Mining wastes occupy huge areas around the world, therefore, research aimed at their disposal and reclamation of disturbed territories is very relevant. We studied artificial soil based on neutralized ombrotrophic peat (Histosols Fibric) with different content (5% and 10% by weight) of copper smelting slag recycling waste ("technical sand"): finely dispersed (less than 0.05 mm), mechanically activated material. We analyzed the content of toxic element in peat, underground and aboveground parts of lawn grasses and potatoes. The coefficients of concentration and accumulation of elements were calculated. It was found that the introduction of 5% waste leads to exceeding the maximum permissible concentrations and approximately permissible concentrations (the regulated values for Russia) for zinc, copper, arsenic, antimony, and lead. The molybdenum content exceeds the Soil Quality Guidelines accepted in Canada, for selenium the values are at the limit level. The content of zinc, copper, cobalt, arsenic, molybdenum, antimony is significantly reduced (by 2-3 times) during the growing season. Ecological assessment of agricultural plants grown on artificial soil with 5% of "technical sand" showed that there are no excesses of the maximum permissible levels for any regulated element for potato tubers; a slight excess of arsenic was detected for lawn grasses. We additionally assessed the safety of potato tubers using the maximum permissible concentrations for food and established an excess of cadmium (3.4 times on the peat, with the addition of waste almost unchanged) and zinc (1.6 times on peat, 2.8 times for a peat with 10% waste).

The goal of this research was to investigate the efficacy photocatalysis with natural solar radiation and artificial UV radiation for disinfecting total coliforms in biologically treated wastewater.   The effect of TiO2 dosage and irradiation time on total coliform inactivation as measured by log reduction values (LRV), removal of BOD, COD, turbidity, and effluent properties as measured by pH and conductivity was investigated. Two sets of experimental equipment were constructed, one for using solar UV light and the other for using artificial UV light. After four hours of irradiation with 60 mg/L TiO2, photocatalysis achieved LRVs of 1.4 and 1, respectively, under UV and solar radiation. COD and BOD were reduced by 67% and 50% respectively under UV and solar radiation after two hours of irradiation with 60 mg/L TiO2. Turbidity was reduced by 71%. Both conductivity and acidity of the effluent were reduced as TiO2 concentration was increased. Photocatalysis with natural solar radiation produced disinfection results that were comparable to that of efficient UV light exposure. Artificial UV light and natural solar radiation can be combined in photocatalysis process to form a hybrid process.

Indoor air quality (IAQ) is a significant concern that affects comfort and health. It is well understood that hospitals are thermal environments in which comfort must be calibrated. This comparative study examined existing international standards of IAQ in Iranian health care facilities. A systematic review of studies on IAQ standards was conducted to test the hypothesis regarding which parameters, and at what level, can have an impact on hospital IAQ: EPA, ASHRAE, LEED, BREEAM, NIOSH, OSHA, WHO, ACGIH, Canadian, and OEL. The inclusion criteria were met by 34 of the 1886 studies that were screened from 2010-2021. The findings of the selected studies were classified into four categories for analysis: monitoring of IAQ according to standards (n=34), IAQ in healthcare facilities (n=1), impact of air pollution on human health (n=9), and interventions to improve IAQ (n=1). Based on these IAQ standards, the acceptable limit for CO2 6300 *10³ µg/m³, for CO 9000 µg/m³, for Formaldehyde 19 µg/m³, for NO2 37 µg/m³, for O3 98 µg/m³, for PM2.5 0.1 µg/m³, for PM10 10 µg/m, and for SO2 31 µg/m³ was suggested. The majority of studies conducted monitoring of pollutants in indoor environments used for homes and schools, with the majority of them relying on WHO IAQ standards. CO, PM, and NO2 concentrations have been the most studied and have the longest track record of research. The acceptable limit for IAQ parameters was proposed.

