Biological-based methods for the removal of volatile organic compounds (VOCs) and heavy metals

Environmental Science and Pollution Research - The current scenario of increased population and industrial advancement leads to the spoliation of freshwater and tapper of the quality of water....     

Energy and exergy analysis of a PCM-based solar powered winter air conditioning using desiccant wheel during nocturnal

In this paper, heating and humidification of air for space have been carried out by using a phase change material (PCM)-based solar-powered desiccant wheel air conditioning (SPDWAC) in winter. The analysis of the setup has been done at different air flow rates. At low and high air flow rates, system has mean thermal coefficient of performance of 0.121 and 0.172, respectively, and mean exergy efficiency of 0.0787 and 0.0846, respectively. The mean thermal coefficient of performance of the system at high air flow rate (127.23 kg h-1) is 1.42 times the low air flow rate (63.62 kg h-1) and average exergy efficiency of the system at high air flow rate is 1.07 times the low air flow rate. It is observed that with an increase in air flow rate, efficiency of the evacuated tube solar air collector (ETSAC) increases. The average efficiency of the ETSAC at high air flow rate is 15.60%. The maximum average energy efficiency (17.80%) and exergy efficiency (17.08%) of the PCM storage system have been obtained at high air flow rate. The overall performance of the system showed that the use of PCM storage is feasible to run the system in winter during the hours of darkness.     

Hexavalent chromium reduction and plant growth promotion by Staphylococcusarlettae strain Cr11

Cr(VI), a mutagenic and carcinogenic pollutant in industrial effluents, was effectively reduced by an indigenous tannery effluent isolate Staphylococcus arlettae strain Cr11 under aerobic conditions. The isolate could tolerate Cr(VI) up to 2000 and 5000 mg L⁻¹ in liquid and solid media respectively. S. arlettae Cr11 effectively reduced 98% of 100 mg L⁻¹ Cr(VI) in 24 h. Reduction for initial Cr(VI) concentrations of 500 and 1000 mg L⁻¹ was 98% and 75%, respectively in 120 h. The isolate was also positive for siderophore, indole acetic acid, ammonia and catalase production, phosphate solubilization and biofilm formation in the presence and absence of Cr(VI). The isolate showed halotolerance (10% NaCl) and cross tolerance to other toxic heavy metals such as Hg²⁺, Ni²⁺, Cd²⁺ and Pb²⁺. Bacterial inoculation of Triticum aestivum in controlled petri dish and soil environment showed significant increase in percent germination, root and shoot length as well as dry and wet weight in Cr(VI) treated and untreated samples. This is the first report of simultaneous Cr(VI) reduction and plant growth promotion for a S. arlettae strain.     

Influence of mercury from fly ash on cattle reared nearby thermal power plant

Cattle grazing nearby coal-fired power stations are exposed to fly ash. The present investigation aims to assess the environmental and health impacts of fly ash containing mercury emitted from thermal power plant. The health effect of fly ash were studied using 20 lactating cattle reared within a 5-km radius of s thermal power plant for the possible effect of fly ash such as the alterations in hematological and biochemical parameters of blood, milk, and urine. Results indicated that the hemoglobin levels (6.65?±?0.40?g/dl) were significantly reduced in all the exposed animals. Biochemical parameters viz., blood urea nitrogen (27.35?±?1.19?mg/dl), serum glutamate oxaloacetate transaminase (43.39?±?3.08?IU/l), albumin, and creatinine were found to be increased, whereas serum glutamate pyruvic transaminase (29.26?±?2.02) and Ca²⁺ were observed to be statistically insignificant in exposed animals. Mercury concentrations estimated in the blood, milk, and urine of exposed (n?=?20) and control (n?=?20) animals were 7.41?±?0.86, 4.75?±?0.57, 2.08?±?0.18, and 1.05?±?0.07, 0.54?±?0.03, 0.20?±?0.02?μg/kg, respectively. The significant increase (P?<?0.01) in the levels of mercury in blood, milk, and urine of exposed animals in comparison to control indicated that the alterations of biochemical parameters in exposed cattle could be due to their long term exposure to fly ash mercury which may have direct or indirect impact on human populations via food chain.     

