TY - JOUR
T1 - Additive toxicity of herbicide mixtures and comparative sensitivity of tropical benthic microalgae
AU - Magnusson, Marie E.
AU - Heimann, Kirsten Ruth
AU - Quayle, Pamela A.
AU - Negri, Andrew Peter
PY - 2010/11
Y1 - 2010/11
N2 - Natural waters often contain complex mixtures of unknown contaminants potentially posing a threat to marine communities through chemical interactions. Here, acute effects of the photosystem II-inhibiting herbicides diuron, tebuthiuron, atrazine, simazine, and hexazinone, herbicide breakdown products (desethyl-atrazine (DEA) and 3,4-dichloroaniline (3,4-DCA)) and binary mixtures, were investigated using three tropical benthic microalgae; Navicula sp. and Cylindrotheca closterium (Ochrophyta) and Nephroselmis pyriformis (Chlorophyta), and one standard test species, Phaeodactylum tricornutum (Ochrophyta), in a high-throughput Maxi-Imaging-PAM bioassay (Maxi-IPAM). The order of toxicity was; diuron>hexazinone>tebuthiuron>atrazine>simazine>DEA>3, 4-DCA for all species. The tropical green alga N. pyriformis was up to 10-fold more sensitive than the diatoms tested here and reported for coral symbionts, and is recommended as a standard tropical test species for future research. All binary mixtures exhibited additive toxicity, and the use of herbicide equivalents (HEq) is therefore recommended in order to incorporate total-maximum-load measures for environmental regulatory purposes.
AB - Natural waters often contain complex mixtures of unknown contaminants potentially posing a threat to marine communities through chemical interactions. Here, acute effects of the photosystem II-inhibiting herbicides diuron, tebuthiuron, atrazine, simazine, and hexazinone, herbicide breakdown products (desethyl-atrazine (DEA) and 3,4-dichloroaniline (3,4-DCA)) and binary mixtures, were investigated using three tropical benthic microalgae; Navicula sp. and Cylindrotheca closterium (Ochrophyta) and Nephroselmis pyriformis (Chlorophyta), and one standard test species, Phaeodactylum tricornutum (Ochrophyta), in a high-throughput Maxi-Imaging-PAM bioassay (Maxi-IPAM). The order of toxicity was; diuron>hexazinone>tebuthiuron>atrazine>simazine>DEA>3, 4-DCA for all species. The tropical green alga N. pyriformis was up to 10-fold more sensitive than the diatoms tested here and reported for coral symbionts, and is recommended as a standard tropical test species for future research. All binary mixtures exhibited additive toxicity, and the use of herbicide equivalents (HEq) is therefore recommended in order to incorporate total-maximum-load measures for environmental regulatory purposes.
KW - Fluorometry
KW - Great Barrier Reef
KW - Herbicide
KW - Photosynthesis
KW - Pollution
UR - http://www.scopus.com/inward/record.url?scp=78049296903&partnerID=8YFLogxK
U2 - 10.1016/j.marpolbul.2010.07.031
DO - 10.1016/j.marpolbul.2010.07.031
M3 - Article
VL - 60
SP - 1978
EP - 1987
JO - Marine Pollution Bulletin
JF - Marine Pollution Bulletin
SN - 0025-326X
IS - 11
ER -