This study was conducted to assess air quality status in the selected cities of Pakistan through Air Quality Index (AQI) and Multi Pollutant Index (MPI) and their correlation. Secondary data on air pollutants’ concentrations for the year 2021 were used from the literature. For this investigation, major air pollutants including carbon monoxide, nitrogen dioxide, sulfur dioxide, and particulate matter were used and compared with Punjab Environmental Quality Standards. Air quality indices, Multi Pollutant Index (MPI) and the Air Quality Index (AQI) were used in the study. Overall condition of the air pollutants in the particular location was described using the Air Quality Index. For this formula, the average concentration of each pollutant across a range of time periods was first calculated. The concentration of each pollutant was then divided by the relevant standard value, which was then cumulatively averaged and represented as a percentage. Results showed that Lahore and Karachi are two of the cities with unhealthy to hazardous AQI values and poor air quality according to MPI values. Air quality is deteriorating in industrial and traffic-congested cities where pollution levels significantly exceeded the threshold values. Using the linear regression, the results confirmed the strong association between the AQI and MPI. There is a need for immediate action to be taken to lower pollutants’ concentrations and improve air quality in urban areas.

Natural quartz mineral was examined as a new sorbent for Hg(II) removal from synthetic wastewater systems. Batch adsorption experiments of Hg(II)  onto quartz mineral were conducted under various conditions such as solution pH, sorbent dosage, contact time, initial Hg(II)  concentration. Adsorption experiments results of Hg(II) by quartz mineral showed good achievement after 180 min with 1.0 g/L sorbent mass at pH of 2.0, agitation speed of 200 rpm and a temperature of 25°C. Moreover, the Hg(II) concentration was directly related to increases the adsorption capacity, the maximum Hg(II) uptake by quartz  sample was 16.52 mg/g for 80 mg/L (C0 (Hg(II)].  Langmuir isotherm and pseudo-second-order kinetics (R2 > 0.99) were found to be the most appropriate models to describe the adsorption of Hg(II) by quartz mineral. The intra-particle diffusion model and the calculated Dubinin–Radushkevich adsorption energy (Eads = 0.78 kJmol-1), confirms a physisorption adsorption reaction occurring in three stages.

The study was conducted in Lake Rinconada, a glacial lake affected by artisanal and small-scale gold mining activities in the southern Andes in Peru. The objectives of the study were to investigate the spatial distribution of heavy metals (As, Cu, Hg, Pb and Zn) in water and sediments and to assess the degree of metal pollution and ecological risk using the geoaccumulation and potential ecological risk indexes. The concentrations of As and Hg in sediments from Lake Rinconada exceeded the Canadian sediment quality regulations, whereas the concentrations of As, Hg and Pb in water and sediments from the mining-affected tributary, Lunar de Oro River exceeded the Peruvian and Canadian guidelines for water and sediments quality respectively. According to the geoaccumulation and potential ecological risk indexes, Lake Rinconada is extremely polluted by As and Hg, and the pollution is mostly concentrated in the northern part of the lake, where the mining-affected Lunar de Oro River flows into the lake. Concentrations of Pb are also high in the northern part of the lake, suggesting that the nearby gold mining town is a source of pollution. The results of this study allows to report that Lake Rinconada is completely deteriorated.

Perfluorinated chemicals (PFCs) are widely used in industrial and commercial applications, leading to their release into the environment. The rapid industrialization and growing population in India make it a suitable case study to investigate PFOS contamination in environmental matrices. The purpose of this study is to investigate PFOS concentrations in river water and groundwater from several locations along the Bharathapuzha river basin and estimate PFOS intakes through drinking water. The highest PFOS level detected in the surface water is 1.3 ng/L and groundwater is 1.0 ng/L, which is significantly lower than the level of PFOS detected in major rivers of many developed countries. It is possible to attribute the low PFOS concentration to factors such as high annual precipitation, reduced industrial and municipal wastewater discharge, and relatively low emissions per capita in a region where agriculture is a major part of the economy. In addition, the daily intake of PFOS through drinking water in all age groups was below the safety threshold for cancer risk.

