Persistence of endothall in aquatic environment as determined by gas-liquid chromatography

Review of USACE-Generated Efficacy and Dissipation Data for the Aquatic Herbicide Formulations Aquathol(R) and Hydrothol(R). Aquatic Plant Control Research Program

“…Conversion was via the tricarboxylic acid cycle and an alternate, unidentified pathway (Sikka and Saxena 1973). Additional work demonstrated microbial degradation of endothall in pond water, and in aquaria in the laboratory using water and hydrosoil from the same pond (Sikka and Rice 1973). A half-life of approximately 6 days is calculable from the pond data, while aquaria showed much faster degradation, with an average half-life of 0.9 day for aquaria treated with 2 and 4 ppm endothall.…”

Fate and persistence of aquatic herbicides

“…A Kp value of approximately 0.4 was calculated from the data presented by Sikka and Rice (1973) in which a Syracuse, NY, farm pond was treated with dipotassium endothall. Therefore, sorption would not be considered a significant environmental fate process for endothall in the environments studied.…”

Advances in Microbial Ecology

“…The reduced lag may have resulted because the microcosms were established originally with pond water and sediment taken from a control pond that was different from the dosed pond. The latter had been previously (12 months earlier) exposed to endothall (Sikka and Rice, 1973). The other differences might be attributable to an approximate 9-fold difference in sediment surface area/water volume ratio between pond and microcosm and possibly slow mixing in the pond.…”

“…For aquatic studies, Pritchard et al (1979) used a 3.5-cm-diameter glass tube containing 200 ml water, in contrast to Perez et al (1977) and Harte et al (1980), who used glass tanks containing 150 and 200 liters, respectively. Quite commonly, 20-gallon aquaria have been used with considerable success (Giddings and Eddleman, 1978;Sikka and Rice, 1973). Long fiberglass troughs, approximately 30 cm square and 6 to 12 m long (S. R. Hansen and Garton, 1982;McIntire, 1965), have been used to model streams.…”

“…Several studies indicate differences in biodegradation rates between the laboratory and the field; such examples could be examined further to determine what factors in microcosm design or operation were responsible for these differences. Sikka and Rice (1973), for example, compared the fate of the herbicide endothall in a farm pond and a laboratory aquarium microcosm. Their results are shown in Fig.…”