Validation of predicted exponential concentration profiles of chemicals in soils

Hollander, Anne; Baijens, Iris; Ragas, A.M.J.; Huijbregts, Mark A. J.; Meent, Dik van de

doi:10.1016/j.envpol.2006.09.018

Cited by 16 publications

(13 citation statements)

References 26 publications

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“…In undisturbed soils, the concentrations of POPs often decrease in an exponential trend below the air-soil interface (Hollander et al, 2007). The concentrations shown in Fig.…”

Section: Vertical Distribution Of Pcbs and Pbdes In Agricultural Soilsmentioning

confidence: 99%

Characteristic accumulation and soil penetration of polychlorinated biphenyls and polybrominated diphenyl ethers in wastewater irrigated farmlands

Wang

et al. 2010

Chemosphere

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a b s t r a c tThe impact of wastewater irrigation on the distribution of two groups of persistent organic pollutants (POPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), in farm soil was investigated in this study. The concentrations of total analyzed PCBs were in the range 256-2140 pg g À1 on dry weight basis in surface soils. There was a higher accumulation of PCBs in farms irrigated by wastewater, with decachlorobiphenyl (CB-209) as the predominant congener. The spatial distributions of PBDEs were similar although not as obvious as that of PCBs, and BDE-209 was the predominant congener at 2040-496 000 pg g À1 dw, accounting for >96% of the total analyzed PBDEs. However, no significant correlations could be found between PCB and PBDE concentrations in the topsoil samples, and also with soil organic content between the different sites. On the other hand, soil vertical profiles showed significant relationship with soil organic content in cores taken from farms irrigated with wastewater. The vertical distribution was quite uniform at the topsoil, corresponding to the plowed layer, and decreased thereafter exponentially. Furthermore, the soil vertical distribution was found to be congener specific for PCBs, where less chlorinated congeners were able to penetrate deeper into the soil while heavier congeners were more restricted in their movement. This fractionation process was however not found for PBDEs. Also, the prevalence and high relative concentrations of CB-11 and CB-209 suggests that these PCB congeners should more often be included in routine environmental analysis in order to identifying unusual contamination sources.

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“…In undisturbed soils, the concentrations of POPs often decrease in an exponential trend below the air-soil interface (Hollander et al, 2007). The concentrations shown in Fig.…”

Section: Vertical Distribution Of Pcbs and Pbdes In Agricultural Soilsmentioning

confidence: 99%

Characteristic accumulation and soil penetration of polychlorinated biphenyls and polybrominated diphenyl ethers in wastewater irrigated farmlands

Wang

et al. 2010

Chemosphere

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“…However, as the majority of soil samples represent the average concentration in the top 5 cm of soil, a potential bias may be introduced as concentrations in soil are expected to decline exponentially with depth. [48][49][50] While incorporating algorithms to account for this factor is justifiable on theoretical and empirical grounds, it is not expected to account for the magnitude of the discrepancies found in this empirical evaluation particularly because a modified version of SimpleBox 3.0 including such algorithms did not produce average soil concentrations that deviated substantially from the unmodified version in an evaluative exercise. 49 …”

Section: Soil Compartmentmentioning

confidence: 99%

Empirical evaluation of spatial and non-spatial European-scale multimedia fate models: results and implications for chemical risk assessment

et al. 2007

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Multimedia environmental fate models are commonly-applied tools for assessing the fate and distribution of contaminants in the environment. Owing to the large number of chemicals in use and the paucity of monitoring data, such models are often adopted as part of decision-support systems for chemical risk assessment. The purpose of this study was to evaluate the performance of three multimedia environmental fate models (spatially-and non-spatially-explicit) at a European scale. The assessment was conducted for four polycyclic aromatic hydrocarbons (PAHs) and hexachlorobenzene (HCB) and compared predicted and median observed concentrations using monitoring data collected for air, water, sediments and soils. Model performance in the air compartment was reasonable for all models included in the evaluation exercise as predicted concentrations were typically within a factor of 3 of the median observed concentrations. Furthermore, there was good correspondence between predictions and observations in regions that had elevated median observed concentrations for both spatiallyexplicit models. On the other hand, all three models consistently underestimated median observed concentrations in sediment and soil by 1-3 orders of magnitude. Although regions with elevated median observed concentrations in these environmental media were broadly identified by the spatially-explicit models, the magnitude of the discrepancy between predicted and median observed concentrations is of concern in the context of chemical risk assessment. These results were discussed in terms of factors influencing model performance such as the steady-state assumption, inaccuracies in emission estimates and the representativeness of monitoring data.

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“…Although, for chemical fate and transport modelling in undisturbed soils, an exponential profile for concentration with depth is generally more appropriate (Hollander et al, 2007), often phenomena such as mechanical or biological turbation and preferential flow determine a more homogeneous chemical profile (Cousins et al, 1999a,b;Armitage et al, 2006), as assumed by many commonly used environmental models (e.g. EC, 2004).…”

Section: Implementation Of a Daily Step Chemical Balance Model And Vementioning

confidence: 99%

On the temporal resolution of mass balance models for soluble chemicals in soils

Pistocchi

2010

Hydrological Processes

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Abstract:A daily step model of chemical mass balance in the topsoil is presented and validated at the three experimental sites in Europe, and subsequently applied to perform two distinct numerical experiments. First, an experiment was run using hypothetic soluble chemicals with half-lives ranging from 10 1 to 10 4 , with a range of representative European climate and soil properties, assuming uniform constant emissions of the chemicals throughout the year. Chemical mass in soil from the daily step model calculations can be surrogated by the monthly step model consistently parameterized in terms of absolute values, patterns and inter-monthly variability with decreasing accuracy at higher chemical half-lives. Leaching fluxes can be also surrogated by the monthly step calculation, although with higher errors. Runoff is correct in the order of magnitude, but it shows only a weak correlation with the monthly mean of the daily model output. For leaching and runoff, the accuracy depends mainly on soil properties. Variability is well reproduced for both leaching and runoff.The second experiment represented a pulse emission of chemicals discharged on a single day in a 12-month period. Results from the annual average mass of chemicals in the soil, annual runoff and leaching fluxes from the daily step model were compared with the results obtained from the experiment assuming constant-removal rates for the year. The two values are within a factor of 10 for half-lives longer than 10 days; therefore, it is possible to emulate the daily step model with a simple constant-removal rate model for screening-level assessment. The experiments suggest that simpler schemes may be a practical screening-level approximation of detailed daily step models for both continuous and pulse emissions, two cases providing extreme bounds of variation to real world emissions.

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Validation of predicted exponential concentration profiles of chemicals in soils

Cited by 16 publications

References 26 publications

Characteristic accumulation and soil penetration of polychlorinated biphenyls and polybrominated diphenyl ethers in wastewater irrigated farmlands

Characteristic accumulation and soil penetration of polychlorinated biphenyls and polybrominated diphenyl ethers in wastewater irrigated farmlands

Empirical evaluation of spatial and non-spatial European-scale multimedia fate models: results and implications for chemical risk assessment

On the temporal resolution of mass balance models for soluble chemicals in soils

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