An integrated vegetated ditch system reduces chlorpyrifos loading in agricultural runoff
- 29 August 2016
- journal article
- research article
- Published by Wiley in Integrated Environmental Assessment and Management
- Vol. 13 (2), 423-430
- https://doi.org/10.1002/ieam.1820
Abstract
Agricultural runoff containing toxic concentrations of the organophosphate pesticide chlorpyrifos has led to impaired water body listings and total maximum daily load restrictions in California's central coast watersheds. Chlorpyrifos use is now tightly regulated by the Central Coast Regional Water Quality Control Board. This study evaluated treatments designed to reduce chlorpyrifos in agricultural runoff. Initial trials evaluated the efficacy of 3 different drainage ditch installations individually: compost filters, granulated activated carbon (GAC) filters, and native grasses in a vegetated ditch. Treatments were compared to bare ditch controls, and experiments were conducted with simulated runoff spiked with chlorpyrifos at a 1.9 L/s flow rate. Chlorpyrifos concentrations and toxicity to Ceriodaphnia dubia were measured at the input and output of the system. Input concentrations of chlorpyrifos ranged from 858 ng/L to 2840 ng/L. Carbon filters and vegetation provided the greatest load reduction of chlorpyrifos (99% and 90%, respectively). Toxicity was completely removed in only one of the carbon filter trials. A second set of trials evaluated an integrated approach combining all 3 treatments. Three trials were conducted each at 3.2 L/s and 6.3 L/s flow rates at input concentrations ranging from 282 ng/L to 973 ng/L. Chlorpyrifos loadings were reduced by an average of 98% at the low flow rate and 94% at the high flow rate. Final chlorpyrifos concentrations ranged from nondetect (<50 ng/L) to 82 ng/L. Toxicity to C. dubia was eliminated in 3 of 6 integrated trials. Modeling of the ditch and its components informed design alterations that are intended to eventually remove up to 100% of pesticides and sediment. Future work includes investigating the adsorption capacity of GAC, costs associated with GAC disposal, and real-world field trials to further reduce model uncertainties and confirm design optimization. Trials with more water-soluble pesticides such as neonicotinoids are also recommended. Integr Environ Assess Manag 2017;13:423-430. © 2016 SETAC.Keywords
Funding Information
- California Department of Pesticide Regulation
This publication has 15 references indexed in Scilit:
- Diazinon and Permethrin Mitigation Across a Grass–Wetland BufferBulletin of Environmental Contamination and Toxicology, 2014
- Sorption and degradation of petroleum hydrocarbons, polycyclic aromatic hydrocarbons, alkylphenols, bisphenol A and phthalates in landfill leachate using sand, activated carbon and peat filtersWater Research, 2014
- Test of significant toxicity: A statistical application for assessing whether an effluent or site water is truly toxicEnvironmental Toxicology and Chemistry, 2011
- Use of vegetated agricultural drainage ditches to decrease pesticide transport from tomato and alfalfa fields in California, USAEnvironmental Toxicology and Chemistry, 2011
- Pesticide and toxicity reduction using an integrated vegetated treatment systemEnvironmental Toxicology and Chemistry, 2011
- Parameter Importance and Uncertainty in Predicting Runoff Pesticide Reduction with Filter StripsJournal of Environmental Quality, 2010
- Evaluating the influence of wetland vegetation on chemical residence time in Mississippi Delta drainage ditchesAgricultural Water Management, 2009
- Mitigation Assessment of Vegetated Drainage Ditches for Collecting Irrigation Runoff in CaliforniaJournal of Environmental Quality, 2008
- Model Evaluation Guidelines for Systematic Quantification of Accuracy in Watershed SimulationsTransactions of the ASABE, 2007
- Joint acute toxicity of diazinon and chlorpyrifos toCeriodaphnia dubiaEnvironmental Toxicology and Chemistry, 1997