Microplastics pollution in mud crab (Scylla sp.) aquaculture system: First investigation and evidence

Microplastics in aquaculture environments: Current occurrence, adverse effects, ecological risk, and nature-based mitigation solutions

Microplastics pose detrimental effects on the environment, aquatic products, and human health. This comprehensive analysis highlights the repercussions of microplastic contamination within aquaculture. Microplastics in aquaculture are primarily from land-based plastic waste, tourism-related disposal, shipping activities, fisheries/aquaculture, and atmospheric deposition. In aquaculture environments, microplastics have the potential to discharge harmful additives, attract pollutants, degrade the aquaculture setting, and induce toxicological effects. These particles pose ecological risks and can impact human health. Assessing the destiny of microplastics in aquaculture ecosystems is crucial to determining the role of aquaculture in contributing to microplastic contamination within the watershed. It particularly emphasizes the ecological consequences for aquaculture species and the subsequent health threats for humans. The review strongly supports strict regulations to control and limit microplastic presence within aquaculture ecosystems. Clear regulations are essential for reducing microplastics in aquaculture, thereby ensuring food safety. A novel nature-based solution is proposed using methods like microplastic biofilters, biodegradation, and wetlands. These innovations can be conducted in aquatic ecosystems to serve as microplastic biofilters, effectively eliminating waterborne microplastics. In the future, however, it is crucial to develop additional emergency treatment measures to avoid the potential negative impacts of microplastics on both aquaculture and human health.

Microplastics have additive effects on cadmium accumulation and toxicity in Rice flower carp (Procypris merus)

Procypris merus, a local fish species found in Guangxi, China is often exposed to both microplastics (MPs) and Cd. However, it remains unclear how these two pollutants affect P. merus. Therefore, we investigated the effects of MPs on Cd accumulation in P. merus. To this end, P. merus was separately exposed to Cd and MPs (500 μg/L) or their combination for 14 days. We found that MPs enhanced Cd accumulation in liver and gills of P. merus. Further, both the single-contaminant (MP and Cd) and combined treatments resulted in lesions in these two tissues, with more severe damage associated with the combined treatment. Even though the effect of MP on the antioxidant defense system of P. merus was limited, the Cd-only and combined treatments considerably affected the antioxidant parameters of P. merus, with the combined treatment showing a stronger effect. GO and KEGG analyses revealed that the differentially expressed genes (DEGs; TNF-related apoptosis-inducing ligand receptor, trail-r) in the Cd-only treatment group were enriched for immune-related GO terms and cell growth and death related pathways, indicating that Cd toxicity affected immune defense in P. merus. The MP-only treatment downregulated DEGs (acyl-CoA synthetase long chain family member 1a, acsl1a) related to lipid metabolism, possibly leading to lipid accumulation in the liver. The combined treatment also upregulated DEGs (aspartate aminotransferase 1, ast 1) associated with immune-related GO terms and amino acid metabolism pathways, suggesting that it affected immune function in P. merus, thereby negatively impacting its health. Results indicated that MPs have additive effects on Cd accumulation and toxicity in rice flower carp. Consequently, MPs ingested by P. merus can promote Cd accumulation, more adverse effects on the health may occur after combined exposure, which can eventually reach humans through the food chain and pose potential risks to human health.

Microplastics in Scylla Serrata: A baseline study from southwest India

Scylla serrata plays a crucial role in India's seafood exports yet there exists limited understanding on the occurrence of microplastics (MPs) in these crabs. In this baseline study, we examined the presence of microplastics in the digestive tracts of S. serrata collected from the Kota mangroves, southwestern coast of India. Our analysis revealed the presence of 264 MPs in all the samples with an average (± standard deviation) of 29.33 (±11.53) MPs/Individual. The most dominant categories were fibres (98.86 %) and fragments (1.14 %). Primarily 0.1-0.3 mm (50.90 %) and 0.3-1 mm (37.65 %) size range dominated. The predominant polymers were polypropylene (33.71 %), high-density polyethylene (31.44 %), and polyethylene terephthalate (17.80 %). Scanning electron microscopy revealed extensive weathering on the surface of the microplastics. Risk assessments indicated severe risks to S. serrata due to microplastic ingestion emphasizing the need to protect delicate ecosystems like mangroves and the biota within.

Microplastics in aquaculture systems: Occurrence, ecological threats and control strategies

With the intensification of microplastic pollution globally, aquaculture environments also face risks of microplastic contamination through various pathways such as plastic fishing gear. Compared to wild aquatic products, cultured aquatic products are more susceptible to microplastic exposure through fishing tackle, thus assessing the impacts of microplastics on farmed species and human health. However, current research on microplastic pollution and its ecological effects in aquaculture environments still remains insufficient. This article comprehensively summarizes the pollution characteristics and interrelationships of microplastics in aquaculture environments. We analyzed the influence of microplastics on the sustainable development of the aquaculture industry. Then, the potential hazards of microplastics on pond ecosystems and consumer health were elucidated. The strategies for removing microplastics in aquaculture environments are also discussed. Finally, an outlook on the current challenge and the promising opportunities in this area was proposed. This review aims to evaluate the value of assessing microplastic pollution in aquaculture environments and provide guidance for the sustainable development of the aquaculture industry.