We analyzed 125 samples collected from Joypurhat district, Bangladesh, in this study. Average inorganic arsenic (IAs) content obtained from collected polished rice, tomato, potato, radish, and arum leaves 0.31 - 0.91, 0.24 - 0.61, 0.49 - 0.88, 0.40 - 0.93, and 0.30 - 0.69 mg/kg, respectively. This report summarized that almost every agronomic sample contains arsenic; the As contents remain within the permissible limit set by FAO/WHO’s guideline (1.00 mg/kg) except for the rice sample. The As concentration for the rice sample was significantly higher (0.31 - 0.91) than the prescribed limit (0.20 mg/kg). But, the As level for water (mean range, 0.10 - 0.72 mg/l), sediment (0.13 - 0.53 mg/kg), and soil samples (24.1 - 43.1 mg/kg) also significantly surpassed the permissible level. The present study is alarming for water samples, where the highest IAs concentration (0.72 mg/l) is 72 times [14 times] higher than WHO/FAO’s [Bangladesh’s] allowable limit (0.01mg/l) [0.05 mg/l]. All agronomic fields contain higher IAs (25.50 - 43.10 mg/kg) than the world standard limit (10 mg/kg). Statistical Igeo confirmed the moderate pollution of the entire agronomic field of Joypurhat except for the river’s sediment. Again, EF values ensured the anthropogenic pollution by the moderately severe enrichment of As for the 65% agronomic field and significant enrichment of As for the 35% agronomic field. Hazard estimation results revealed the privileged possibility of non-carcinogenic [carcinogenic] health hazards to regular polished rice [water] consumers. So, present study suggests that authorities should take necessary steps to prevent contamination/upcoming health risks.

The simulation of photocatalytic reactor is conducted using computational fluid dynamics. Turbulence is described by using the RNG k-ε turbulence model. The DO radiation model is used to simulate the irradiance distribution in the photocatalytic reactor. The effects of operating parameters on the performance of photocatalytic reactor are considered. Results show that the degradation rate of oxalic acid decreases with the increase of inlet flow. The degradation efficiency decreases from 50% to 40% when the flow rate changes from 2.5 m3 h−1 to 10 m3 h−1. The degradation rate of oxalic acid can be improved by increasing the irradiance of the lamp. The degradation efficiency of oxalic acid in the photocatalytic reactor first reaches a maximum degradation efficiency with the increase of titanium dioxide concentration, and then decreases with the increase of titanium dioxide concentration. An optimal concentration of catalysts exists. The maximum degradation efficiency is 27% for the catalyst concentration of 20 µgL−1.

Coronavirus (COVID-19) pandemic ushered in a new era that led to the adjustments of diverse ecosystems. The pandemic restructured the global socio-economic events which prompted several adaptation measures as a response mechanism to cushion the negative impact of the disease pandemic. Critical health safety actions were imperative to curtail the spread of the disease such as wearing personal protective equipment (PPEs), masks, goggles, and using sanitizers for disinfection purposes. The daily demands for the products by individuals and medical personnel heightened their production and consumption, leading to a corresponding increase of COVID-19 wastes in the environment following indiscriminate waste disposal and poor waste management. The persistent occurrence of COVID-19 wastes aggravated microplastics (MPs) contamination in the aquatic ecosystem following the breakdown of PPEs-based plastics via oxidation, fragmentation, and photo-degradation actions. These MPs are transported in the aquatic environment via surface runoff and wind action, apart from discrete sources. MPs' presence in the aquatic systems is not without repercussions. Ingestion of MPs by aquatic organisms can cause several diseases (e.g., poor growth, oxidative distress, neurotoxicity, developmental toxicity, reproductive toxicity, immunotoxicity, and organ toxicity). Humans are at high risk of MPs uptake. Apart from aerial and soil contamination sources, consumption of aquatic food products is a critical pathway of MPs into the human body. MP toxicities in humans include liver disorder, respiratory failure, infertility, hormonal imbalance, diarrhea, developmental disorder, and mortality. Measures to alleviate the effect of COVID-19 waste litters include effective waste management plans and the adoption of technologies to extract cum degrade MPs from the aquatic and terrestrial environment.