Background. Lead is a heavy metal that is well known to pose a threat to human health. Although the sale and use of lead paint has been banned in much of the developed world, lead is still commonly used in enamel paints in the developing world, including Cambodia. As Cambodia's economy grows, this may increase the purchase and use of lead-based paints, thus potentially exposing more of the population to the toxic effects of lead. Objective. This study was performed to evaluate the concentration of lead in enamel paints in Cambodia using a method that is quick, effective, and cost-efficient. Methods. A handheld X-ray fluorescence analyzer was used to evaluate 21 samples of enamel paint, including 8 replicates that were randomly purchased from three shops in Phnom Penh, Cambodia to evaluate the level of metals. All of the paint samples in the current study were manufactured in Thailand. Discussion. Ninety percent of the enamel paints sampled in Cambodia exceeded the voluntary standard of 100 μg/g lead of the producing country, Thailand. The mean and median levels for lead were 11,833 μg/g, and 4,961 μg/g, respectively. Conclusion. Based on our pilot-scale assessment, high levels of lead appear to be common in enamel paints in Cambodia, and a fuller assessment of the situation is warranted. Import and production of such toxic products should be avoided and appropriate labeling and public warnings should be provided.

The mutagenic and genotoxic activity of vinasses collected from a fuel alcohol plant, located in the municipality of Frontino, Northwestern Colombia, were evaluated. Two samples obtained from an 82-L capacity hybrid reactor (UASB-anaerobic filter (AF)-UASB) were studied under laboratory conditions after being treated with biological oxidation, the first, and the second with Fenton reaction consecutively. Mutagenicity was evaluated in vitro by the Ames test using strains TA98 and TA100 with and without S9 metabolic activation. The genotoxic analysis was conducted using the Allium cepa roots assay where chromosomal aberrations were used as clastogenic or aneugenic response markers, and micronuclei as mutagenic response. The Ames test results showed a strain-dependent positive linear association with the vinasse sample concentration before treatment (dose–response effect). Unlike TA100, strain TA98 showed a mutagenic effect in both the presence and absence of metabolic enzymes. After the biological oxidation treatment, vinasse mutagenicity significantly decreased. Finally, after Fenton treatment, the sample did not induce any mutagenic event. Genotoxic activity was observed in all three samples, but there was a higher frequency in the vinasse sample before treatment. Concerning the frequency of micronuclei, no clear association was observed with either the concentration or the type of sample.

Catalytic ozonation process (COP) is a promising advanced oxidation process for petrochemical wastewater (PCW) treatment. However, the lack of economical and effective catalysts limits its application. Manganese sand ore (MSO) was utilized as a heterogeneous catalyst for ozonation of organic contaminants in PCW in this study. The calcined MSO-assisted COP (cMSO-COP) of aniline exhibited greater degradation than natural MSO-assisted COP or single ozonation process (SOP). The cMSO significantly promoted hydroxyl radical-mediated oxidation, decreased the ozonation activation energy by about 20 %, and doubled the reaction rates in comparison with SOP. The cMSO-COP increased the chemical oxygen demand (COD) removal of PCW twofold relative to SOP. The number of polar organic contaminants decreased by 50 % after cMSO-COP treatment. This study demonstrated the potential use of cMSO for efficient ozonation of petrochemical-derived contaminants at low cost.

In this work, an assessment of groundwater quality and its compliance with Brazilian environmental protection standards was carried out. Ground waters from the Serra Geral aquifer are currently used for human consumption at the western region of the Brazilian state of Paraná. Ground water samples from 10 wells covering the entire Toledo municipality rural region were collected and analysed by two highly accurate and sensitive spectrometric techniques: inductively coupled plasma–optical emission spectrometry (ICP-OES) and total reflection X-ray spectrometry (TXRF). Among all detected elements, 18 elements (As, Ba, Br, Ca, Pb, Cl, Co, Cu, Cr, Fe, P, S, Mn, Ni, K, Ti, V and Zn) were measured by the TXRF technique while three elements (B, Mg and Na) were measured by ICP-OES. Trace element concentration levels were then compared with Brazilian environmental legislation (BEL). From the results obtained, concentrations of chromium, iron, arsenic, selenium, manganese and barium were detectable in some wells at slightly above the maximum limits allowed by the BEL.

