Use-Exposure Relationships of Pesticides for Aquatic Risk Assessment

Luo, Yuzhou; Spurlock, Frank; Deng, Xin; Gill, Sheryl; Goh, Kean S.

doi:10.1371/journal.pone.0018234

Cited by 13 publications

(11 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Examples of the first type are the dispersion of particles and movement through air, which can be modelled by AgDRIFT [77] and Gaussian models [78], soil erosion and sedimentation of runoff [79] and leaching of water-soluble fractions into the soil profile, e.g. Pesticide Root-Zone Model (PRZM) [80] and others [81]. By contrast, multimedia models such as fugacity [82] aim at predicting the concentrations of chemicals in all environmental media.…”

Section: Exposure Assessmentmentioning

confidence: 99%

Environmental Risk Assessment of Agrochemicals — A Critical Appraisal of Current Approaches

Sánchez‐Bayo¹,

Tennekes²

2015

Toxicity and Hazard of Agrochemicals

View full text Add to dashboard Cite

This chapter provides insights into the difficulties and challenges of performing risk evaluations of agrochemicals. It is a critical review of the current methodologies used in ecological risk assessment of these chemicals, not their risks to humans. After an introduction to the topic, the current framework for ecological risk assessment is outlined. Two types of assessments are typically carried out depending on the purpose: i) regulatory assessments for registration of a chemical product; and ii) ecological assessments, for the protection of both terrestrial and aquatic ecosystems, which are usually site-specific. Although the general framework is well established, the methodologies used in each of the steps of the assessment are fraught with a number of shortcomings. Notwithstanding the subjectivity implicit in the evaluation of risks, there is scepticism in scientific circles about the appropriateness of the current methodologies because, after so many years of evaluations, we are still incapable of foreseeing the negative consequences that some agrochemicals have in the environment. A critical appraisal of such methodologies is imperative if we are to improve the current assessment process and fix the problems we face today. The chapter reviews first the toxicity assessment methods, pointing to the gaps in knowledge about this essential part of the process and suggesting avenues for further improvement. Deficiencies in the current regulations regarding toxicity testing are discussed, in particular the effect of the time factor on toxicity and the issue of complex mixtures.

show abstract

Section: Exposure Assessmentmentioning

confidence: 99%

Environmental Risk Assessment of Agrochemicals — A Critical Appraisal of Current Approaches

Sánchez‐Bayo¹,

Tennekes²

2015

Toxicity and Hazard of Agrochemicals

View full text Add to dashboard Cite

show abstract

“…Monitoring studies in California showed that the worst‐case exposure concentrations were usually detected in small, static to semi‐static water bodies. For example, in California's Central Valley, one of the nation's most productive agricultural areas, monitoring concentrations are substantially higher in small creeks dominated by irrigation return flows, as compared with larger streams that receive dilution flow from nontreated areas and nonagricultural headwaters (Domagalski and Munday, 2003; Luo et al, 2011). In another study, the Pyrethroid Working Group compiled and analyzed the pyrethroids monitoring data available in the United States and showed that the highest dissolved concentrations detected in agricultural sites were all found in tailwater ditches in California (USEPA, 2016b).…”

Section: Resultsmentioning

confidence: 99%

Regulatory Modeling of Pesticide Aquatic Exposures in California's Agricultural Receiving Waters

et al. 2018

Self Cite

View full text Add to dashboard Cite

For the aquatic exposure assessment of pesticides, the USEPA uses the Variable Volume Water Model (VVWM) to predict the estimated environmental concentrations (EECs) of a pesticide in a water body that receives runoff inputs from the Pesticide Root Zone Model (PRZM). The standard farm pond and additional generalized static and flowing water bodies used in endangered species assessment (aquatic bins) are used by USEPA to model the worst‐case aquatic exposure for the nationwide exposure assessment. However, whether or not model results are relevant to state‐specific conditions has not been validated. In this study, the USEPA water body scenarios are examined for their capability of providing a conservatively realistic estimate of pesticide aquatic exposures in California's agricultural settings. The sensitivity of modeled EECs to key water body parameters (dimensions, flow, and mass transfer) was explored with a one‐at‐a‐time approach by using the standard farm pond as a baseline. The EECs generated from different USEPA water bodies for the worst‐case loading were compared with the monitoring data observed in California's agriculturally influencing water bodies. Results showed that the farm pond EECs well captured the worst‐case monitoring data, whereas the aquatic bins EECs, especially the flowing bins, tended to overestimate data. The conceptual model of the standard farm pond was also found to be relevant to the highly vulnerable water bodies in California's agricultural areas. The study confirms that VVWM with the standard farm pond scenario is appropriate for the screening‐level regulatory exposure assessment in California's agricultural settings. Core Ideas Protectiveness of exposure modeling with the USEPA farm pond is verified in California. The sensitivity of model results to key water body parameters is explored. The USEPA farm pond well captures worst‐case exposure in California's agricultural settings. The farm pond better reproduces the worst‐case monitoring data than endangered species bins.

