Binary mixtures of alcohol ethoxylates, nonylphenol ethoxylates and pesticides exhibit comparative bioactivity against three pests and toxicological risks to aquatic organisms

Nonylphenol ethoxylates are widely used surfactants in the industry and agriculture. However, seeking for alternatives has been imperative considering their effects of the hormonal and other toxicological risks. In the current study, the synergistic effects of nonylphenol ethoxylates or alcohol ethoxylates on the bioactivity of indoxacarb and acetamiprid were compared. Results showed that synergistic ratios of nonylphenol ethoxylates (TX-7∼TX-30) and alcohol ethoxylates (MOA-5∼MOA-20) against Spodoptera exigua, Agrotis ipsilon and Aphis citricola decreased with the EO (ethylene oxide) numbers, although different magnitudes of decreases were observed. Single toxicities of all ethoxylates to Daphnia magna and Brachydanio rerio also dramatically decreased with the EO numbers. In terms of joint toxicity, the combined effects of all ethoxylates and pesticides upon D. magna turned from synergism to antagonism with the increasing EO numbers; the combined effects of nonylphenol ethoxylates and pesticides turned from synergism to antagonism with the increasing EO numbers of ethoxylates, whereas alcohol ethoxylates and pesticides always showed antagonistic effects whatever EO numbers. Overall, alcohol ethoxylates may be potential alternatives for nonylphenol ethoxylates as they exhibited nearly comparative bioactivity against tested pests and toxicities to D. magna and B. rerio.