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Thompson JT, Lott DJ, Lin AM, Bowden JA, Stuchal L, Townsend TG. Assessing the suitability of leachability-based screening levels for per- and polyfluoroalkyl substances (PFAS) risk assessment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 928:172430. [PMID: 38621546 DOI: 10.1016/j.scitotenv.2024.172430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/09/2024] [Accepted: 04/10/2024] [Indexed: 04/17/2024]
Abstract
In recent years, soil screening levels have been adopted by regulatory agencies for certain per- and polyfluoroalkyl substances (PFAS) to assess the risk of groundwater contamination through leaching. These soil screening levels, determined using an established equilibrium-based partitioning equation, have high variability among regulatory groups largely attributed to the diverse reported partitioning coefficients in the literature. This variability between reported partitioning coefficients, and subsequently soil screening levels, is due to the complex leaching behavior of PFAS not being predicted well by the standard equilibrium-based model. This has led one regulatory group to require batch leaching to assess risk rather than setting default soil screening levels based on partitioning equations. In this work, we conducted leaching experiments on five field-sampled soils impacted by aqueous film-forming foams (AFFF), following Leaching Environmental Assessment Framework (LEAF) Method 1316 and compared the results to expected leaching utilizing an equilibrium-based partitioning equation commonly employed by regulatory agencies to establish soil screening levels. Our analysis found among the six PFAS detected in the soils, which have regulatory leaching thresholds established, the partitioning values assumed by the U.S. EPA exhibited the highest accuracy in predicting leachate concentrations. These partitioning values predicted actual leaching within a ± 20 % margin of error for approximately 50 % of sample points, highlighting limitations in relying solely on equilibrium-based partitioning values as predictors of leaching behavior. This discrepancy between predicted and actual leaching has implications for site managers and regulatory entities overseeing PFAS-contaminated sites, suggesting that soil screening level determinations for PFAS might need to be revised to account for the unique transport characteristics of PFAS.
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Affiliation(s)
- Jake T Thompson
- Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL 32611-6450, USA.
| | - Dreyton J Lott
- Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL 32611-6450, USA.
| | - Ashley M Lin
- Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL 32611-6450, USA.
| | - John A Bowden
- Department of Physiological Sciences, University of Florida, Gainesville, 1333 Center Drive, Basic Science Building, Room 324, Gainesville, FL 32610, USA.
| | - Leah Stuchal
- Center for Environmental & Human Toxicology, University of Florida; Gainesville, 2187 Mowry Road, CEHT-Building 471, Room 2, Gainesville, FL 32608, USA.
| | - Timothy G Townsend
- Department of Environmental Engineering Sciences, University of Florida, PO Box 116450, Gainesville, FL 32611-6450, USA.
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Gutierrez-Carazo E, Dowle J, Coulon F, Temple T, Ladyman M. Investigating residue dissolution of insensitive high explosives in two sandy soil types: A predictive modelling approach. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166968. [PMID: 37704157 DOI: 10.1016/j.scitotenv.2023.166968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 09/04/2023] [Accepted: 09/08/2023] [Indexed: 09/15/2023]
Abstract
The demand for munitions that are less likely to detonate accidentally has led to an increased use of Insensitive High Explosives (IHE), which contain substances like 2,4-dinitroanisole (DNAN) and 5-nitro-1,2,4-triazol-3-one (NTO). These substances have different properties compared to traditional explosives, and their potential environmental impact is not well understood. When these explosives are used in live-fire training exercises, their residues end up in the soil. It is important to determine how these residues dissolve and enter the soil. This study aimed to experimentally measure the rate at which an IHE formulation dissolves when exposed to rainwater with pH levels of 5.0 and 6.5, and to simulate how these residues dissolve and move through two different soil types. The dissolution rates were determined by conducting experiments in which IHE particles (30-60 mg) were exposed to water with varying pH levels and temperatures. The results showed that the dissolution rate of NTO did not vary with pH, while the dissolution rate of DNAN and RDX decreased with decreasing pH. Specifically, the dissolution rate of DNAN decreased from 18 ± 40 μg min-1 at pH 6.5 to 6 ± 4 μg min-1 at pH 5.0, while the dissolution rate of RDX decreased from 8 ± 4 to 3 ± 1 μg min-1. These findings were used to develop a stochastic model that successfully simulated the concentration of IHE in the leachate from soil columns over time. A sensitivity analysis revealed that while dissolution rates determined the amount of mass entering the soil, they did not significantly regulate the amount of mass that migrated through the soil and leached out of the soil columns.
