Influences of aquatic plants on the fate of the pyrethroid insecticide Lambida‐cyhalothrin in aquatic environments

Abstract

Aquatic exposure assessments for pesticides are generally based on laboratory studies performed in water alone or water sediment systems. Although aquatic macrophytes, which include a variety of bryophytes, macroalgae, and angiosperms, can be a significant component of many aquatic ecosystems, their impact on pesticide fate is generally not included in exposure assessments. To investigate the influence of aquatic plants on the fate and behavior of the pyrethroid insecticide lambda (lambda)-cyhalothrin, two laboratory experiments (to assess adsorption and degradation) and an indoor microcosm study (to assess fate under semirealistic conditions) were conducted. In the laboratory studies, adsorption to macrophytes was extensive and essentially irreversible, and degradation occurred rapidly by cleavage of the ester bond. In the indoor microcosm, which contained water, sediment, and macrophytes from a pond, degradation was also rapid, with DT50 and DT90 values of less than 3 and 19 h, respectively, for dissipation from the water column and of less than 3 and 56 h, respectively, for the whole system. For adsorptive and readily degraded pesticides like lambda-cyhalothrin, we conclude that macrophytes have considerable influence on fate and behavior in surface waters.

Can a low concentration of an organophosphate insecticide cause negative effects on an aquatic macrophyte? Exposure of Potamogeton pusillus at environmentally relevant chlorpyrifos concentrations

“…Prevention of oxidative damage to cells has been suggested as one of the mechanisms of stress tolerance (Parween et al, 2012a,b). During pesticide exposure, the uptake, metabolization and accumulation of these compounds can occur in aquatic macrophytes (Karen et al, 1998;Knuteson et al, 2002;Gao et al, 2000;Hand et al, 2001;Pietsch et al, 2006). Differences in plant metabolism are considered the major cause of variation in pesticides sensitivity among species.…”

Fate and Effects of Azinphos-Methyl in a Flow-Through Wetland in South Africa

“…The latter process seems more likely, particularly with respect to the short time periods involved. However, the role of plants including attached algal and microbial communities for insecticide sorption has already been demonstrated by various other workers (2,4,25,30,31).…”

Dissipation and Migration of Pyrethroids in Auricularia polytricha Mont. from Cultivation to Postharvest Processing and Dietary Risk

“…The average removal percentage of pyrethroids by the NaCl solution is lower than that of tap water, except at the 0.1% concentration, whereas removal of pyrethroids by NaHCO 3 was more effective than tap water at high concentrations, especially for fenpropathrin. This may be due to the alkaline nature of the solution (pyrethroid pesticides are stable in acidic and neutral conditions but aqueous hydrolysis occurs under alkaline conditions) can enhance the solubility, and the release from the A. polytricha [ 29 ]. A similar process was studied by Wang et al [ 30 ] who found that soaking in a dilute alkaline solution (pH 9.0) only eliminated 37.82% of the residues of the β-cypermethrin in contaminated vegetables, further demonstrating that pesticides have different behavior in different materials.…”