Influence of the organophosphorus insecticide phosphamidon on lentic water

The inland freshwater resources are being increasingly subjected to heavy stress as a result of indiscriminate dumping of industrial wastes, domestic sewage and agricultural run-off causing deterioration of the water quality and adverse impact on aquatic biota. Pesticides drained to the aquatic environment are primarily of agricultural origin. Phosphamidon (widely used organophosphate pesticide in paddy field) significantly reduced dissolved oxygen (DO) at 1.8 mg/l exposure and reduced alkalinity at 0.9 and 1.8 mg/l. Hardness also reduced gradually but not significantly. Free carbondioxide was increased significantly at 1.8 mg/l of the insecticide compared to control. The insecticide had no influence on pH and temperature. There was maximum reduction of phytoplankton and zooplankton population at 1.8 mg/l of phosphamidon. Though gradual reduction of plankton community was also noticed at different lower concentrations of pesticides but in case of phytoplankton an abrupt reduction (about 50% of the control) was observed. The normal behaviour and feeding rate of air breathing teleost, Channa punctatus was also hampered. Therefore, phosphamidon even at low concentrations may create disorders in the aquatic ecosystem.     

Studies on nanomaterial-based p-type semiconductor gas sensors

Environmental Science and Pollution Research - The development of various metal oxide semiconductor materials has resulted in better performance of the gas sensors in terms of selectivity,...     

Cu(II) removal using green adsorbents: kinetic modeling and plant scale-up design

Cu(II) adsorption in continuous column using green adsorbents like peanut and almond shell was investigated. Fourier transform infrared (FTIR) spectroscopy, Brunaer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), and Point of Zero charge (pH_pzc) determination have been used for characterization of the adsorbents. Experiments were conducted at various operating conditions to calculate the adsorption capacity of the adsorbents. Adsorption studies signify that both the adsorbents have good adsorptive capacity for Cu(II) ion. Equilibrium of adsorption was described using Langmuir isotherm and the highest q_max value for both the adsorbent were obtained at an operating condition of 20 ml/min flow rate, 15 mg/L influent Cu(II) concentration, and 7 cm bed depth. Regeneration of both the adsorbents suggests that these adsorbents can be used several times for Cu(II) removal. Seven different kinetic models were tested among which the modified dose response model was fitted well for peanut shell and the Thomas model was fitted well for almond shell. These fitted models were further used for scale-up design. Regeneration studies show that peanut shell and almond shell are useful up to the fifth adsorption cycle. Application of these adsorbents with industrial effluent was also reported. This study reveals that peanut and almond shells can be used for Cu(II) removal for industrial wastewater.

     

Hydrogeochemical behavior of arsenic-enriched groundwater in the deltaic environment: comparison between two study sites in West Bengal, India

Groundwaters have been collected from deltaic areas of West Bengal (Chakdaha and Baruipur blocks) to record their hydrogeochemical characteristics, and to verify the mechanism of arsenic (As) release. The data reveals that shallow (<70 m) groundwaters in both areas are of Ca-Mg-HCO(3) type; however deeper (>70 m) groundwaters in Baruipur areas are slightly enriched with Na, Cl and SO(4), indicating possible saline water intrusion. The groundwater is anoxic (mean Eh: -124 and -131 mV) with high levels of As (mean: 116 and 293 mug/L), Fe (mean: 4.74 and 3.83 mg/L), PO(4) (mean: 3.73 and 3.21 mg/L) and Mn (mean: 0.37 and 0.49 mg/L), respectively for Chakdaha and Baruipur areas. The observed values of As and bicarbonate (mean: 409 and 499 mg/L) in the shallow aquifer are indicative of redox processes (e.g., oxidation of organic matter) favouring the release of As. Moreover, the presence of DOC in the shallow aquifer suggests that organic matter is young and reactive, and may actively engage in redox driven processes. Our study further confirms that both Fe- and Mn-reduction processes are the dominant mechanisms for As release in these groundwaters.     

Correction to: Method development,validation, monitoring,seasonal effect and risk assessment of multiclass multi pesticide residues in surface and ground water of new alluvial zone in eastern India

Environmental Science and Pollution Research -