Biological effects of the benzotriazole ultraviolet stabilizers UV-234 and UV-320 in early-staged zebrafish (Danio rerio)

Abstract

Among the benzotriazole ultraviolet stabilizers (BUVSs), UV-234 and UV-320 are frequently detected in aquatic ecosystem. Despite the fact that these chemicals are present in low ng/L levels in surface water, they show high bio-accumulation potential and pose exposure risks to aquatic organisms. However, there are limited toxicological data available in fish. In this study, zebrafish embryos were exposed to 0.01, 0.1 and 1 mM UV-234 or UV-320 for up to 6 days. Developmental toxicity as well as effects on mitochondrial bioenergetics, immune system responses, and locomotor activity in zebrafish were measured. After UV-234 treatment (0.1e1 mM), hatching time of embryos was increased compared to controls. There was also a~20e40% reduction in non-mitochondrial respiration and oligomycindependent mitochondrial respiration in embryos treated with 1 mM UV-234 for 24 and 48 h respectively; conversely basal respiration and non-mitochondrial respiration were increased~20e30% in embryos treated with 1 mM UV-320 at 48 h. Transcript levels of sod1 were down-regulated with BUVSs while sod2 mRNA was highly up-regulated with both UV-234 and UV-320, suggesting an oxidative damage response. Considering that mitochondrial signaling regulates innate immune pathways, we measured the expression of immune related transcripts (tlr5a, tlr5b, mmp9, il8, tnfa, cxcl-C1c, nfkb1, and ifng). Of these, only il8 and cxcl-C1c mRNA were decreased in response to 0.1 mM UV-320. To associate early molecular events with behavior, locomotor activity was assessed. UV-234 reduced larval activity in a dark photokinesis assay by~15%, however behavioral responses at environmentally-relevant concentrations of BUVSs were not consistent across experiments nor BUVSs. These data suggest that BUVSs can perturb mitochondrial bioenergetics, embryonic development, and locomotor activity of zebrafish, but these responses appear to be dose-, time-and BUVSs dependent, suggesting these chemicals may have unique modes of action.

Tissue-Specific Accumulation, Biotransformation, and Physiologically Based Toxicokinetic Modeling of Benzotriazole Ultraviolet Stabilizers in Zebrafish (Danio rerio)

“…24 It has also been reported that BUVSs can perturb mitochondrial bioenergetics, embryonic development, locomotor activity, and the thyroid system of zebrafish. 24,64 The accumulation in the ovaries further highlights the importance of understanding the effects of exposure to these industrial chemicals on the early-life stage of fish.…”

“…The accumulated BUVSs in the ovaries can be transferred to eggs and induce adverse effects on offspring. Previous studies indicated that exposure of zebrafish to BUVSs led to increased hatching time of embryos 64 and decreased heart rates of the larval fish. 24 It has also been reported that BUVSs can perturb mitochondrial bioenergetics, embryonic development, locomotor activity, and the thyroid system of zebrafish.…”

Identification of Triazine UV Filters as an Emerging Class of Abundant, Ubiquitous Pollutants in Indoor Dust and Air from South China: Call for More Concerns on Their Occurrence and Human Exposure

“…Because of their extensive and increasing use, a large variety of UV filters are leaching into the environment, gaining more and more attention regarding their risks to the environment and human health. , Current concerns over UV filters are primarily focused on the benzophenone- and benzotriazole-type chemicals . These two types of UV filters have been recorded worldwide to occur in various environmental and biological matrices, including air, water, sediment, dust, sludge, bird eggs, and human urine. ,− Furthermore, multiple toxic effects of these UV filters have also been widely demonstrated, including endocrine disruption, neurotoxicity, reproductive toxicity, and developmental toxicity. − …”

Phase partitioning, transport and sources of Benzotriazole Ultraviolet Stabilizers during a runoff event

“…Such widespread use leads to detectable concentrations of BT-UVs in environmental matrices, which have been reported for surface water ( Lu et al., 2016 ), sea water ( Montesdeoca-Esponda et al., 2020 ), sediment ( Cantwell et al., 2015 ), biota ( Lu et al., 2019 ), wastewater ( Song et al., 2014 ) and plastic debris ( Rani et al., 2017 ). The toxic and bio-accumulative properties of BT-UVs are well documented ( Kim et al., 2011 ; Liang et al., 2019 ); and as a result, some BT-UVs have been classified under the European Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) regulation as substances of very high concern (European Chemicals Agency (ECHA), 2014 ).…”