Pesticide and toxicity reduction using an integrated vegetated treatment system

Abstract

The California, USA, central coast is one of the most productive agricultural areas in the world, and numerous stakeholders are working there to implement conservation practices to reduce contaminated runoff. Practices include vegetated treatment systems (VTS) designed to promote contaminant reduction and breakdown. The current study evaluated the effectiveness of a vegetated drainage ditch incorporating a sedimentation basin, a vegetated section, and a Landguard organophosphate-A (OP-A) enzyme dosing system. The VTS was constructed on a working farm and was designed to remove organophosphate and pyrethroid pesticides, the primary pesticides causing toxicity in Salinas Valley watersheds. The present study was conducted during five separate irrigation events on tailwater runoff containing mixtures of pesticides and suspended sediments. Water samples were collected at four stations within the system, and these were subjected to chemical analyses and tested for toxicity to Ceriodaphnia dubia. All inflow samples were highly toxic to C. dubia, and this was largely because of diazinon. Treatment of diazinon-contaminated runoff was only partially effective using aquatic vegetation. All diazinon remaining after vegetated treatment was effectively removed after treatment with the Landguard OP-A enzyme. Chemical analysis of the VTS water samples showed that pyrethroid and organochlorine pesticide concentrations in water were greatly reduced in the sedimentation section of the ditch, and these pesticides were further reduced in the vegetated section of the ditch. The overall conclusion from these analyses is that the VTS was effective at reducing the more hydrophobic organochlorine and pyrethroid pesticides from water. The water-soluble pesticide diazinon was not sufficiently removed during the VTS residence times observed in this study; however, residual diazinon was effectively removed using Landguard OP-A.

An integrated vegetated ditch system reduces chlorpyrifos loading in agricultural runoff

“…The target chlorpyrifos dose was approximately 2600 ng/L. Flow rates and target chlorpyrifos concentrations used in the Year 1 and 2 trials were within the ranges previously measured in local irrigation runoff (Anderson et al ; Phillips et al ).…”

“…Although these systems reduce pesticides, vegetation alone is only partially effective for OPs. Integrated vegetated treatment systems consisting of multiple treatment areas or installations can provide additional pesticide reduction, and the use of the Landguard™ enzyme can remove residual OP concentrations (Anderson et al ; Phillips et al ). Landguard is effective but not currently available to growers and its future commercial availability is uncertain.…”

The use of constructed wetlands for removal of pesticides from agricultural runoff and drainage: A review

“…Bennett et al (2005) pointed out that historically, the values and function of agricultural ditches have been ignored except for occasional dredging to remove built-up sediments and plants impeding efficient drainage. Recently, it has been shown in several studies that agricultural ditches with wetland vegetation may be useful traps for commonly used pesticides (Moore et al, 2001a(Moore et al, , 2008Bennett et al, 2005;Roessink et al, 2005;Dabrowski et al, 2006;Gill et al, 2008;Rogers and Stringfellow, 2009;Anderson et al, 2011).…”

Environmental Factors, Oxidative Stress, and Adverse Developmental Outcomes

“…Maternal exposure to pesticides is well known to adversely affect prenatal development and birth outcomes (Sharp and Eskenazi 1986). Soil and groundwater contamination from agricultural runoff (Bengtsson et al 2007;Anderson et al 2011 contaminated by pesticides, particularly insecticides, as a result of treatments of many crops (Keikotlhaile et al 2010). Aquatic habitats throughout the world receive great amounts of environmental pollutants due to increasing industrial and agricultural activities, as well as human waste (Valavanidis et al 2006).…”