Toxic effects of Triclosan on the detoxification system and breeding of Daphnia magna

Abstract

The toxic effects of different concentrations of Triclosan (TCS) (1-128 μg/L) on Daphnia magna (D. magna) were investigated by acute (48 h) and chronic (21-day) toxicity tests. The response of antioxidase system and Phase I metabolism process of D. magna exposed to TCS were investigated by measuring a series of biomarkers including glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), 7-ethoxyresorufin O-deethylase (EROD), Erythromycin N-demethylase (ERND) and Aminopyrine N-demethylase (APND). The 48 h LC50 of TCS was 330 μg/L for D. magna. In the chronic test, total number of neonates per female, body length and the intrinsic rate of natural increase (r) of D. magna increased at the low exposure concentrations (1-16 μg/L) and decreased at the high concentrations (64-128 μg/L), while the total number of molting per adult decreased continually. The GST and CAT activities showed no significant increase in all treatments, and SOD activities were induced after 24-h exposure and inhibited after 48-h exposure at 4-128 μg/L of concentrations. The MDA content increased after 6-h exposure but decreased after 48-h exposure at 4-128 μg/L. EROD activities initially increased after 6-h exposure, but decreased after 24 and 48-h exposure, ERND and APND activities showed a similar temporal pattern among different treatments groups. SOD, MDA and APND were sensitive to TCS, thus they are suitable as potential biomarkers for the exposure to TCS.

Perturbations in polar lipids, starvation survival and reproduction following exposure to unsaturated fatty acids or environmental toxicants in Daphnia magna

“…We observed a concentration-dependent drop in reproduction during triclosan exposures from 0.022 – 0.345 μM, but it was not statistically significant by ANOVA. Previous studies reported 0.22 μM (64 μg/L) triclosan reduced reproduction during chronic toxicity tests with D. magna (Peng et al, 2013). To our knowledge, this is the first paper to report the reproductive toxicity of DHA or LA (Suppl File 1).…”

1H NMR-based metabolomics of Daphnia magna responses after sub-lethal exposure to triclosan, carbamazepine and ibuprofen

“…Previous studies have examined the acute toxicity of triclosan, carbamazepine and ibuprofen to D. magna and reported 48 hour LC 50 (the concentration that causes 50% mortality) values of 7 330 µg/L, mg/L, 132.6 mg/L, respectively (Han et al, 2006;Peng et al, 2013) After preliminary tests to confirm the hour sub-lethal contaminant concentrations, D. magna adults were exposed over 48 hours to either sub-lethal triclosan concentrations (0, 6.25, 12.5, 25, 50, 75 and 100 µg/L), sub-lethal carbamazepine concentrations (0, 1.75, 3.5, 5.25, 7, 10.5 and 14 mg/L) or sub-lethal ibuprofen concentrations (0, 1.75, 3.5, 5.25, 7, 10.5 and 14 mg/L). For every exposure concentration, two groups of 60 individuals each were kept in separate 2 L beakers with a density of 1 daphnid per 30 mL.…”

Ecotoxicity and genotoxicity of a binary combination of triclosan and carbendazim to Daphnia magna

“…The biocide triclosan inhibits the enoyl-acyl carrier protein reductase (ENR), which is involved in the bacterial lipid biosynthesis, so bacteria are unable to reproduce (Heath and Rock, 2000). In D. magna, triclosan enhances the activity of glutathione S-transferase (GST), and decreases the superoxide dismutase (SOD) activity, which may indicate damage in the cell membranes, confirming that triclosan causes oxidative stress (Peng et al, 2013).…”