TY - JOUR

T1 - Semi-automated analysis of microplastics in complex wastewater samples

AU - Horton, A.A.

AU - Cross, R.K.

AU - Read, D.S.

AU - Jürgens, M.D.

AU - Ball, H.L.

AU - Svendsen, C.

AU - Vollertsen, J.

AU - Johnson, A.C.

PY - 2021/1/1

Y1 - 2021/1/1

N2 - In order to assess risks to the natural environment from microplastics, it is necessary to have reliable information on all potential inputs and discharges. This relies on stringent quality control measures to ensure accurate reporting. Here we focus on wastewater treatment works (WwTWs) and the complex sample matrices these provide. Composite samples of both influent and effluent were collected over a 24 h period on two separate occasions from eight different WwTWs across the UK. Sludge samples were taken on five occasions from five WwTWs. The WwTW treatments included activated sludge, trickling filter and biological aerated flooded filter with or without tertiary treatment. Using micro-FTIR analysis, microplastics ≥25 μm were identified and quantified. Procedural blanks were used to derive limits of detection (LOD) and limits of quantification (LOQ). Where values were above the LOQ, microplastics in the influent ranged from 955 to 17,214 microplastic particles/L and in the effluent from 2 to 54 microplastic particles/L, giving an average removal rate of 99.8%. Microplastics could be quantified in sludge at concentrations of 301–10,380 microplastics/g dry weight, this analytical method therefore revealing higher concentrations than reported in previous studies. The most common polymers present overall were polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET). We also report on critical considerations for blank corrections and quality control measures to ensure reliable microplastic analysis across different sample types.

AB - In order to assess risks to the natural environment from microplastics, it is necessary to have reliable information on all potential inputs and discharges. This relies on stringent quality control measures to ensure accurate reporting. Here we focus on wastewater treatment works (WwTWs) and the complex sample matrices these provide. Composite samples of both influent and effluent were collected over a 24 h period on two separate occasions from eight different WwTWs across the UK. Sludge samples were taken on five occasions from five WwTWs. The WwTW treatments included activated sludge, trickling filter and biological aerated flooded filter with or without tertiary treatment. Using micro-FTIR analysis, microplastics ≥25 μm were identified and quantified. Procedural blanks were used to derive limits of detection (LOD) and limits of quantification (LOQ). Where values were above the LOQ, microplastics in the influent ranged from 955 to 17,214 microplastic particles/L and in the effluent from 2 to 54 microplastic particles/L, giving an average removal rate of 99.8%. Microplastics could be quantified in sludge at concentrations of 301–10,380 microplastics/g dry weight, this analytical method therefore revealing higher concentrations than reported in previous studies. The most common polymers present overall were polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET). We also report on critical considerations for blank corrections and quality control measures to ensure reliable microplastic analysis across different sample types.

KW - Aliphatic compounds

KW - Effluents

KW - Microplastic

KW - Plastic bottles

KW - Polyethylene terephthalates

KW - Polypropylenes

KW - Risk assessment

KW - Wastewater treatment

KW - Limits of detection

KW - Microplastic particles

KW - Natural environments

KW - Polyethylene terephthalates (PET)

KW - Semi-automated analysis

KW - Tertiary treatment

KW - Time-efficient methods

KW - Wastewater treatment works

KW - Quality control

KW - effluent

KW - experimental study

KW - plastic waste

KW - pollutant removal

KW - removal experiment

KW - sludge

KW - wastewater treatment

KW - United Kingdom

U2 - 10.1016/j.envpol.2020.115841

DO - 10.1016/j.envpol.2020.115841

M3 - Journal article

VL - 268

JO - Environmental Pollution

JF - Environmental Pollution

SN - 0269-7491

M1 - 115841

ER -