Toxicity herbicides

Suleiman, S.A. and J.B. Stevens. 1987. Bipyridylium herbicide toxicity effects of paraquat and diquat on isolated rat hepatocytes. Jour. Environ. Pathol. Toxicol. Oncol. 7 73-84. 

Wong, R.C. and J.B. Stevens. 1986. Bipyridilium herbicide toxicity in vitro comparative study of the cytotoxicity of paraquat and diquat toward the pulmonary alveolar macrophage. Jour. Toxicol. Environ. Health 18 393-407. 

Call, D.J., Brooke, L.T., Kent, R.J., Knuth, M.L., Poirier, S.H., Huot, J.M., Lima, A.R. (1987) Bromacil and diuron herbicides Toxicity, uptake, and elimination in freshwater fish. Arch. Environ. Contam. Toxicol. 16, 607-613. 

Metosulam (198) was C-radiolabeled in the 2-position or in the benzene ring by modified synthetic routes (97MI6). This way data on the pharmacokinetics in mammals could be provided (97MI4). Flumetsulam (197) was toxicologically examined (03MI5) and included in QSAR studies of herbicide toxicity (06BMC2779). 

Nalewaja JD and Matysiak R Spray carrier salts affect herbicide toxicity to kochia (Kochia scoparia), Weed Technology 7(1) 154-8 (1993). 

Pharmacol. Rev. 14, 225 (1962), use Selective herbicide. Toxicity Inhalation hazard is low in humans. Acutely poisoned sheep and cattle show muscular spasms, fasciculations, stiff gait, increased respiratory rates. Adrenal degeneration, congestion of lungs, liver, kidneys observed. No apparent skin irritation or other toxic manifestations in humans Clinical Toxicology of Commercial Products, R. E. Gosselin et al. Eds. (Williams Wilkins, Baltimore, 4th ed., 1976) Section II. p 207. 

TABLE 20-1. Selected Herbicides Toxic to Ruminants at Dosages Less Than 100 mg/kg... 

Combustion in an incinerator is the only practical way to deal with many waste streams.This is particularly true of solid and concentrated wastes and toxic wastes such as those containing halogenated hydrocarbons, pesticides, herbicides, etc. Many of the toxic substances encountered resist biological degradation and persist in the natural environment for a long period of time. Unless they are in dilute aqueous solution, the most effective treatment is usually incineration. 

CgH,3BrN202. A soil-acting herbicide. White crystalline solid, m.p. 158-159" C. It is a non-selective inhibitor of photosynthesis used for weed control In citrus and cane fruit plantations. It is relatively non-toxic to animal life. 

Sodium trichloroacetate [650-51-17, C2Cl202Na, is used as a herbicide for various grasses and cattails (2). The free acid has been used as an astringent, antiseptic, and polymerisation catalyst. The esters have antimicrobial activity. The oral toxicity of sodium trichloroacetate is quite low (LD q rats, 5.0 g/kg). Although very corrosive to skin, trichloroacetic acid does not have the skin absorption toxicity found with chloroacetic acid (28). 

The FDA has pubhshed methods for the deterrnination of residual solvents in spice extracts such as oleoresins and has limited the concentrations of those specific solvents that are permitted. Chlorinated hydrocarbons and benzene have been almost completely removed from use as extracting solvents in the United States their use continues overseas where toxicity regulations are less stringent. The presence of pesticides or herbicides in spices is rigidly controHed by the FDA. 

The mode of action has not yet been elucidated but the manufacturer states that it probably behaves like the herbicide triflurolin and its congeners. These materials inhibit cell division by binding to tubuHn thereby internipting micro-tubule development. This, in turn, stops spindle fiber formation essential to mitosis and cell division. Experiments with C-labeled Prime+ show that it is acutely toxic to fish with estimated LC q (96 h) of less than 100 ppb for rainbow trout and bluegiU. sunfish. However, channel catfish did not exhibit any toxic response at the maximum attainable water concentration (10). 

Herbicides are also sometimes classified according to mode of action, selectivity, registered uses, and toxicity. The ever-increasing importance of herbicides and other pesticides and agrochemicals to a wide range of users, regulators, and researchers has led to the development of multiple and extensive computer databases. The primary database resources contain collected information relevant to herbicides, and numerous resource pubHcations are available to those needing information on the various aspects of herbicides (2). 

Biorational approaches have proven useful in the development of classes of herbicides which inhibit essential metaboHc pathways common to all plants and thus are specific to plants and have low toxicity to mammalian species. Biorational herbicide development remains a high risk endeavor since promising high activities observed in the laboratory may be nullified by factors such as limitations in plant uptake and translocation, and the instabiHty or inactivity of biochemical en2yme inhibitors under the harsher environmental conditions in the field. Despite these recogni2ed drawbacks, biorational design of herbicides has shown sufficient potential to make the study of herbicide modes of action an important and growing research area. 

W. J. Hayes, Jr., and E. R. Laws, Jr., eds.. Handbook of Pesticide Toxicology, Academic Press, Inc., San Diego, Calif., 1990. Three volume set provides detailed toxicological profiles of more than 250 insecticides, herbicides, and fungicides each compound described by identity, properties, and uses toxicity to humans, laboratory animals, domestic animals, and wildlife includes comprehensive coverage of diagnosis, treatment, prevention of injury, effects on domestic animals, wildlife, and humans - ISjOOO references. 

The majority of 2-methylphenol is used in the production of novolak phenoHc resins. High purity novolaks based on 2-methylphenol are used in photoresist appHcations (37). Novolaks based on 2-methylphenol are also epoxidized with epichlorohydrin, yielding epoxy resins after dehydrohalogenation, which are used as encapsulating resins in the electronics industry. Other uses of 2-methylphenol include its conversion to a dinitro compound, 4,6-dinitro-2-methylphenol [534-52-1] (DNOC), which is used as a herbicide (38). DNOC is also used to a limited extent as a polymerization inhibitor in the production of styrene, but this use is expected to decline because of concerns about the toxicity of the dinitro derivative. 

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