Chlorothalonil toxicity

Forestomach and the renal proximal tubule are the primary target tissues of chlorothalonil toxicity in Sprague-Dawley rats. Toxicity is characterized by hypertrophy, hyperplasia, vacuolization, and degeneration of renal tubular epithelium and acanthosis, hyperkeratosis, and hyperplasia of the squamous epithelium of the forestomach. Chlorothalonil is a well-known skin and eye irritant. Sustained contact with the squamous epithelium of the forestomach can lead to an inflammatory response. The earliest observation following chlorothalonil administration at 175 mgkg day to rats for varying periods of time for up to 91 days has been characterized by multifocal ulceration and rosion of the mucosa,... 

Chemical/Physical. Emits toxic fumes of nitrogen oxides, cyanides, and chlorine when heated to decomposition (Sax and Lewis, 1987). Chlorothalonil is resistant to hydrolysis under acidic conditions. At pH 9, chlorothalonil (0.5 ppm) hydrolyzed to 4-hydroxy-2,5,6-trichloroisophthalo-nitrile and 3-cyano-2,4,5,6-tetrachlorobenzamide. Degradation followed first-order kinetics at a rate of 1.8% per day (Szalkowski and Stallard, 1977). 

Sherrard, R.M., Murray-Gulde, C.L., Rodgers Jr, J.H. and Shah, Y.T. (2003) Comparative toxicity of chlorothalonil Ceriodaphnia dubia and Pimephales promelas, Ecotoxicology and Environmental Safety 56 (3), 327-333. 

PCNB, hexachlorobenzene (HCB), and dichloran have only slight irritant effects and relatively low single-dose toxicity. Several formulated products of chlorothalonil are classified in Toxicity Category I and are corrosive to eyes and skin (Bravo, ClortoCaffaro, Daconil, Echo). Other formulations are classified in Toxic Category II as severe irritants to eyes and skin. 

Chlorothalonil is moderately persistent in soil, having a half-life of up to 3 months in moderately moist soil. The principal breakdown product of chlorothalonil in the soil is 4-hydroxy-2,5,6-trichloroisophthalonitrile, which is slightly toxic to aquatic organisms and moderately toxic to birds and mammals. Chlorothalonil is almost insoluble in water and does not evaporate easily. 

Chlorothalonil is highly toxic to fish and other aquatic invertebrate animals. However, it is relatively nontoxic to birds, mammals, and bees. 

Gallagher, E.P., R.C. Cattley, and R.T. di Giulio. 1992. The acute toxicity and sublethal effects of chlorothalonil in channel catfish (Ictalurus punctatus). Chemosphere 24 3-10. 

Gallagher, E.P., Canada, A.T., Di Giulio, R.T., 1992. The protective role of glutathione in chlorothalonil-induced toxicity to channel catfish. Aquat, Toxicol. 23, 155-168. 

Fig. 12 Degradation pathway, physicochemical descriptors, and toxicity model of chlorothalonil. Physicochemical properties are (a) experimental value from Episuite [39], (b) estimated values from Episuite [39], (c) [50], (d) [51], (e) [52], if) [49], (g) http //europa.eu.int/comm/food/plant/protection/evaluation/existactive/list bromoxynil, (h) [44]...

Fig. 13 Fractions of metabolites formed,/, and toxic potential of the metabolites, TPf, and the mixture, TPmixture> for chlorothalonil. Bars correspond to the average between TPf, min and TPf, max and the error bars indicate the range between min and max...

Forturf, Termil, and Chlorothalonil, it was developed to replace the more toxic pentachlorophenol, and is itself a benzene derivative (Fig. 2). Among 20 workers in one wooden-ware factory, 7 of the 14 workers who had reactions to TCPN were shown to be allergic by positive patch testing (Johnsson et al. 1983). Symptoms in exposed workers included contact dermatitis, xerosis, thinning of skin particularly on the upper eyelid, and yellow discoloration of hands and feet. TCPN has been shown to elicit positive reactions in those allergic at patch-test concentrations of 0.01% in acetone, and at 1% produced reactions in both of two non-allergic control subjects in a 1980 case report (Bach and Pedersen 1980). 

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