Antibiotic residues and antimicrobial resistance in surface water are issues of global concern, especially in developing countries. In this study, the occurrence of seven antibiotics and one ...antiparasitic agent was determined in surface water samples collected from four rivers running through Hanoi urban area in the Red River Delta, northern Vietnam. The pharmaceuticals in water samples were analyzed by solid-phase extraction combined with liquid chromatography–tandem mass spectrometry method. The concentrations of pharmaceuticals in our samples ranged from 3050 to 16,700 (median 7800) ng/L, which were generally higher than levels found in river water from many other locations in the world. Amoxicillin, oxfendazole, and lincomycin were the most dominant and frequently detected compounds (detection rate 100%), which together accounted for 76 ± 14% of total concentrations. Sulfacetamide and sulfamethoxazole were detected at moderate concentrations in more than two-thirds of the analyzed samples. The remaining antibiotics (i.e., azithromycin, ciprofloxacin, and ofloxacin) were found at lower detection frequency and concentrations. Antibiotic concentrations in the water samples were not significantly different between the investigated rivers. Meanwhile, levels of pharmaceuticals in the samples collected in February 2020 were higher than those found in the remaining samples, largely due to the sharp decrease in sulfamethoxazole and azithromycin concentrations of the samples collected in March and April. Considerable ecological risks of antibiotics in surface water were estimated for some compounds such as amoxicillin, ciprofloxacin, and ofloxacin.
This review provides focused insights into the contamination status, sources, and ecological risks associated with multiple classes of antibiotics in surface water from the East and Southeast Asia ...based on publications over the period 2007 to 2020. Antibiotics are ubiquitous in surface water of these countries with concentrations ranging from <1 ng/L to hundreds μg/L and median values from 10 to 100 ng/L. Wider ranges and higher maximum concentrations of certain antibiotics were found in surface water of the East Asian countries like China and South Korea than in the Southeast Asian nations. Environmental behavior and fate of antibiotics in surface water is discussed. The reviewed occurrence of antibiotics in their sources suggests that effluent from wastewater treatment plants, wastewater from aquaculture and livestock production activities, and untreated urban sewage are principal sources of antibiotics in surface water. Ecological risks associated with antibiotic residues were estimated for aquatic organisms and the prevalence of antibiotic resistance genes and antibiotic-resistant bacteria were reviewed. Such findings underline the need for synergistic efforts from scientists, engineers, policy makers, government managers, entrepreneurs, and communities to manage and reduce the burden of antibiotics and antibiotic resistance in water bodies of East and Southeast Asian countries.
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•Antibiotic contamination status in East/Southeast Asia's surface water is reviewed.•Antibiotics are ubiquitous in surface water, especially in aquaculture and urban areas.•Antibiotic levels varied greatly from few ng/L to hundreds μg/L in surface water.•Ecological risks and prevalence of antibiotic resistance were widely observed.•Regional monitoring studies and environmental guidelines for antibiotics are needed.
Unsubstituted and methylated polycyclic aromatic hydrocarbons (22 PAHs and 17 Me-PAHs) were examined in surface sediments collected from the Red River and four inner-city rivers of Hanoi City, ...Vietnam. Concentrations of total PAHs and Me-PAHs ranged from 52 to 920 (median 710) and from 70 to 2600 (median 1000) ng/g dry weight in samples of dry and wet seasons, respectively. Significant correlation was observed between total PAHs and organic carbon contents (Spearman's
ρ
= 0.782;
p
< 0.05). PAHs were more abundant than Me-PAHs in all samples and dominated by 4–6 ring compounds. The most predominant PAHs were benzo
ghi
perylene, benzo
b/j
fluoranthene, chrysene, pyrene, fluoranthene, and phenanthrene. Methylated derivatives of naphthalene, phenanthrene, anthracene, and benz
a
anthracene were frequently detected. The patterns of PAHs indicated principal pyrogenic sources (notably gasoline exhaust) in this highly urbanized area. The occurrence of several PAHs were occasionally associated with adverse effects on benthic organisms of the inner-city rivers.
