Polyhalogenated carbazoles (PHCZs) are dioxin-like emerging contaminants, but limited information exists on their neurotoxicity and mechanisms. This study employed zebrafish embryos to investigate the adverse effects of 3-bromocarbazole (3-BCZ), a typical PHCZ, exposure in their early life stages and found that the 120 h post fertilization (hpf)-median lethal concentration (LC50) value of 3-BCZ in zebrafish larvae was 2.88 mg/L. The results revealed that 3-BCZ inhibited tail coiling at ≥0.06 mg/L, decreased hatchability at ≥2.88 mg/L, increased mortality and malformation rates at ≥1.44 mg/L, induced aryl hydrocarbon receptor effects and reduced body length at ≥0.58 mg/L, and inhibited behavior activities at ≥0.06 mg/L. Further mechanism investigations showed that 3-BCZ exposures repressed the motor neuron axon length via downregulating the mRNA transcription levels of α1-tubulin, Gap43, Syn2a, and shha, and decreased central nervous system neurogenesis via downregulating the mRNA transcription levels of elavl3, nrd, mbp, and gfap. Overall, 3-BCZ induces developmental neurotoxicity in zebrafish larvae at 0.06 mg/L (1/50 LC50). Tail coiling activity at 24 hpf and swimming total distance at 120 hpf could be ideal indicators of 3-BCZ health risks in zebrafish. These findings provide valuable insights for health and ecological risk assessments of 3-BCZ and other PHCZs.
Allergies have become an important public health issue as their occurrence is reportedly on the rise around the world. Exposure to environmental factors is considered as trigger for allergic diseases. However, there was limited data on the importance of each factor, particularly in China. In this study, we aimed to investigate the association between occurrence of allergic diseases with exposure to multiple environmental factors via wastewater surveillance across 28 cities in China. The surveillance was conducted by measuring biomarkers of proxies of allergic diseases, i.e. antihistamines, asthma drug, and of smoking, i.e. cotinine in wastewater. Data of green space and air quality were also collected. We observed the level of antihistamine use were significantly associated with smoking, green space and pollen but not significant with air pollution. People in Northern China used more antihistamines than their compatriots in Southern China, an observation aligning with previous reporting of more allergy prevalence in the North than the South of China. Our study affirmed that in China smoking is responsible for a rise in allergy and asthma in the population. Meanwhile, selected sensitizing pollens (occurring during summer) could have stronger impact to trigger allergies than other pollens (occurring in winter).
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