show abstract

“…Historically, research models such as RZWQM and Opus were criticized for having high input requirements (Engel et al, 1993; Luo et al, 2011). As environmental data are becoming more accessible to the public, it has become easier to obtain data for many of parameters in these models.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of Three Models for Simulating Pesticide Runoff from Irrigated Agricultural Fields

Zhang

Goh

2015

J. Environ. Qual.

View full text Add to dashboard Cite

Three models were evaluated for their accuracy in simulating pesticide runoff at the edge of agricultural fields: Pesticide Root Zone Model (PRZM), Root Zone Water Quality Model (RZWQM), and OpusCZ. Modeling results on runoff volume, sediment erosion, and pesticide loss were compared with measurements taken from field studies. Models were also compared on their theoretical foundations and ease of use. For runoff events generated by sprinkler irrigation and rainfall, all models performed equally well with small errors in simulating water, sediment, and pesticide runoff. The mean absolute percentage errors (MAPEs) were between 3 and 161%. For flood irrigation, OpusCZ simulated runoff and pesticide mass with the highest accuracy, followed by RZWQM and PRZM, likely owning to its unique hydrological algorithm for runoff simulations during flood irrigation. Simulation results from cold model runs by OpusCZ and RZWQM using measured values for model inputs matched closely to the observed values. The MAPE ranged from 28 to 384 and 42 to 168% for OpusCZ and RZWQM, respectively. These satisfactory model outputs showed the models' abilities in mimicking reality. Theoretical evaluations indicated that OpusCZ and RZWQM use mechanistic approaches for hydrology simulation, output data on a subdaily time-step, and were able to simulate management practices and subsurface flow via tile drainage. In contrast, PRZM operates at daily time-step and simulates surface runoff using the USDA Soil Conservation Service's curve number method. Among the three models, OpusCZ and RZWQM were suitable for simulating pesticide runoff in semiarid areas where agriculture is heavily dependent on irrigation. Evaluation of Three Models for Simulating Pesticide Runoff from Irrigated Agricultural FieldsXuyang Zhang* and Kean S. Goh O ff-site movement of pesticides from applied agricultural areas has been recognized as one of the major contributors to the contamination of surface waters worldwide (Schulz, 2004;Gangbazo, 1999;Humenik et al., 1987;Line et al., 1997;Loague, 1998). Pesticides move into surface water via drift, surface runoff, or subsurface flow. Among these routes, surface runoff generated by rainfall events has attracted the most attention (Schulz, 2004). In semiarid regions, such as California, pesticide runoff occurs not only during the rainy season but also during the dry growing season between March and October when the crops are irrigated and pesticides are applied. Surface runoff generated by irrigation events has been identified as a major cause for the detection of pesticides in agricultural areas of California during the dry season (Starner et al. 2005;Starner, 2009;Foe, 1995).To assess the ecological risks of pesticides in surface water, mathematical models that predict exposure to pesticides have been increasingly used in addition to water quality monitoring. Prediction of pesticide loss at the edge of a field is fundamental to exposure assessment both at local and watershed scales. In agricultural lands, field applicatio...

show abstract

Use-Exposure Relationships of Pesticides for Aquatic Risk Assessment

Cited by 13 publications

References 18 publications

Environmental Risk Assessment of Agrochemicals — A Critical Appraisal of Current Approaches

Environmental Risk Assessment of Agrochemicals — A Critical Appraisal of Current Approaches

Regulatory Modeling of Pesticide Aquatic Exposures in California's Agricultural Receiving Waters

Evaluation of Three Models for Simulating Pesticide Runoff from Irrigated Agricultural Fields

Contact Info

Product

Resources

About