Effect of DDT on plant mineral nutrition

DDT added to soil at a concentration of 50 microg g(-1) had no inhibitory effects on germination and plant growth of barley, mung and rice, but considerably inhibited the oilseed species tested in the laboratory. The uptake of one or other ions was affected in varying degrees, with plants grown in DDT-treated soils. Detailed field studies of a peanut crop further confirmed the inhibition of ion uptake with DDT, especially Ca(2+) and K(+). Reduced uptake of (86)Rb by germinated peanut seeds in the presence of DDT further supported the observations made with K(+). Cell number and length in plants were reduced in plants grown in DDT-treated soil and the role of calcium is discussed. It appears that growth inhibition in oil seed plants may arise from the low levels of Ca(2+) and K(+) in plants grown in DDT-treated soils.     

Concentrations of some heavy metals in commercially important finfish and shellfish of the River Ganga

Heavy metals are dangerous to aquatic organisms and it can be bioaccumulated in the food chain leading to diseases in human. Cumulative effects of metals or chronic poisoning may occur as a result of long-term exposure even to low concentrations. The accumulation of heavy metals varies depending upon the species, environmental conditions, and inhibitory processes. Concentrations of zinc, copper, lead, and cadmium were determined in finfish and shellfish species in the Gangetic delta using a PerkinElmer Sciex ELAN 5000 ICP mass spectrometer and expressed as milligrams per kilogram of dry weight. In finfish and shellfish species the concentrations of Zn, Cu, Pb, and Cd were comparatively higher at stations 1 and 2 than the permissible level of WHO. The concentration of metals exhibited significant spatial variation and followed the order station 1 > station 2 > station 3 > station 4, which may be related to different degree of contamination in different location. The metal accumulation exhibited species specificity.     

The earth system: regional–global linkages

Understanding the earth system requires that the two-way linkages between regions and the global system be well understood and predictable. Most studies of global change are undertaken thematically across limited disciplinary boundaries; few are attempted holistically across many disciplines within regions. The regional approach offers many advantages. Here a variety of linkages associated with the regions of Southern Africa, South Asia, East Asia and Southeast Asia are presented to illustrate the power of a regional approach to earth system science. Major findings include the extent to which long-range transport of aerosols and nutrients affect terrestrial and marine ecosystem functioning in and around southern Africa. Aerosol transport, and the development of a regional haze layer, over South Asia are shown to alter significantly the radiative forcing of change in the atmosphere over the region. Changes in land cover and use over East Asia over along period of time are shown to have affected the strength of the monsoon circulation significantly. Finally, rampant economic development and globalization in Southeast Asia are demonstrated to have been a significant driver of regional change. Electronic Publication     

Wastewater Fines Influence the Adsorption Behavior of Pollutants onto Microplastics

Millions of tons of microplastics (MPs) enter the wastewater collection systems every day and interact with raw sewage. In addition to MPs, varieties of organic and inorganic fines from urban effluents release into the sewer system and provide suitable surfaces for adsorption. To better understand the quantitative assessment of MPs sorption in wastewater and the role of fines, batch reactor experiments were performed using synthetic wastewater solutions containing organic, inorganic, and mixed organic–inorganic fines, and the results compared to a solution without fines. The MPs were two types of clean polypropylene (PP) particles, isotactic (iPP) and atactic (aPP). The results showed in all applied solutions the adsorption of pollutants was higher for the aPP averaging 1.3 mg/g compared with 0.5 mg/g for iPP, indicating that the adsorption varies with the type of polymer and surface properties. Further experiments also revealed a decrease in the sorption values of MPs for solutions containing inorganic fines, measured as the partition coefficient (K_d) and adsorbed concentration at equilibrium (q_e). The result of the measured reference conductivity (к₂₅) of the solutions for the same tests showed similar trends indicating that the magnitude of pollution adsorption onto MPs surfaces is controlled by the surface charge potential of the fine particles. The relationship between the qualitative assessments of ion removal, measured in terms of к₂₅, and their quantitative assessment of adsorption values in terms of K_d in several identical tests, verifying that the conductivity of the solution was modified after adsorption of wastewater constituents onto the MPs.

     

Climate change-induced salinity variation impacts on a stenoecious mangrove species in the Indian Sundarbans

The alterations in the salinity profile are an indirect, but potentially sensitive, indicator for detecting changes in precipitation, evaporation, river run-off, glacier retreat, and ice melt. These changes have a high impact on the growth of coastal plant species, such as mangroves. Here, we present estimates of the variability of salinity and the biomass of a stenoecious mangrove species (Heritiera fomes, commonly referred to as Sundari) in the aquatic subsystem of the lower Gangetic delta based on a dataset from 2004 to 2015. We highlight the impact of salinity alteration on the change in aboveground biomass of this endangered species that, due to different salinity profile in the western and central sectors of the lower Gangetic plain, shows an increase only in the former sector, where the salinity is dropping and low growth in the latter, where the salinity is increasing.     

Characterization of cadmium-resistant Klebsiella pneumoniae MCC 3091 promoted rice seedling growth by alleviating phytotoxicity of cadmium

Environmental Science and Pollution Research - Cadmium (Cd) phytotoxicity in agricultural land is a major global concern now-a-days resulting in very poor yield. Plant growth-promoting...     

Evolution and kinetics of volatile organic compounds generated during low-temperature polymer degradation

A method using direct flame ionization detector (FID) measurement was developed to study total volatile organic compound (VOC) emissions during thermal degradation of polymers. This method was used to estimate organic emissions from different polymers, such as low-density polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and commingled postconsumer streams, such as recycled carpet residue and auto shredder residue (ASR). The effects of process parameters, such as temperature, heating rate, and residence time, were also studied. Significant VOC emissions were observed at normal processing temperatures, particularly from recycled polymers. Each polymer showed a distinct evolution pattern during its thermal degradation. The kinetics of VOC emissions were also studied using a nonisothermal technique. The kinetic parameters were in agreement with data from the literature.