EFFECT OF SULFOMETURON METHYL ON GROUND WATER AND STREAM QUALITY IN COASTAL PLAIN FOREST WATERSHEDS¹

Abstract

Sulfometuron methyl [methyl 2‐[[[[4,6‐dimethly 2‐(pyrimidinyl) a‐mino] carbony l]amino] sulfonyl] benzoate] was applied by a ground sprayer at a maximum labeled rate of 0.42 kg ha‐1 a.i. to a 4 ha Coastal Plain flatwoods watershed as site preparation for tree planting. Herbicide residues were detected in Streamflow for only seven days after treatment and did not exceed 7 mg m‐3. Sulfometuron methyl was not detected in any stormflow and was not found in any sediment (both bedload and suspended). Sampling of a shallow ground water aquifer, > 1.5 m below ground surface, did not detect any sulfometuron methyl residues for 203 days after herbicide application. Lack of herbicide residue movement was attributed to low application rates, rapid hydrolysis in acidic soils and water and dilution in streamflow.

Herbicide dissipation studies in southern forest ecosystems

“…Both injection and spot treatment, very popular methods of competition control on National Forest and small nonindustrial, private forest, landowner lands, are thought to be similar in terms of environmental safety. To test this hypothesis a large research project was established to compare stream contamination for the two methods (sites 2-7 and [14][15][16][17][18][19]. Hexazinone, a soil-active herbicide, was applied as the liquid formulation (L) containing 0.24 kg active ingredient (ai.)…”

“…Furthermore, a lack of knowledge of the site-specific behavior of herbicides hinders development of mitigating management practices. This paper summarizes the findings of several studies that monitored the environmental fate of forestry herbicides in the southern United States (Table 3*), but it focuses on the highlights of three large research projects: a comparison of off-site movement of a herbicide used for single-stem injection (picloram, sites [14][15][16][17][18][19] and a herbicide used for "spot treatment" (hexazinone, sites 2-7); an environmental fate study on imazapyr that compared off-site movement from two similar sites, but with and without stream protection via an untreated buffer strip streamside management zone (SMZ); and a study to compare the dissipation of sulfometuron methyl in two formulations on adjacent plots and from two very dissimilar sites, all with streamside protection (sites 22-23).…”

Environmental Fate and Impacts of Sulfometuron on Watersheds in the Southern United States

“…Simulated rainfall (69 mm h −1 , total < 30 mm) within 24 h of herbicide application produced runoff concentrations up to 700 μg L −1 They also reported that grass‐covered plots yielded the same total offsite movement as observed from bareground plots, indicating that most offsite movement occurred in overland flow as a result of the high‐intensity rainfall simulation. Concentrations of SM in runoff from the agricultural applications and simulated rainfall of Hubbard et al (1989) and Wauchope et al (1990) are 142‐ and 100‐fold (respectively) greater than values reported by Neary and Michael (1989) for natural rainfall on treated forest sites.…”

“…The fate of sulfonylurea herbicides has been reviewed (Blair and Martin, 1988). Neary and Michael (1989) monitored a 4‐ha watershed on deep sandy soil in Florida treated with SM at the rate of 0.42 kg a.i. ha −1 , and found offsite movement for only 7 DAT.…”

Effects of the herbicide imazapyr on benthic macroinvertebrates in a logged pond cypress dome

“…Because of concern over potential herbicide contamination of surficial water, many herbicide fate studies have been conducted in southern pine forests [1][2][3]. Michael and Neary [4] and Neary et al [5] reviewed literature on herbicide fate, dissipation, and environmental effects and found that few studies had examined herbicide toxicity on aquatic biota.…”