Toxicity of nitromusks in early lifestages of South African clawed frog (Xenopus laevis) and zebrafish (Danio rerio)

Abstract

Musk xylene (MX), musk ketone (MK) and musk moskene (MM) are synthetic nitro-containing fragrances. Due to their inherent lipophilicity and environmental persistence, they are frequently detected in environmental samples and especially in aquatic ecosystems. Despite this, the current environmental toxicity database of nitromusks is limited. Although nitromusks have been shown to accumulate in aquatic organisms, little is known about their potential developmental effects in the respective aquatic species. To investigate the developmental toxicity of these compounds to amphibians and fish, early lifestages of xenopus (Xenopus lae6is) and zebrafish (Danio rerio) were exposed to three nitromusks for 96 h to examine the developmental effects of these compounds in the two species. Nitromusk body concentration measurements were carried out in parallel for correlation with potential developmental effects. No increased mortality, malformation or growth inhibition was observed in either species following 96-h exposure to 400 mg/l MX, MK and MM. However, an approximately 20% reduced viability was observed in xenopus larvae when exposed to 400 mg/l MX, MK and MM for 11 days. Xenopus and zebrafish exposed to 10, 153, 871 and 1637 mg/l 14 C-MX for 96 h resulted in whole-body concentrations of 0.7 90.1, 11.191.1, 38.79 1.9 and 76.3 9 18.3 mg/g, and 4.3 90.6, 73.3911.8, 440.0972.7 and 664.09 47.7 mg/g wet body weight, respectively. Exposure of xenopus larvae to 400 mg/l MX, MK and MM for 11 days, resulted in whole body concentrations (extrapolated from gas chromatographic determinations) of 4700 95000, 13009 300 and 46009 4800 mg/g wet weight for MX, MK and MM, respectively. The latter toxicity results, in conjunction with the fact that the concentrations used for the above experiments were between 400-and 10 000-fold higher than those detected in the environment, suggest that environmental concentrations of nitromusks are not hazardous for early lifestages of fish and amphibians.

Trends in the musk xylene concentrations in plasma samples from the general population from 1992/1993 to 1998 and the relevance of dermal uptake

“…Since MX was only found in 12% of the samples in low concentrations the risk of exposure to MX for the general population in Germany is estimated to be very low. Together with the low acute and chronic toxicity of MX in animal experiments (Christian et al 1999;Chou and Dietrich 1999) and the non-relevance to humans of MXinduced liver tumors in mice (Lehman-McKeeman and Caudill 1995;Lehman-McKeeman et al 1997a, 1997b, the toxic risk is also estimated to be very low. Decreased human risk is also probably true for other countries where the use of MX has been limited or banned.…”

Inhibition of polyisoprenylated methylated protein methyl esterase by synthetic musks induces cell degeneration

“…The adverse impact of synthetic musk exposure to developing organisms has been reported (Rimkus and Wolf, ; Chou and Dietrich, ; Carlsson et al, ). Knockouts of polyisoprenylation pathway enzymes result in embryonic lethality, cardiomyopathy (Bergo et al, ) and extensive degeneration (Perez‐Sala, ; Tolmachova et al, ; Krishnan et al, ).…”

Interactions of nitromusk parent compounds and their amino-metabolites with the estrogen receptors of rainbow trout (Oncorhynchus mykiss) and the South African clawed frog (Xenopus laevis)

“…Consequently, contamination analysis of aquatic organisms revealed that in some cases, these metabolites were present at higher concentrations (mg/kg lipid) than their respective parent compounds (Rimkus et al, , 1999. All of the data presented so far demonstrate that nitromusks exert negligible acute toxicity on aquatic organisms even at the highest possible soluble concentrations tested (Tas and van de Plassche, 1996;Chou and Dietrich, 1999). However, no data are available regarding the potential endocrine modulating activity of these compounds and/or their metabolites in aquatic organisms.…”