Plant Uptake Model Research Articles

Innovative Juncus effusus plant biofilter for enhanced ammonia removal: design, construction, and preliminary testing

A developing trend in stormwater treatment and management is the use of green technologies. Plant biofilters have been gaining increasing use in support of green technology objectives. This technical note reports on the development and preliminary testing of a laboratory-scale plant biofilter prototype for ammonia removal using a South African native plant species (Juncus effusus). The prototype design was based on a conceptual model for nitrogen fixation, plant uptake, bacterial nitrification and soil sorption. Additionally, a plug compartment was incorporated into the design to simulate plug flow as part of the conceptual model. Biofilter models with and without inoculated bacteria were compared. Ammonia reduction, nitrite and nitrate formation were observed. Results showed that the inoculated plant biofilter performed best, with an average of 61% reduction in ammonia within the filter compared to 15% in the normal plant biofilter. The incorporation of a plug compartment aided in slowing down the ammonia infiltration rate, increasing the retention time, and allowing for nitrification to occur.

Investigating the correlation between pesticide bioconcentration and human disease through the integration of remote sensing and physical modeling

ABSTRACT Nowadays, the risk of pesticides to the environment and human health arises with its increasing applications. Bioconcentration Factor (BCF) is utilized to evaluate the potential plant contamination by pesticides from the soil. Large-scale BCF mapping is significant to urban planning, yet it remains challenging. To address this issue, this study integrates the plant uptake model with remote sensing techniques to map BCF considering various land surface properties. Two simplified approaches were developed: the first involves relative humidity and air temperature (RA-model), while the second uses plant transpiration (PT-model). To evaluate these models, BCF mappings generated by each approach were compared and found to be consistent in space and time, with R 2 at 0.68 over the continental U.S. Both approaches showed that the eastern part of the U.S. had higher BCF values than the west throughout the year, with an annual cycle of BCF where the highest values occurred in summer and the lowest in winter. To further analyze the impact of BCF on human health, spatial heterogeneity detection was used to examine seven diseases at the county scale. The results suggest that BCF may explain the incidence of spatial heterogeneity of most diseases, specifically high blood pressure (q-value >0.3). Overall, this study demonstrates the potential of integrating plant uptake modeling with remote sensing to map BCF and provides insight into the impact of BCF on human health.

Assessing potential soil pollution from plant waste disposal: A modeling analysis of pesticide contamination

Pesticide residues can be taken up by plants after pesticide application, potentially resulting in soil pollution following the disposal of plant wastes at harvest. Currently, there is a lack of simple and efficient methods that can conduct high-throughput simulations to explore this problem across various chemicals and plant species. We present a modeling approach to simulating pesticide residue concentrations in soil as a result of plant waste disposal to assess the impact of plant wastes on agricultural soil pollution with respect to pesticide residues. This modeling approach employs well-established plant uptake models, providing versatility in evaluating different chemicals and plant species. The simulation process was tabulated in the spreadsheet interface, providing users with the flexibility to adjust input values for specific chemicals, plant species, and regions. The simulation results revealed that pesticides with relatively low lipophilicity (i.e., log KOW < 2) had low simulated residue concentrations in the soil as a result of plant waste disposal at harvest, whereas soil concentrations for lipophilic pesticides dramatically rose. This indicated that disposal of plant waste in agricultural soils will not pose significant ecological concerns to pesticides with low lipophilicity. The variability analysis showed that for certain pesticides, environmental factors (such as temperature and humidity) had a significant impact on the simulated residue concentrations in the soil as a result of plant waste disposal, which aided in the assessment of regional ecological risk as well as plant disposal management. Although some modeling aspects such as plant decomposition process, advanced plant uptake models, heterological distribution of residue concentrations in the soil, and plant waste stacking patterns require further research, the proposed approach can be used to assist in managing soil pesticides from plant waste disposal in preliminary stages.