The aim of the present study is to determine four anionic alkyl sulfate (AS) surfactants with different alkyl chains, namely, C8, C10, C12, and C14, in wastewater by CE with capacitively coupled ...contactless conductivity detection (CE‐C4D). The conditions effective for the separation of the four AS surfactants were systematically optimized and found to be in a Tris‐His (50 mM/20 mM) BGE solution at a pH of 8.95, using a separation voltage of +15 kV, hydrodynamic injection by siphoning using a 20 cm injection height and an injection time of 20 s. The LODs for C8, C10, C12, and C14 were 2.58, 2.30, 2.08, and 3.16 mg/L, respectively. The conditions used to achieve the simultaneous adsorption and preconcentration of the AS surfactants using Al2O3 beads were pH of 3 and 0.1 mM NaCl. The adsorption efficiencies were found to be 45.6, 50.8, 81.7, and 99.9%, while the desorption efficiencies reached 66.1, 70.4, 83.9, and 100.0% for C8, C10, C12, and C14, respectively. The concentrations of the AS surfactants in wastewater samples were quantified by CE‐C4D after preconcentration by simultaneous adsorption using Al2O3 beads. The results obtained from the proposed method were consistent with those obtained by HPLC‐MS/MS, with a deviation of less than 15%. Our results indicate that the CE‐C4D performed after preconcentration by an adsorption technique using Al2O3 beads is a new, inexpensive, and suitable method for quantifying AS surfactants in wastewater samples.
In this study, the development of our purpose‐made capacitively coupled contactless conductivity detection (C4D) for CE is reported. These systems have been employed as a simple, versatile, and ...cost‐effective analytical tool. CE‐C4D 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‐C4D, with most recent work on determination of aminoglycoside and glycopeptide antibiotics being communicated. For aminoglycosides, the development of CE‐C4D 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‐C4D 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‐C4D methods was 0.5 mg/L. Good agreement between results from CE‐C4D 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.
•New design of CE-C4D purpose-made system.•CE-C4D methods for analyses of β-lactam-based antibiotics.•Affordable tool for quality control and detection of counterfeiting of antibiotic formulations.
A ...simple and inexpensive approach for determination of various antimicrobial drugs using a purpose-made compact capillary electrophoresis (CE) instrument with capacitively coupled contactless conductivity detection (C4D) is reported. The objective of the work is to propose an affordable and easily-implemented tool for quality control and detection of counterfeiting of antibiotic formulations in resource constrained developing countries. The design of the purpose-made CE-C4D system was improved according to the feedback from over 10 years of use of our previous instrument. CE-C4D methods were for the first time developed to analyze β-lactam-based antibiotics commonly used in Vietnam, including single- β-lactam antibiotics (i.e. Cephalexin, Cefotaxime Sodium, Cefixime and Sulbactam) as well as β-lactams co-formulated with Sulbactam (i.e. Amoxicillin, Ampicillin, Cefoperazone and Sulbactam). Single β-lactam antibiotics were analyzed using a background electrolyte (BGE) composed of Tris/Ace (10 mM, pH 7.8) whereas β-lactam – Sulbactam combinations were simultaneously separated using a BGE containing Tris/Ace (10 mM, pH 7.5). The best achieved detection limits were 2.0 mg/L and 1.0 mg/L for these two groups, respectively. Good agreement between results obtained from CE-C4D and standard confirmation methods (LCMS) was achieved, with a coefficient of determination, r2, of 0.9991. The applicability of the developed CE-C4D method was demonstrated for quality control of 24 β-lactam-based antimicrobial drugs available in Vietnam.
We report the first study of adsorption of a strong polycation, poly(3-methacryloylamino propyl-trimethylammonium chloride) (PMAPTAC) on nanosilica (nano-SiO2) extracted from rice husk. PMAPTAC was ...successfully synthesized and characterized by 1H-nuclear magnetic resonance (1H NMR) and gel-permeation chromatography (GPC) methods. PMAPTAC characteristics were found to be Mn = 1.61 × 105, Mw = 2.16 × 106, Mw/Mn = 13.4. Beta-lactam cefixime (CEF) removal was dramatically enhanced after polymer coating by pre-adsorption of PMAPTAC on nano-SiO2. The new adsorbent was dubbed PMAPTAC coated nano-SiO2 (PCNS). Required time for adsorption, PCNS dosage, pH, and KCl concentration were thoroughly optimized for CEF removal and achieved at 120 min, 10 mg/mL, 4, and 1 mM, respectively. A two-step model can be used to fit the PMAPTAC on nano-SiO2 and CEF on PCNS isotherms at different ionic strengths. Adsorption kinetics of CEF on PCNS appears to be pseudo-second-order. CEF removal using PCNS reached 89%, saturating at 10.9 mg/g. The driving force for CEF adsorption on PCNS was primarily Coulombic interaction of negative CEF species and positive surface charge of PCNS. After three reuses, CEF elimination was still greater than 85%. The influence of some organics on CEF treatment using PCNS was insignificant while CEF removal from a real hospital wastewater sample was greater than 70%. Our study indicates that a hybrid and new adsorbent based on nano-SiO2 rice husk with pre-adsorption with PMAPTAC is useful for antibiotic removal from wastewater.
