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Reduction of Pesticide Toxicity Under Field‐Relevant Conditions? The Interaction of Titanium Dioxide Nanoparticles, Ultraviolet, and Natural Organic Matter
Author(s) -
Lüderwald Simon,
Meyer Frederik,
Gerstle Verena,
Friedrichs Lisa,
Rolfing Katrin,
Schreiner Verena C.,
Bakanov Nikita,
Schulz Ralf,
Bundschuh Mirco
Publication year - 2020
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.4851
Subject(s) - pesticide , environmental chemistry , ecotoxicity , chemistry , pesticide degradation , daphnia magna , titanium dioxide , toxicity , organic chemistry , chemical engineering , agronomy , biology , engineering
In surface waters, the illumination of photoactive engineered nanomaterials (ENMs) with ultraviolet (UV) light triggers the formation of reactive intermediates, consequently altering the ecotoxicological potential of co‐occurring organic micropollutants including pesticides due to catalytic degradation. Simultaneously, omnipresent natural organic matter (NOM) adsorbs onto ENM surfaces, altering the ENM surface properties. Also, NOM absorbs light, reducing the photo(cata)lytic transformation of pesticides. Interactions between these environmental factors impact 1) directly the ecotoxicity of photoactive ENMs, and 2) indirectly the degradation of pesticides. We assessed the impact of field‐relevant UV radiation (up to 2.6 W UVA/m²), NOM (4 mg TOC/L), and photoactive ENM (nTiO 2 , 50 µg/L) on the acute toxicity of 6 pesticides in Daphnia magna . We selected azoxystrobin, dimethoate, malathion, parathion, permethrin, and pirimicarb because of their varying photo‐ and hydrolytic stabilities. Increasing UVA alone partially reduced pesticide toxicity, seemingly due to enhanced degradation. Even at 50 µg/L, nano‐sized titanium dioxide (nTiO 2 ) reduced but also increased pesticide toxicity (depending on the applied pesticide), which is attributable to 1) more efficient degradation and potentially 2) photocatalytically induced formation of toxic by‐products. Natural organic matter 1) partially reduced pesticide toxicity, not evidently accompanied by enhanced pesticide degradation, but also 2) inhibited pesticide degradation, effectively increasing the pesticide toxicity. Predicting the ecotoxicological potential of pesticides based on their interaction with UV light or interaction with NOM was hardly possible, which was even more difficult in the presence of nTiO 2 . Environ Toxicol Chem 2020;39:2237–2246. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.