Accumulation and transport of atmospherically deposited PFOA and PFOS in undisturbed soils downwind from a fluoropolymers factory

PFOA and PFOS are widely found PFAS components in Dutch topsoils. PFOA was emitted to the atmosphere during 1970-2012 from a fluoropolymers factory, and was deposited mainly within a radius of 50 km. For the first time, detailed concentration-depth profiles of PFOA and PFOS were measured in undisturbed soils downwind of the factory. Three locations were selected with about 3 meters of sand soil and free infiltration of rain. An adjacent peat soil was selected for comparison. In the sand soils, concentration-depth profiles of PFOA showed a distinct bell-shaped pattern with the highest contents at 0.2-0.5 m below surface, and lower contents both at the surface and at further depth (up to 3.5 m below surface). This observation indicates that the highest atmospheric deposition has passed, and that PFOA gradually migrates towards groundwater. Concentrations of PFOS are highest near the surface and reach the detection limit at 1 m below surface, suggesting that its downward migration occurs much slower. HYDRUS was used to model PFAS transport in the vadose zone assuming steady-state infiltration. The PFOA depth profiles in the sand soils can be described assuming plausible historic, atmospheric emission of PFOA from the factory and Koc values within the literature range. However, the retention observed must be attributed to linear partitioning between water and both soil organic matter and the air-water interface. Somewhat stronger retention holds for PFOS, but PFOS cannot originate from the factory in the extent found. An alternative explanation is historic, rather parallel emissions from nearby sources such as waste incinerators. Based on measurements and modelling, this study illustrates that PFOA, and to a lesser extent PFOS, should not be treated as immobile contaminants in topsoil as is currently the case in Dutch soil policy, but rather as mobile contaminants of which the legacy amounts in soil will pollute groundwater for many decades

Partitioning of hydrophobic organic contaminants between polymer and lipids for two silicones and low density polyethylene

Polymers are increasingly used for passive sampling of neutral hydrophobic organic substances (HOC) in environmental media including water, air, soil, sediment and even biological tissue. The equilibrium concentration of HOC in the polymer can be measured and then converted into equilibrium concentrations in other (defined) media, which however requires appropriate polymer to media partition coefficients. We determined thus polymer-lipid partition coefficients (KPL) of various PCB, PAH and organochlorine pesticides by equilibration of two silicones and low density polyethylene (LDPE) with fish oil and Triolein at 4 °C and 20 °C. We observed (i) that KPL was largely independent of lipid type and temperature, (ii) that lipid diffusion rates in the polymers were higher compared to predictions based on their molecular volume, (iii) that silicones showed higher lipid diffusion and lower lipid sorption compared to LDPE and (iv) that absorbed lipid behaved like a co-solute and did not affect the partitioning of HOC at least for the smaller molecular size HOC. The obtained KPL can convert measured equilibrium concentrations in passive sampling polymers into equilibrium concentrations in lipid, which then can be used (1) for environmental quality monitoring and assessment, (2) for thermodynamic exposure assessment and (3) for assessing the linkage between passive sampling and the traditionally measured lipid-normalized concentrations in biota. LDPE-lipid partition coefficients may also be of use for a thermodynamically sound risk assessment of HOC contained in microplastics. © 201

Presence and fate of veterinary antibiotics in age-dated groundwater in areas with intensive livestock farming