Estimation of risk to soil and human health during irrigation using ZnO nanoparticles-containing water

This work estimated ecological and human health risks for the exposure pathway of spinach irrigation with metal oxide nanoparticles- contaminated river water. Using literature studies, log-logistic plant uptake models were developed to predict metal uptake in plant parts. Reported or expected values of ZnO nanoparticles (NPs) in surface water were collected from published literature for realistic scenarios and used to estimate the risk to human health in terms of hazard quotient (HQ). Monte Carlo simulation and uncertainty analysis were conducted to assess the variability in the obtained results. The Hazard Quotient (HQ) values obtained at environmental concentrations of ZnO nanoparticles were all below 1 for all age groups. Although the 99th percentile value of HQ was found to be the highest (3.57 ×10−3) for the age group (1−6) years, the probability of HQ value being greater than unity was found to be null for all age groups. The 99th percentile values of contamination factor, potential ecological risk factor, and geo-accumulation index, computed as part of ecological risk assessment, were found to be 0.098, 0.098, and − 0.62, respectively, well within their respective contamination limits. Bio-concentration and translocation factors were also computed to quantify the internal uptake of the plant. The results implied that at the current levels of zinc oxide nanoparticles in surface water, no health risk would be exerted on humans upon spinach consumption under the assumptions used. Also, negligible chances of soil contamination were observed due to zinc accumulation after irrigation. The approach proposed in this work can be used to determine potential health and ecological risks when reusing metal oxide NP-contaminated water for irrigating edible crops. This especially gains significance in a future perspective due to a likely increase in nanoparticles' concentration in the environmental media.

Generalizing routes of plant exposure to pesticides by plant uptake models to assess pesticide application efficiency

Pesticide application techniques are critical not only for integrated pest management (IPM) but also for food and environmental safety. Assessing pesticide application efficiency on plants can help optimize IPM and reduce pesticide environmental impacts. With hundreds of pesticides registered for use in agriculture, this study proposed a modeling approach based on plant uptake models for generalizing routes of plant chemical exposures that can correspond to different types of pesticide application methods and evaluating their respective efficiency on plants. Three representative pesticide application methods (i.e., drip irrigation, foliar spray, and broadcast application) were selected for modeling simulations. The simulation results for three representative pesticides (i.e., halofenozide, pymetrozine, and paraquat) revealed that the soil-based transpiration exposure route facilitated the bioaccumulation of moderately lipophilic compounds in leaves and fruits. While the plant surface-based exposure route (i.e., leaf cuticle penetration) made it easier for highly lipophilic compounds to enter plants, moderately lipophilic pesticides (i.e., log KOW ∼ 2) were more soluble in phloem sap, which enhanced their subsequent transport within plant tissues. In general, moderately lipophilic pesticides had the highest simulated residue concentrations in plant tissues for the three specific application methods, indicating they had the highest application efficiency due to their enhanced uptake routes (via transpiration and surface penetration) and increased solubility in xylem and phloem saps. Compared to foliar spray and broadcast application, drip irrigation produced higher residue concentrations for a wide variety of pesticides, exhibiting the highest application efficiency for many pesticides, especially for moderately lipophilic compounds. Future research should incorporate plant growth stages, crop safety, pesticide formulations, and multiple application events into the modeling approach for understanding pesticide application efficiency evaluation.

Digital mapping of pesticides bioconcentration by integrating remote sensing techniques and plant uptake model

ABSTRACT Although pesticides have been widely used worldwide to enhance crop yield and product quality, most pesticides are harmful to the environment and human health. Plants absorb pesticides mainly from air and soil. Therefore, the soil-plant pathway is essential for pesticide absorption. Bioconcentration factor (BCF) has extensively been applied to evaluate potential plant contamination by pesticides from soil. Hence, this study developed a simplified plant transpiration-based plant uptake model (PT-model) to estimate plant pesticides’ BCF from soil based on plant transpiration. Remote sensing techniques were employed to generate spatiotemporal continuous plant transpiration via evapotranspiration. Pesticide BCF mapping was achieved by integrating PT-model with Moderate Resolution Imaging Spectroradiometer (MODIS) remotely sensed data. The results were compared with a verified model driven by relative humidity and air temperature (RA-model), which has been confirmed by findings from previous studies. The estimated BCF was within the boundaries of the RA-model, indicating the simulation’s overall acceptability. In this study, the BCF temporal trend estimated by the proposed method agreed with the RA-model assimilating meteorology datasets, while the spatial distribution was partially inconsistent. Overall, the proposed method generates the spatiotemporal patterns of pesticide BCF with relatively consistent results supported by previous records and findings.

