The toxicity of chlorothalonil to aquatic fauna and the impact of its operational use on a pond ecosystem

Abstract

Chlorothalonil is a fungicide whose heavy use in eastern Canada gives it the potential for significant aquatic contamination. Laboratory bioassays and field treatments of a pond system were undertaken to determine the toxic effects of chlorothalonil on aquatic fauna. The 96-h LC50 of technical chlorothalonil for rainbow trout (Oncorhynchus mykiss) was 76 micrograms/L and was not significantly different (p less than 0.05) from that of the formulated product (Bravo 500). The 96-h LC50 of Bravo 500 for blue mussels (Mytilus edulis) and clams (Mya arenaria) was 5.9 mg/L and 35.0 mg/L respectively, while its 48-h LC50 to Daphnia magna was between 130 micrograms/L and 200 micrograms/L. Chlorothalonil exposure of Daphnia to concentrations as low as 32 micrograms/L significantly (p less than 0.05) increased the time to production of first young, but there were no delayed effects on number of young produced or growth at concentrations of 180 micrograms/L or less. Chlorothalonil was initially accumulated by blue mussels to concentrations approximately ten times greater than exposure concentrations; however, tissue concentrations returned to the same level as exposure concentrations within 96 h. Spraying of ponds resulted in mortality of caged water boatmen (Sigara alternata) and threespine stickleback (Gasterosteus aculeatus) which could be related to chlorothalonil exposure, however, caddisfly larvae (Limnephilus sp.), freshwater clams (Psidium sp.), water beetles (Haliplus sp.), scud (Gamarus spp.) and midge larvae (Chironomidae) did not suffer substantial chlorothalonil-induced mortality. Changes in endemic benthic invertebrate abundance after sprays were not remarkable or related to treatment. Faunal impacts in the pond were generally of a smaller magnitude than were predicted by bioassay results.(ABSTRACT TRUNCATED AT 250 WORDS)

Behavioral Responses of Daphnia Magna to Stresses of Chemicals with Different Toxic Characteristics

“…It also depletes glutathione (GSH), a non-enzymatic reducing agent involved in cell detoxification (Tillman et al 1973). The effects of chlorothalonil on the survival of Daphnia magna (Ernst et al 1991;Fernández-Alba et al 2002) and the reproduction of the meiobenthic estuarine copepod Amphiascus tenuiremis (Bejarano et al 2005) are reported. Nitrofen, which is a diphenyl ether herbicide, interferes with thyroid hormone and/or retinoic acid signaling and induces organ damage (Manson 1986;Brandsma et al 1994;Mascrez et al 1998;Greer et al 2003) and it produces a spectrum of fetal abnormalities in rodents (Kling et al 2005).…”

Environmental Fate and Toxicology of Chlorothalonil

“…Laboratory and field bioassays were conducted to determine the potential hazard chlorothalonil poses towards aquatic fauna. Rainbow trout (96-h LC 50 = 69 ug/L) was more sensitive than blue mussels (96-h LC 50 = 5.94 mg/L) and the water flea (48-h EC50= 97ug/L), when exposed under laboratory conditions (Ernst et al 1991). However, caged organisms, exposed under field conditions (aerially treated pond), were less sensitive, and exposed rainbow trout did not suffer any mortality.…”

“…However, caged organisms, exposed under field conditions (aerially treated pond), were less sensitive, and exposed rainbow trout did not suffer any mortality. Ernst et al (1991) concluded that environmental factors such as, microbial degradation, dilution and adsorption to suspended matter reduced chlorothalonil's toxicity.…”

Determinacion y evaluacion de los componentes presentes en las pinturas anti incrustantes utilizadas en la acuicultura y sus posibles efectos en sedimentos marinos del sur de Chile

“…Por muchos años el tributil-estaño (TBT) fue uno de los principios activos más usados en el mundo para la fabricación de pinturas anti-incrustantes (Ernst et al, 1991;Thomas, 2001;Thomas & Brooks, 2010) pero debido a su fuerte impacto en los ecosistemas acuáticos se ha regulado internacionalmente (EPC, 1998), dando paso a una nueva generación de alternativas, principalmente basadas en el óxido cuproso (Cu2O), pero que se acumula en sedimentos finos y anóxicos (Brooks & Mahnken, 2003), combinado con biocidas orgánicos (Burridge et al, 2010). Consecuentemente, altas concentraciones de estas sustancias han sido encontradas en estuarios y bajo balsas-jaulas de salmones y no existe suficiente información para evaluar el riesgo ambiental que puedan provocar.…”