Nontarget Deposition and Losses of Chlorothalonil in Irrigation Runoff Water from a Commercial Foliage Plant Nursery

Abstract

Commercial foliage plant production requires the use of pesticides for controlling pests and pathogens that can reduce aesthetic qualities of crops, rendering them unwanted by consumers. Chlorothalonil is a common, broad-spectrum, foliar fungicide used for protecting plants from a variety of fungal diseases. This fungicide may also be acutely toxic to nontarget aquatic organisms due to its mode of action. This study evaluated the amount of chlorothalonil deposited on nontarget ground surfaces during normal sprayer applications at a commercial nursery using Teflon targets. One day following application, irrigation runoff events were initiated and runoff water samples were collected and analyzed for chlorothalonil. Discharge volumes were also measured to allow estimation of the total mass of chlorothalonil discharged during each event. Results indicated that 9.8 to 53.6% of the active ingredient applied landed on nontarget ground surfaces depending on plant size, spacing, and row lengths (short rows sprayed from one side vs. longer rows sprayed from both ends). On an entire production-area scale, 29.2% of the active ingredient applied was deposited on ground surfaces. Of the total nontarget deposition, 0.25 to 0.53% was detected in runoff water discharged from the production area. Concentrations ranged from 1.2 to 500 microg/L during the first runoff events following application.

Diffusing Water Conservation and Treatment Technologies to Nursery and Greenhouse Growers

“…Although the volume of water and application efficiency are vitally important to conserving water, water quality experts are also concerned about the presence of pathogens and agrichemicals in irrigation runoff from these same operations (Raudales, Parke, Guy, & Fisher, 2014;White, 2013b;Wilson, Riiska, & Albano, 2010). For example, in the U.S. there is a concern that contaminated water could impact plant communities in areas such as the Florida Everglades, the Chesapeake Bay watershed, the Great Lakes Basin, and the San Francisco Bay (White, 2013a;Wilson & Boman, 2011;Wilson & Foos, 2006).…”

Field studies of pollutant removal from nursery and greenhouse runoff by constructed wetlands

“…Influent concentrations of some pesticides, nitrate, and phosphorus are an order of magnitude lower than those found in other studies of nursery runoff in bedding plant nurseries (Briggs, Whitwell, & Riley, ; White, Taylor, Chandler, Whitwell, & Klaine, ; Wilson et al., ) (Tables and ).…”

“…Pesticide concentrations in pot leachate can be toxic to aquatic organisms (Graves, Vogel, Belden, Rebek, & Simpson, ). For example, Wilson, Riiska, and Albano () found that 29% of chlorothalonil application in a nursery setting was deposited on the ground surface instead of in pots, which led to concentrations up to 500 μg L −1 in runoff, a level toxic to aquatic microorganisms (e.g., 96‐h LC 50 , the concentration that will kill half of a test population, for adult grass shrimp is 150 μg L −1 according to Key, Meyer, & Chung, ). Excess nutrients lead to algal blooms and are an ongoing challenge in both agricultural and urban runoff (Anderson, Gilbert, & Burkholder, ; Kandel, Vogel, Penn, & Brown, ; Paerl et al., ; Smith, ; Smith, King, & Williams, ; Watson et al., ).…”

Testing An Adoption Decision-Making Model of Nursery and Greenhouse Growers’ Water Reuse in the United States

“…Bixio et al [9] argued the limited adoption of treatment technologies stems from their costs and maintenance requirements, which are prohibitive for many growers. Others [6,7,10,11] have argued that grower adoption of water treatment systems is constrained by the risks associated with phytopathogen transfer if technologies do not work consistently and efficiently. Furthermore, few studies have conducted a systematic analysis of how nursery and greenhouse growers make decisions about adopting or not adopting water treatment technologies, and what specific cognitive and social factors play a role in these processes.…”