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Affiliation(s)
- Encina Gutierrez-Carazo
- Cranfield University, Centre for Defence Chemistry, Defence Academy of the United Kingdom, Shrivenham SN6 7LA, UK
| | - James Dowle
- Golder, Sirius Building, The Clocktower, Edinburgh EH12 9LB, UK
| | - Frederic Coulon
- Cranfield University, School of Water, Energy and Environment, Cranfield MK43 0AL, UK
| | - Tracey Temple
- Cranfield University, Centre for Defence Chemistry, Defence Academy of the United Kingdom, Shrivenham SN6 7LA, UK
| | - Melissa Ladyman
- Cranfield University, Centre for Defence Chemistry, Defence Academy of the United Kingdom, Shrivenham SN6 7LA, UK.
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Pawlowski S, Aicher L, Berends A, Curtis-Jackson P, Häner A, Hollender J, Jene B, Jenner K, Redman A, Sanders G, Vallotton N, Wang N, Wheeler JR. Mobility in the context of exposure-based assessment of chemicals for drinking water resource protection. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2023; 19:775-791. [PMID: 36281826 DOI: 10.1002/ieam.4705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
In order to protect European Union (EU) drinking water resources from chemical contamination, criteria for identifying persistent, mobile, and toxic (PMT) chemicals and very persistent and very mobile (vPvM) chemicals under the EU REACH Regulation were proposed by the German Environment Agency (Umweltbundesamt-UBA). Additionally, new hazard classes for PMT and vPvM substances in the revised EU classification, labeling, and packaging (CLP Regulation) are intended. Therefore, a reliable approach in the identification of potential drinking water resource contaminants is needed. The scientific basis of the property-based PMT/vPvM criteria, focusing on mobility, which dictates the migration of chemical drinking water sources, was evaluated, and a critical analysis of the deviation of sorption metrics from simple behavior was carried out. Based on our evaluation, a Koc may be used for nonionic substances on a screening level only, requiring a higher tier assessment. It is considered inappropriate for hydrophilic and ionizable chemicals, particularly for soils with low organic carbon contents. The nonextractable residue formation is complex and not well understood but remains significant in limiting the mobility of chemicals through soils and sediments. In order to inform the EU commission's work on the introduction of new hazard classes for PMT and vPvM substances into the European legislation, the derivation of a tiered approach is proposed, which utilizes the weight of evidence available, with adoption of appropriate higher tier models commensurate with the nature of the substance and the data available. Integr Environ Assess Manag 2023;19:775-791. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
| | - Lothar Aicher
- Swiss Centre for Applied Human Toxicology (SCAHT), Basel, Switzerland
| | | | | | | | - Juliane Hollender
- Swiss Federal Institute of Aquatic Science and Technology, Eawag, Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zürich, Switzerland
| | | | | | - Aaron Redman
- ExxonMobil Biomedical Sciences Inc., Annandale, New Jersey, USA
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Ullucci S, Menaballi L, Di Giorgi S, Luini M, Riva C, Schlitt C, Clementi E, Azimonti G. Pesticides groundwater modelling relies on input data characterised by a high intrinsic variability: Is the resulting risk for groundwater credible? THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 839:156314. [PMID: 35640749 DOI: 10.1016/j.scitotenv.2022.156314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 05/04/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
In the framework of Regulation (EC) 1107/2009, concerning the placing of plant protection products (PPP) on the market, FOCUS models are used to predict active substances concentration in groundwater. The predicted environmental concentration in groundwater (PECGW) are influenced by active substance specific parameters, namely DT50, KOM and Freundlich coefficient (1/n), whose minimal variation in certain combinations of intervals significantly affects PECGW output. Considering that minimal variation are intrinsic in all laboratory studies, this approach may lead to not acceptable variations in the results for regulatory purposes. In the present article, PECGW were calculated for all maize crop scenarios, using 808 dummy active substances with different combinations of DT50, KOM and 1/n values, in order to quantify the influence of each single parameter on the final result of PEARL and PELMO models. The results obtained were used to create a classification system for the input parameters KOM and DT50 in order to minimise the input uncertainty effects. Even if this approach is scientifically viable yet, due to its conservative nature, it cannot be considered suitable in the regulatory framework, where acceptability of an active substance is strictly related to the limit value of 0.1 μg/L. Nevertheless, this classification system could represent an important screening or preliminary assessment to plan pesticide monitoring programmes. Based on the results of this analysis, it is believed that the assessment of pesticide leaching into groundwater should be revised to take into account this variability. Considering that both PEARL and PELMO FOCUS models deal with interaction between a chemical and a complex system like soil and weather, the selection of input data cannot pretend to rely on single specific number. Considering that intrinsic uncertainty cannot be eliminated from experimental work, a revision of the criteria used to identify the proper input data and a thorough revision of the actual groundwater modelling is recommended.
