Dataset containing concentration of accumulated pollutants in 29 stormwater biofilters in the USA

Accumulation of metals, organic micropollutants, PFAS, and microplastics was studied in 29, 12, 20, and 9 bioretention facilities, respectively. The facilities treat runoff from urban catchments with different land use characteristics, including parking lots, roads, downtown urban areas, and industrial, commercial, and residential areas. The bioretention facilities were located in Ohio, Michigan, and Kentucky (USA). The weather and climate in these areas are described as hot-summer humid continental, humid subtropical, and warm-summer humid continental climate with annual precipitation roughly around 760 mm to 1100 mm. The facilities varied in age from 7 to 16 years old at the time of sampling (2019) and the filter surface areas ranged from approximately 10 m2 to 1900 m2. The contributing catchment areas varied in size from approximately 50 m2 to 125 ha, which results in a variation in the ratio of the filter areas and catchment areas of 0.1% to 20%. All evaluated bioretention systems were equipped with an underdrain pipe. Nine samples were collected from the filter materials and one from forebay sediments (if forebay existed) at each bioretention facility as described in more detail the documentation file, except for the smaller facilities (24 and 25), in which only three samples each were collected. The methodology included three sampling locations along each bioretention filter (i.e., three distances from the inlet) located approximately 1 m, 3 m, and 6 m from the inlet at three different depths. However, for sites 5, 8, 12, which were smaller, these distances were scaled down to fit the three sampling locations within the site and for sites 24 and 25, only one sample point was included. The filter materials show great variation between the different sites including sand, loamy sand, sandy loam to silt loam (classification according to the USDA soil textural triangle). The content of organic matter (loss on ignition (LOI)) varies between 1% and 46% with a median of 10% of dry matter (DM). Some maintenance has been performed at the sites (e.g. vegetation pruning, removal of trash), but to our best knowledge the filter materials had not been replaced recently. Samples in the field were collected by digging a core (approximately 5 cm × 15 cm × 15 cm for layer 1 and 10 cm × 10 cm × 10 cm for layers 2 and 3), with approximately 11.5 kg of filter material collected from each of the nine sampling points. The filter material was stored in diffusion-tight plastic bags (18 cm × 35 cm), which were sealed shut with cable ties. The outdoor temperature during sampling was between −12 and +6 °C and the samples were refrigerated before laboratory analysis. Samples were sent to accredited laboratories for pre-treatment and analysis of pollutants: ALS Scandinavia AB for Metals, organic micropollutants, and microplastics and Eurofins Water Testing Sweden AB for PFAS and PFAS-TOP assay. To determine the total concentrations, the samples were dried (50 °C) and sieved (2 mm) according to the Swedish standards. Drying at 105 °C was conducted with sample analysis to correct to a dry matter (DM) concentration. Analysis of metal leachate water was performed on samples acidified with 1 ml concentrated HNO3 (Suprapur for trace analysis) per 100 ml. Analysis was performed with Inductively Coupled Plasma Sector Field Mass Spectrometry (ICP-SFMS) according to Swedish standards and U.S. EPA method 2008. Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES or ICP-AES) was also performed according to Swedish standards and U.S. EPA methods. Analysis of 108 samples for the concentrations of organic compounds included four groups of organic micropollutants (OMPs): 16 PAHs, seven PCBs, 13 phthalates and two alkylphenols using gas chromatography–mass spectrometry. Concentrations of 16 PAHs (i.e., naphthalene (Nap), acenaphthylene (Acyl), acenaphthene (Acen), fluorene (F), phenanthrene (Phen), anthracene (A), fluoranthene (Fluo), pyrene (Pyr), benzo(a)anthracene (BaA), chrysene (Chry), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF), benzo(a)pyrene (BaP), dibenzo(a,h)anthracene (DahA), benzo(g,h,i)perylene (Bper), and indeno(1,2,3-cd) pyrene (IP)) were analyzed according to US EPA 8270 (Pitt et al., 1994) and ISO 18287 (ISO, 2006). The Σ16PAH was calculated as the sum of the concentrations of all 16 PAHs. The sum of PAHs with low molecular weights (PAH-L) was calculated as the sum of naphthalene, acenaphthylene and acenaphthene, PAHs with medium molecular weights (PAH-M) as the sum of fluorene, phenanthrene, anthracene, fluoranthene, and pyrene, PAHs with high molecular weights (PAH-H) as the sum of benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-c,d)pyrene, dibenzo(a,h)anthracene, and benzo(g,h,i)perylene. Concentrations of seven PCBs indicator congeners (i.e., PCB 28, PCB 52, PCB 101, PCB 118, PCB 153, PCB 138, PCB 180) were analyzed following DIN ISO 10382 (DIN ISO, 2002). The grouping Σ7PCB was calculated as the sum of these seven PCBs. Concentrations of 13 phthalates (i.e., dimethylphthalate (DMP), diethylphthalate (DEP), di-n-propylphthalate (DPP), diisobutylphthalate (DIBP), di-n-butylphthalate (DBP), di-n-pentylphthalate (DNPP), di-n-octylphthalate (DNOP), di-(2-ethylhexyl)phthalate (DEHP), butylbenzylphthalate (BBP), dicyclohexylphthalate (DCP), diisodecyl phthalate (DIDP), diisononyl phthalate (DINP) and di-n-hexylphthalate (DNHP)) were analyzed following E DIN19742 (E DIN, 2014). The concentrations of two alkylphenols (i.e., 4-tert-octylphenol (OP) and 4-nonylphenols (NP) were analyzed. 128 samples were also analyzed for PFAS using two techniques: 1) targeted analysis for 35 PFASs including C4-14,16 PFCAs, C4-13 PFSAs, three fluorotelomer sulfonic acids (FTSAs) (n:2 FTS; n=4, 6, or 8), seven perfluoroalkane sulfonamido substances (PFASAs) (EtFOSA, EtFOSE, EtFOSAA, MeFOSA, MeFOSE, MeFOSAA, FOSAA), perfluorooctane sulfonamide (PFASA), 7H-perfluoroheptanoic acid (HPFHpA), and perfluoro-3,7-dimethyloctanoic acid (P37DMOA)) using liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and 2) the total oxidizable precursor assay (TOP) measured for 30 PFASs using the oxidation step developed by Houtz and Sedlak (2012) and HPLC-MS/MS. Limits of quantification (LoQ) of substances ranged between 0.03−1 µg/Kg-DW in 35 PFAS analysis and 0.1−2 µg/Kg-DW in TOP (chemical characteristics and LoQ of the methods for all substances are in Table S3). Measurement uncertainties of ±23% and ±36% were reported for PFAS and TOP assay, respectively. Microplastic contents and polymer types in the 33 samples were analyzed after removing natural organic matter and sediment particles by the Fenton reaction and density separation with zinc chloride solution (1.76 g/cm 3), respectively. Samples containing substantial amounts of plant material according to visual inspection were subjected to an extra cellulose dissolution step according to Olsen et al. (2020). The samples were analyzed with μFTIR and ATR-FTIR and the size range of analyzed microplastic particles was 40–5000 μm. To identify the microplastic polymers detected by the μFTIR spectroscopy, the Sys tematic Identification of MicroPLastics in the Environment (SiMPle) library compiled by Aalborg University, Denmark, and Alfred Wegener Institute, Germany (Primpke et al., 2020) was applied. At the time of analysis the library included reference spectra for 150 types of plastics, including polyethylene (PE), polypropylene (PP), polyurethane (PUR), polyethylene terephthalate (PET), PA, polystyrene (PS), polyvinyl chloride (PVC), ethylene propylene diene monomer rubber (EPDM rubber), polymethyl methacrylate (PMMA), and polylactic acid (PLA). Another library (Spektrum IR, version 10, 6, 2,1159, PerkinElmer,Inc.), which includes 4000 organic and plastic as well as styrene-butadiene rubber (SBR) reference spectra was used to identify plastics detected by the ATR-FTIR spectroscopy. For quality assurance and control, laboratory blanks were handled and analyzed together with the samples.

Ohio, Michigan, and Kentucky (USA)