The Garden Snail (Helix Aspersa) as a Bioindicator of Organophosphorus Exposure: Effects of Dimethoate on Survival, Growth, and Acetylcholinesterase Activity

Abstract

The garden snail (Helix aspersa) is currently used as bioindicator of metallic pollution. Our objective was to extend its use to organic chemicals by studying the effects and tissue concentrations of the organophosphorus pesticide dimethoate following dietary uptake. After exposure for four weeks to increasing doses of pesticide in the diet, the median lethal concentration (LC50) was determined to be 3,700 microg/g food. Clinical signs indicated a no-observed-effect concentration of 100 microg/g and a lowest-observed-effect concentration of 250 microg/g. The growth parameters were decreased with increasing exposure to the pesticide. The median effective concentration (EC50), which was evaluated based on both shell diameter and dry weight inhibitions, was 665 and 424 microg/g, respectively, and the EC10 was 180 and 145 microg/g, respectively. Accumulation in the viscera was related to the amount of dimethoate in the food. The bioconcentration factors were low (>6 x 10(-3)). Acetylcholinesterase (AChE) activity was strongly decreased (80% from 250 microg/g). In conclusion, we demonstrated that the species H. aspersa could be a useful sentinel organism for organophosphorus contamination surveys. Among the effects measured, the inhibition of AChE activities and clinical signs were the most sensitive, followed by the growth parameters. These results confirm the suitability of the garden snail for development of sublethal toxicity tests using primary consumers and aboveground organisms.

Neuropathological effect of carbamate molluscicides on the land snail, Eobania vermiculata

“…In addition, Coeurdassier et al (2001Coeurdassier et al ( , 2002 mentioned that the anti-AChE pesticide (dimethoate) induced the reduction in the growth of H. aspersa and attributed that to the inhibitory effect of this compound on AChE activity.…”

Glyphosate and glufosinate-based herbicides: fate in soil, transfer to, and effects on land snails

“…Bars represent standard deviation Beeby and Richmond 2002;Scheifler et al 2002;de Vaufleury et al 2006;Hispard et al 2007), few studies have reported such phenomenon for pesticides. Coeurdassier et al (2001) found a low accumulation of dimethoate in H. aspersa tissues exposed to artificially contaminated food and Schuytema et al (1994) did not find atrazine or azinphosmethyl bioaccumulation in the same species, probably in relation with the degradation of chemicals in tissues and/or to a low sensitivity of the analytical methods. Glyphosate accumulation was not expected due to the chemical characteristics of the molecule, such as for instance its high solubility in water (10,500 mg l −1 ) and its low K ow (log K ow =−3.1).…”

“…Concentrations in snails given in milligrams per kilogram fw were converted into dw by considering 80% of water content in snails (Gomot 1998). Calculation of BAF (dw/dw) of a pesticide by snail is usually expressed by considering the tissue concentrations in dry weight (Coeurdassier et al 2001). It allows minimizing the influence of variability of water content in snails following the humidity of the medium and facilitating comparisons of data of experiments performed in various environmental conditions.…”

“…Terrestrial snails constitute suitable models not only for the risk assessment of metals (Beeby and Richmond 2002;Scheifler et al 2003) but also of pesticides (Coeurdassier et al 2001;Snyman et al 2005;Laguerre et al 2009) in soils. Unlike earthworms, which are mainly exposed to soil and decomposing organic matter, land snails may be exposed to three sources of contamination: air, soil, and plants.…”

Contamination of terrestrial gastropods, Helix aspersa maxima, with 137Cs, 85Sr, 133Ba and 123mTe by direct, trophic and combined pathways

“…Some authors have used other gastropods to monitor mercury exposure (Bertani et al, 1994). Coeurdassier et al (2001) consider other groups of contaminants (pesticides, polycyclic aromatic hydrocarbons (PAH), etc). Pihan and Gomot de Vaufleury (2000) used 2 terrestrial snail species (H. aspersa aspersa and H. pomatia) to assess the contamination of an industrial waste dump site (pollution by heavy metals) and to monitor the efficiency of in situ remediation techniques.…”