Size Matters: Ingestion of Relatively Large Microplastics Contaminated with Environmental Pollutants Posed Little Risk for Fish Health and Fillet Quality

Abstract

In this study, we investigated biological effects associated with ingestion of polystyrene (PS) microplastic (MPs) in fish. We examined whether ingestion of contaminated PS MPs (100–400 μm) results in chemical stress in rainbow trout (Oncorhynchus mykiss) liver and we explored whether this exposure can affect the oxidative stability of the fillet during ice storage. Juvenile rainbow trout were fed for 4 weeks with four different experimental diets: control (1) and feeds containing virgin PS MPs (2) or PS MPs exposed to sewage (3) or harbor (4) effluent. A suite of ecotoxicological biomarkers for oxidative stress and xenobiotic-related pathways was investigated in the hepatic tissue, and included gene expression analyses and enzymatic measurements. The potential impact of MPs exposure on fillet quality was investigated in a storage trial where lipid hydroperoxides, loss of redness and development of rancid odor were assessed as indications of lipid peroxidation. Although, chemical analysis of PS MPs revealed that particles sorb environmental contaminants (e.g., PAHs, nonylphenol and alcohol ethoxylates and others), the ingestion of relatively high doses of these PS MPs did not induce adverse hepatic stress in fish liver. Apart from small effect on redness loss in fillets of fish exposed to PS MPs, the ingestion of these particles did not affect lipid peroxidation or rancid odor development, thus did not affect fillet’s quality.

Toxicity of Microplastics and Nanoplastics in Mammalian Systems

“…An important general phenomenon to note is that toxicological responses typically arise from smaller plastic particles. Larger PS particles at around 100 µm or above were shown not to have any significant effect in a number of studies [65][66][67]. MP/NP feeding can result in behavioral abnormalities in terms of feeding and movement of adults and larvae [35,[68][69][70][71][72][73][74], as well as reproduction in adults [75][76][77].…”

Current Progress on Marine Microplastics Pollution Research: A Review on Pollution Occurrence, Detection, and Environmental Effects

“…The addition of microplastics (10 mg/L) did not increase the toxicity of 4-n-nonlphenol to both normal and starved sea-urchin larvae because sea-urchin larvae could egest microplastics after hours of ingestion without allowing significant pollutants desorption [162]. Even after ingesting relatively high doses of environmental contaminated microplastics, the rainbow trout did not show any obvious adverse hepatic stress in liver, and the fillets quality was not affected, either [163]. However, the specific properties of microplastics should be considered.…”

It's the product not the polymer: Rethinking plastic pollution

“…Though variable within taxa, research on the effects of microplastic exposure on fish and aquatic invertebrates in particular has regularly found no, or minimal negative effects (Foley, Feiner, Malinich, & Höök, 2018). This is true even when studies have used experimental microplastic concentrations far in excess of those recorded in the environment (Ašmonaitė, Larsson, Undeland, Sturve, & Carney Almroth, 2018; Mateos‐Cárdenas, Scott, Seitmaganbetova, van Pelt Frank, & AK, 2019; Weber, Scherer, Brennholt, Reifferscheid, & Wagner, 2018).…”