This work investigates the possibility of using constructed wetland system for the management of municipal wastewaters with reuse strategies for the irrigation of landscapes in Ouled Djellal city of Biskra, Algeria. The design of this system was based on the characteristics (volume and physico-chemical properties) of wastewaters and the urban plan of the studied city. Results showed that studied effluent is easily biodegradable with COD/BOD5 of  1.84 (< 3), BOD5 (325 - 365 mg/L), COD (620-644 mg/L) and TSS (120-250mg/l). The peak of raw wastewater flow was found to be 32.4 m3 /h, which was used for the calculation of drip network for the landscape irrigation. The selected variant for the configuration of the CW system is HF-VF-HF, which occupies an area of 11.580 m2 and will reduce significantly the water pollution. The treated wastewater will be reused for the irrigation of landscapes via the dimensioned drip network. Results of this study showed that the proposed design for the system (treatment and reuse) would be effective in reducing pollution in the urban environment by ensuring possibility of the reuse of the treated water for irrigation. This gives also a great opportunity for using this strategy in small neighborhoods in other cities.

This study was conducted in order to assess the level of heavy metals in the water, soil, and tissues of Pomacea canaliculata from Lake Dakong Napo, Esperanza, Philippines as well as identify the histopathological alterations in the gonads and muscles of the snail. Heavy metals were detected using Atomic Absorption Spectrometry and slides for histological studies were prepared using histological routine procedure. Results revealed that in sediments Cr (174.67±62 mg/L) and Ni (269.33±17.56 mg/L) were above from the recommended safe limits of the international standards, US EPA (≤25) and FAO (≤50) while concentrations of Pb (16.35± 0.58 mg/L), Cd (5±1.42 mg/L), and Cr (1±0 mg/L) in water were above from the recommended safe limits of the national standards, DAO (≤0.05; ≤0.01; ≤0.05). These heavy metals were below the permissible limits in the gonads and muscles of P. canaliculata however, alterations in the tissues of the snail are evident suggesting that these heavy metals and other environmental stressors are negatively affecting the organisms inhabiting the lake.

Microplastics pollution has become a matter of global concern because of its effects on aquatic life and the ecosystem. This study investigated the abundance and types of microplastics found in an urban canal of Thailand. Water quality and the relationship between microplastics pollutants and the physicochemical properties of water quality were also analyzed to provide evidence for this study. The mean abundance of microplastics was 370 ± 140 particle(p)/m3. The highest number and concentration of microplastics were found on surface water corelated with urbanization. Transparent brown and transparent colors in the form of film and fiber/lines were the predominant morphology. Polypropylene (PP) and polyethylene (PE) were the most abundant polymer type in all surface water samples. Furthermore, water quality was related with microplastic pollution. The physicochemical properties of turbidity (0.99), conductivity (0.97), total solid (0.95) and biological oxygen demand (0.84) were accounted for greatest influences on microplastics distribution. The estimated equation of microplastics was also closely corelated with water quality. These results demonstrate that microplastic pollution has progressed more in poor water quality than good water quality, indicating that the inflow process and sources of microplastics are similar to those of other pollutants. Therefore, this study is expected to encourage and enforce solid waste and wastewater management policies that prevent microplastics pollution in the environment.

In developing countries, wastewater treatment is confined to secondary systems. Hence even after treatment, wastewater effluent has a high level of nutrients which causes eutrophication and has destructive impacts on receiving bodies. Literature reveals that phycoremediation can be the best solution to address the problem faced but is time-consuming, ranging from days to weeks. Hence, the present study aimed to determine an optimum detention time for the microalgal system to treat domestic wastewater. The retention time for treatment in the study was divided into an aeration and settling periods. During the study, aeration time varied from 2 hours to 24 hours, followed by 1-hour settling period for each aeration time. Optimum detention time for microalgal treatment was obtained at 11 hours of detention time (10 hours aeration and 1-hour settling). Parameters analyzed during the study were pH, EC, TS, TSS, TDS, nitrate, phosphate, ammonia, COD and DO. However, the main focus was on nutrients (phosphate and ammonia) and organics (COD) removal while determining the optimum detention time. Maximum removal efficiency obtained for COD, ammonia and phosphate for non-filtered effluent was 75.61%, 90.63% and 83.29%, respectively. However, removal efficiency further increased for filtered effluents to 86.34%, 100% and 91.12% for COD, ammonia and phosphate, respectively. Algal treatment offers an ecologically safe and more affordable system for nutrient removal and eliminates the need for tertiary treatment.

This article is devoted to the study of the impact of the development of the Lomonosov diamond deposit on the pollution of watercourses with trace metals. The high water cut of the exposed rock strata and the presence of groundwater require the constant pumping of wastewater into the filtration fields, and then to the nearby river. This work shows a significant contribution of discharge processes and drainage waters to the trace metal contents in the surface waters of the Zolotitsa river; an increase in the concentrations of Mg, Sr, Zn, Cu, Cd, As , and Se was noted. The seasonal variations of physicochemical parameters, the trace metal contents, as well as the total uranium and U isotope 234U, 238U, and 235U were analysed. Calculations of water quality indices (HMEI, HMPI, and HMTL) and public health risks (HI and CR) revealed a high level of pollution of certain sections of watercourses. Radiological studies of polluted rivers in the area showed a satisfactory situation. The results of this study can provide a basis for the subsequent monitoring of the impact of anthropogenic activities on nearby watercourses in the development of diamond deposits.

