Comparative analysis between native and reference cladocerans to assess the toxic effects of products used by the oil industry in Mexico

Abstract

In this study, native cladocerans, Scapholeberis armata freyi and Macrothrix elegans, were collected from the region and their offspring were used as test organisms to assess the effects of 18 corrosion and scale inhibitors, widely used to protect oil pipelines. Daphnia magna and Ceriodaphnia dubia were used as international reference species, and their sensitivity was compared to native species and assessed with the reference toxicant Cr(VI). We also determined the correlation between the native and the reference species. Corrosion inhibitors were grouped according to their uses and acute toxicity gradient; those used for multifunction pipelines are considered moderately toxic (LC₅₀ of 10 to 100 mg/L), and the remainder as toxic (LC₅₀ between 1.0 and 10 mg/L). Scale inhibitors are considered non-toxic, since the LC₅₀ for the 4 species exceeded 2,000 mg/L. Sensitivity test to Cr(VI) indicated that M. elegans was the least sensitive species. There was a high correlation (> 90%) in sensitivity among M. elegans, D. magna, and C. dubia to the corrosion inhibitors used. Hence, it is feasible to use these native species from Southeast Mexico as substitutes of the typical reference species.

Keywords:

• Cladocerans
• acute toxicity
• corrosion inhibitors
• pipelines

Acknowledgments

This Project was funded partially by SIP-IPN (formerly CGPI-IPN). Muñoz-Mejía thanks CONACYT for the fellowship. Martínez-Jerónimo thanks the COFAA-IPN and EDI-IPN systems for their support. Thanks are due to two anonymous reviewers who contributed to improve significantly this paper.

Notes

*Not significant (P > 0.05);

**Significant (P < 0.01). t-test.^{[ 19 ]}