Premium
Fate and acute toxicity of bromoxynil esters in an experimental prairie wetland
Author(s) -
Muir D. C. G.,
Kenny D. F.,
Grift N. P.,
Robinson R. D.,
Titman R. D.,
Murkin H. R.
Publication year - 1991
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620100312
Subject(s) - bromoxynil , hyalella azteca , toxicity , zoology , chemistry , acute toxicity , phenol , environmental chemistry , biology , agronomy , ecology , crustacean , organic chemistry , amphipoda , weed control
The partitioning, degradation and toxicity of a single spray application of a 1:1 mixture of bromoxynil octanoate (BO) and bromoxynil butyrate (BB) were studied in fifteen 0.01‐ha ponds located in the Delta marsh area of Manitoba. Intensive sarnpling of two ponds treated at 2.5 μg/L and two treated at 50 μg/L (nominal concentrations) showed that BO and BB persisted in the surface microlayer (0–1 mm) of the water at levels 50‐ to 100‐fold higher than the intended treatment level, with half‐lives of 0.8 to 2.5 h. In subsurface waters (10–20 cm depth) the major forms of the herbicide were bromoxynil‐phenol and its monobromo‐ analog (3‐bromo‐4‐hydroxybenzonitrile; MBBP). Half‐lives of the phenol averaged 9.2 d in ponds treated at 50 μg/L and 14.5 d in those receiving 2.5 μg/L. Low ng/g (dry wt.) levels of BO, BB, MBBP and bromoxynil‐phenol were present in bottom sediments (0–2 cm depth) during the first 15 d posttreatment and declined to near detection limits (<0.5 ng/g) by 120 d after spray application. Complete mortality of brook sticklebacks ( Culaea inconstans ), held in cages in subsurface waters, occurred within 24 h at the two highest treatment levels (nominal concentrations of 100 and 500 μg/L). Mortality of caged Hyalella azteca at the highest dose levels ranged from 85 to 95% at 50 h.