Water, Air, and Soil Pollution

A unique test chamber system, which enables experiments with plants under highly controlled environmental conditions, was used to examine the pollutant removal efficiency of plants. For this purpose, the removal of two different volatile organic compounds (VOC) (toluene, 2-ethylhexanol) from the air by aerial plant parts of two common indoor plant species (Dieffenbachia maculata and Spathiphyllum wallisii) was monitored. While the control over environmental conditions (temperature, relative humidity, CO2 content, and light condition) worked very well in all experiments, control experiments with the empty chamber revealed high losses of VOC, especially 2-ethylhexanol, over the test duration of 48 h. Nonetheless, compared to the empty chamber, a significantly stronger and more rapid decline in the toluene as well as in the 2-ethylhexanol concentrations was observed when plants were present in the chamber. Interestingly, almost the same VOC removal as by aerial plant parts could be achieved by potting soil without plants. A comparative literature survey revealed substantial heterogeneity in previous results concerning the VOC removal efficiency of plants. This can be mainly attributed to a high diversity in experimental setup. The experimental setup used in the current study offers an excellent opportunity to examine also plant physiological responses to pollutant exposure (or other stressors) under highly controlled conditions. For the analysis of VOC removal under typical indoor conditions, to obtain data for the assessment of realistic VOC removal efficiencies by plants in rooms and offices, a guideline would be helpful to achieve more coherent findings in this field of research.

This study was carried out to investigate the efficacy of electrokinetics to remediate two identical soft kaolinite clay slurries with a water content of 70%. The first slurry was contaminated with copper at a concentration of 150 mg/kg of dry soil and the second with cadmium at the same concentration. The tests were performed in four identical electrokinetic columns (two for the electrokinetics tests and two for control) with a volume capacity of 14 L. An electric field intensity of 140 V/m was applied during 118 h of remediation with the top electrode serving as the anode (+ ve) and the bottom electrode acting as the cathode (− ve). The results showed that electrokinetics removed 2070 mL of water from the soil with copper contamination (compared to only 693 mL in the control test) and 1828 mL of water from the soils with cadmium contamination (compared to 839 mL in the control test). Electrokinetics was successful in removing significant portion of the copper and cadmium from most of the contaminated soil with the highest removal in copper (67%) and in cadmium (89%) in the soil sections near the anode. Electrokinetics was more effective in mobilizing the cadmium in the clay soil as compared to copper. Energy consumption determination revealed that electrokinetic remediation was successful in the removal of copper and cadmium from the section near the anode at rates of 77 and 100 mg/kg per kWh, respectively.

The bracket-like polypore fungus, Ganoderma australe, was selected for its potential to degrade lindane in liquid agitated sterile cultures. An orthogonal central composite design based on response surface methodology was used to find the optimum biodegradation and biosorption conditions of this pesticide and the growth conditions of the fungus. The factors tested include nitrogen content, initial concentration of lindane, incubation time, and temperature. The optimization parameters investigated were fungus biomass, fungus growth rate, final pH, specific biodegradation, specific biosorption, specific biodegradation rate, biodegraded to biosorbed ratio. The results of the experiments were statistically analyzed and the significance and effect of each factor on responses was assessed. The optimum (maximum) lindane biodegradation (3.11 mg biodegraded lindane per gram biomass) was obtained with nitrogen content of 1.28 g/L, lindane concentration of 7.0 ppm, temperature of 18.0°C, and 5 days of cultivation time.

This article describes the water quality scenario of freshwater springs of Baramulla district of Kashmir Valley in light of pollution threats and predicted climate change consequences for Himalayan ecosystems. The study was designed to have insights to what extent the community is relying on the spring water and what policy initiatives and planning perspectives at the government level are currently in vogue for sustainable management of these freshwater springs. Our results indicated that the springs are mild hard water type with nitrate concentration, conductivity, and iron values ranging from 19 to 675 μg/L, 185 to 811 μS/cm, and 1 to 308 μg/L respectively. Water quality index (WQI) revealed that the majority of the springs have excellent to good water quality category, while as in few springs like Aboora (26), Harwan (27), Fugipora (29), and Goigam (30), it was falling under poor to very poor category. Principal component analysis (PCA) generated mainly three components (VF1, VF2, and VF3) with higher Eigen values of 2.0 or more (2.23–6) accounting for 56.92%, 28.85%, and 10.64% of the total variance respectively. The survey highlights revealed the dependence of a large proportion of population for drinking water besides other uses, but no signs of involvement from the government level. Keeping in view the importance of these springs, it is necessitated that this situation should catch the attention of government and policy makers for the management of freshwater springs which can play an important role in fulfilling the UN (United Nations) Sustainable Development Goal (SDG) of access to safe drinking water.

