Impacts of cetylpyridinium chloride on the behavior and brain neurotransmitter levels of juvenile and adult zebrafish (Danio rerio).

Cetylpyridinium chloride (CPC) is a cationic surfactant that has been widely used as an antibacterial ingredient in pharmaceutical and personal care products. Due to its high residue in surface waters, there is increasing concern over the potential risk of CPC to aquatic ecosystems. However, knowledge of its impacts on fish is still limited. Therefore, this study exposed juvenile and adult zebrafish to CPC (0, 10, and 40 µg/L) for four days. Subsequently, changes in their behavioral traits and brain levels of several neurotransmitters were investigated. The behavioral assay showed that CPC exposure significantly decreased the locomotor activity and social interaction of zebrafish at both life stages, and juveniles were more sensitive to CPC exposure than adults. In the control groups, the brain neurotransmitters concentrations increased with age in zebrafish. However, CPC exposure tended to increase the brain neurotransmitter levels of juveniles but decreased their levels in adults. Correlation analysis revealed that the brain monoamine neurotransmitters and their turnover might play important roles in the life stage-dependent behavioral response to CPC. In particular, the DOPAC/DA ratio was significantly associated with CPC-induced hypoactivity and reduced social interactions in juveniles but not adults. Our findings demonstrated that CPC exposure could cause abnormal behavior in juvenile and adult zebrafish and disturb their brain neurotransmitters, even at environmentally relevant concentrations, and thus highlighted the necessity for further assessing its potential risks to aquatic ecosystems.

Impacts of Cetylpyridinium Chloride on the Survival, Development, Behavior, and Oxidative Stress of Early-Life-Stage Zebrafish (Danio rerio).

Cetylpyridinium chloride (CPC) is a widely used surfactant that has been detected in various water ecosystems. However, knowledge on the toxicity of CPC to fish remains scarce. Here, we examined the survival, development, behavior, and oxidative stress in the early life stages of zebrafish exposed to CPC (0, 4, 40, 400, and 1200 µg/L) until 120 h post-fertilization (hpf). Results showed that CPC induced significant mortality at 400 and 1200 µg/L, with a 120 h-EC50 value of 175.9 µg/L. CPC significantly decreased the heart rate of embryos (48 hpf; 4-400 µg/L) and larvae (72 hpf; 40 and 400 µg/L). At 120 hpf, CPC exhibited a dual effect on the locomotion activity (decreased at 400 µg/L and increased at 4 and 40 µg/L) and elevated the reactive oxygen species, superoxide dismutase, and glutathione levels in zebrafish larvae at 400 µg/L. In addition, a correlation analysis revealed that CPC-induced oxidative stress might play a critical role in mediating the cardiac and behavioral toxicity of CPC to zebrafish larvae. Our findings suggest that CPC may disturb the fish's development, behavior, and oxidative status at environmentally relevant concentrations, which should not be ignored when assessing its potential risks to aquatic ecosystems.

Assessment of Perceptions and Cancer Risks of Workers at a Polychlorinated Biphenyl-Contaminated Hotspot in Ethiopia.

BACKGROUND: Polychlorinated biphenyls (PCBs) are synthetic and persistent toxic chemicals with a high potential to bioaccumulate in human tissue. There is no existing literature on workers' perceptions and occupational cancer risk due to exposure to PCBs in Ethiopia. OBJECTIVES: The aim of the present study was to assess workers' perceptions of occupational health and safety measures of PCB management and to evaluate the cancer risk posed by PCBs to workers handling these chemicals in Ethiopia. METHODS: A total of 264 questionnaires were administered to workers at the study area to obtain information about PCB management. A mathematical model adopted from the United States Environmental Protection Agency (USEPA) was used to assess the potential cancer risk of people working in PCB-contaminated areas. RESULTS: The results showed that the majority of the workers had little knowledge of safe PCB management practices. Furthermore, 82.6% had not received training on chemical management and occupational health and safety protocols. The association between respondents' responses on the impact of PCBs to the use of personal protective equipment was statistically significant (p <0.005). Accidental ingestion, dermal contact and inhalation exposure pathways were considered in assessing the cancer risk of people working in these areas. The estimated cancer risk for PCBs via dermal contact was higher than for the accidental ingestion and inhalation pathways. The health risk associated with dermal contact was 73.8-times higher than the inhalation exposure route. Workers at the oil tanker and oil barrel area and swampy site are at higher risk of cancer via dermal contact at the 95th centile (879 and 2316 workers per million due to PCB exposure, respectively). However, there is very low cancer risk at the staff residence and garden area via the inhalation route. CONCLUSIONS: Training programs would help improve the knowledge of workers in the area of occupational health and safety of chemical handling. Further studies on PCBs in the exposed workers will provide information on their blood sera PCB levels and consequently identify potential health impacts. PARTICIPANT CONSENT: Obtained. ETHICS APPROVAL: Ethics approval was obtained from the Research Ethics Review Committee of Adama Hospital Medical College, Adama, Ethiopia. COMPETING INTERESTS: The authors declare no competing financial interests.