Occurrence and treatment of emerging contaminants in water: A comprehensive review

Biodegradation of petroleum contaminants in natural water was studied within an Asian river context where high-suspended sediment content exists. Petroleum contaminant is one of the main pollutants in the Yellow River; at the same time, there is a high sediment content in the river system. This research highlighted the effect of sediment on the biodegradation of petroleum contaminants, as well as the related mechanisms regarding the effect. Biodegradation of petroleum contaminants was studied under different sediment contents. The distribution of petroleum contaminants in water and sediment phases as well as the relevant biodegradation kinetics were also investigated. The results showed that in water system with the sediment content of 0.5 g/L, about 84% of petroleum contaminants with the initial concentration of 11.64 mg/L could be degraded after incubation for 63 days at 20°C. It was also indicated that the presence of sediment exerted significant influences on the biodegradation of petroleum contaminants in water system, and the influences were different from one cultivation stage to another. In the first stage, the biodegradation rate was higher in the water system with sediment than in that without sediment. In the second stage, the biodegradation rate was lower in the former than in the latter. In the last stage, the biodegradation rate was higher in the water system with sediment than in that without sediment. The presence of sediment could stimulate the growth of petroleum contaminant-degrading bacteria. Moreover, about 90% of the contaminants and bacteria were attached on the sediment. The sorbed contaminants on sediment could also be biodegraded by bacteria. The biodegradation of contaminants in water and sediment phases all fit well with the first-order kinetics, and the biodegradation rate constant in water phase was higher than that in sediment phase. However, as the contaminant concentration at the sediment phase was much higher than that in water phase, the biodegradation of petroleum contaminants mainly occurred at the sediment phase.

Purpose. The aim of this study was to assess the effect of water and saliva contamination on the shear bond strength and failure site of orthodontic brackets and lingual buttons. Materials and Methods. 120 bovine permanent mandibular incisors were randomly divided into 6 groups of 20 specimens each. Both orthodontic brackets and disinclusion buttons were tested under three different enamel surface conditions: (a) dry, (b) water contamination, and (c) saliva contamination. Brackets and buttons were bonded to the teeth and subsequently tested using a Instron universal testing machine. Shear bond strength values and adhesive failure rate were recorded. Statistical analysis was performed using ANOVA and Tukey tests (strength values) and Chi squared test (ARI Scores). Results. Noncontaminated enamel surfaces showed the highest bond strengths for both brackets and buttons. Under water and saliva contamination orthodontic brackets groups showed significantly lower shear strengths than disinclusion buttons groups. Significant differences in debond locations were found among the groups under the various enamel surface conditions. Conclusions. Water and saliva contamination of enamel during the bonding procedure lowers bond strength values, more with orthodontic brackets than with disinclusion buttons.

Because studies have shown that adherence to dentin of resin-modified glass ionomers (RMGI) can be improved by surface treatment with a self-etching adhesive (SEA), the purpose of this in vitro study was to evaluate the water and saliva tolerance of this combination before and after application of SEA. Seventy cylinders of an RMGI (Fuji II LC) were bonded to the dentin of human teeth: 10 without any surface treatment, 10 after polyalkenoic acid conditioning, 10 after application of SEA, 10 after application of SEA on water contaminated dentin, 10 after application of SEA on saliva contaminated dentin, 10 on water contaminated light-cured SEA, and 10 on saliva contaminated light-cured SEA. The shear bond strength (SBS) was determined in a universal testing machine and the site of bond failure recorded. A Kruskal-Wallis test was performed followed by Games-Howell post-hoc pairwise comparison tests on the SBS results (p < 0.05), and a chi-square test was used for the fractographic analysis (p < 0.05). The lowest SBS was obtained without conditioning (5 ± 1 MPa). Polyalkenoic acid improved SBS (8 ± 2 MPa) and SEA increased it very significantly (15 ± 2 MPa), even in the case of water contamination (16 ± 2 MPa before application of SEA, 21 ± 4 MPa after application of SEA), or saliva contamination (20 ± 7 MPa before application of SEA, 19 ± 6 MPa after application of SEA). The group bonded without conditioning resulted in only adhesive fractures, showing a statistically significant difference from the other groups. SEA in association with the Fuji II LC RMGI increased the SBS very significantly, even in the case of water or saliva contamination.

Water dispensers remove disinfectant residues from tap water and thus are commonly present in Korean households; however, microbial contamination in water dispensers has recently become a major issue. To understand the occurrence of microbial contamination in water dispensers, we investigated microbial contamination in different dispenser types through heterotrophic plate count (HPC) and MiSeq-based microbial community analyses. Two newly purchased water dispensers were placed in a basement room and left for approximately 2 months; the HPC analysis indicated microbial contamination in the drinking water collected from these dispensers (160,000 and 48,000 CFU/mL, respectively). Taxonomic classification indicated that the basement dispensers were likely contaminated by freshwater bacteria, such as Acidovorax and Methylotenera. However, two dispensers located at the half landing and the first floor showed lower microbial contamination (110 and 78 CFU/mL, respectively). Furthermore, frequently used dispenser on the first floor showed higher HPCs on the faucet surface, which were classified as general oral bacteria like Hyphobacterium. We also observed that a deserted dispenser (6-year-old with no maintenance) placed on the half landing showed the least HPCs, although it seemed to have lost its filtration ability. Our results suggested that removal of disinfectant residues leads to an increase in the freshwater bacterial population in water tanks within dispensers, which could be avoided by frequent water circulation.