Abstract The combination of emerging antibiotic resistance and lack of discovery of new antibiotic classes poses a threat to future human welfare. Antibiotics are administered to livestock at a large scale and these may enter the environment by the spreading of manure on agricultural fields. They may leach to groundwater, especially in the Netherlands which has some of the most intensive livestock farming and corresponding excessive manure spreading in the world. This study investigates the presence of antibiotics in groundwater in two regions with the most intensive livestock farming in the Netherlands. If so, the hydrochemical conditions were further elaborated. Ten multi-level wells with in total 46 filters were sampled, focusing on relatively young, previously age-dated groundwater below agricultural fields. Twenty-two antibiotics were analyzed belonging to the following antibiotic groups: tetracyclines, sulfonamides, trimethoprims, β-lactams, macrolides, lincosamides, quinolones, nitrofurans and chloramphenicol. The samples were analyzed for these antibiotics by LC-MS/MS ESI-POS/NEG (MRM) preceded by solid phase extraction which resulted in importantly low detection limits. Six antibiotics were found above detection limits in 31 filters in seven wells: sulfamethazine, sulfamethoxazole, lincomycin, chloramphenicol, ciprofloxacin, and sulfadiazine. The concentrations range from 0.3 to 18 ng L−1. Sulfonamides were detected at all measured depths down to 23 meters below surface level with apparent groundwater ages up to 40 years old. No antibiotics were detected below the nitrate/iron redox cline, which suggests that the antibiotics might undergo degradation or attenuation under nitrate-reducing redox conditions. This study provides proof that antibiotics are present in groundwater below agricultural areas in the Netherlands due to the spreading of animal manure

Presence and fate of veterinary antibiotics in age-dated groundwater in areas with intensive livestock farming

Abstract The combination of emerging antibiotic resistance and lack of discovery of new antibiotic classes poses a threat to future human welfare. Antibiotics are administered to livestock at a large scale and these may enter the environment by the spreading of manure on agricultural fields. They may leach to groundwater, especially in the Netherlands which has some of the most intensive livestock farming and corresponding excessive manure spreading in the world. This study investigates the presence of antibiotics in groundwater in two regions with the most intensive livestock farming in the Netherlands. If so, the hydrochemical conditions were further elaborated. Ten multi-level wells with in total 46 filters were sampled, focusing on relatively young, previously age-dated groundwater below agricultural fields. Twenty-two antibiotics were analyzed belonging to the following antibiotic groups: tetracyclines, sulfonamides, trimethoprims, β-lactams, macrolides, lincosamides, quinolones, nitrofurans and chloramphenicol. The samples were analyzed for these antibiotics by LC-MS/MS ESI-POS/NEG (MRM) preceded by solid phase extraction which resulted in importantly low detection limits. Six antibiotics were found above detection limits in 31 filters in seven wells: sulfamethazine, sulfamethoxazole, lincomycin, chloramphenicol, ciprofloxacin, and sulfadiazine. The concentrations range from 0.3 to 18 ng L−1. Sulfonamides were detected at all measured depths down to 23 meters below surface level with apparent groundwater ages up to 40 years old. No antibiotics were detected below the nitrate/iron redox cline, which suggests that the antibiotics might undergo degradation or attenuation under nitrate-reducing redox conditions. This study provides proof that antibiotics are present in groundwater below agricultural areas in the Netherlands due to the spreading of animal manure

Time integrative sampling properties of Speedisk and silicone rubber passive samplers determined by chemical analysis and in vitro bioassay testing

Compared to grab samples, passive samplers have the advantage that they sample over a longer time period and can detect lower compound concentrations in water quality monitoring campaigns. To allow the determination of time-weighted average concentrations, however, sampler uptake should remain linear in time over the entire sampling period. Therefore, the time integrative or linear uptake properties of adsorption-based Speedisks and partitioning-based silicone rubber samplers were assessed with respect to chemically analyzed single compounds and measured bioactivity in in vitro bioassays. Both sampler types were deployed in consecutive and overlapping time series in a WTTP effluent and in the river Meuse up to 105 days. Extracts were chemically analyzed for PCBs, PAHs and pesticides and tested in the Aliivibrio fischeri and DR-LUC bioassays. Speedisks showed time integrative sampling for the detected pesticides as well as for bioassay responses at both sampling locations for the entire sampling period. The silicone rubber samplers showed poor linear uptake in time for the unknown compounds causing bioassay responses. The bioassay results indicate that conversion of a bioassay response to a passive sampler extract into a time-weighted average bioactivity per liter water seems justified for Speedisks, confirming that concentrations in the samplers correspond to a single volume of sampled water for all compounds. The bioassay results also indicate that a similar conversion for silicone rubber extracts should be interpreted with caution. In principle, it is actually impossible, because the concentration of each compound contributing to the bioassay response corresponds to a different sampled water volume

