Microplastics in a Stormwater Pond

Abstract

Large amounts of microplastics (MPs) enter our environment through runoff from urban areas. This study presents results for MPs in stormwater from a wet retention pond in terms of its water, sediments, and vertebrate fauna. The analysis was done for the size range 10–500 μm, applying a focal-plane array-based µFourier transform infrared (FPA-µFTIR) imaging technique with automated data analysis. Sample preparation protocols were optimized towards this analytical method. The study revealed 270 item L−1 in the pond water, corresponding to 4.2 µg L−1. The MPs in the pond were highly concentrated in its sediments, reaching 0.4 g kg−1, corresponding to nearly 106 item kg−1. MPs also accumulated in vertebrates from the pond—three-spined sticklebacks and young newts. In terms of particle numbers, this accumulation reached levels nearly as high as in the sediments. The size of the MPs in the pond water and its fauna was quite similar and significantly smaller than the MPs in the sediments. A rough estimate on MPs retention in the pond indicated that MPs were retained at efficiencies similar to that of other particulate materials occurring in the stormwater runoff.

Stormwater Detention Reservoirs: An Opportunity for Monitoring and a Potential Site to Prevent the Spread of Urban Microplastics

“…In addition, it is similar to the quantities of MP in sediments at the San Francisco Bay Region (up to 60,000 units/kg) [25], which was explained by wastewater and urban stormwater runoff at the bay. However, a quantity of up to 950,000 units/kg of MPs was found in a stormwater pond in Viborg, Denmark [45]. This high MP concentration was generated by the accumulated sediments of runoffs from urban and highway areas.…”

Removal of >10 µm Microplastic Particles from Treated Wastewater by a Disc Filter

“…We identified 701 MPs in total in the triplicate aliquots of the BF sample and 560 MPs in the aliquots of the AF sample. As we quantified background contamination in the same laboratory, at the same time, and applied virtually identical sampling and sample treatment methods as well as quality assurance measures, the results of [23,26] led us to expect that approximately 6-8 MPs were likely to have derived from background contamination. Since the contamination rate was approximately 1%, we did not correct the data for contamination in further calculations.…”

Single‐Pot Method for the Collection and Preparation of Natural Water for Microplastic Analyses: Microplastics in the Mississippi River System during and after Historic Flooding

“…If the remaining solids collected on the sieves or filters are organic‐rich, they are typically subjected to either enzymatic digestion (Cole et al 2014) or wet peroxide oxidation, the latter sometimes in the presence of an Fe(II) catalyst (Tagg et al 2017; Hurley et al 2018), to digest labile organic matter and “clean” the plastic surfaces. A final filtering step is used to concentrate the microplastics, which can then be examined directly on a filter by conventional light microscopy (Masura et al 2015), stained with Nile red dye, and examined by fluorescence microscopy (Erni‐Cassola et al 2017) or transferred to a spectroscopic window/slide or a suitable filter for chemical imaging by focal plane array (FPA)‐µFTIR or Raman spectroscopy (Löder et al 2015; Tagg et al 2015; Olesen et al 2017; Wolff et al 2019). Note that prior to chemical imaging the microplastics on the filter are transferred (dispersed) into a solvent such as ethanol (often by sonication) before an aliquot is applied on the spectroscopic window and dried (Liu et al 2019).…”