The time series model has been exploited to estimate the relationship between meteorological variables and air in Mashhad with respiratory mortality. For this purpose, data on respiratory mortality was based on data recorded on March 2014 to 2015. In order to investigate the effect of meteorological variables and air pollution values on respiratory mortality, the Box- Jenkins time series model has been utilized. Moreover, the effect of age and seasons on the number of respiratory deaths was assessed by the linear regression and ANOVA test. The fit of the final model to determining the monthly relationship between meteorological variables and air pollutants with the number of respiratory mortalities is a (1,0,2) ARIMA. In the monthly survey, temperature and rainfall have the inverse relationship and pressure has the direct relationship with the average of 7.4, 3.2, and 17.42 on the respiratory mortality. It was also found direct relationship between the mortality from respiratory diseases and CO and O3 and inverse relationship with SO2, NO2 and PM2.5 pollutants with an average of 67.40, 17.42, 17.89, 6.83, and 0.68, respectively. Also, the results of this study indicate that older people are more likely to be affected by the inappropriate status of air quality by 0.37%. The results showed a significant difference between respiratory mortality in different seasons of the year, and the highest number of deaths occurred in the winter.

Fat, oil, and grease (FOG) deposits in the urban sewer system affect the optimal performance of the wastewater collection system and treatment plant, while increasing sewer maintenance costs. The interaction of microplastics (MPs) and FOG in the sewer system could drastically change the quality of deposited materials and the fate of MPs in raw sewage. In this study, the batch experiment was conducted to explain the mechanism of FOG formation by synthetic wastewater and its interaction with polystyrene (PS) and polymethyl methacrylate (PMMA) particles. We found three different segments for FOG deposits in the batch, namely static and buoyant micro-deposits, gel-like, and solid deposits. The average size of micro-deposits adhered to the solid-liquid interface of the container was 25 µm and buoyant deposits with a small size of 3 µm adsorbed onto the MPs at the liquid-air interface. The gel-like formation promoted a virtual liquid phase where PS and PMMA were confined and segregated. Some PMMA particles were entrapped in the self-assembly of biopolymers that formed between the PS particles. This research indicates that FOG deposition in the urban sewers contains high numbers of MPs, such that any plan involving a reuse or disposal program requires a risk assessment.

The present study aims at determining the geotechnical properties of the tailings and the natural bed at Iran Mineral Processing Company, Sites 1 and 5. It qualitatively studies the subsurface layers of the company’s tailings storage site. After drilling different boreholes and conducting in-situ tests, it has made laboratory analyses in the form of field exploration to determine the geotechnical parameters of the extracted samples. Results from the analyses show the permeability coefficient of the subsurface layer of Site No. 1 and 5 to be very small, in the range of 10-7 cm/sec. Considering the conformity of permeability coefficient, percentage of fine grains (98% to 99%), plasticity index (28.5-29.5), and clay content of different layers of Sites 1 and 5 (68%-80%), based on the compacted clay liner criteria, it can be concluded that by nature, the subsurface layers of the mentioned sites are sealed with no need for any compacted clay liner. The tailings for storage Site 5 are fine-grained (80-88<75mm), basically in ML range according to USCS system, with a permeability coefficient of about 10-6 cm/sec. Therefore, the tailings themselves act as a relatively primary sealing layer against the infiltration of hazardous leachates into the natural bed. The method, used in the process of site selection of tailings storage facilities (TSF), can cut the construction time as well as the expenditures, thus reducing the production costs in the long run.

High levels of dioxins and dioxin-like compounds in the food and their adverse effects on human health are of increasing concern. Since milk is one of the most essential human nutritional resources, the present study aims at determining dioxins and PCBs in raw milk samples from four farms in North of Iran and raw and pasteurized samples from three farms and five dairy factories in Vicinity of Tehran (capital of Iran). Total toxic equivalence (TEQ) of dioxin and PCBs have been determined, using the DR-CALUX® bioassay. Results reveal that all samples are contaminated with dioxins and PCBs, comparatively. The total dioxins and PCBs levels in raw milk samples from the north range from 4.08 to 0.97 pg/gfat and for the raw samples and pasteurized samples from Tehran Province from 1.89 to 0.63 pg/gfat and 0.1 to 0.03 pg/gfat, respectively. The mean concentration of dioxins/PCBs is higher in samples from the north of Iran. This may be because of the common method of removing domestic and agricultural disposal in this area.

Plastic production has inevitably increased in the past few decades and is one of the diverse material used in today’s world. With this increasing production and wider use, the aquatic ecosystems have become the trash barrel for all kinds of plastic resulting in it becoming a looming spectre to the habitat and functions of both inland and offshore ecosystems. Plastic pollution is considered as an emerging global environmental concern which could significantly affect the biological diversity and may have potential to cause inimical effects on human health. These plastics have shown to gradually degrade into micro fragments and are reported to cause toxic effects on the aquatic organisms. In comparison to the studies on presence of microplastic in marine ecosystems, the studies on the presence of it in freshwater ecosystems have received relatively lesser attention although some studies have shown that the contamination is as grievous as that of in marine environment. This review article focuses on the literature available on the reports of microplastic occurrence, its distribution in freshwater ecosystems across the world and its insidious effects which are of emerging concern. The effect of such microplastic ingestion in both aquatic organisms and the potential health hazards due to such plastic consumption in humans have also been examined. The paper also discusses the existing knowledge gaps so that future research directions can be taken accordingly and the findings in this paper would significantly help all the countries across the world to understand the present plastic pollution scenario and work towards the mitigation of the same.