The use of Solea solea as sentinel in the Ebre river marine platform

Abstract

In order to assess if extractive works from a toxic load situated in an industrial plant about 90 km upstream of the Ebre river could be reflected in the health status of the fish living at the continental platform in the river mouth, 150 specimens of Solea solea were sampled. The samplings were carried out during spring in 3 consecutive years (2013, 2014 and 2015) nearby the river mouth (l=40.65° N, L=0.84° E) at 12 m depth. Infection parasite level (prevalence and abundance), enzymatic data and histopathological alterations were obtained from fish and used as health indicators. The biomarkers selected are part of the energy metabolism system and pollution indicators of toxic exposures, neurotoxicity, xenobiotic metabolism and oxidative stress. In addition, analyses of heavy metals were also obtained from both fish and sediments. An in vitro approach was also attempted to see the capacity of common emerging contaminants to interact with the liver microsomal detoxification system of this species. A total of 9 metazoan parasite taxa were found: two digeneans, three cestodes, one acantocephala, two nematodes and one copepod. The most prevalent and abundant parasite was the acantocephalan Pseudorhadinorhynchus sp. The most prevalent histopathological alterations were unspecific inflammatory foci in liver and cysts of unknown etiology (CUEs) in liver, spleen and gills. Higher levels of the cestode Tetraphyllidea gen. sp. and CUEs were observed in 2015 related with higher levels of copper in fish. An enhancement in most detoxification parameters and an elevation of the tissue damage was also observed in 2015 due to an oxidative stress situation. Also five, out of the ten chemicals tested in vitro, interacted with the CYP3A4 (BFCOD) enzymatic activity while the lipid regulators simvastatin and fenofibrate inhibited CbE activity as it occurs in higher vertebrates