The aim of this study was to evaluate the efficiency of a passive point-of-use treatment system, namely, a polyvinyl (alcohol) (PVA) nanofiber membrane/activated carbon column, for the treatment of harvested rainwater. The efficiency of SMI-Q10 [quaternized poly (styrene-co-maleimide)] nanofiber membrane disks placed in a filtration assembly for the treatment of surface water (Plankenburg River, Western Cape, South Africa) and harvested rainwater was also assessed. Two rainwater harvesting tanks were installed at the Welgevallen Experimental farm, Stellenbosch, South Africa, with the filtration system intermittently attached to the tanks for collection of rainwater samples throughout the study period. Parameters used to monitor the filtration systems included heterotrophic bacteria, Escherichia coli, and total coliform enumeration and the presence/absence of adenovirus. When compared to drinking water guidelines, the results indicated that 3 L of potable water could be produced by the synthesized PVA nanofiber membrane/activated carbon column. However, PCR assays indicated that adenovirus and numerous bacteria such as Klebsiella spp., Legionella spp., Pseudomonas spp., and Yersinia spp. were not effectively removed by the filtration system utilized. Additionally, the SMI-Q10 nanofiber membrane disks did not remove viruses from the river or tank water samples as bovine adenovirus 3 strain, simian adenovirus, and human adenovirus A strain were detected in all water samples analyzed. Thus, while the microfiltration system was efficient in reducing the level of indicator organisms to within drinking water standards, further optimization of the electrospun filtration membranes is required as molecular analysis revealed that numerous opportunistic bacterial pathogens and viruses persisted after filtration.

In this study, natural calcium-rich attapulgite (NCAP) was used to develop a low-cost adsorbent for removing fluoride (F⁻) from contaminated water. The results showed that calcination can dramatically increase the F⁻ sorption capacity of NCAP and that the maximum F⁻ sorption capacity occurred at 700 °C. The sorption of F⁻ on NCAP heated at 700 °C (NCAP700) followed pseudo-second-order kinetics and was described by the Langmuir equilibrium model. The estimated F⁻ sorption capacity was approximately 140.0 mg/g at pH 8.0, which was comparable with the sorption capacities of some nanomaterials. The sorption of F⁻ on NCAP700 performed well at pH values of 7 to 10. In addition, anions such as NO₃ ⁻ and SO₄ ²⁻ did not affect fluoride removal, but PO₄ ³⁻ and HCO₃ ⁻ moderately influenced fluoride removal. A column study conducted using NCAP700 with a particle size of 0.2–0.5 mm indicated that the adsorbent could effectively purify nearly 200 bed volumes (BV) of water containing 3.0 mg F/l at pH 8.5. The removal of F⁻ from water mainly resulted from the formation of calcium fluoride precipitates and the complexation of fluoride with the –OH group of NCAP700, which was further confirmed by scanning electron microscopy–energy dispersive spectrometry (SEM-EDS) and X-ray photoelectron spectroscopy (XPS).

The epibenthic amphipod Melita plumulosa shows unique gene expression profiles when exposed to different contaminants. We hypothesized that specific changes in transcript abundance could be used in a battery of quantitative polymerase chain reaction (qPCR) assays as a toxicity identification evaluation (TIE)-like approach to identify the most relevant stressor in field-contaminated sediments. To test this hypothesis, seven candidate transcriptomic markers were selected, and their specificity following metal exposure was confirmed. The performance of these markers across different levels of added metals was verified. The ability of these transcripts to act as markers was tested by exposing amphipods to metal-contaminated field-collected sediments and measuring changes in transcript abundance via qPCR. For two of the three sediments tested, at least some of the transcriptomic patterns matched our predictions, suggesting that they would be effective in helping to identify metal exposure in field sediments. However, following exposure to the third sediment, transcriptomic patterns were unlike our predictions. These results suggest that the seven transcripts may be insufficient to discern individual contaminants from complex mixtures and that microarray or RNA-Seq global gene expression profiles may be more effective for TIE. Changes in transcriptomics based on laboratory exposures to single compounds should be carefully validated before the results are used to analyze mixtures.

The study analyzes the presence and the origin of heavy metals in environmental compartments affected by anthropogenic activities. The paper presents the results of a field study performed on the sediments of two of the main small urban creeks of the city of Prague (Czech Republic). The aim of the survey was to verify the presence and bioavailability of heavy metals (Cu, Cr, Ni, Pb, Zn) in the aquatic environment (water as well as bottom sediments), and to assess the source of these pollutants. The results were processed to evaluate the enrichment factor and the partition coefficient, and were statistically analyzed through the analysis of variance and the principal component analysis. Comparison with relevant environmental quality standards showed that measured heavy metal concentrations were always lower than the probable effect concentration (PEC). On the contrary, the threshold effect concentration (TEC) was frequently exceeded. Sequential extraction analysis showed that the bioavailability of studied metals is quite high, suggesting that they could be easily released from the sediment to the aquatic environment. Overall, several sources of pollution, different for the different metals, were identified, all related with anthropogenic factors.

Photocatalysis is one of environment-friendly and efficient methods for municipal wastewater disinfection. In this research, two pathogens, Staphylococcus aureus and fecal coliform, were chosen to investigate the disinfection effects of several TiO₂ photocatalysts on sewage plant secondary treatment effluent, compared with UV disinfection. The results show that TiO₂ species and concentrations, light intensity, light time, and pH all have significant influences on the pathogen deactivation. It was found that the optimum operation parameters were as follows: the P25 commercial TiO₂ powder at the concentration of 0.5 g/L, the light intensity of 40 W, and the radiation duration of 20 min. The photocatalyst performed better at either acid or alkaline condition than neutral. The TiO₂ photocatalytic deactivation to S. aureus was more effective than the UV.