Single and combined effects of microplastics and mercury on juveniles of the European seabass (Dicentrarchus labrax): Changes in behavioural responses and reduction of swimming velocity and resistance time

Abstract

Microplastics and mercury are environmental pollutants of great concern. The main goal of the present study was to investigate the effects of these pollutants, both individually and in binary mixtures, on the swimming performance of juvenile European seabass, Dicentrarchus labrax. Microplastics alone, mercury alone and all the mixtures caused significant reduction of the swimming velocity and resistance time of fish. Moreover, changes in behavioural responses including lethargic and erratic swimming behaviour were observed. These results highlight that fish behavioural responses can be used as sensitive endpoint to establish the effects of contamination by microplastics and also emphasizes the need to assess the combined effects of microplastics and other environmental contaminants, with special attention to the effects on behavioural responses in fish and other aquatic species.

Microplastics in Freshwater Biota: A Critical Review of Isolation, Characterization, and Assessment Methods

“…Laboratory based studies describe a wide range of effects of MPs on different taxa including effects on morphology and life history traits, such as reduction in food intake and somatic growth, increased mortality, behavior, or altered enzymatic activity 67–70,87–92. However, the lack of observed effects on measured parameters are also described 54,71,93,94.…”

Combined effects of nanoplastics and copper on the freshwater alga Raphidocelis subcapitata

“…To date, few studies have investigated the consequences of exposure to combined plastics and metals, such as adsorption and possible synergistic effects, suggesting a general lack of knowledge on occurring interactions, especially concerning nanoplastics (Barboza et al 2018a, Barboza et al 2018b, Davarpanah &Guilhermino 2015, Farhan et al 2015, Kim et al 2017, Luís et al 2015.…”

Microplastics increase mercury bioconcentration in gills and bioaccumulation in the liver, and cause oxidative stress and damage in Dicentrarchus labrax juveniles

“…In this species, exposure to microplastics can cause several adverse effects, including behavioral changes, intestinal alterations, and neurotoxicity 27 – 29 , 34 . Moreover, the exposure of D. labrax juveniles to mixtures of microplastics and mercury (another common contaminant of high concern found in different concentrations in the environment such as 0.5 to 200 ng/L in the North Sea 35 , 39 to 430 ng/L in the Wuli Estuary, China 36 , and 990 to 27,060 ng/L in the Mediterranean Sea 37 ) was found to reduce the swimming performance, cause neurotoxicity, and induce changes in the activity of energy-related enzymes 27 , 28 .…”