Mercury in Juvenile Solea senegalensis: Linking Bioaccumulation, Seafood Safety, and Neuro-Oxidative Responses under Climate Change-Related Stressors

Abstract

Mercury (Hg) is globally recognized as a persistent chemical contaminant that accumulates in marine biota, thus constituting an ecological hazard, as well as a health risk to seafood consumers. Climate change-related stressors may influence the bioaccumulation, detoxification, and toxicity of chemical contaminants, such as Hg. Yet, the potential interactions between environmental stressors and contaminants, as well as their impacts on marine organisms and seafood safety, are still unclear. Hence, the aim of this work was to assess the bioaccumulation of Hg and neuro-oxidative responses on the commercial flat fish species Solea senegalensis (muscle, liver, and brain) co-exposed to dietary Hg in its most toxic form (i.e., MeHg), seawater warming (ΔT°C = +4 °C), and acidification (pCO2 = +1000 µatm, equivalent to ΔpH = −0.4 units). In general, fish liver exhibited the highest Hg concentration, followed by brain and muscle. Warming enhanced Hg bioaccumulation, whereas acidification decreased this element’s levels. Neuro-oxidative responses to stressors were affected by both climate change-related stressors and Hg dietary exposure. Hazard quotient (HQ) estimations evidenced that human exposure to Hg through the consumption of fish species may be aggravated in tomorrow’s ocean, thus raising concerns from the seafood safety perspective.

Special Issue on Bioconversion, Bioaccumulation and Toxicity of Mercury in a Changing World

“…Two papers addressed food web transfer of Hg to fish [4,5]. The paper, authored by Gentès et al (2020), determined the bioavailability of MMHg in aquatic freshwater system, revealing MMHg production in plant roots and MMHg trophic transfer to Pseudancistrus sp.…”

“…Authors highlight that MMHg formed in the periphyton could significantly participate in food web contamination, because aquatic plants are an important food source [4]. The paper, authored by Camacho et al (2020), assessed the bioaccumulation of Hg in the commercial marine flat fish species Solea senegalensis co-exposed to dietary MMHg and climate change (warming and acidification) [5]. Fish liver exhibited the highest Hg concentration, followed by brain and muscle [5].…”

“…The paper, authored by Camacho et al (2020), assessed the bioaccumulation of Hg in the commercial marine flat fish species Solea senegalensis co-exposed to dietary MMHg and climate change (warming and acidification) [5]. Fish liver exhibited the highest Hg concentration, followed by brain and muscle [5]. Warming enhanced Hg bioaccumulation, whereas acidification decreased this element's levels [5].…”

“…Fish liver exhibited the highest Hg concentration, followed by brain and muscle [5]. Warming enhanced Hg bioaccumulation, whereas acidification decreased this element's levels [5]. Hazard quotient (HQ) estimations evidenced that human exposure to Hg through the consumption of fish species may be aggravated in tomorrow's oceans, thus raising concerns for future seafood safety [5].…”

“…Two papers detailed effects of Hg in biota [3,5]. In the macrophyte E. nuttallii, IHg reduced chlorophyll, while MMHg increased anthocyanin [3].…”