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•Synthesized PMAPTAC coated nanosilica forms highly positive charge PCNS as a novel adsorbent.•The treatment of antibiotic cefixime (CEF) reached 90 % with pH 4, time for adsorption 120 min, and dosage of PCNS 10 mg/mL.•Adsorption isotherm of CEF was in accordance with two-step model while adsorption kinetic was well fitted by pseudo-second-order model.•The treatment of CEF using PCNS was greater than 85% after three regenerations.
Plastic pollution in freshwater ecosystems, including microplastics (MPs) smaller than 5 mm, has become an emerging global concern. Asia is considered a “hot spot” for plastic pollution due to rapid ...economic and demographic growth, together with rapid urbanization. Here, we provide an overview of the current knowledge on MP abundance, sources, fate, and transfer in Asian freshwater ecosystems based on publications from January 2014 to May 2021. MP contamination in freshwater compartments, including water, sediment, and biota, was found to vary strongly. In water, it ranged from 0.004 items m−3 in a moderately urbanized region to more than 500,000 items m−3 in a dumping river in a highly populated watershed. In the sediment, MP abundance ranged from 1 to more than 30,000 items kg−1 dry weight. Polyethylene (PE) and polypropylene (PP) were predominant in both water and sediment compartments. MP was detected in biota samples from all the studied species, but their abundance depended on the locations and species studied. Overall, MP characteristics (form, size, color, and polymer type) depended on sources and natural constraints (mainly hydrodynamics). This study also revealed that MP in Asian freshwater ecosystems mainly originated from domestic wastewater/runoff, followed by industrial emissions, fisheries and aquaculture wastewater. Plastic waste is not efficiently recycled or incinerated in Asia, leading to MP transfer and accumulation in the aquatic environment, and, more importantly, to ingestion by low to high trophic level organisms. This work highlights several knowledge gaps to guides future research to improve MP pollution management for the sustainable development of highly populated regions such as Asia.
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•Overview of microplastics (MPs) in Asian freshwater ecosystems•High variability in MP abundances in water and sediment samples between studies•Various sources and factors influencing MP contamination and transfers in Asia•Perspectives for better MP management for sustainable development in Asia
This study investigated the contamination levels and sources of As and Cd vicinity area from Nui Phao mine that is one of the largest tungsten (W) open pit mines in the world. Soil and plant samples ...were collected from the study area to identify the concentrations of As and Cd using aqua-regia or HNO
3
digestion. According to the Vietnamese agricultural soil criteria, all soil samples were contaminated with As and Cd. The distribution of As concentration is related to the distance from the Nui Phao mine. The higher As concentrations were measured in the area close to the mine. However, the Cd distribution in the soil showed a different pattern from As. Enrichment factor and Geoaccumulation Index (Igeo) indicated that As in the soil is derived from the mining activities, while Cd could have other geogenic or anthropogenic sources. The ranges of As and Cd concentration in polished rice grains in the Nui Phao mine area exceeded the CODEX criteria (0.2 mg/kg), which indicated extreme contamination. The arsenic concentration between soil and plant samples was determined to be a positive correlation, while the Cd concentration showed a negative correlation, implying that As and Cd have different geochemical behavior based on their sources.
•Vitamin B6 and Mg were simultaneously determined by CE-C4D.•Vitamin B6 and Mg peaks were well separated within < 10 min.•A simple and reliable method was developed for pharmaceutical/nutraceutical ...samples.•Single-run CE-C4D analysis can replace HPLC and ICP-OES conventional methods.•Acceptable agreement between measured/label claim contents was achieved.
Vitamins and minerals are usually incorporated in pharmaceutical and nutraceutical products, but a simple, rapid, and inexpensive analytical method for their simultaneous determination is still lacking. In this study, we developed a quantification method for pyridoxine (vitamin B6) and magnesium (Mg) by using purpose-made capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) instrument. Main analytical conditions include: fused silica capillary (total length 55 cm, effective length 40 cm, inner diameter 50 μm); background electrolyte consisted of 10 mM L-arginine/acetic acid (pH 5) with 20% acetonitrile; separation voltage + 20 kV; hydrodynamic injection (siphoning at 20 cm in 25 s). Detection limits of vitamin B6 and Mg were 1 and 0.1 mg/L, respectively. Good linearity (R2 > 0.999) was observed for vitamin B6 and Mg calibration curves over concentration ranges of 3–100 and 0.3–200 mg/L, respectively. The method was applied to analyze vitamin B6 and Mg in several pharmaceutical and nutraceutical samples. The analytical results obtained by our method were in good agreement with reference methods (i.e., HPLC for vitamin B6 and ICP-OES for Mg). High-efficient and low-cost CE-C4D method can accordingly serve as a promising tool for concurrent analysis of inorganic and organic species in pharmaceutical and nutraceutical analysis.
