Insight into heavy metal chemical fractions in ash collected from municipal and industrial waste incinerators in northern Vietnam.

This investigation involved the collection of fly ash and bottom ash specimens from seven waste incinerators situated in the northern provinces of Vietnam, aimed at assessing the composition and distribution patterns of five chemical fractions of heavy metals (Pb, Cr, As, Cd Cu, and Zn) present in incinerator waste ash. The outcomes reveal that fly ash exhibited a relatively elevated concentration of industrial waste metals (25-66%) such as As, Cd, and Pb primarily in exchangeable (F1) and carbonate fractions (F2), which are mobile forms susceptible to environmental dissolution and consequential bioaccumulation posing health risks to humans. The predominant states of the metals Cr, Cu, and Zn were identified as residual, Fe-Mn oxide, and carbonate, respectively, with their relative proportions showing minimal variation. Conversely, heavy metals were predominantly present in residual residue and Fe-Mn bound form (F3) in bottom ash derived from both residential and commercial waste incineration operations. The non-carcinogenic hazard indices (HI) associated with the examined metals, ranked for both adults and children, were as follows: Pb > Cr > As > Cd > Cu > Zn. Notably, the HI values for Pb, Cr, and As exceeded the permissible threshold (HI > 1) for children. However, the risk of As, Cd, and Pb-related cancer via exposure pathways remained within acceptable limits for both age groups. Conversely, the probability of carcinogenic effects attributable to Cr surpassed the permissible threshold (>10-4), indicating significant health concerns associated with heavy metals in waste incinerators for humans, particularly children.

Low-cost and versatile analytical tool with purpose-made capillary electrophoresis coupled to contactless conductivity detection: Application to antibiotics quality control in Vietnam.

In this study, the development of our purpose-made capacitively coupled contactless conductivity detection (C4 D) for CE is reported. These systems have been employed as a simple, versatile, and cost-effective analytical tool. CE-C4 D devices, whose principle is based on the control of the ion movements under an electrical field, can be constructed even with a modest financial budget and limited infrastructure. A featured application was developed for quality control of antimicrobial drugs using CE-C4 D, with most recent work on determination of aminoglycoside and glycopeptide antibiotics being communicated. For aminoglycosides, the development of CE-C4 D methods was adapted to two categories. The first one includes drugs (liquid or powder form) for intravenous injection, containing either amikacin, streptomycin, kanamycin A, or kanamycin B. The second one covers drugs for eye drops (liquid or ointment form), containing either neomycin, tobramycin, or polymyxin. The CE-C4 D method development was also made for determination of some popular glycopeptide antibiotics in Vietnam, including vancomycin and teicoplanin. The best detection limit achieved using the developed CE-C4 D methods was 0.5 mg/L. Good agreement between results from CE-C4 D and the confirmation method (HPLC- Photometric Diode Array ) was achieved, with their result deviations less than 8% and 13% for aminoglycoside and glycopeptide antibiotics, respectively.

An Exposure Assessment of Arsenic and Other Trace Elements in Ha Nam Province, Northern Vietnam.

Concentrations of As and other trace elements were measured in groundwater, rice, hair, urine, and blood samples of people consuming As-contaminated groundwater in a village of Ha Nam province, northern Vietnam to understand the recent status of contamination and assess the possible risks of human exposure. Elevated concentrations of As in groundwater were still observed, exceeding the WHO guideline value in most of the tube wells investigated. Significant positive correlations between As concentrations in groundwater and human samples (hair and urine) were observed. Arsenic concentrations in human and hair appeared to be related to the groundwater usage habit, with higher levels found in drinking group than those in the washing group. Significant good correlations were also encountered between cumulative intakes of As, Mn, and Ba through groundwater consumption and hair concentrations. All these results indicate the chronic exposure to As and some other elements such as Mn and Ba. The total intakes of As, Mn, and Ba through rice and groundwater consumption were estimated to be ranged from 80-836, 49.3-1850, and 311-97100 µg/day, respectively. The daily intakes of As of the study area ranged from 1.6-16.7 µg/kg body wt./day, mean: 7.15 µg/kg body wt./day, in which about 85% of the subjects were above the provisional tolerable daily intake proposed by WHO.