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Intermolecular degradation of aromatic compound and its derivatives via combined sequential and hybridized process

Lau YY, Wong YS, Ong SA, Lutpi NA, Sam ST, Teng TT, et al.

Bioprocess Biosyst Eng, 2023 Mar;46(3):359-371.
PMID: 35796867 DOI: 10.1007/s00449-022-02743-7

The under-treated wastewater, especially remaining carcinogenic aromatic compounds in wastewater discharge has been expansively reported, wherein the efficiency of conventional wastewater treatment is identified as the primary contributor source. Herein, the advancement of wastewater treatments has drawn much attention in recent years. In the current study, combined sequential and hybridized treatment of thermolysis and coagulation-flocculation provides a novel advancement for environmental emerging pollutant (EP) prescription. This research is mainly demonstrating the mitigation efficiency and degradation pathway of pararosaniline (PRA) hybridized and combined sequential wastewater treatment. Notably, PRA degradation dominantly via a linkage of reaction: thermal cleavage, deamination, silication and diazene reduction. Thermolysis acts as an initiator for the PRA decomposition through thermally induced bond dissociation energy (BDE) for molecular fragmentation whilst coagulation-flocculation facilitates the formation of organo-bridged silsesquioxane as the final degradation product. Different from conventional treatment, the hybridized treatment showed excellent synergistic degradability by removing 99% PRA and its EPs, followed by combined sequential treatment method with 86% reduction. Comprehensive degradation pathway breakdown of carcinogenic and hardly degradable aromatic compounds provides a new insight for wastewater treatment whereby aniline and benzene are entirely undetectable in effluent. The degradation intermediates, reaction derivatives and end products were affirmed by gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy and ultraviolet-visible spectrophotometry (GC-MS, FTIR and UV-Vis). This finding provides valuable guidance in establishing efficient integrated multiple-step wastewater treatments.

Matched MeSH terms: Benzene/analysis
Fulltext A case study: Chemical health risk assessment in three footwear small industries in Bogor-Indonesia year 2019

Savira YM, Tejamaya M, Putri AA

Gac Sanit, 2021 12 22;35 Suppl 2:S374-S378.
PMID: 34929854 DOI: 10.1016/j.gaceta.2021.10.054

OBJECTIVE: This study aimed to analyse the health risks related to the use of chemicals among workers in small footwear factories.
METHODS: This was a descriptive case study conducted in three selected small footwear factories located in Ciomas, Bogor, Indonesia. The assessment was conducted using the chemical health risk assessment method by the Department of Safety and Health Malaysia Year 2018.
RESULTS: Results showed that the level of risk of chemicals through inhalation fell on the moderate and high-risk categories, indicating that high exposure could lead to carcinogenic effects. Dermal exposure was categorised as moderate risk, causing such health effects as skin and eye irritation.
CONCLUSION: Factory X, Y, and Z have been found to have a significant risk of hazardous chemical exposure (i.e., benzene and toluene), specifically at the glueing stations, either from inhalation or dermal contact.

Matched MeSH terms: Benzene/analysis
BTEX compositions and its potential health impacts in Malaysia

Latif MT, Abd Hamid HH, Ahamad F, Khan MF, Mohd Nadzir MS, Othman M, et al.

Chemosphere, 2019 Dec;237:124451.
PMID: 31394440 DOI: 10.1016/j.chemosphere.2019.124451

This study aims to determine the composition of BTEX (benzene, toluene, ethylbenzene and xylene) and assess the risk to health at different sites in Malaysia. Continuous monitoring of BTEX in Kuala Lumpur City Centre, Kuala Terengganu, Kota Kinabalu and Fraser Hill were conducted using Online Gas Chromatograph. For comparison, BTEX at selected hotspot locations were determined by active sampling method using sorbent tubes and Thermal Desorption Gas Chromatography Mass Spectrometry. The hazard quotient (HQ) for non-carcinogenic and the life-time cancer risk (LTCR) of BTEX were calculated using the United States Environmental Protection Agency (USEPA) health risk assessment (HRA) methods. The results showed that the highest total BTEX concentrations using continuous monitoring were recorded in the Kuala Lumpur City Centre (49.56 ± 23.71 μg/m3). Toluene was the most dominant among the BTEX compounds. The average concentrations of benzene ranged from 0.69 ± 0.45 μg/m3 to 6.20 ± 3.51 μg/m3. Measurements using active sampling showed that BTEX concentrations dominated at the roadside (193.11 ± 114.57 μg/m3) in comparison to petrol station (73.08 ± 30.41 μg/m3), petrochemical industry (32.10 ± 13.13 μg/m3) and airport (25.30 ± 6.17 μg/m3). Strong correlations among BTEX compounds (p<0.01, r>0.7) at Kuala Lumpur City Centre showed that BTEX compounds originated from similar sources. The values of HQ at all stations were <1 indicating the non-carcinogenic risk are negligible and do not pose threats to human health. The LTCR value based on benzene inhalation (1.59 × 10-5) at Kuala Lumpur City Centre were between 1 × 10-4 and 1 × 10-5, representing a probable carcinogenic risk.

Matched MeSH terms: Benzene/analysis*
Indoor generated PM2.5 compositions and volatile organic compounds: Potential sources and health risk implications

Idris SA', Hanafiah MM, Khan MF, Hamid HHA

Chemosphere, 2020 Sep;255:126932.
PMID: 32402880 DOI: 10.1016/j.chemosphere.2020.126932

The aim of the present study was to investigate the potential sources of heavy metals in fine air particles (PM2.5) and benzene, toluene, ethylbenzene, and isomeric xylenes (BTEX) in gas phase indoor air. PM2.5 samples were collected using a low volume sampler. BTEX samples were collected using passive sampling onto sorbent tubes and analyzed using gas chromatography-mass spectrometry (GC-MS). For the lower and upper floors of the evaluated building, the concentrations of PM2.5 were 96.4 ± 2.70 μg/m3 and 80.2 ± 3.11 μg/m3, respectively. The compositions of heavy metals in PM2.5 were predominated by iron (Fe), zinc (Zn), and aluminum (Al) with concentration of 500 ± 50.07 ng/m3, 466 ± 77.38 ng/m3, and 422 ± 147.38 ng/m3. A principal component analysis (PCA) showed that the main sources of BTEX were originated from vehicle emissions and exacerbate because of temperature variations. Hazard quotient results for BTEX showed that the compounds were below acceptable limits and thus did not possess potential carcinogenic risks. However, a measured output of lifetime cancer probability revealed that benzene and ethylbenzene posed definite carcinogenic risks. Pollutants that originated from heavy traffic next to the sampling site contributed to the indoor pollution.

Matched MeSH terms: Benzene/analysis