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Affiliation(s)
- Sonia Ullucci
- International Centre for Pesticide and Health Prevention, L. Sacco University Hospital, via Giovanni Battista Grassi, 74, 20157 Milano, Italy.
| | - Luca Menaballi
- International Centre for Pesticide and Health Prevention, L. Sacco University Hospital, via Giovanni Battista Grassi, 74, 20157 Milano, Italy
| | - Sabrina Di Giorgi
- Ministero della Salute, Direzione Generale per l'Igiene e la Sicurezza degli Alimenti e della Nutrizione, Viale Giorgio Ribotta, 5, 00144 Roma, Italy.
| | - Mara Luini
- International Centre for Pesticide and Health Prevention, L. Sacco University Hospital, via Giovanni Battista Grassi, 74, 20157 Milano, Italy.
| | - Cristian Riva
- International Centre for Pesticide and Health Prevention, L. Sacco University Hospital, via Giovanni Battista Grassi, 74, 20157 Milano, Italy.
| | - Christian Schlitt
- International Centre for Pesticide and Health Prevention, L. Sacco University Hospital, via Giovanni Battista Grassi, 74, 20157 Milano, Italy.
| | - Emilio Clementi
- International Centre for Pesticide and Health Prevention, Dept Biomedical and Clinical Sciences, L. Sacco University Hospital, Università di Milano, 20157 Milano, Italy; Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy.
| | - Giovanna Azimonti
- International Centre for Pesticide and Health Prevention, L. Sacco University Hospital, via Giovanni Battista Grassi, 74, 20157 Milano, Italy.
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Siek M, Paszko T, Jerzykiewicz M, Matysiak J, Wojcieszek U. Mechanisms of Tebuconazole Adsorption in Profiles of Mineral Soils. Molecules 2021; 26:molecules26164728. [PMID: 34443316 PMCID: PMC8398351 DOI: 10.3390/molecules26164728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 07/20/2021] [Accepted: 08/02/2021] [Indexed: 02/05/2023] Open
Abstract
The study attempted to identify the soil components and the principal adsorption mechanisms that bind tebuconazole in mineral soils. The KF values of the Freundlich isotherm determined in 18 soils from six soil profiles in batch experiments after 96 h of shaking ranged from 1.11 to 16.85 μg1-1/n (mL)1/n g-1, and the exponent 1/n values from 0.74 to 1.04. The adsorption of tebuconazole was inversely correlated with the soil pH. Both neutral and protonated forms of this organic base were adsorbed mainly on the fraction of humins. The adsorption of the protonated form increased in the presence of hydrogen cations adsorbed in the soil sorption sites. Fourier transform infrared spectroscopy coupled with the molecular modeling studies and partial least squares regression analysis indicated that the tebuconazole molecule is bound in the organic matter through the formation of hydrogen bonds as well as hydrophobic and π-π interactions. Ion exchange was one of the adsorption mechanisms of the protonated form of this fungicide. The created mathematical model, assuming that both forms of tebuconazole are adsorbed on the organic matter and adsorption of the protonated form is affected by the potential acidity, described its adsorption in soils well.
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Affiliation(s)
- Marcin Siek
- Department of Chemistry, University of Life Sciences, Akademicka 13, 20-950 Lublin, Poland; (M.S.); (J.M.); (U.W.)
| | - Tadeusz Paszko
- Department of Chemistry, University of Life Sciences, Akademicka 13, 20-950 Lublin, Poland; (M.S.); (J.M.); (U.W.)
