Implication of global environmental changes on chemical toxicity-effect of water temperature, pH, and ultraviolet B irradiation on acute toxicity of several pharmaceuticals in Daphnia magna

Abstract

Global environmental change poses emerging environmental health challenges throughout the world. One of such threats could be found in chemical safety in aquatic ecosystem. In the present study, we evaluated the effect of several environmental factors, such as water pH, temperature and ultraviolet light on the toxicity of pharmaceutical compounds in water, using freshwater invertebrate Daphnia magna. Seven pharmaceuticals including ibuprofen, acetaminophen, lincomycin, ciprofloxacin, enrofloxacin, chlortetracycline and sulfathiazole were chosen as test compounds based on their frequent detection in water. The experimental conditions of environmental parameters were selected within the ranges that could be encountered in temperate environment, i.e., water temperature (15, 21, and 25 degrees C), pH (7.4, 8.3, and 9.2), and UV-B light intensity (continuous irradiation of 15.0 microW/cm(2)). For acetaminophen, enrofloxacin and sulfathiazole, decrease in water pH generally led to increase of acute lethal toxicity, which could be explained by the unionized fraction of pharmaceuticals. Increase of water temperature enhanced the acute toxicity of the acetaminophen, enrofloxacin and chlortetracycline, potentially due to alteration in toxicokinetics of chemicals as well as impact on physiological mechanisms of the test organism. The presence of UV-B light significantly increased the toxicity of sulfathiazole, which could be explained by photo-modification of this chemical that lead to oxidative stress. Under the UV light, however, acute toxicity of enrofloxacin decreased, which might be due to photo-degradation. Since changing environmental conditions could affect exposure and concentration-response profile of environmental contaminants, such conditions should be identified and evaluated in order to better manage ecosystem health under changing global environment.

Population-level effects of spinosad and Bacillus thuringiensis israelensis in Daphnia pulex and Daphnia magna: comparison of laboratory and field microcosm exposure conditions

“…Therefore, such studies are highly desired, while laboratory studies should be considered as complementary, and used to help explain the patterns observed in natura. In this study, one might have expected stronger effects to be emphasized in the field, due to the potentially large amount of interacting factors (e.g., Duchet et al 2010;Kim et al 2010).…”

Inhibitory effect of salinity on the photocatalytic degradation of three sulfonamide antibiotics

“…The data revealed that the products in the photocatalytic processes of the SAs had higher toxicities to V. fischeri than did the parent compounds. Kim et al (2010) reported that UV irradiation significantly increased the toxicity of another SA antibiotic, sulfathiazole, to a freshwater zooplankton, Daphnia magna. By contrast, the photodegradation intermediates of oxolinic acid, a veterinary antibiotic used in aquaculture, exhibited nonsignificant toxicity to the bacteria Escherichia coli after an oxidative reaction with TiO 2 and UV, although significant toxicity was detected in its parent compound (Palominos et al, 2008).…”

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“…Trocas totais da água de cultivo, com limpeza dos recipientes e contagem dos organismos adultos, foram realizadas a cada 48-h. Nesse momento as D. similis foram alimentadas com a alga Pseudokirchneriella subcapitata, e as C. dubia com P. subcapitata e vitohormônio (ração fermentada adicionada de leveduras). As sensibilidades das D. similis e das C. dubia foram avaliadas mensalmente utilizando como controle positivo o cloreto de sódio (NaCl) (ABNT, 2009;Liguoro et al, 2009;ABNT, 2010;Kim et al, 2010). Para os testes com D. similis foram utilizadas neonatas com 2 a 24-h de idade (ABNT, 2009).…”