Science - technology & environment

ISO 9001:2015

VIMCERT 025

NATIONAL WORKING ENVIRONMENT MONITORING STATION

VILAS 441

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Science - technology & environment

Survey of the environment and factors related to health in workers occupationally exposed to trichloroethylene

Mô tả Comparative cross-sectional descriptive study was conducted from September 2022 to September 2023.The study was conducted on a total of 146 workers in groups exposed to trichloroethylne (TCE) in the working environment and groups not exposed to TCE in the working environment. TCE levels are monitored at the average shift worker's breathing area. At the same time, the interview was based on a prepared questionnaire on personal characteristics, clinical symptoms of eyes, skin, respiration, and nerves of employees. The research results we recorded: The group was exposed to TCE in the working environment, the average TCE concentration was 6.6 ± 5.1 mg/m3. Meanwhile, in the group not exposed to TCE in the working environment, the TCE concentration was below the detection threshold (detection limit - MDL is 1.516 µg/m3). In the group exposed to TCE in the labor market, the rate of respiratory symptoms was the most (21.9%), followed by eyes (13.7%), nerves (11,%), skin (6.9%). Workers in the group exposed to TCE in the labor market had a 2.3-fold higher incidence of respiratory symptoms (cough, shortness of breath, wheezing, rhinitis) than the non-contact group (95% CI 1.03-5.0), the difference was statistically significant. Respiratory symptoms among workers in the TCE-exposed group in the working environment were higher than among those not exposed to TCE. However, exposure follow-up studies, combined with subclinical manifestations, are required before a definitive causal association between TCE and worker health can be established.

Actual status of the labor environment of underground coal mining workers in some coal mines in quang ninh province

Mô tả A cross - sectional survey was conducted on 80 working environment measurement samples at underground coal mining and 40 measurement samples at other locations, not underground coal mining. Research locations at two coal mining companies in Quang Ninh province. Research using calibrated measuring equipment. Measuring methods according to the instructions in the Technical Regulations on Occupational Health and Environment of the Ministry of Health. Measurement results are compared with current Standards. The results of measuring the working environment in the exposed group had a higher proportion of samples that did not meet the allowable standards than in the comparison group in terms of humidity, wind speed, and noise. The average results of these parameters in the exposure group were higher than in the comparison group. The measurement results of coal dust concentration in the exposed group are dozens of times higher than the allowed standard. Specifically, the average total dust concentration measured in the exposed group was 61.16 mg/m3, more than 20 times higher than the allowed standard (3 mg/m3). The average concentration of respiratory dust in the exposed group was 23.06 mg/m3, more than 11 times higher than the allowed standard (2 mg/m3).

Presence of Perfluoroalkyl Carboxylic Acids and Sulfonates in Vietnamese Food Contact Materials

Mô tả Per- and polyfluoroalkyl substances (PFASs) are considered as persistent organic pollutants (POPs), which should be restricted or eliminated. In this study, concentrations of four perfluoroalkyl carboxylic acids (perfluorobutanoic acid PFBA, perfluorohexanoic acid PFHxA, perfluorooctanoic acid PFOA, perfluorodecanoic acid PFDA) and four perfluoroalkyl sulfonates (perfluorobutane sulfonate PFBS, perfluorohexane sulfonate PFHxS, perfluorooctane sulfonate PFOS, perfluorodecane sulfonate PFDS) were analyzed in food contact materials (FCM) collected from Hanoi, Vietnam. A total of 15 FCM samples was obtained including several categories such as instant drink/food boxes, bags, cups, wrappers, and tray. The FCM samples were untrasonic extracted with methanol, concentrated, and filtered before analysis by a liquid chromatography– tandem mass spectrometry (LC-MS/MS) system. Recoveries of native and surrogate standards ranged from 70% to 130% with RSD < 20% in replicated analysis. Method detection limits of PFASs ranged from 0.04 to 0.08 ng/g. Concentrations of ∑8PFASs ranged from not detected (ND) to 1.46 (average ± SD: 0.417 ± 0.479) ng/g. Detection frequencies of PFASs decreased in the order: PFDA (33%) > PFBA, PFOA, PFHxS, PFOS (27%) > PFDS (13%) > PFHxA (7%) > PFBS (0%). Average concentrations of individual compounds decreased in the order: PFOS > PFDA > PFHxS > PFOA > PFBA > PFHxA > PFDS > PFBS. Relatively low PFAS concentrations found in the FCM samples of this study indicated that these substances were mainly derived from unintentional sources rather than intentionally added to the materials. Keywords: PFASs, PFCAs, PFSs, food contact materials, LC-MS/MS.