0
Systematic Review Tier 1 Detection Methods Human Health Effects Marine & Wildlife Policy & Risk Sign in to save

Analysis, prevalence and impact of microplastics in freshwater and estuarine environments: an evidence review

2020 2 citations

AI summary Read the abstract

This systematic review summarized the existing research on microplastics in freshwater rivers, lakes, and estuaries. It found that current microplastic levels in most freshwater environments are below the concentrations that cause lethal harm to aquatic life, but the highest-pollution sites may already pose risks for subtler health effects on fish and other organisms. The review also highlighted that different sampling methods produce very different results, making it hard to compare studies.

Study Type Review

We used the systematic review procedure to assess the evidence available on the analysis, prevalence and impact of microplastics in freshwater and estuarine environments. As the study of microplastics in freshwaters is relatively new, measurement methods are yet to be standardized, and a wide variety of methods of variable robustness have been used. Critically, the sampling methodology used in the literature had a systematic influence on the concentration of microplastic particles returned. The volume of water sampled varied over many orders of magnitude, and there was a direct relationship between the size of the smallest particles studied and the volume of water sampled in both freshwater and estuaries: large volumes of water can only be sampled using nets of relatively coarse mesh, which in turn do not capture smaller particles. Consequently, the mean abundance of microplastic particles reported was inversely correlated with both the volume of water sampled and the size of particles studied.The size of microplastic particles had a substantial and overriding effect on threshold concentrations above which microplastics affect freshwater and estuarine biota. For the ecotoxicological endpoints of feeding, behaviour, growth and survival there was a clear relationship between the size of the particles used in the test and the threshold concentration at which an effect was seen. Although the taxonomic coverage of test organisms was limited, there were sufficient data to test the influence of taxonomic group used on size-specific thresholds for Crustacea, fish and algae. There was no significant effect of either the endpoint measured or the taxonomic group used, suggesting that there might not be any difference in sensitivity among different taxa.In order to establish a threshold concentration where microplastics present a hazard to a limited number of taxa, quantile regression was used to determine the size-specific concentration of microplastics that was lower than 90% of the thresholds identified for survival and, as a more conservative limit, across all endpoints tested including sublethal effects. By comparing these thresholds with the data on concentrations of microplastics reported by field studies, it was apparent that the calculated size specific threshold concentration for lethal effects was considerably higher than 99% of reported environmental concentrations. Lethal effects of microplastics on freshwater and estuarine biota are likely to be limited to exceptional circumstances. Over certain size ranges the calculated size specific threshold concentration for sublethal effects was exceeded by the highest 10% of concentrations reported from environmental samples, suggesting that there is a risk of sublethal effects in a small proportion of sites.

More Papers Like This

Systematic Review Tier 1

Microplastic contamination, an emerging threat to the freshwater environment: a systematic review

AI summary Read the abstract

Researchers systematically reviewed the spread of microplastics in freshwater ecosystems — rivers, lakes, and streams — documenting their sources, how they move through water, the damage they cause to aquatic organisms, and the methods used to detect them. Their review serves as a baseline reference for future research and calls for improved waste management to protect freshwater environments from ongoing microplastic contamination.

Review Tier 2

Microplastics in freshwater systems: A review of the emerging threats, identification of knowledge gaps and prioritisation of research needs

AI summary Read the abstract

This review synthesizes the growing body of research on microplastic contamination in freshwater rivers, lakes, and sediments, which has received far less attention than marine environments. Researchers found that freshwater microplastic concentrations can rival or exceed those reported in ocean studies, particularly near urban and industrial areas. The study identifies critical knowledge gaps including the lack of standardized sampling methods and limited understanding of how microplastics affect freshwater organisms and ecosystems.

Review Tier 2

A Review of Microplastics in Freshwater Environments: Locations, Methods, and Pollution Loads

AI summary Read the abstract

This review chapter summarizes global research on microplastics in freshwater environments, covering detection locations, sampling methods, and pollution levels. Because many freshwater bodies serve as drinking water sources, understanding where microplastics occur and in what quantities is critical for assessing risks to human health.

Systematic Review Tier 1

Microplastic Contamination, an Emerging Threat to the Freshwater Environment and Human Health: A Systematic Review

AI summary Read the abstract

This systematic review summarizes existing research on microplastic contamination in freshwater environments and its implications for human health. The evidence shows that microplastics are widespread in rivers, lakes, and drinking water sources, and they can absorb toxic chemicals, making freshwater plastic pollution a direct concern for the safety of our water supply.

Article Tier 2

Emerging threats and persistent conservation challenges for freshwater biodiversity

AI summary Read the abstract

This review provides a comprehensive overview of microplastic pollution in freshwater environments, covering sources, distribution, and ecological impacts in rivers, lakes, and reservoirs. Researchers found that freshwater microplastic contamination is widespread globally but that standardized sampling and analysis methods are still lacking. The study calls for more consistent research approaches so that contamination levels across different water bodies can be meaningfully compared.

Research digests by email

When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.

Email me about

Share this paper