Field Studies on Exposure, Effects, and Risk Mitigation of Aquatic Nonpoint‐Source Insecticide Pollution: A Review

Abstract

Recently, much attention has been focused on insecticides as a group of chemicals combining high toxicity to invertebrates and fishes with low application rates, which complicates detection in the field. Assessment of these chemicals is greatly facilitated by the description and understanding of exposure, resulting biological effects, and risk mitigation strategies in natural surface waters under field conditions due to normal farming practice. More than 60 reports of insecticide-compound detection in surface waters due to agricultural nonpoint-source pollution have been published in the open literature during the past 20 years, about one-third of them having been undertaken in the past 3.5 years. Recent reports tend to concentrate on specific routes of pesticide entry, such as runoff, but there are very few studies on spray drift-borne contamination. Reported aqueous-phase insecticide concentrations are negatively correlated with the catchment size and all concentrations of > 10 microg/L (19 out of 133) were found in smaller-scale catchments (< 100 km2). Field studies on effects of insecticide contamination often lack appropriate exposure characterization. About 15 of the 42 effect studies reviewed here revealed a clear relationship between quantified, non-experimental exposure and observed effects in situ, on abundance, drift, community structure, or dynamics. Azinphos-methyl, chlorpyrifos, and endosulfan were frequently detected at levels above those reported to reveal effects in the field; however, knowledge about effects of insecticides in the field is still sparse. Following a short overview of various risk mitigation or best management practices, constructed wetlands and vegetated ditches are described as a risk mitigation strategy that have only recently been established for agricultural insecticides. Although only 11 studies are available, the results in terms of pesticide retention and toxicity reduction are very promising. Based on the reviewed literature, recommendations are made for future research activities.

Ability of Four Emergent Macrophytes to Remediate Permethrin in Mesocosm Experiments

“…Permethrin, like other pesticides and agricultural pollutants, can end up in aquatic receiving systems in a variety of ways; however, it is most often as a result of runoff generated either from an irrigation release or from a storm event (Schulz 2004). Willis et al (1986Willis et al ( , 1994 conducted studies on permethrin washoff from cotton plants as a result of rainfall.…”

Compensatory response of fathead minnow larvae following a pulsed in-situ exposure to a seasonal agricultural runoff event

“…In many Midwestern streams, agrichemical concentration is seasonal with the highest concentrations occurring during the spring (Kolok et al 2014). As a pollutant mixture, agricultural runoff contains fertilizers (Kaushal et al 2011), pesticides (Schulz 2004;Vecchia et al 2009;Lerch et al 2011a), and veterinary pharmaceuticals (Kolok and Sellin 2008;Biswas et al 2013;Jaimes-Correa et al 2015) which move downstream as "pulses" that persist on an order of days to weeks depending on the hydrology of the affected watershed (Blann et al 2009). Throughout the spring there will be a series of short-term pulsatile events which in composite will make up the overall spring pulse .…”

Endocrine Disrupters: The Hazards for Human Health

“…Many aspects about the toxicity of pesticides are well know, in particular about their neurotoxic effects, in fact pesticides organophosphates and carbamates act as covalent and irreversible inhibitors of acetylcholinesterase, the key enzyme of the central nervous system. It has been reported that many organochlorine pesticides, such as DTT, methoxychlor and dieldrine [8] are identified as endocrine disrupters, even if organophosphorous and carbamate pesticides are less persistent in the environment with respect to the organochlorines, they are also present in food and in animals and humans [17,18], many evidences are collecting regard their effect as endocrine disrupters [17,[19][20][21].…”