10.1021/acs.estlett.5b00136.s001
Zhe Lu
Zhe
Lu
Jonathan
K. Challis
Jonathan
K.
Challis
Charles S. Wong
Charles S.
Wong
Quantum Yields for Direct Photolysis of Neonicotinoid
Insecticides in Water: Implications for Exposure to Nontarget Aquatic
Organisms
American Chemical Society
2015
thiamethoxam
quantum
Nontarget Aquatic OrganismsEnvironmental fate processes
e.g
photolysi
surface waters
neonicotinoid
Direct
2015-07-14 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Quantum_Yields_for_Direct_Photolysis_of_Neonicotinoid_Insecticides_in_Water_Implications_for_Exposure_to_Nontarget_Aquatic_Organisms/2150455
Environmental
fate processes of neonicotinoid insecticides are
of significant interest, given the serious threats these chemicals
can pose to nontarget organisms such as pollinators (e.g., bees).
Direct photolysis was investigated using a laboratory photoreactor
approximating full-spectrum sunlight to predict the aquatic fate of
neonicotinoids. Quantum yields (ϕ<sub>c</sub>) were 0.019 ±
0.001, 0.013 ± 0.001, 0.0092 ± 0.0005, 0.0022 ± 0.0003,
and 0.0013 ± 0.0002 for thiamethoxam, clothianidin, imidacloprid,
acetamiprid, and thiacloprid, respectively. On the basis of these
values, estimated half-lives were 0.2–1.5 days for different
seasons in surface waters at temperate latitudes for thiamethoxam,
consistent with the 0.98 day half-life observed experimentally outdoors
at Winnipeg, Manitoba, Canada (50°N), for thiamethoxam in summer.
Light attenuation through shallow clear surface waters (e.g., by natural
organic matter) indicated that photolysis of thiamethoxam at depths
greater than 8 cm was negligible, which may help explain reports of
its environmental persistence.