Identification and quantification of microplastics in wastewater using focal plane array-based reflectance micro-FT-IR imaging

Microplastics (<5 mm) have been documented in environmental samples on a global scale. While these pollutants may enter aquatic environments via wastewater treatment facilities, the abundance of microplastics in these matrices has not been investigated. Although efficient methods for the analysis of microplastics in sediment samples and marine organisms have been published, no methods have been developed for detecting these pollutants within organic-rich wastewater samples. In addition, there is no standardized method for analyzing microplastics isolated from environmental samples. In many cases, part of the identification protocol relies on visual selection before analysis, which is open to bias. In order to address this, a new method for the analysis of microplastics in wastewater was developed. A pretreatment step using 30% hydrogen peroxide (H2O2) was employed to remove biogenic material, and focal plane array (FPA)-based reflectance micro-Fourier-transform (FT-IR) imaging was shown to successfully image and identify different microplastic types (polyethylene, polypropylene, nylon-6, polyvinyl chloride, polystyrene). Microplastic-spiked wastewater samples were used to validate the methodology, resulting in a robust protocol which was nonselective and reproducible (the overall success identification rate was 98.33%). The use of FPA-based micro-FT-IR spectroscopy also provides a considerable reduction in analysis time compared with previous methods, since samples that could take several days to be mapped using a single-element detector can now be imaged in less than 9 h (circular filter with a diameter of 47 mm). This method for identifying and quantifying microplastics in wastewater is likely to provide an essential tool for further research into the pathways by which microplastics enter the environment.This work is funded by a NERC (Natural Environment Research Council) CASE studentship (NE/K007521/1) with contribution from industrial partner Fera Science Ltd., United Kingdom. The authors would like to thank Peter Vale, from Severn Trent Water Ltd, for providing access to and additionally Ashley Howkins (Brunel University London) for providing travel and assistance with the sampling of the Severn Trent wastewater treatment plant in Derbyshire, UK. We are grateful to Emma Bradley and Chris Sinclair for providing helpful suggestions for our research

Metals impact into the Paranaguá Estuarine Complex (Brazil) during the exceptional flood of 2011

Abstract Particulate and dissolved metal concentrations were determined after the largest flood in the last 30 years on the east-west axis of the Paranaguá Estuarine Complex (PEC) and compared to the those of the dry period at two stations. Results confirmed that the flood greatly affected riverine outflows and the behavior of metals in the PEC. In particular, a sharp decrease in salinity was followed by extremely high SPM concentrations leading to a decrease in DO concentrations at both stations. For the dissolved phase, ANOSIM analysis showed a significant dissimilarity at each station between the sampled periods, whereas for the particulate phase this dissimilarity was found only for the samplings taken at the Antonina Station. KD values suggested dissolved Cu behavior was related to the presence of organic complexes and dissolved Mn had sediment resuspension of redox sediments and or/pore water injection as sources. Metal concentrations were lower than in polluted estuaries, though high enrichment factors found after the flood pointed to the influence of anthropogenic sources. In conclusion, the flood's influence was more evident at the Antonina Station, due to its location in the upper estuary, whereas in Paranaguá a high SPM content with low metal concentration was found, following the common pattern generally found in other marine systems subject to heavy rainfall events

Mapping the spatio-temporal distribution of threatened batoids to improve conservation in a subtropical estuary

The spatio-temporal distributions of four batoid species were examined in a subtropical estuary. Fluvial gradient was the most important factor explaining abundances, reflecting positive relationships with either salinity or distance from urbanised areas that were consistent across seasons and depths. The results support existing protected areas