Generic Model for Plant Uptake of Ionizable Pharmaceuticals and Personal Care Products.

Plant uptake of pharmaceuticals and personal care products (PPCPs) has been recognized as a potential path to human exposure. Most existing regressions and uptake models are limited to neutral organic compounds, but 80% of pharmaceuticals and an unknown number of personal care products ionize under environmentally relevant conditions. A widely used generic plant uptake model was expanded step-by-step with processes relevant for weak and strong acids and bases, such as ionization, membrane permeability, ion trap, phloem transport, and sorption to proteins. The differential equation system was solved analytically, and the equations were implemented in a spreadsheet version. The changes in predicted plant uptake of neutral substances, acids, and bases were found for a range of key input data (log KOW , pKa , pH, sorption to proteins). For neutral compounds, sorption to proteins and phloem transport are of relevance only for the more polar compounds (low log KOW , ≤2). Weak acids (pKa ≤6) are trapped in phloem due to pH-related effects, and in roots when pH in soil is low (pH 4-5). Cations sorb stronger and hence show less bioavailability and less translocation than anions. Sorption to proteins reduces translocation to leaves and fruits for all substances, but this is more evident for polar and ionic compounds that have negligible sorption to lipids. The new generic model considers additional processes that are of relevance for polar and ionizable substances. It might be used instead of existing standard approaches for chemical risk assessment and assessment of the environmental fate of PPCPs. Environ Toxicol Chem 2023;42:793-804. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Including the bioconcentration of pesticide metabolites in plant uptake modeling.

Although several models of pesticide uptake into plants are available, there are few modeling studies on the bioconcentration of metabolites in plants. Ignoring metabolites in plant uptake models can result in an underestimation of the parent compound's overall impacts on human health associated with pesticide residues in harvested food crops. To address this limitation, we offer a metabolite-based plant uptake model to predict the bioconcentration of the parent compound and its metabolites in plants. We used the uptake of glyphosate and its major metabolite (aminomethylphosphonic acid, AMPA) into potato as an example. The analysis of variability revealed that soil properties (affecting the soil sorption coefficient), dissipation half-life in soil, and metabolic half-life in the potato had a significant impact on the simulated AMPA concentration in the potato, indicating that regional variability could be generated in the plant bioconcentration process of metabolites. The proposed model was further compared using the non-metabolite model. The findings of the comparison suggested that the non-metabolite model, which is integrated with the AMPA bioconcentration process, can predict the AMPA concentration in the potato similarly to the proposed model. In conclusion, we provide insight into the bioconcentration process of metabolites in tuber plants from a modeling viewpoint, with some crucial model inputs, such as biotransformation and metabolic rate constants, requiring confirmation in future studies. The modeling demonstration emphasizes that it is relevant to consider bioaccumulation of metabolites, which can propagate further into increased overall residues of harmful compounds, especially in cases where metabolites have higher toxicity effect potency than their respective parent compounds.

Considering degradation kinetics of pesticides in plant uptake models: proof of concept for potato.

Degradation kinetics of pesticides in plants are crucial for modeling mechanism-based pesticide residual concentrations. However, due to complex open-field conditions that involve multiple pesticide plant uptake and elimination processes, it is difficult to directly measure degradation kinetics of pesticides in plants. To address this limitation, we proposed a modeling approach for estimating degradation rate constants of pesticides in plants, using potato as a model crop. An operational tool was developed to backward-estimate degradation rate constants, and three pesticides were selected to perform example simulations. The simulation results of thiamethoxam indicated that the growth dynamics of the potato had a significant impact on the degradation kinetic estimates when the pesticide was applied during the early growth stage, as the size of the potato determined the uptake and elimination kinetics via diffusion. Using mepiquat, we demonstrated that geographical variations in weather conditions and soil properties led to significant differences in the dissipation kinetics in both potato plants and soil, which propagated the variability of the degradation rate constant. Simulation results of chlorpyrifos differed between two reported field studies, which is due to the effect of the vertical distribution of the residue concentration in the soil, which is not considered in the majority of recent studies. Our proposed approach is adaptable to plant growth dynamics, preharvest intervals, and multiple pesticide application events. In future research, it is expected that the proposed method will enable region-specific inputs to improve the estimation of the degradation kinetics of pesticides in plants. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Distribution, behavior, and risk assessment of chlorinated paraffins in paddy plants throughout whole growth cycle.

