Evaluation of the developmental toxicity of solvents, metals, drugs, and industrial chemicals using a freshwater snail (Biomphalaria glabrata) assay

ABSTRACT

A freshwater snail assay was employed to assess the embryotoxicity of solvents including acetone, methanol, ethanol, isopropanol, dimethyl-sulfoxide, glycerin, metals/metalloids including mercuric chloride (HgCl₂), cadmium chloride (CdCl₂,), antimony salts Sb⁺³ and Sb⁺⁵, drugs including colchicine, hydroxyurea, cyclophosphamide, an industrial chemical sodium azide (SA), an anionic surfactant dodecyl sodium sulfate-(DSS), H₂O₂ and sodium chloride (NaCl). The assay consists of exposing Biomphalaria glabrata egg masses (EM) to the substances for 96-hr and following up embryo/snail development for lethality, abnormal morphology (teratogenicity), and day of hatching up to day 10 or 14 after spawning. Based upon concentration-response relationships, LC_50%s (embryolethality), EC_50%s (teratogenicity) and IC_50%s (hatching retardation) and 95%CIs were determined for tested chemicals. The LOECs indicated that HgCl₂ (37 nM) and CdCl₂ (140 nM) are potent embryotoxic agents in snails. Teratogenic indices (TI = LC₅₀/EC₅₀) for almost all tested chemicals were lower than or close to unity suggesting that these compounds were not teratogenic in this assay. The snail assay may be adequately performed in a cost-effective standardized protocol which enables testing a number of environmental chemicals over a broad concentration range. The snail assay needs to undergo further validation to be recognized for an internationally harmonized hazard identification in ecotoxicity risk assessment.

KEYWORDS:

• Embryotoxicity
• teratogenicity
• ecotoxicological risk assessment
• heavy metals
• solvents
• mollusks

Acknowledgments

The authors thanks Dr Sérgio Alves da Silva (National Institute for Health Quality Control - FIOCRUZ) for his assistance with the use of the statistical software.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author, [FJRP], upon reasonable request.

Additional information

Funding

This work was supported by a grant from the National Council for Scientific and Technological Development of Brazil (CNPq - 308837/2018-5) given to FJR.