Soil and Herbicide Properties Influenced Mobility of Atrazine, Metolachlor, and Primisulfuron‐Methyl in Field Lysimeters

Abstract

Understanding herbicide mobility in soils is necessary to prevent groundwater contamination. We studied the mass balance distribution of three 14C‐labeled herbicides (atrazine, metolachlor, and primisulfuron‐methyl) in four soils (Dothan, Portsmouth, Rion, and Wagram) 128 d after application to soil column field lysimeters. Analyses were made of surface soil, subsoil, and leachate samples, and metabolites were identified in surface soil and leachate. Our objectives were to examine, measure, and correlate the leaching patterns of the chemicals and correlate their leaching characteristics with the physicochemical properties of the soils. Metolachlor was the most mobile herbicide as indicated by the retardation factor (Rf) (Rf = 0.35 in 1992 and 0.17 in 1993), followed by atrazine (Rf = 0.19 in 1992 and 0.09 in 1993) and primisulfuron‐methyl (Rf = 0.15 in 1992 and 0.12 in 1993). Herbicide mobility (Rf) was related to leachate volume collected from the four soils, herbicide aqueous solubility, and longevity of the chemicals. The herbicides were of greatest mobility in Rion and Wagram soils and of lowest mobility in Portsmouth and Dothan soils. Soil factors affected the weakly basic atrazine differently than the nonionizable metolachlor or the weakly acidic primisulfuron‐methyl. Volatility losses of the herbicides were inversely related to longevity (disappearance time in the field (DT50) of the compounds and to humic matter contents of the soils. Carbon‐14 herbicide in the subsoil and in the leachate was correlated with herbicide mobility (Rf), total leachate volume, and 50% disappearance time values. Herbicide mobility was in agreement with predictability using a simple decision‐aid model.

Leaching of the S-metolachlor herbicide associated with paraquat or glyphosate in a no-tillage system

“…In general, it is known that the leaching of metolachlor depends on factors such as the occurrence and intensity of rainfall or irrigation, temperature and soil surface area, as well as humic acid, clay and organic matter content in the soil (Patakioutas & Albanis 2002, Weber et al 2006a, Baran & Gourcy 2013, Long et al 2014). However, mathematical models demonstrate that metolachlor has leaching potential (Inoue et al 2003).…”

Ecologically sustainable weed management: How do we get from proof‐of‐concept to adoption?

“…In terrestrial systems, herbicides can move from sites of application via surface water runoff, groundwater leaching, aerial drift, and volatilization (Prueger et al 2005, Shipitalo and Owens 2006, Weber et al 2006, Gish et al 2012. Depending on the particular materials used, application methods, and specific environmental conditions (e.g., soil and hydrogeological characteristics, precipitation patterns, wind speed, and topography), the scale of herbicide transport can range from centimeters to kilometers.…”

Application of Ultrasound‐Assisted Supercritical Extraction to Soil Remediation

“…Although SFE with CO 2 is considered an environmentally friendly remediation technique , the use of organic co‐solvents is a major drawback to its application. Supercritical extraction with CO 2 has been successfully applied to the removal of a great variety of contaminants from soils, even those most resistant to treatment, such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) . SFE has also been used by the Environmental Protection Agency (EPA) as an analytical technique to determine the contents of PAHs and total petroleum hydrocarbons (TPH) in soils.…”