Surveillance of Seafood for Microplastics

Abstract

Surveillance of seafood for microplastic is in high demand, but there are challenges in the establishment of appropriate methods. Even though there are more than hundred scientific publications presenting numbers about the occurrence of plastics in seafood organisms, currently, these numbers are largely not comparable and afflicted with high uncertainty. They represent rather pioneering work, than surveillance. The research field is developing rapidly, continuously challenging and updating definitions and descriptions on the location, quality and quantity of microplastic. A major reason behind those challenges is of a new type, due to the particular nature of this pollutant, as opposed to other previously analyzed pollutants, which are soluble. When dealing with particle uptake into organisms, we claim that it is pivotal to take into account the size and shape of the particles. Most often, only plastic particles above several hundred μm and only from the gastrointestinal tract were included in field studies, typically leading to observations of on average 0-3 particles per fish. However, for both seafood organisms and human health, plastic particles in edible tissue are of higher concern, than those passing through the gastrointestinal system. According to exposure studies, the size of microlitter particles that are most likely to be transported into tissue and have accumulation potential, is lower than 50 μm. The few publications investigating the smaller size classes and tissues, do detect and report microlitter contamination, and therefore, warrant further investigation. Additionally, appropriate quality control needs to be included, and measurement uncertainties assessed.

Micro and Nano Plastics Distribution in Fish as Model Organisms: Histopathology, Blood Response and Bioaccumulation in Different Organs

“…Plastic fragments, in the form of microfibers or microbeads, may accumulate in digestive tract of fish via food and water [147,148]. The bioavailability of MP/NPs and consequently the effects at different levels depend mainly on their size, shape, concentration, and the presence of chemical pollutants [18,149]. The contaminants, species, developmental stage are considered as co-factors for plastic particle toxicity (PPT) [18].…”

“…The bioavailability of MP/NPs and consequently the effects at different levels depend mainly on their size, shape, concentration, and the presence of chemical pollutants [18,149]. The contaminants, species, developmental stage are considered as co-factors for plastic particle toxicity (PPT) [18]. As evidenced by numerous studies carried out under experimental conditions, the ingestion of microplastics can generate two different types of impacts on marine organisms: physical injuries to the organs where accumulation occurs and chemical damage by transfer and accumulation of pollutants with an enhancement of toxicant uptake or an increase in their bioavailability [17].…”

“…Therefore, adverse effects of microplastics and nano plastics may result from a combination of intrinsic toxicity of plastics and ability to absorb, concentrate, and release environmental pollutants into living organisms [17]. In addition, it has become well documented that the different particles sizes exert effects through different physiological pathways, in relation to quantity and quality in different species at different developmental stage and in different tissues [18]. Micro plastics are small synthetic solid particles mostly composed of blends of polymers and functional additives with different chemical compositions, shapes, colors, sizes, and densities.…”

The presence and danger of microplastics in the oceans

“…The first problem related to the contamination of the marine environment with microplastics relates to their bioaccumulation by marine organisms. According to [19], the main potential of accumulation is the ratio of the size of microplastic particles and the size of marine organisms. Moreover, according to [18], that is especially reflected in large predators, marine mammals that are at the top of the marine food chain.…”

“…It is estimated that by 2025, the ratio of plastic to fish in the world's seas and oceans will be 1 to 3 tons, which is equivalent to 600 plastic bags for every 10 kilograms of fish [13]. That is not surprising, despite the fact that approximately 100 million tons of seafood are consumed annually, and the plastic produced is close to 400 million tons per year [19]. Overfishing of fish and other marine organisms, along with an enormous plastic production, results in the previously listed facts.…”