Development,validation of QuEChERS-based method for simultaneous determination of multiclass pesticide residue in milk,and evaluation of the matrix effect

Extraction and quantification of pesticide residue from the milk matrix at or below the established maximum residue limit (MRL) is a challenging task for both analytical chemists and the regulatory institutions to take corrective actions for the human health and safety. The main aim of the study is to develop a simple rapid and less expensive QuEChERS extraction and cleanup method for simultaneous analysis of 41 multiclass pesticide residue in milk by gas chromatography-electron capture detector (GC-ECD), followed by confirmation of the residues with gas chromatography-mass spectrometer (GC-MS). Effect of sorbent type, temperature, spiking concentration, matrix effect (ME), measurement uncertainty (MU), inter- and intra-assay repeatability, reproducibility of recovery, and trueness of the results were investigated to validate the effectiveness of the method. Limit of determination (LOD) and limit of quantitation (LOQ) for all the analytes ranged within 0.001–0.02 and 0.002–0.05 µg mL^?1, respectively. The % recovery of all the pesticides ranged between 91.38 and 117.56% with relative standard deviation (RSD) below 2.79%. The MU for all the analytes was ≤29% of respective LOQs, and except for few pesticides, the ME was largely negative. The method fulfilled all the SANTE guidelines and thus can be extended for routine analysis of multiclass pesticide residue in milk.     

Experimental investigation of solar-powered desiccant cooling system by using composite desiccant “CaCl<Subscript>2</Subscript>/jute”

A solar-powered composite desiccant cooling system has been experimentally investigated. It consists of evacuated tube solar water heater, composite desiccant bed heat exchanger (CDBHE), direct evaporative cooling unit and cooling tower. The composite desiccant material has been synthesized by using iron mesh and jute layer impregnated with calcium chloride solution, and this composite desiccant is placed in shell- and tube-type heat exchanger to make CDBHE. In this desiccant cooling system, the evacuated tube solar water heater is used to produce required hot water for regeneration of composite desiccant material. A cooling tower is used to produce cooling water which is pumped into CDBHE during dehumidification process to remove heat of adsorption. Direct evaporative cooling unit is used to cool the outlet process air of CDBHE. It has been found that the average dehumidification rate increases by 54.1 % when using circulating cooling water. The COP_th of desiccant cooling system has been found to be 0.46 with a cooling capacity of 353.8 W.     

Source identification of particulate matter and associated intake of elements through inhalation in an industrial area of Odisha,India

Particulate matter concentrations were measured in an industrial region in the Ganjam district of Odisha. The average levels of suspended particulate matter (SPM) were measured to be 142 ± 8 and PM₁₀ of particulate matter with a size of less than 10 micrometers (PM₁₀) to be 50 ± 15 μg m^?3. Out of the 14 elements determined, Ca, Na, Mg, Fe, and K contributed more than 95% of the total weight. In enrichment factors, the trace elements, i.e., Zn, Pb, Cd, and Hg were observed to be highly enriched in the SPM and PM₁₀. Factor analysis indicates that more than 75% of the variance was due to five component factors, which have eigenvalues greater than 1. Intake of elements through inhalation route to adults has been estimated.     

Pesticide-induced impairment of thyroid physiology in the freshwater catfish, Heteropneustes fossilis

Effects of BHC (8 mg litre(-1)) and malathion (10 mg litre(-1)) exposure for 96 h have been studied on T(3) and T(4) concentrations in plasma, and in pharyngeal thyroid tissue preparations. Thyroid peroxidase (TPO) activity in the pharyngeal thyroid tissue, along with the extra-thyroidal conversion of T(4) into T(3) were measured in a freshwater catfish, Heteropneustes fossilis. BHC stimulated TPO activity in this fish, during both in vitro and in vivo studies. In contrast, malathion was found to stimulate TPO activity during the in vitro experiments but to inhibit it in the in vivo study. Concentrations of T(3) and T(4) increased in the thyroid gland, as well as in the plasma, in response to BHC exposure. However, in both these tissues, malathion increased T(3) concentrations and reduced T(4) concentrations. The extrathyroidal conversion of T(4) into T(3) was stimulated by malathion and inhibited by BHC.