- Correspondence: ; Tel.: +48-814456640
| | - Maria Jerzykiewicz
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland;
| | - Joanna Matysiak
- Department of Chemistry, University of Life Sciences, Akademicka 13, 20-950 Lublin, Poland; (M.S.); (J.M.); (U.W.)
| | - Urszula Wojcieszek
- Department of Chemistry, University of Life Sciences, Akademicka 13, 20-950 Lublin, Poland; (M.S.); (J.M.); (U.W.)
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Mendes KF, Wei MCF, Furtado IF, Takeshita V, Pissolito JP, Molin JP, Tornisielo VL. Spatial distribution of sorption and desorption process of 14C-radiolabelled hexazinone and tebuthiuron in tropical soil. CHEMOSPHERE 2021; 264:128494. [PMID: 33022507 DOI: 10.1016/j.chemosphere.2020.128494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/27/2020] [Accepted: 09/28/2020] [Indexed: 06/11/2023]
Abstract
The understanding of the interaction between soil physicochemical attributes and herbicide behavior is fundamental for optimizing the efficient use of PRE-emergence herbicides in a more sustainable approach. However, it is still a poorly studied area within precision agriculture. Thus, the objective of this research was to evaluate the correlation of soil physicochemical attributes with the sorption and desorption processes of hexazinone and tebuthiuron to support application maps considering the field level variability. Soil samples from an agricultural area had their physicochemical attributes analyzed and were submitted to sorption and desorption studies of 14C-tebuthiuron and 14C-hexazinone using the batch equilibrium method. The values of sorption and desorption apparent coefficients (Kd), sorption and desorption percentage and bioavailability were correlated with soil attributes by Pearson's correlation. The Kd values of tebuthiuron and hexazinone sorption ranged from 1.2 to 2.9 mL g-1 and 0.4-0.6 mL g-1, respectively. For desorption of tebuthiuron and hexazinone, Kd values ranged from 3.4 to 4.4 mL g-1 and 2.6-3.0 mL g-1, respectively. A positive correlation among clay content, soil organic matter (OM), and tebuthiuron and hexazinone sorption Kd values were found. Both herbicides had variable retention according to geographic position in the area. The recommendation of application of PRE herbicides, such as tebuthiuron and hexazinone, observing the physicochemical attributes of the soil is an alternative to increase efficiency in weed control and decrease the risk of environmental contamination.
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Rodríguez-Liébana JA, Peña A. Differences in the sorption kinetics of various non-ionisable pesticides in a limited number of agricultural soils from the Mediterranean basin. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 276:111336. [PMID: 32920461 DOI: 10.1016/j.jenvman.2020.111336] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 08/02/2020] [Accepted: 08/30/2020] [Indexed: 06/11/2023]
Abstract
Adsorption in soil of organic contaminants, such as pesticides, is a time-dependent process, which can be relevant for understanding and predicting the potential pollution risk of different water sources. The adsorption behavior of six different pesticides with a wide range of physicochemical properties (log KOW 1.26-5.8) was evaluated in up to three different soils with low organic carbon (OC) content (≤1.2%). Pesticide sorbed amounts were fitted to several mathematical models to unravel the mechanisms involved in the adsorption process. The linear distribution constants revealed that pendimethalin and the pyrethroid insecticides were strongly retained in soil, whereas the other three compounds were moderately or weakly adsorbed. In the three soils, the pseudo second order model described more accurately the sorption kinetics of all the contaminants. The more hydrophobic pesticides (log KOW ≥ 4.6) presented lower kinetic rates as compared with the other compounds under study. Both Elovich and intraparticle diffusion models reflected a strong contribution of a rapid initial adsorption on soil surface for thiacloprid, dimethenamid and fenarimol. For the hydrophobic pesticides this contribution was moderate according to the intraparticle diffusion model. Therefore, slower diffusion into the soil micropores was more relevant for the more hydrophobic compounds and for the bigger molecules, and less significant for the more polar pesticides because almost 90% of the total amount adsorbed was achieved in the rapid initial stage.
