0
Article Tier 2 Detection Methods Environmental Sources Marine & Wildlife Remediation Sign in to save

Hydrologic controls on the accumulation of different sized microplastics in the streambed sediments downstream of a wastewater treatment plant (Catalonia, Spain)

Environmental Research Letters 2021 46 citations

AI summary Read the abstract

Researchers found that microplastic accumulation in streambed sediments downstream of a wastewater treatment plant in Catalonia was governed by hydrodynamic conditions, with smaller particles traveling farther and concentrations decreasing with distance from the effluent discharge point.

Study Type Environmental

Abstract Wastewater treatment plants (WWTPs) act as a point source of microplastics (MPs) to freshwater ecosystems. Although MP abundance has been linked to high-density population areas, the mechanisms of how river hydrodynamics and particle size influence MP accumulation in streams are still largely unknown. This study investigated the spatial distribution of MPs within streambed sediments downstream of a WWTP effluent in Cànoves stream (Montseny, Catalonia) during baseflow conditions. MP concentrations from an upstream control site were compared to the WWTP bypass that added untreated wastewater at times when stream discharge exceeded capacity. The 450 m section investigated downstream of the WWTP consisted of three geomorphically altered sub-reaches interspersed between three unaltered buffer sub-reaches, each ∼75 m that provided a range in hydrologic conditions. Measurements of MP characteristics, hydrogeomorphic variables, and fine particles were simultaneously taken. MPs were quantified following the Nile red fluorescence method for large (>64 µ m) and small (10–64 µ m) particles. MPs in sediment samples downstream of the WWTP were mainly fragments with a higher abundance of small MPs (85 particles/g of sediment) vs large MPs (9 particles/g of sediment). While the abundance of large MPs in streambed sediments decreased with distance from the WWTP point source, the abundance of small MPs increased. Furthermore, the area of small MPs decreased with distance from the WWTP. MPs were most abundant at the WWTP bypass, suggesting these infrequent inputs during storm events represent an important source of MPs to the stream. Higher MP abundance coincided with increased organic matter content and smaller sediment grain sizes. Overall, our results present significant findings that could help explain differences in transport and accumulation patterns of MPs that influence their retention times in streambeds, suggesting a combination of preferential filtration in the streambed sediments, and fragmentation of larger particles.

More Papers Like This

Article Tier 2

Microplastic accumulation in streambed sediment downstream of a wastewater treatment plant in response to dynamic flow conditions

AI summary Read the abstract

Researchers studied how microplastics accumulate in streambed sediment downstream of a wastewater treatment plant in a UK rural stream, sampling under both high- and low-flow conditions. They found that microplastics deposited during low flows were resuspended and flushed during storm events, creating a dynamic cycle of accumulation and release. A transport model combining measurements and flow data helped estimate microplastic inputs and retention timescales in the stream.

Article Tier 2

Transport dynamics of microplastics from land to sea: the role of particle properties and stream morphology.

AI summary Read the abstract

Researchers measured how particle properties including size, density, and polymer type interact with stream morphology to determine microplastic transport distances in 15 streams. Both plastic characteristics and stream structure independently influenced how far microplastics travel before settling, with implications for estimating fluxes to the ocean.

Article Tier 2

Transport of microplastics in a stream that receives the discharge of effluents from wastewater treatment plants of a medium-sized city in the southeast of the Buenos Aires province in Argentina

AI summary Read the abstract

Researchers studied microplastic transport dynamics in a stream receiving wastewater treatment plant effluents in Buenos Aires province, Argentina, examining how MPs move along waterways and undergo sedimentation and resuspension processes downstream of point-source contamination.

Article Tier 2

Spatio-temporal distribution of microplastics in a Mediterranean river catchment: The importance of wastewater as an environmental pathway

AI summary Read the abstract

Microplastic concentrations were mapped across a Mediterranean river catchment in central Spain over multiple seasons, finding that wastewater treatment plant effluents were the dominant point source and that storm events transiently increased concentrations in downstream reaches by mobilizing accumulated particles from river beds and floodplains.

Article Tier 2

Distribution of microplastics present in a stream that receives discharge from wastewater treatment plants

AI summary Read the abstract

Researchers traced microplastic pollution along a stream running through a Spanish city and found that wastewater treatment plant discharge accounted for 97% of microplastics in the water, with concentrations peaking at 72,000 particles per liter immediately downstream of the plants.

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