Accumulation and transport of atmospherically deposited PFOA and PFOS in undisturbed soils downwind from a fluoropolymers factory

PFOA and PFOS are widely found PFAS components in Dutch topsoils. PFOA was emitted to the atmosphere during 1970-2012 from a fluoropolymers factory, and was deposited mainly within a radius of 50 km. For the first time, detailed concentration-depth profiles of PFOA and PFOS were measured in undisturbed soils downwind of the factory. Three locations were selected with about 3 meters of sand soil and free infiltration of rain. An adjacent peat soil was selected for comparison. In the sand soils, concentration-depth profiles of PFOA showed a distinct bell-shaped pattern with the highest contents at 0.2-0.5 m below surface, and lower contents both at the surface and at further depth (up to 3.5 m below surface). This observation indicates that the highest atmospheric deposition has passed, and that PFOA gradually migrates towards groundwater. Concentrations of PFOS are highest near the surface and reach the detection limit at 1 m below surface, suggesting that its downward migration occurs much slower. HYDRUS was used to model PFAS transport in the vadose zone assuming steady-state infiltration. The PFOA depth profiles in the sand soils can be described assuming plausible historic, atmospheric emission of PFOA from the factory and Koc values within the literature range. However, the retention observed must be attributed to linear partitioning between water and both soil organic matter and the air-water interface. Somewhat stronger retention holds for PFOS, but PFOS cannot originate from the factory in the extent found. An alternative explanation is historic, rather parallel emissions from nearby sources such as waste incinerators. Based on measurements and modelling, this study illustrates that PFOA, and to a lesser extent PFOS, should not be treated as immobile contaminants in topsoil as is currently the case in Dutch soil policy, but rather as mobile contaminants of which the legacy amounts in soil will pollute groundwater for many decades

Calibration of polydimethylsiloxane and polyurethane foam passive air samplers for measuring semi volatile organic compounds using a novel exposure chamber design

Passive air sampling is increasingly used for air quality monitoring and for personal sampling. In a novel experimental exposure chamber study, 3 types of polydimethylsiloxane (PDMS, including sheet and wristband) and 1 type of polyurethane foam (PUF) passive air samplers were tested for gas-phase uptake of 200 semi volatile organic compounds (SVOCs) during six months. For 155 SVOCs including PAH, PCB, phthalates, organophosphate esters, musk compounds, organochlorine- and other pesticides, a normalized generic uptake rate (Rs) of 7.6 ± 1.3 m 3 d −1 dm −2 and a generic mass transfer coefficient (MTC) of 0.87 ± 0.15 cm s −1 at a wind speed of 1.3 m s −1 were determined. Variability of sampling rates within and between passive sampling media and analyte groups was not statistically significant, supporting the hypothesis of air-side controlled uptake regardless of sampling material. A statistical relationship was developed between the sampling rate and windspeed which can be used to obtain a sampling rate applicable to specific deployment conditions. For 98 SVOCs, partition coefficients (Ksampler-air) for PUF and PDMS were obtained, which determine the duration of linear uptake and capacity of the sampler for gas-phase uptake. Ksampler-air for PDMS were approximately 10 times higher than for PUF, suggesting that PDMS can be deployed for longer time per volume of sampler, while uptake remains in the linear phase. Statistical relationships were developed to estimate Kpuf-air and Kpdms-air from Koa. These results improve the understanding of the performance of PDMS and PUF passive samplers and contribute to the development of PDMS for the use as a promising personal sampler