Source apportionment and health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the coastal ecosystem of the Brunei Bay, Brunei

Seasonal variations, source apportionment, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in sediments from Klip River, Johannesburg, South Africa

The widespread occurrence of polycyclic aromatic hydrocarbons (PAHs) in water bodies is a significant cause of concern due to their persistence and toxicity. This study aimed at assessing the qualitative and quantitative profile of 16 EPA PAHs present in sediment collected from nine sites along the Klip River, Johannesburg, South Africa. The target compounds were extracted from sediment by microwave-assisted extraction (MAE). The extraction method accuracy was evaluated by analyzing certified reference material of sediment (CRM-104). The total concentration of PAHs detected in sediment samples ranged from 1.46 to 7.41 mg/kg. High molecular weight (HMW) PAHs were found to be in higher concentrations for both low flow (24.5 mg/kg) and high flow (19.4 mg/kg) seasons compared to the lower molecular weight (LMW) PAHs, which had 11.1 mg/kg for low flow and 5.63 mg/kg for high flow seasons. For identification of source of PAHs in sediments, the diagnostic ratio was employed, which revealed the PAHs were from petrogenic and pyrogenic sources. Toxicity test using zebrafish embryo development test (ZFET) resulted in high mortality, low hatch rate, and high malformations, which indicated the contamination of sediments from the Klip River. These findings suggest that exposure to this water system poses risks to the environment, aquatic life, and humans who depend on it.

Toxicity of Crude Oil Wastewater Treated with Nano-ZnO as a Photocatalyst on Labeo rohita: A Biochemical and Physiological Investigation

This study aimed to evaluate the effects of the water-soluble fraction of crude oil (WSFO) on Indian carp (Labeo rohita) with and without treatment with zinc oxide nanoparticles (Nano-ZnO). A total of 225 fish were randomly assigned to five groups in triplicate for 21 days. Group I served as the control group. Groups II and III were exposed to 0.5% and 1% untreated WSFO, respectively. Groups IV and V received 5% and 10% WSFO treated with Nano-ZnO, while Groups VI and VII received 5% and 10% WSFO treated without Nano-ZnO. No blood samples were obtained from fish exposed to untreated WSFO, due to increased hemolysis. Exposure to treated WSFO increased creatine phosphokinase, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, and gamma-glutamyl transferase activities, while alanine aminotransferase activity decreased. Although a significant decrease was observed in total protein, globulin, and triglyceride levels, albumin and cholesterol increased. Thiol groups and glutathione peroxidase activity significantly decreased, while superoxide dismutase, catalase, total antioxidant capacity, and malondialdehyde levels increased. The findings showed that exposure to WSFO, whether treated or untreated, induces significant biochemical and oxidative stress responses in Labeo rohita. Although WSFO treated with Nano-ZnO mitigated hemolysis, it was unable to prevent enzyme and antioxidant imbalances, indicating persistent physiological stress.

Distinct anthropogenic signatures: A comparative analysis of polycyclic aromatic hydrocarbons in sediments from two southeastern Chinese bays

Sansha and Luoyuan Bay are influenced by different industrial structure, but the sources and pollution status of polycyclic aromatic hydrocarbons (PAHs), especially alkylated PAHs, are poorly understood. We studied 25 PAHs in surface sediments from the two bays. The results showed that PAHs concentrations in Sansha and Luoyuan Bay sediment range from 6.54 to 479.28 ng/g and 118.82 to 2984.09 ng/g, respectively. Alkylated PAHs dominated in Sansha (48.86 % of Σ25PAHs), while 3-ring PAHs dominated in Luoyuan (36.32 % of ∑25PAHs). Results of sources analysis indicated oil spills as the main PAHs source in Sansha, and domestic emissions and fossil fuel combustion in Luoyuan. Ecological risk assessment of showed low sediment risk, but in Luoyuan was higher than in Sansha. Compared with Luoyuan Bay, Sansha Bay emits less industrial pollutants, so the pollution is lower than Luoyuan Bay. Increased attention to protecting Luoyuan Bay is recommended.

Distribution characteristics, source analysis and risk assessment of polycyclic aromatic hydrocarbons in sediments of Kuye River: a river in a typical energy and chemical industry zone

This study systematically analyzed the distribution characteristics, sources, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in Kuye River sediments, located in an energy and chemical industry base in northern Shaanxi, China. The results that revealed the concentrations of 16 PAHs in the sediment ranged from 1090.04 to 32,175.68 ng∙g-1 dw, with the four-ring PAHs accounting for the highest proportion. Positive matrix factorization analysis (PMF) revealed the main sources of PAHs as incomplete fossil fuel combustion, biomass combustion, and traffic emissions. The total toxic equivalent concentration of BaP, risk quotient, and lifetime carcinogenic risk of PAHs suggested moderate to high contamination of PAHs in the area. The higher incremental lifetime carcinogenic risk (ILCR) indicated that PAH ingestion was the primary route of impact on public health, with children potentially being more susceptible to PAH exposure. This study can provide valuable theoretical support for implementing pollution prevention measures and ecological restoration strategies for rivers in energy and chemical industry areas.

Seasonal variations in the distribution of aliphatic hydrocarbons in surface sediments from the Selangor River, Peninsular Malaysia's West Coast

The seasonal variation of petroleum pollution including n-alkanes in surface sediments of the Selangor River in Malaysia during all four climatic seasons was investigated using GC-MS. The concentrations of n-alkanes in the sediment samples did not significantly correlate with TOC (r = 0.34, p > 0.05). The concentrations of the 29 n-alkanes in the Selangor River ranged from 967 to 3711 µg g-1 dw, with higher concentrations detected during the dry season. The overall mean per cent of grain-sized particles in the Selangor River was 85.9 ± 2.85% sand, 13.5 ± 2.8% clay, and 0.59 ± 0.34% gravel, respectively. n-alkanes are derived from a variety of sources, including fresh oil, terrestrial plants, and heavy/degraded oil in estuaries. The results of this study highlight concerns and serve as a warning that hydrocarbon contamination is affecting human health. As a result, constant monitoring and assessment of aliphatic hydrocarbons in coastal and riverine environments are needed.

Source apportionment and human health risk of PAHs accumulated in edible marine organisms: A perspective of "source-organism-human"

Most PAHs produced by human activities can be absorbed and accumulated by edible organisms and pose a potential hazard to human health. However, the source apportionment and human health risk of PAHs accumulated in edible organisms remains largely unknown. Therefore, we conducted source analysis and health risk assessment based on the PAH concentrations in ten marine fish from coastal areas of Guangdong, China. Results showed that the pollution of PAHs in fish organisms was at "Minimally polluted" level, and that all marine fish had the ability to accumulate PAHs. Risk assessment indicated Carcinogenic risk of PAHs in four populations was at a "Cautionary risk" level, with urban children suffered the highest risk. Petroleum pollution, Coal and biomass combustion, and Marine transport emissions were identified as the main anthropogenic sources for PAHs in organisms, and Marine transport emissions accounted for the highest Carcinogenic risk. The Acceptable daily intake for all populations were far below their actual daily intake without causing "Cautionary risk". Our findings provide new insights into the source apportionment and health risk of PAHs from a "source-organism-human" perspective, and suggested that joint management of three anthropogenic sources would be an effective way to prevent the health risks of PAHs.