Effects of heavy metal pollution on soil microbial biomass

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Estimation of ambient chronic toxicity in a polluted creek system

Ambient water toxicity estimations were conducted in Piles Creek as part of an ecological risk assessment study. This creek is part of a highly polluted estuarine system located near Linden, New Jersey. An upstream and a downstream site in the creek were evaluated for effects on survival, growth and sexual maturity of the estuarine mysid, Mysidopsis bahia. Manasquan Inlet, Manasquan, New Jersey, served as the reference site. Seven-day screening toxicity tests were conducted once a month over a three month period. Results indicate that survival of mysids was not affected in any toxicity test. Mysid growth was significantly reduced at both of the test sites, in two out of three trials. Sexual maturity was shown to be adversely affected in mysids exposed to ambient waters from both test sites throughout the duration of the study.     

Competitive role of nitrogen functionalities of N doped GO and sensitizing effect of Bi2O3 QDs on TiO2 for water remediation

The promising solar irradiated photocatalyst by pairing of bismuth oxide quantum dots (BQDs) doped TiO₂ with nitrogen doped graphene oxide (NGO) nanocomposite (NGO/BQDs-TiO₂) was fabricated. It was used for degradation of organic pollutants like 2,4-dichlorophenol (2,4-DCP) and stable dyes, i.e. Rhodamine B and Congo Red. X-ray diffraction (XRD) profile of NGO showed reduction in oxygenic functional groups and restoring of graphitic crystal structure. The characteristic diffraction peaks of TiO₂ and its composites showed crystalline anatase TiO₂. Morphological images represent spherical shaped TiO₂ evenly covered with BQDs spread on NGO sheet. The surface linkages of $\text{NO}?\mathrm{O}?\text{Ti}$, $\mathrm{C}?\mathrm{O}?\text{Ti}$, $\mathrm{B}\mathrm{i}?\mathrm{O}?\text{Ti}$ and vibrational modes are observed by Fourier transform infrared spectroscopy (FTIR) and Raman studies. BQDs and NGO modified TiO₂ results into red shifting in visible region as studied in diffused reflectance spectroscopy (DRS). NGO and BQDs in TiO₂ are linked with defect centers which reduced the recombination of free charge carriers by quenching of photoluminescence (PL) intensities. X-ray photoelectron spectroscopy (XPS) shows that no peak related to $\mathrm{C}?\mathrm{O}$ in NGO/BQDs-TiO₂ is observed. This indicated that doping of nitrogen into GO has reduced some oxygen functional groups. Nitrogen functionalities in NGO and photosensitizing effect of BQDs in ternary composite have improved photocatalytic activity against organic pollutants. Intermediate byproducts during photo degradation process of 2,4-DCP were studied through high performance liquid chromatography (HPLC). Study of radical scavengers indicated that ${\mathrm{O}}_2^{·?}$ has significant role for degradation of 2,4-DCP. Our investigations propose that fabricated nanohybrid architecture has potential for degradation of environmental pollutions.     

Kachchh (India) earthquake 2001--causes,severity and impact on groundwater resources

Earthquake 2001 in Bhuj region of Kachchh district of Gujarat(India) was one of the most devastating earthquakes in the Indian history. This earthquake has caused severe damage to human life and properties. The impact of earthquake on groundwater resources at many locations was significant. Steep rise in static water level due to earthquake was observed at Bhachau and Chandarani. At other location groundwater followed the declining trend.     

Biodiversity of mosquitoes in Manipur State and their medical significance

Entomological studies conducted during monsoon and post-monsoon season in Manipur State revealed the presence of fifty-five species of mosquitoes under ten genera. Out of the seventeen Anopheles species recorded, Anopheles aconitus, An. dirus and An. nivipes were recorded for the first time from the state. The present study has confirmed the existence of An. dirus, the major malaria vector in the Northeast from a selected area of the state. Among Culicines, four species viz., Aedes nigrostriatus, Malaya genurostris, Aediomyia catasticta and Toxorhynchites splendens which were not reported earlier from this state have been recorded in the present study. With the addition of these seven species of mosquitoes to the earlier record of mosquitoes so far reported from Manipur, the mosquito fauna swells up to one hundred and eleven including the major vectors of malaria of the Northeast and the potential vectors of Japanese encephalitis and dengue virus transmission in India.     

The interaction of SO2 and root-knot nematode on tomato

Intermittent exposure of tomato plants (cv. Pusa Ruby) to SO(2) at 286 microg m(-3) (3 h every heavy third day for 75 days) induced slight chlorosis of leaves. At 571 microg m(-3), considerable chlorosis with browning developed on the foliage. These symptoms were more pronounced and appeared earlier on SO(2)-exposed plants infected with Meloidogyne incognita race 1 (Mi), especially in post- and concomitant-inoculation exposures. Mi and/or SO(2) significantly reduced different parameters of plant growth. Synergistic (positive) interactions between SO(2) and Mi occurred in concomitant- and post-inoculation exposures at 286 and 571 microg m(-3), respectively. In other treatments, an antagonistic (negative) interaction was observed. However, in a few cases, additive effects of SO(2) and Mi were also recorded. Intensity of root-knot (galling) was enhanced at both concentrations of SO(2), while reproduction (egg mass production) of Mi was enhanced in concomitant-inoculation exposures at 286 microg m(-3) and inhibited at 571 micro m(-3). Exposure to SO(2) and/or Mi decreased the number and size of stomata but increased the number and length of trichomes on both the leaf surfaces. Stomatal aperture was significantly wider in the plants exposed to 571 microg SO(2) m(-3) alone and in pre-, post-, and concomitant-inoculation exposures at 286 or 571 microg m(-3). Stomatal aperture was directly related to foliar injury and reductions in growth, yield, and leaf pigments.     

A general agreement on commodity organization : A ‘GATT for primary commodities’

Having reponded to various crises since the Paris Sugar Convention 1864, the process of international commodity organization is now recognized as a positive means of securing expansion of world trade and of bringing about development in producing countries. But these objectives necessitate multi-dimensional measures. The supply-management techniques, hitherto the pivot of international commodity agreements, have proved to be inadequate. It is argued in this article that the trade and development objectives can be better achieved by the provision of varied measures; that a ‘GATT for primary commodities’ is among such measures; and that such an organization does not negate, but supplements, the existing system.     

Mapping pesticide contamination potential

Groundwater contamination by agricultural chemicals is a major environmental pollution issue nation-wide. The regulatory agencies of towns and counties face the problem of finding a methodology for assessing the ground-water contamination potential of a large number of agricultural pesticides. Because of the spatial nature of the problem and the limited data availability for comprehensive pesticide movement models, a contamination potential index was employed for preliminary assessment. A specially designed geographic information system was used to create ground-water contamination likelihood maps for a 1500 km² area. The results suggest that this methodology can be used successfully for evaluating the relative contamination potential of a large number of pesticides over large areas with limited input data. A tentative approach for using this method for monitoring and registration of pesticides is also discussed.