Evaluation of pepper mild mottle virus, human picobirnavirus and Torque teno virus as indicators of fecal contamination in river water

Phthalates are endocrine disruptors, reported to cause deformities and reproductive damages in animals. Numerous studies reported the presence of phthalates in water samples of rivers, wetlands, and estuaries, while the scenario in case of ponds is different, however they are reported as an integral part of biosphere. In this study, the level of phthalates’ contamination in the water samples collected from the different ponds of Amritsar district for four consecutive seasons in two years was analysed. The maximal level of phthalate contamination was found in samples collected during the monsoon season (July 2015) of first year of sampling followed by post-monsoon (October 2015) and winter season (January 2016). S8 sampling site was found to be the most phthalate contaminated site followed by S1=S11&gt;S2=S9=S4=S5=S7&gt;S6=S3&gt;S10. Benzyl butyl phthalate was most abundant (found in 32% water samples) followed by di-n-butyl and dimethyl phthalate, while diallyl phthalate and diethyl phthalate were not detected. The two main drivers for these seasonal variations were observed to be temperature and precipitation. Hence, this data will be useful to explain the temporal and spatial distributions of phthalates in aquatic ecosystem, as well as to devise cost-effective ways to reduce their ecological footprints.

This review article explores the applications of Basella alba (Malabar spinach), a fast-growing vine plant known for its numerous health benefits, culinary uses, and potential in dye and oil production. Fluoride contamination in water poses a significant global health and environmental challenge, particularly in regions where natural and industrial activities lead to elevated fluoride levels. Among its varied applications, B. alba has shown significant promise in the phytoremediation of contaminants in both water and soil, owing to its hyper accumulating capacities. The plant has a transfer factor value of more than 1 which means that there is higher accumulation of contaminants in parts of the plant than in soil. The objective of this review is to assess the feasibility of B. alba in contributing to sustainable water management solutions for fluoride contamination, while offering a comprehensive evaluation of its environmental remediation potential. The article examines the biosorption capabilities of B. alba based on its established use in phytoremediation, offering insights into its suitability for addressing fluoride contamination in water. This article is organized into sections starting with an introduction, which brings explains the global challenge of fluoride, and different treatment techniques justifying why biosorption needs to be considered, cases of application of phytoremediation using B. Alba, and finally exploring the success factors for plants that have been applied for both biosorption and phytoremediation.

&amp;lt;p&amp;gt;&amp;lt;strong&amp;gt;Abstract&amp;lt;/strong&amp;gt;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;This study investigated the physicochemical and microbial contamination in the drinking water of fifteen villages in the Nowshera District. For this purpose, water samples (n=165) were collected and analyzed for pH, alkalinity, total dissolved solids, anions: carbonate (CO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;), bicarbonate (HCO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;), chloride (Cl), fluoride (F), nitrate (NO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;) and sulphate (SO&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;), cations: sodium (Na), potassium (K), calcium (Ca), magnesium (Mg) and arsenic (As) and microbial parameters (total coliform, fecal coliform and E coliform). Results revealed higher F, NO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; and Fecal coliform contaminations in drinking water of the study area that have surpassed 28%, 5% and 30% of sampling respectively.&amp;amp;#160; Higher level of these contaminants in drinking water could cause health hazards such as dental and skeletal fluorosis, joint pain, dysentery, diarrhea and various other water borne diseases among the inhabitants of the study area. Fluoride contamination in water could be attributed to the F containing carbonates rocks of Peshawar Basin. Higher NO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; and Fecal coliform contaminations in water could be attributed to surface ongoing agriculture activities and animals wastes that have affected dominantly the shallow aquifers in the study area. The study, therefore, strongly recommends deep well boring and defluoridation of the drinking water in the study area.&amp;amp;#160; &amp;amp;#160;&amp;amp;#160;&amp;lt;/p&amp;gt;

Predicting the spread of contamination in water distribution networks laid on sloping terrains

Ensuring food and water safety using magnetic mesoporous silica nanomaterials-based biosensors