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Affiliation(s)
| | - Aránzazu Peña
- Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Avenida de las Palmeras 4, 18100-Armilla, Granada, Spain
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Rodríguez-Liébana JA, Peña A. Adsorption-desorption of dimethenamid and fenarimol onto three agricultural soils as affected by treated wastewater and fresh sewage sludge-derived dissolved organic carbon. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 217:592-599. [PMID: 29649731 DOI: 10.1016/j.jenvman.2018.03.119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/24/2018] [Accepted: 03/26/2018] [Indexed: 06/08/2023]
Abstract
The use of treated wastewaters (TWW) in agriculture is widening in areas suffering drought, such as southern Europe, to preserve freshwater supply for human consumption. The composition of TWW, especially concerning their organic carbon (OC) content, has been demonstrated to influence the processes governing the behavior of non-ionic pesticides in soils. Three OC-poor agricultural soils (SV, RM1 and RM3) from the province of Granada (Spain) were chosen for the assessment of the adsorption and desorption of the herbicide dimethenamid (DIM) and the fungicide fenarimol (FEN). TWW and sewage sludge extracts at different dissolved OC (DOC) concentrations (30, 90 and 300 mg L-1) were considered to evaluate their effect on pesticide adsorption-desorption. As expected by their properties, DIM and FEN were weakly and moderately adsorbed to the soils, respectively. Soil OC seemed to be the major factor controlling FEN adsorption, whereas the mineral fraction played a key role in DIM adsorption, especially in RM1 with high clay:OC ratio. Although TWW did not significantly modify the adsorption of pesticides, it enhanced DIM desorption from the three soils. Adsorption of FEN to SV and RM3 was directly related to the concentration of DOC, possibly due to co-sorption phenomena. Hysteretic desorption was found in all cases, indicating partially reversible adsorption. While FEN desorption was not altered by the solutions, the use of sludge extracts at the highest DOC concentration (300 mg L-1) enhanced DIM desorption as occurred with TWW. Interactions with DOC in solution seemed to predominate for this less hydrophobic compound, thus increasing the risk of natural waters contamination if TWW will be used.
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Affiliation(s)
- José Antonio Rodríguez-Liébana
- Instituto Andaluz de Ciencias de la Tierra (IACT), Consejo Superior de Investigaciones Científicas-Universidad de Granada (CSIC-UGR), Avda. de las Palmeras, 4, 18100-Armilla, Granada, Spain.
| | - Aránzazu Peña
- Instituto Andaluz de Ciencias de la Tierra (IACT), Consejo Superior de Investigaciones Científicas-Universidad de Granada (CSIC-UGR), Avda. de las Palmeras, 4, 18100-Armilla, Granada, Spain.
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Jarvis N. Meta-analysis of pesticide sorption in subsoil. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2018; 37:755-761. [PMID: 29057488 DOI: 10.1002/etc.4011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/05/2017] [Accepted: 10/17/2017] [Indexed: 06/07/2023]
Abstract
Models used to assess leaching risks generally use organic carbon partition coefficient (kOC ) values derived from batch experiments on topsoil samples to estimate pesticide sorption in subsoils of much smaller organic carbon contents. This can introduce significant errors in leaching risk calculations, because inorganic sorbents can play an important role for sorption in subsoil. The objectives of the present study were therefore to summarize the available literature data on pesticide sorption in subsoils and to test whether a simple alternative model could improve on the standard kOC approach used in risk assessment models for pesticide leaching. This model describes the sorption constant as a power law function of the organic carbon content. A database with the results of batch sorption experiments was collated from published studies that emphasized measurements in subsoils. This database contains 1029 data entries from 36 published studies with data for 29 active substances (11 nonionic compounds, 10 weak acids, 6 weak bases, one cation, and one zwitterion). The results show that whereas the constant kOC model proved to be an adequate model for 17 of the 63 individual datasets, the power law model gave acceptable fits (p < 0.05) for 60 of these cases. The exponent in the power law model varied over a wide range, from slightly negative to near unity. It also differed significantly (p = 0.015) for ionized and nonionized compounds, with median values of 0.25 and 0.55, respectively. It is concluded that the power law model could be used to parameterize subsoil sorption in regulatory leaching models, because it has widespread applicability and is simple enough for this purpose. Suitable ways of incorporating this approach in risk assessment procedures are discussed. Environ Toxicol Chem 2018;37:755-761. © 2017 SETAC.
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Affiliation(s)
- Nicholas Jarvis
- Department of Soil and Environment, Swedish University of Agricultural Sciences, Uppsala, Sweden
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