Paddy plants provide staple food for 3 billion people worldwide. This study explores the environmental fate and behavior of a high-volume production emerging contaminants chlorinated paraffins (CPs) in the paddy ecosystem. Very-short-, short-, medium-, and long-chain CPs (vSCCPs, SCCPs, MCCPs, and LCCPs, respectively) were analyzed in specific tissue of paddy plants at four main growth stages and soils from the Yangtze River Delta, China throughout a full rice growing season. The total CP concentrations in the paddy roots, stalks, leaves, panicles, hulls, rice, and soils ranged from 181 to 1.74×103, 21.7-383, 19.6-585, 108-332, 245-470, 59.6-130, and 99.6-400ng/g dry weight, respectively. The distribution profile indicated the translocation of SCCPs and MCCPs from soils to paddy tissue, highlighting their elevated bioaccumulative potential. The evolution of CP level/mass/pattern during the whole growth cycle suggested atmospheric CPs deposition on leaves and hulls, as well as stalk-rice transfer. CSOIL plant uptake model well predicted the level, distribution pattern, and bioconcentration factors (BCFs) of SCCPs and MCCPs in paddy shoot and recognized the soil-air-shoot pathway as the major contributor. Moreover, risk evaluation indicated that MCCPs intake and subsequent risks dominated the total exposure to CPs via rice ingestion. This is the first report on the occurrence, fate and risk assessment of all CPs classes in paddy ecosystems, and the results underline the potential health effects caused by the in-use MCCPs via rice ingestion.

Uptake of endosulfan isomers from soils by leafy vegetable lettuce: A comparative study between model-predicted and field-experimented results

The organochlorine insecticide endosulfan has been classified as a persistent organic pollutant due to its long persistence and high toxicity, and banned in most countries. However, endosulfan residues are still detected in various environmental sites (even in non-agricultural areas) and have a likelihood to return to agricultural soils through various routes. In this study, time-dependent uptake of α- and β-isomers of endosulfan by lettuce from soils was estimated using theoretical models which include parameters describing sorption/dissipation in soil and plants, plant transpiration, root–soil transfer, and plant growth. A chemical-specific residue (CSR) model developed in a previous study was used as a sub-model to estimate the portion of endosulfan residues in soils ready to be absorbed by lettuce, and the accuracy of the CSR model was verified by properly estimating concentrations of endosulfan isomers in soils with different organic matters; a low mean deviation (18.8 %) was observed between the modeled and measured values. Modeled results of β-endosulfan using a soil–lettuce uptake model satisfactorily matched the experimentally measured results, with a moderate correlation (R2 > 0.79) and a low residual error (0.42) against a mean factor of −1.04. However, the uptake model showed the low potential to predict the soil–lettuce uptake of α-endosulfan (176.3 % mean deviation), probably due to not considering an intrinsic trait of β-isomer converting to α-isomer. Although the improvement with more sophisticated parameters is needed, the plant uptake model developed in this study could be utilized to predict soil–lettuce uptake of at least β-endosulfan and as a model template that may apply for other types of plants and contaminants.

Dissipation kinetics, residue modeling and human intake of endosulfan applied to okra (Abelmoschus esculentus)

The non-judicious application of the harmful pesticide endosulfan on okra, one of India's most consumed vegetable crops, has resulted in the frequent detection of residues in food samples. This can lead to resistance and the resurgence of various pests and diseases. In this context, combined dissipation and residue dynamics of different endosulfan components or mixtures (isomers and metabolites) in crop compartments are not yet well understood. To address this research gap, the present study evaluates the dissipation and persistence behavior of different endosulfan isomers (alpha-, beta-isomers) and major metabolite (endosulfan sulfate) on okra during 2017 and 2018. The half-life of endosulfan on okra leaves was found to be between 1.79 and 3.47 days. Half of the endosulfan deposits on okra fruits at the recommended doses were dissipated after 2.39 days compared to 1.99 days at double recommended doses (mean of 2017 and 2018 residue data). Measured endosulfan residues were evaluated against the dynamic plant uptake model dynamiCROP. The better fits were observed between modeled and measured residues for fruits (R2 from 0.84 to 0.96 and residual standard error (ER) between 0.6 and 1.47) as compared to leaves (R2 from 0.57 to 0.88). We also report fractions of endosulfan components ingested by humans after crop harvest. Intake fractions range from 0.0001–7.2 gintake/kg of applied pesticide. Our results can evaluate pesticide residues in different crops grown for human consumption, including their isomers and metabolites. They can be combined with dose-response information to evaluate human exposure and/or health risk assessment.

