery of the algal population could be described not only by the toxicity characteristics but also by toxicokinetics, such as rate of uptake, transport to the target site, and elimination of the substance from algal cells. Environ. Toxicol. Chem. 2011; 30:1898–1905. © 2011 SETAC