Bacteroides-Prevotella group is one of the most promising targets for detecting fecal contamination in water environments, principally due to its host-specific distributions and high concentrations in feces of warm-blooded animals. We developed real-time PCR assays for quantifying chicken/duck-, chicken-, and duck-associated Bacteroides-Prevotella 16S rRNA genetic markers (Chicken/Duck-Bac, Chicken-Bac, and Duck-Bac). A reference collection of DNA extracts from 143 individual fecal samples and wastewater treatment plant influent was tested by the newly established markers. The quantification limits of Chicken/Duck-Bac, Chicken-Bac, and Duck-Bac markers in environmental water were 54, 57, and 12 copies/reaction, respectively. It was possible to detect possible fecal contaminations from wild ducks in environmental water with the constructed genetic marker assays, even though the density of total coliforms in the identical water samples was below the detection limit. Chicken/Duck-Bac marker was amplified from feces of wild duck and chicken with the positive ratio of 96 and 61%, respectively, and no cross-reaction was observed for the other animal feces. Chicken-Bac marker was detected from 70% of chicken feces, while detected from 39% of cow feces, 8.3% of pig feces, and 12% of swan feces. Duck-Bac marker was detected from 85% of wild duck feces and cross-reacted with 31% of cow feces. These levels of detection specificity are common in avian-associated genetic markers previously proposed, which implies that there is a practical limitation in the independent application of avian-associated Bacteroides-Prevotella 16S rRNA genetic markers and a combination with other fecal contamination markers is preferable for detecting fecal contamination in water environments.

ABSTRACTThis article presents a novel non-destructive microwave technique for predicting fluoride contamination in pure water. The proposed microwave-based sensing technique uses an open-ended coaxial probe (OECP) microwave sensor for monitoring fluoride concentration in water. The sensor output is the input of Artificial Neural Network (ANN) for predicting the complex dielectric constant of contaminated water, which has direct correlation with fluoride contamination in water. The ANN is trained through analytically generated sensor output for various lossy liquid materials and tested for experimental data obtained through laboratory prepared samples. Hence, the proposed technique has the capability to compute the amount of fluoride contamination faster, when compared to analysis only method. The results shows that a well-trained ANN is computationally efficient and capable of predicting the amount of fluoride level in the pure water. The results also has good agreement with the data published in the literature at room temperature.

A semipermeable membrane device (SPMD) is described for passive in-situ monitoring of organic contaminants in water. The device consists of a thin film of neutral lipid (molecular mass generally ≥600 Da), such as triolein, enclosed in thin-walled layflat tubing made of low-density polyethylene or another nonporous polymer. Mathematical models are developed for the device and fitted to concentration data from 2,2',5,5'-tetrachlorobiphenyl and phenanthrene flow-through exposures and dissipation experiments. Model estimates of the average concentrations of test chemical in laboratory exposure water differed from the measured concentrations by <2-fold, indicating that it may be feasible to use the device to determine average concentrations of organic contaminants in natural waters

The Citarum watershed is West Java Province's most important water resource; hence, harmful compounds should be monitored regularly. This study assessed pollution levels along with ecological and health risks from Cd, Pb, Mn, Fe, Cu, Cr, and Hg contamination in river water, sediment, groundwater, and soil in Citarum's upper watershed. In river water, the average amounts of Cd, Pb, Mn, Fe, Cu, Cr, and Hg were 0.002, 0.05, 0.092, 0.649, 0.022, 0.001, and 0.421mg/L. In sediment, they were 7.4, 1175.1, 32,289.9, 37.3, 3.9, and 0.015mg/kg. The mean concentrations of Cd, Pb, Mn, Fe, Cu, Cr, and Hg in groundwater were 0.004, 0.046, 0.567, 0.366, 0.019, 0.001, and 0.177mg/L, and in soil, BDL, 10.2, 744.6, 50,094.1, 45.6, 5.9, and 0.015mg/kg. The river water and groundwater were highly polluted by PTEs, with HPI values of 14,733 and 933, respectively. While PTEs pollution levels and risk in sediment and soil were low based on I-geo, CF, PLI, and M-ERM-Q values, PTEs contamination in river water may cause adverse impacts on aquatic living organisms (HQ > 1). The population doing recreational activities in river ecosystems was still safe from non-carcinogenic and carcinogenic impacts due to PTEs exposure from river water and sediment (THI < 1 and TCR value < 1E-04), while the population in the upper Citarum River was not safe from the carcinogenic risk due to PTE exposure from groundwater and soil (TCR > 1E-04). The sensitivity analysis showed that Cd concentration in groundwater is the most influential factor in cancer risk, with a total contribution of 99.9%. Therefore, a reduction in Cd concentration in groundwater is important to reduce cancer risk in the population.

Exposure to fecal contamination continues to be a major public health concern for low-income households in sub-Saharan Africa. Drinking water and hands are known transmission routes for pathogens in household environments. In an effort to identify explanatory variables of water and hand contamination, a variety of analytical approaches have been employed that model variation in E. coli contamination as a function of behaviors and household characteristics. Using data collected from 1217 households in Bagamoyo, Tanzania, this investigation compares the explanatory variables identified in the three different modeling methods to explain hand and water contamination: ordinary least squares regression, logistic regression, and classification tree. Although the modeling approaches varied, there were some similarities in the results, with certain explanatory variables being consistently identified as being related to hand and water contamination (e.g., water source type for the water models and activity prior to sampling for the hand models). At the same time, there were also marked differences across the models. In sum, these results suggest there are benefits to using multiple analysis methods to assess relationships in complex systems. The models were also characterized by low explanatory power, suggesting that variation in hand and water contamination is difficult to capture when analyzing one-time water and hand rinse samples. For improved model performance, future studies could explore modeling of repeat measures of water quality and hand contamination.