Spatio-temporal distribution of microplastics in a Mediterranean river catchment: The importance of wastewater as an environmental pathway.
Schell Theresa,Hurley Rachel,Nizzetto Luca,Rico Andreu,Vighi Marco
Journal of hazardous materials
Microplastics (MPs) are considered to be ubiquitous contaminants in freshwater ecosystems, yet their sources and pathways at the river catchment scale need to be better determined. This study assessed MP (55-5000 µm) pollution in a Mediterranean river catchment (central Spain) and aimed to identify the importance of wastewater as an environmental pathway. We sampled treated and untreated wastewaters, and raw and digested sludge from five WWTPs during two seasons. River water and sediments were sampled at three locations with different anthropogenic influences during three seasons. On average, 93% (47-99%) of MPs were retained by WWTPs. Concentrations in river water and sediment ranged between 1 and 227 MPs/m and 0-2630 MPs/kg dw, respectively. Concentrations strongly depended upon land-use, with pollution levels increasing significantly downstream of urban and industrial areas. Seasonality influenced the observed MP concentrations strongly. During high flow periods, higher water but lower sediment concentrations were observed compared to low flow periods. We estimate that 1 × 10 MPs are discharged into the catchment via treated and untreated wastewater annually, which constitutes up to 50% of the total MP catchment discharge. Thus, we conclude that the wastewater system represents a major environmental pathway for MPs into Mediterranean rivers with low dilution capacity.
10.1016/j.jhazmat.2021.126481
Contribution of mulch film to microplastics in agricultural soil and surface water in China.
Ren Shu-Yan,Kong Si-Fang,Ni Hong-Gang
Environmental pollution (Barking, Essex : 1987)
Agricultural mulch film (AMF) is deemed an important source of microplastics (MPs) in agricultural soil (AS). However, quantitating the contribution of AMFs to MPs in farmland soil and surface water remains a considerable challenge to date. In the present study, a basic framework was developed to address these concerns. First, the concentrations of MPs in soil derived from AMF abrasion (C) and the total MPs from all sources in AS (C) were measured. Then, the ratios of C to C, i.e., the contribution of AMFs to MPs in AS, were calculated. The contribution of AMFs to MPs in surface water via soil erosion was calculated based on C values, the ratios of C to C, soil erosion intensities (SEIs), and farmland areas. Furthermore, the potential contribution of soil erosion to MPs in the ocean was estimated. In China, the inventory of MPs in surface AS in 2018 ranged from 4.9 × 10 to 1.0 × 10 tons according to our results. AMFs contributed 10%-30% of the C with certainties of 60-95%. Assuming that all MPs in AS can be exhaustively transferred to surface water via soil erosion, the national mass transfer amount of MPs (MT) from AS to surface water reached 1.2 × 10-2.2 × 10 tons (∼2% of the inventory of MPs in the AS of China); the fluxes of MPs into the ocean from AS were 3.4 × 10-6.6 × 10 tons, assuming that all MPs in the AS of coastal provinces enter the ocean. It is likely that AMFs contributed 10%-30% MT and fluxes of MPs to the ocean according to the ratios of C to C. Apparently, approximately 30% of the national MT (i.e., the rate of MP flux to the ocean to MT) was input to the ocean.
10.1016/j.envpol.2021.118227
Combined exposure to microplastics and zinc produces sex-specific responses in the water flea Daphnia magna.
Journal of hazardous materials
Microplastics are ubiquitous environmental pollutants and a great threat to the aquatic environment. Due to their small size (ranging from 1 µm to 5 mm), microplastics be easily ingested by a wide range of organisms and can serve as a vector for various contaminants. In this study, additive or possible synergistic effects of microplastics and zinc were demonstrated through sex-specific alterations in behavior, redox status, and modulation of detoxification-related genes in Daphnia magna, with males being more sensitive than females with stronger modulations of antioxidant responses, particularly on glutathione S-transferases expressions. Furthermore, we demonstrated microplastics may act as vectors for metals (Zn) in the aquatic environment in D. magna, with reduced bio-concentration of the total Zn concentration, inducing greater toxicity. Our findings demonstrated synergistic toxicity of the heavy metal Zn and microplastics and could contribute to greater understanding of sex-specific effects of microplastics in aquatic organisms.
10.1016/j.jhazmat.2021.126652
Marine macrophytes retain microplastics.
Esiukova E E,Lobchuk O I,Volodina A A,Chubarenko I P
Marine pollution bulletin
Microplastics (MPs, 0.2-5 mm) contamination of water outside/inside thickets of macrophytes in the Baltic Sea was studied. The amount of MPs particles in water samples taken within thickets is on average 1.7 times higher than in water samples taken in the areas outside thickets. Fibres are the predominant type of MPs (92.5%). For algae growing on boulders, the abundance of MPs is 1245 ± 1020 items/m. Per kilogram of dry algae mass the MPs abundance is 376 ± 404 items/kgDW for all shapes of MPs particles. This value is one order of magnitude higher than in sands of the swash zone in the given area. It is shown that filamentous algae retain more fibres than cartilaginous ones: 1.9-8.5 versus 1-1.1 items/l on average. Obviously, areas covered by sea grasses are much more contaminated than water and sediments in the given region.
10.1016/j.marpolbul.2021.112738