Development and application of a numerical dynamic model for pesticide residues in apple orchards.

Limited understanding of the fate of pesticides in apple orchards may lead to recurring pests or pose risks to food safety. In this study, through a field experiment conducted in an apple orchard, a dynamic plant uptake model, coupled with a soil water model, was developed to simulate measured pesticide concentrations in soil and different plant compartments. Results showed that the overall model could adequately describe the data set of four pesticides in the apple orchard. An estimated 15%-24.7% of applied pesticides were deposited on leaves and 0.37%-0.58% on fruits. Decreasing pesticide concentrations in fruits were observed after pesticide application, with 9.6%-64.8% of this decrease explained by biodegradation, 29.8%-75.8% by fruit growth dilution and 11.3%-47.6% by wash-off. Furthermore, a first estimation of dietary risks indicated that ingestion of the apples may not represent an acute or chronic risk to human health. The dynamic plant uptake model, coupled with the tipping buckets soil water model, could successfully be fitted to describe to the data set for the fate of four pesticides applied in an apple orchard. The contribution of different pathways to pesticide concentration was highly influenced by precipitation, fruit growth dilution and the characteristics of different pesticides. This model can improve our understanding of pesticide fate in apple orchards and has great potential for supporting food safety assessment and decision-making to minimize impacts arising from pesticide applications. © 2022 Society of Chemical Industry.

Modeling plant uptake of organic contaminants by root vegetables: The role of diffusion, xylem, and phloem uptake routes

The uptake of organic contaminants by root vegetables involves diffusion, transport by xylem and phloem saps, degradation, and volatilization. To understand the role of uptake and elimination routes in the bioconcentration modeling of organic contaminants, a two-compartment uptake model (root and leaf compartments) was proposed. The results showed that for the root compartment, logarithm values of bioconcentration factors (log BCF, the concentration ratio between plant tissues and soil) of chemicals fell within a narrow range when the logarithm of octanol-water partition coefficient (log KOW) was less than 3.0, whereas log BCF values decreased rapidly with increasing log KOW values when log KOW was greater than 3.0. This is because the diffusion route had a significant impact on the root uptake of chemicals, wherein the first-order rate constant dropped rapidly for high-lipophilicity chemicals, resulting in very low log BCF values. For the leaf compartment, chemicals with moderate lipophilicity (log KOW of 3.0–4.0) had the highest simulated log BCF values. This is because moderate log KOW values generated the highest transpiration stream concentration factors (TSCFs, the concentration ratio between xylem or phloem saps and water), resulting in high uptake efficiency of chemicals by leaves. Furthermore, we improved the uptake model by considering the surface-deposition route for pesticides (foliar spray), and the simulation results indicated that this uptake route cannot be neglected for lipophilic compounds. Although the simulations agreed with an experimental study and some reported data, future studies should focus on factors, such as plant physiology (plant varieties, periderm effects and compositions of xylem and phloem saps) and environmental conditions (soil properties and weather conditions), to improve the plant uptake model.

