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Background Plant growth regulators are widely used in agriculture for increasing the growth and ripening of plants, but they endanger the aquatic ecosystem. The current study assessed the effect of sublethal exposure to RIPEX 48% EC concentrations (8 and 16 µL/L) on oxidative stress parameters, sex hormones, immune potential enzymes, differential hemocyte counts, and the histopathology of digestive glands and ovotestis in Biomphalaria alexandrina snails. Results RIPEX exposure caused an overall increase in Superoxide dismutase and Glutathione-S-Transferase activities in B. alexandrina. However, extreme RIPEX exposure inhibits SOD activity in snails. Malondialdehyde activity showed an increase in B. alexandrina exposed to both concentrations after all exposure periods. RIPEX also caused a significant increase in testosterone in snails exposed to 16 µL/L, it did, however, reduce hormone levels in snails exposed to 8 µL/L at 7 days. Regarding estradiol, there was a significant increase after 3 days of exposure to 16 µl/L and 7 days of exposure to 8 µL/L. RIPEX exposure also increased the activities of Myeloperoxidase and Adenosine deaminase enzymes in the digestive glands of snails. It increased the total hemocyte count of exposed snails as well as the number of granulocytes. Snail digestive glands and ovotestis showed pathological alterations after 7 days of RIPEX exposure. Conclusions These findings suggest that RIPEX is toxic to B. alexandrina and that this snail can be used as a bioindicator for environmental contamination with plant growth regulators.

SummaryBiomphalaria alexandrina snails have received much attention due to their great medical importance as vectors for transmitting Schistosoma mansoni infection to humans. The main objective of the present work was to assess the efficacy of miltefosin a synthetic molluscicidal drug and artemether a natural molluscicidal drug. The correlation between immunological and histological observations from light and electron microscopy of the hemocytes of B. alexandrina post treatment with both drugs was also evaluated. LC50 and LC90 values were represented by 13.80 ppm and 24.40 ppm for miltefosine and 16.88 ppm and 27.97 ppm for artemether, respectively. The results showed that the treatment of S. mansoni-infected snails and normal snails with sublethal dose of miltefosine (LC25=8.20 ppm) and artemether (LC25=11.04 ppm) induced morphological abnormalities and a significant reduction in hemocytes count.

Nanotechnology has come a long way in our lives. However, it maintains some negative effects on the environment. This study aims to use the land snail Helix aspersa as a bioindicator. Titanium dioxide nanoparticles (TiO2NPs) had been used at 70 and 140 µg/L for two weeks by the spraying method. The oxidative biomarkers, condition index (CI), DNA damage, hemocyte count, and phagocytic activity were estimated. The toxicity of TiO2NPs was determined (LC50 = 544 µg/L). The exposure to TiO2NPs caused a significant reduction of the activities of superoxide dismutase (SOD) and catalase (CAT) in the digestive gland of Helix aspersa (the activity of CAT was 3.4 ± 0.1 (P = 0.001), SOD was 11 ± 1 (P = 0.0002) at concentration 140 µg/L after two weeks). The activity of glutathione peroxidase (GPX) was (1.13 ± 0.01 µ/mg protein at 140 µg/L compared with controls (5.47 ± 0.01 µ/mg protein). The treatment caused DNA damage in the hemocytes (tail DNA % = 8.66 ± 0.02 and tail moment = 52.99 ± 0 at140 µg/L (P = 0.002)). In the digestive gland, both tail DNA % and tail moment increased (tail moment = 78.38 ± 0.08 compared with control = 2.29 ± 0.09 (P = 0.0001)). The total count of hemocytes significantly decreased after two weeks (the average number was 71 ± 1.5 compared with controls 79 ± 1.1 at 140 µg/L). Furthermore, TiO2NPs caused histological alterations in the digestive gland of Helix aspersa. It can be concluded that the Helix aspersa can be used as environmental pollution bioindicator. A comprehensive evaluation of toxic effects induced by TiO2NPs in vivo assays must be investigated.