Performance optimization using process parameters of an indoor air filtration system is a requirement that has to be established through experimental and analytical means for increasing machine efficacy. A closed casing containing a motor-driven blower is placed in a glass-encapsulated control volume. Air flows axially through an inlet filter and is thrown radially by the blower. In the radial path, air is treated with free radicals from the UVC-irradiated nano-TiO2 coated in the inner wall of casing. A known quantity of Staphylococcus aureus bacteria is populated (Courtesy: EFRAC Laboratories) in the glass-encapsulated control volume. The bacterial colony count is measured at different time intervals after the machine is switched on. Machine learning approaches are applied to develop a hypothesis space and the hypothesis based on best R2 score is used as a fitness function in genetic algorithm to find the optimal values of input parameters. The present research aims to determine the optimum time for which the setup is operated, the optimum air flow velocity in the chamber, the optimum setup-chamber-turning-radius affecting the air flow chaos, and the optimum UVC tube wattage, which when maintained yields the maximum reduction in bacterial colony count. The optimal values of the process parameters were obtained from genetic algorithm using the hypothesis obtained from multivariate polynomial regression. A reduction of 91.41% in bacterial colony count was observed in the confirmation run upon running the air filter in the optimal condition.

Mục tiêu của công trình này là tổng hợp attapulgite (ATP-SH) được sửa đổi mercapto và khám phá hiệu quả cũng như cơ chế của ATP-SH trong việc phục hồi đất bị ô nhiễm cadmium. ATP-SH đã được áp dụng để phục hồi đất bị ô nhiễm cadmium với nồng độ 5,48 mg/kg thông qua thí nghiệm trồng lúa trong chậu. Các thay đổi về tính chất lý hóa của đất, hàm lượng Cd trong lúa và rơm, Cd có sẵn và các dạng khác nhau của Cd trong đất đã được nghiên cứu sau khi bổ sung ATP-SH. Một số phương pháp như XRD, FTIR, và XPS đã xác nhận thành công sự kết hợp của mercapto. Việc bổ sung ATP-SH có ảnh hưởng nhỏ đến các tính chất lý hóa chính của đất. So với nhóm đối chứng (CK), với sự gia tăng liều lượng ATP-SH, hàm lượng Cd có sẵn trong đất và hàm lượng Cd trong lúa và rơm giảm đáng kể, với tỷ lệ giảm tối đa lần lượt là 73,1%, 92,6% và 85,7%; các dạng Cd có thể trao đổi (EX-Cd) và Cd liên kết với carbonate (CAR-Cd) trong đất giảm đáng kể, trong khi Cd liên kết với oxide Fe/Mn (FMO-Cd) và Cd liên kết với hữu cơ mạnh (SO-Cd) tăng đáng kể. Kết hợp với một số lượng lớn kết luận trước đây, chúng tôi tin rằng các đám mây electron Si-2p và Al-2p trong ATP-SH chuyển đổi và thay đổi các thuộc tính điện của sắt, từ đó tăng cường khả năng hấp phụ Cd trên bề mặt của nó, và sau đó hình thành lớp phủ để tạo ra FMO-Cd. Trên bề mặt của vật liệu có một lượng lớn sulfhydryl và hydroxyl, có tác động liên kết mạnh mẽ với Cd để hình thành SO-Cd. Việc ứng dụng ATP-SH có thể giảm hiệu quả hàm lượng Cd trong rơm và lúa thông qua tác động cộng hưởng của ATP, S và Fe thay vì làm tăng pH đất để ổn định kim loại nặng. Đây là một chất phục hồi hiệu quả cho đất ruộng bị ô nhiễm cadmium, với triển vọng ứng dụng thực tiễn tốt.

This study assesses the effect of salinity in bioavailability and toxicity of Zn by means of laboratory bioassays by observing contamination in both sediment and water, accumulation of Zn in biological tissues, and histopathological damage in the gills and guts tissues of Ruditapes philippinarum clams, which were exposed to different types of sediments from the Gulf of Cádiz (SW Spain) as well as two dilutions of toxic mud coming from an accidental mining spill. With this objective, the coefficients of distribution (K D) for Zn between overlying water and sediments were calculated, the histopathological frequencies in the tissues of the gills and guts of clams were determined, and the biota-sediment bioaccumulation factors as well as the bioaccumulation factors were quantified in the different stations. Results showed that the greatest histopathological damages appeared when the salinity values decreased. Statistical results showed that salinity was inversely correlated with histopathological damage (p < 0.01) for the lesion index for gills. The most outstanding results were observed in the two dilutions of toxic mud (0.3% and 7.9%) at a salinity value of 10. Salinity was inversely correlated with the concentration of Zn in biological tissues (p < 0.05) and inversely correlated with the concentration of Zn in water and sediment. Zn mobilization to the overlying water is produced when salinity values decrease.