Modeling pesticide residues in nectar and pollen in support of pesticide exposure assessment for honeybees: A generic modeling approach

Pesticide residues in nectar and pollen of plants can damage honeybees; however, few modeling approaches have simulated residue levels in nectar and pollen in support of exposure assessment for honeybees. This study introduced a generic modeling approach based on plant uptake models and simple partitioning rules that specifies soil incorporation and foliar spray application scenarios of pesticides and is flexible for conducting variability analysis for various environmental conditions, pesticide application patterns, chemical individuals, and plant varieties. The results indicated that, in general, systemic or moderate lipophilicity (log KOW of ~2.5) pesticides have relatively high simulated residue levels in nectar and pollen because of the enhanced residue uptake process from soil. For non-systemic or highly lipophilic pesticides, the residue uptake via leaf surface deposition pathway can be enhanced, and more residues will be bioaccumulated in pollen than nectar due to a relatively high lipid content of pollen (as compared to nectar), but the overall residue levels in nectar and pollen are lower than systemic or moderately lipophilic pesticides. The variability analysis showed that environmental conditions, pesticide application patterns, chemical properties, and plant varieties cause considerable variations in simulated residue levels in nectar and pollen, indicating that spatiotemporal, chemical, and plant-related factors must be considered in pesticide exposure assessment for honeybees. Moreover, the comparison between the simulated and measured data showed a high degree of consistency, indicating that the proposed model could be used to conduct a screening-level pesticide exposure assessment for honeybees.

Improved plant bioconcentration modeling of pesticides: The role of periderm dynamics.

BACKGROUNDThere is a continuous need to advance pesticide plant uptake models in support of improving pest control and reducing human exposure to pesticide residues. The periderm of harvested root and tuber crops may affect pesticide uptake, but is usually not considered in plant uptake models. To quantify the influence of the periderm on pesticide uptake from soil into potatoes, we propose a model that includes an explicit periderm compartment in the soil–plant mass balance for pesticides.RESULTSOur model shows that the potato periderm acts as an active barrier to the uptake of lipophilic pesticides with high K OW, while it lets more lipophobic pesticides accumulate in the medulla (pulp). We estimated bioconcentration factors (BCFs) for over 700 pesticides and proposed parameterizations for including the effects of the periderm into a full plant uptake modeling framework. A sensitivity analysis shows that both the degradation half‐life inside the tuber and the lipophilicity drive the contributions of other aspects to the variability of BCFs, while highlighting distinct dynamics in the periderm and medulla compartments. Finally, we compare model estimates with measured data, showing that predictions agree with field observations for current‐use pesticides and some legacy pesticides frequently found in potatoes.CONCLUSIONConsidering the periderm improves the accuracy of quantifying pesticide uptake and bioconcentration in potatoes as input for optimizing pest control and minimizing human exposure to pesticide residues in edible crops.

Model-based analysis of the uptake of perfluoroalkyl acids (PFAAs) from soil into plants.

Perfluoroalkyl acids (PFAAs) bioaccumulate in crops, with uptake being particularly high for short-chain PFAAs that are constantly transported with transpiration water to aerial plant parts. Due to their amphiphilic surfactant nature and ionized state at environmental pH, predicting the partitioning behavior of PFAAs is difficult and subject to considerable uncertainty, making experimental data highly desirable. Here, we applied a plant uptake model that combines advective flux with measured partition coefficients to reproduce the set of empirically derived plant uptake and soil-partitioning data for nine PFAAs in red chicory, in order to improve the mechanistic understanding and provide new insights into the complex uptake processes. We introduced a new parameter for retarded uptake (R) to explain the slow transfer of PFAA across biomembranes of the root epidermis, which has led to low transpiration stream concentration factors (TSCFs) presented in literature so far. We estimated R values for PFAAs using experimental data derived for red chicory and used the modified plant uptake model to simulate uptake of PFAA into other crops. Results show that this semi-empirical model predicted PFAAs transport to shoots and fruits with good accuracy based on experimental root to soil concentration factors (RCFdw) and soil to water partition coefficients (Kd) as well as estimated R values and plant-specific data for growth and transpiration. It can be concluded that the combination of rather low Kd with high RCFdw and the absence of any relevant loss are the reason for the observed excellent plant uptake of PFAAs.

