Effects of the herbicide surfactant MON 0818 on oviposition and viability of eggs of the ramshorn snail (Planorbella pilsbryi)

Abstract

The surfactant mixture MON 0818 is an adjuvant in various commercial formulations of the herbicide glyphosate. Initial studies have shown that MON 0818 is more toxic to aquatic animals than the active ingredient. However, few studies have examined the effect of exposure to MON 0818 on species of mollusks, and no studies have examined the effect on gastropods. The present study investigated the effect of acute exposure (96 h) of MON 0818 to the eggs, juveniles, and adults of the file ramshorn snail (Planorbella pilsbryi). Concentrations of MON 0818 up to 9.9 mg/L did not have a significant effect on the viability of eggs (p > 0.05). Juvenile snails (50% lethal concentration [LC50] = 4.0 mg/L) were more sensitive than adult snails (LC50 = 4.9-9.1 mg/L). Oviposition was inhibited by exposure to MON 0818 (median effective concentration [EC50] = 0.4-2.0 mg/L). However, oviposition resumed when snails were removed to clean water, even after 96-h exposure to up to 4.9 mg/L of MON 0818. Exposure to a concentration ≥2.7 mg/L caused visible damage to the tentacles of adult snails, which could potentially impact chemoreception. A deterministic hazard assessment indicated that environmentally relevant concentrations of MON 0818 could pose a hazard to the deposition of eggs. However, because of the relatively short half-life of MON 0818 in aquatic systems and the ability of snails to resume oviposition following the dissipation of MON 0818, environmentally relevant concentrations of MON 0818 likely pose a de minimis risk to populations of ramshorn snails. Environ Toxicol Chem 2017;36:522-531. © 2016 SETAC.

Transgenerational Effects of Copper on a Freshwater Gastropod, Planorbella pilsbryi

“…In the Parental Recovery, snails in the highest treatment (75.0 lg/L Cu) were the first to begin laying egg masses, possibly indicating an overcompensation mechanism after the week-long inhibition of mobility and reproduction. The same species (P. pilsbryi) demonstrated recovery with overcompensation in reproduction when exposed to sublethal concentrations of the surfactant MON 0818, resulting in significantly higher egg production in treatment groups exposed to the highest concentrations compared with those that were not exposed (Prosser et al 2017). This response is similar to what was observed in the current study with exposure to sublethal concentrations of Cu resulting in faster oviposition (Fig.…”

Re-registration Challenges of Glyphosate in the European Union

“…Among a number of surfactants used in the formulation of PPPs (Table 1), POEA appears to be associated with highest toxicity concerns, particularly in of formulated glyphosate-based PPPs (Romano et al, 2010;Mesnage et al, 2013a;Székács et al, 2014;Farkas et al, 2018). Considering this unfavorable toxicity profile, particularly as related to aquatic toxicity (Prosser et al, 2017;Rodriguez-Gil et al, 2017a,b), cytotoxicity and also the assessment by EFSA (European Food Safety Authority, 2015c), the EC has recommended EU MSs in September, 2016 to exclude POEA as a co-formulant from the use in PPPs containing glyphosate (European Commission, 2016a,b). As a result, a number of glyphosate-based herbicides containing POEA as a formulant have been banned for use in Hungary ( Table 2) (National Food Chain Safety Office, 2016) and in other EU MSs.…”

An integrative omics approach to unravel toxicity mechanisms of environmental chemicals: effects of a formulated herbicide

“… 32 for earthworms, springtails, and predatory soil mites, and also in the present study for springtails. The differences between observations with the active substance and the formulation tested in our study must therefore consider the adjuvants used in the formulation to enhance stability and penetration of the active compounds into plant cells 33 . Adjuvants are declared as inert diluents, not being directly responsible for the intended pesticide activity 24 , although effects on other non-target organisms are known.…”

“…Ethoxylated adjuvants are substances with a surfactant action, having alkyl chains and/or ethoxy groups in the ethoxylated chains, which can penetrate cell membranes disrupting their structure and functions 34 . Contrary to what is expected from a pesticide adjuvant, POEA has been reported in the last few years to present even higher toxicity to non-plant organisms than glyphosate alone 33 , 35 . A statement released by EFSA 36 on this subject concluded that “compared to glyphosate, a higher toxicity of the POE-tallowamine was observed on all endpoints investigated”.…”