The Role of Temperature on the Impact of Remediated Water towards Marine Organisms

Francesca Coppola,Paula Marques,Eduarda Pereira,Etelvina Figueira,Bruno Henriques,Amadeu M V M Soares,Tania Russo,Ana Bessa,Gianluca Polese,Rosa Freitas

doi:10.3390/w12082148

Francesca Coppola, Paula Marques + Show 8 more

Open Access

https://doi.org/10.3390/w12082148

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Abstract

Marine organisms are frequently exposed to pollutants, including trace metals, derived from natural and anthropogenic activities. In order to prevent environmental pollution, different approaches have been applied to remove pollutants from waste water and avoid their discharge into aquatic systems. However, organisms in their natural aquatic environments are also exposed to physico-chemical changes derived from climate change-related factors, including temperature increase. According to recent studies, warming has a negative impact on marine wildlife, with known effects on organisms physiological and biochemical performance. Recently, a material based on graphene oxide (GO) functionalized with polyethyleneimine (PEI) proved to be effective in the remediation of mercury (Hg) contaminated water. Nevertheless, no information is available on the toxic impacts of such remediated water towards aquatic systems, neither under actual nor predicted temperature conditions. For this, the present study assessed the toxicity of seawater, previously contaminated with Hg and remediated by GO-PEI, using the clam species Ruditapes philippinarum exposed to actual and a predicted temperature conditions. The results obtained demonstrated that seawater contaminated with Hg and/or Hg+GO-PEI induced higher toxicity in clams exposed to 17 and 22 °C compared to organisms exposed to remediated seawater at the same temperatures. Moreover, similar histological and biochemical results were observed between organisms exposed to control and remediated seawater, independently of the temperatures (17 and 21 °C), highlighting the potential use of GO-PEI to remediate Hg from seawater without significant toxicity issues to the selected marine species.

Highlights

Studies conducted in the last decade have demonstrated that the increase of greenhouse effect gases, such as carbon dioxide, is intrinsically related with global warming [1,2,3,4,5]
At the end of the experimental period the highest mortality (44%) was recorded in clams submitted to Hg at both temperatures (17 and 22 ◦ C) and in organisms exposed to graphene oxide (GO)-PEI at 17 ◦ C and Hg+GO-PEI
Lower mortality was observed in GO-PEI at 22 ◦ C and Hg+GO-PEI treatments at 17 ◦ C

Summary

Introduction

Studies conducted in the last decade have demonstrated that the increase of greenhouse effect gases, such as carbon dioxide, is intrinsically related with global warming [1,2,3,4,5]. Global warming is responsible for atmospheric temperature rise and for the increase in mean water temperature. Associated with temperature increase in aquatic systems, it is predicted that inhabiting organisms may be subjected to deleterious effects as already shown by different authors [9,10,11]. Biochemical alterations have been observed in different clam’s species in response to temperature rise, including increased antioxidant capacity [18,25] and cellular damage [26,27]. Recent studies further demonstrated that change in temperature negatively impacted bivalve’s embryo-larval development [28,29]

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