Modeling the Translocation and Transformation of Chemicals in the Soil‐Plant Continuum: A Dynamic Plant Uptake Module for the HYDRUS Model

AbstractFood contamination is responsible for thousands of deaths worldwide every year. Plants represent the most common pathway for chemicals into the human and animal food chain. Although existing dynamic plant uptake models for chemicals are crucial for the development of reliable mitigation strategies for food pollution, they nevertheless simplify the description of physicochemical processes in soil and plants, mass transfer processes between soil and plants and in plants, and transformation in plants. To fill this scientific gap, we couple a widely used hydrological model (HYDRUS) with a multicompartment dynamic plant uptake model, which accounts for differentiated multiple metabolization pathways in plant's tissues. The developed model is validated first theoretically and then experimentally against measured data from an experiment on the translocation and transformation of carbamazepine in three vegetables. The analysis is further enriched by performing a global sensitivity analysis on the soil‐plant model to identify factors driving the compound's accumulation in plants' shoots, as well as to elucidate the role and the importance of soil hydraulic properties on the plant uptake process. Results of the multilevel numerical analysis emphasize the model's flexibility and demonstrate its ability to accurately reproduce physicochemical processes involved in the dynamic plant uptake of chemicals from contaminated soils.

Multi-criteria decision analysis of optimal planting for enhancing phytoremediation of trace heavy metals in mining sites under interval residual contaminant concentrations

As one of the most cost-effective and sustainable methods for contaminants' removal, sequestration and/or detoxification, phytoremediation has already captured comprehensive attention worldwide. Nevertheless, the accurate effects of various spatial pattern in enhancing phytoremediation efficiency is not yet clear, especially for the polluted mining areas. This study designed nine planting patterns (monocropping, double intercropping and triple intercropping) of three indigenous plant species (Setaria viridis (L.), Echinochloa crus-galli (L.) and Phragmites australis (Cav.) Trin. ex Steud.) to further explore the effects of plants spatial pattern on phytoremediation efficiency. Considering the uncertainties of the residual contaminants' concentration (RCC) caused by soil anisotropy, permeability and land types, the interval transformation was introduced into the plant uptake model to simulate the remediation efficiency. Then multi-criteria decision analysis (MCDA) were applied to optimal the planting patterns, with the help of criteria of (a) the amount of heavy metal absorption; (b) the concentration of residual contaminant in soil; (c) root tolerance of heavy metals; (d) the total investment cost. Results showed that (1) the highest concentrations of Zn, Cd, and Pb of the polluted area were 7320.02, 14.30, 1650.51 mg kg−1 (2) During the 180 days simulation, the highest RMSE of residue trace metals in soil are 3.02(Zn), 2.67(Pb), 2.89(Cd), respectively. (3) The result of IMCDA shows that the planting patterns of Setaria viridis, Echinochloa crus-galli and Phragmites australis in alternative a9 (269 mg kg−1 year−1) had the highest absorption rate of heavy metals compared with a7 (235 mg kg−1 year−1) and a2 (240 mg kg−1 year−1). After 20 years of remediation, the simulated RCC in a9 is far below the national standard, and the root toxicity is 0.12 (EC ≤ EC20). In general, the optimal alternative derived from interval residual contaminant concentration can effectively express the dynamic of contaminant distribution and then can be effectively employed to evaluate the sustainable remediation methods.

Dynamic modeling of famoxadone and oxathiapiprolin residue on cucumber and Chinese cabbage based on tomato and lettuce archetypes.

We analyzed the uptake and distribution of two pesticides (famoxadone and oxathiapiprolin) in herbaceous vegetables (cucumber and tomato) and leafy vegetables (Chinese cabbage and lettuce) to test the viability of applying existing archetypes in the dynamic plant uptake model dynamiCROP to modeling pesticide residue in other crops. Using field data and modeling, we showed that tomato was an unsuitable match for cucumber (R2 of 0.5325-0.6862) though lettuce was a good fit for Chinese cabbage (R2 of 0.8649-0.8862). We then used our cucumber data to add this as a new crop species archetype in dynamiCROP; further tests proved the accuracy of this approach (R2 of 0.8097-0.9152). In addition, we analyzed the distribution, uptake, and translocation of the two pesticides in cucumber and Chinese cabbage, using the model to better understand the mechanisms of pesticide residues over time and evaluate potential human exposure to pesticide residues from consumption of these crops. The fractions of famoxadone and oxathiapiprolin eventually ingested by humans based on our field trials ranged from 10-4 to 10-3 kg intake kg applied-1; that is, per kilogram of pesticide applied, humans would eventually consume less than one gram.