Malathion-induced sublethal toxicity on the hematology of cricket frog (Fejervarya limnocharis)

The effect of malathion [diethyl(dimethoxythiophosphorylthio)succinate] at sublethal concentration (0.006 ppm) on hematological parameters of the cricket frog (Fejervarya limnocharis) was studied for 24 hrs to 240 hrs of exposure and remarkable hematological alterations were observed. The study on hematological parameters revealed a highly significant decrease (P < 0.01) in the total erythrocytes count in malathion-exposed animals from 24 hours to 96 hrs of exposure as compared to control. Significant decreases (P < 0.01) of hemoglobin and packed cell volume were also observed from 48 hrs to 240 hrs. A significant increase (P < 0.01) in leucocytes count was noted throughout the exposure period. Elevated numbers of lymphocytes and eosinophils as found in the present study revealed lymphocytosis as well as eosinophilia, suggesting that this was a result of direct stimulation of the immunological defense due to the presence of a toxic substance or may be associated with tissue damage. The cytomorphological and cytopathological study of erythrocytes and leucocytes in malathion-exposed frogs at 0.006 ppm concentration revealed various cytotoxic effects at different exposure times. It was noted that the size and the shape of the erythrocytes were subjected to variation in different blood disorders.     

Contribution of small-scale mining to employment,development and sustainability – an Indian scenario

Small-scale mining is more prevalent in India. The maximum production capacity of 50,000 tonnes/year has been accepted as a criterion to Indian small-scale mine. Such mines constitute about 90% of total number of mines, 42% of the total non-fuel minerals and metals, 5% of the fuel minerals. Some 3000 small scale mines account for a work force of about 0.5 million people. Yet this sector is a neglected sector in Indian economy and still considered as an unorganized sector. This paper examines the contribution of small-scale mines to employment and national mineral production, practices, and Indian policy on small-scale mining. It identifies the drawbacks in the existing Government policy and discusses the role of Government for up gradation in this sector. It focuses the need for technical up gradation and to ensure the economic and social infrastructure. It also discusses how the pursuit of sustainable livelihoods, poverty alleviation and indigenous peoples right in artisanal and small-scale mining be more effective when these communities are disadvantaged or neglected by Government policies. This paper concludes that this sector can make significant contribution to Indian economy and employment generation. It recommends that by establishing mining centre consist of shared mining and processing facilities, educating and training related initiatives it can be achieved.     

Rent dissipation in a limited-access common-pool resource: Experimental evidence

This paper examines group behavior in an experimental environment designed to parallel the conditions specified in noncooperative models of limited-access common-pool resources. Using experimental methods, we investigate the strength of theoretical models which predict that users of such resources will appropriate units at a rate at which the marginal returns from appropriation are greater than the marginal appropriation costs. Our results confirm the prediction of suboptimal accrual of rents and offer evidence on the effects of increasing investment capital available to appropriators.     

The effects of long-term unemployment on attitudes to employment

This paper is concerned with whether long-term unemployment (6-24 months) affects people's attitudes to employment once they have found a new job. One hundred and forty men aged 25-40 were asked whether they felt various aspects of employment (e.g. job security, pay) are more important to them as a result of being unemployed. The effects of mental well-being when unemployed on attitudes to employment are explored. Unemployment is reported to have made most aspects of employment more important to people. Those whose mental health was worst when unemployed report that job security is most important to them.     

On the importance of knowing the affective meaning of job demands

Theorizing about the effects of job demands on mental health, job satisfaction and performance can be enhanced by allowing for a more complicated view of job demands. This paper describes an empirical attempt aimed at investigating facets of job demands. It hypothesizes that (1) many individuals will agree that job demands of certain kinds and strengths, will be associated with either satisfaction, or dissatisfaction, (2) that there will be no general agreement for some types of demands. Correlational analysis was performed on two independent sets of data to test the hypotheses, which were both supported. These results raised questions about the status of the concept of demands itself and a recommendation is made that it be replaced by the more neutral term ‘job demands milieu’ which can be applied to other aspects of the job environment such as task-based milieu, role-based milieu, or physical environmental milieu.     

Studies of the possibility of measuring changes in environmental pollution with the pixe method using moths as a monitor

The possibility has been investigated of using the PIXE method to yield long and reliable time series for indicating changes in the environment, with moths or butterflies as a sample target. The suitability of this approach was demonstrated by studying standard deviations of measurements of single moths and those of populations of moths. The properties of targeting at different anatomical sites were investigated and the wing gave the most stable results, perhaps because its metabolic development is completed at the imago (newborn butterfly) stage. According to test measurements of different populations it seems possible to use moth or butterfly wing measurements to study environmental changes over the past century or so using moth or butterfly collections.     

Soil availability,plant uptake and soil to plant transfer of 99Tc--a review

The fission yield of 99Tc from 239Pu and 235U is similar to that of 137Cs or 90Sr and it is therefore an important component of nuclear weapons fall-out, nuclear waste and releases from nuclear facilities. There is particular current interest in 99Tc transfer from soil to plants for: (a) environmental impact assessments for terrestrial nuclear waste repositories, and (b) assessments of the potential for phytoextraction of radionuclides from contaminated effluent and soil. Vascular plants have a high 99Tc uptake capacity, a strong tendency to transport it to shoot material and accumulate it in vegetative rather than reproductive structures. The mechanisms that control 99Tc entry to plants have not been identified and there has been little discussion of the potential for phytoextraction of 99Tc contaminated effluents or soil. Here we review soil availability, plant uptake mechanisms and soil to plant transfer of 99Tc in the light of recent advances in soil science, plant molecular biology and phytoextraction technologies. We conclude that 99Tc might not be highly available in the long term from up to 50% of soils worldwide, and that no single mechanism that might be easily targeted by recombinant DNA technologies controls 99Tc uptake by plants. Overall, we suggest that Tc might be less available in terrestrial ecosystems than is often assumed but that nevertheless the potential of phytoextraction as a decontamination strategy is probably greater for 99Tc than for any other nuclide of radioecological interest.     

Natural remobilization of multicomponent DNAPL pools due to dissolution

Mixtures of dense nonaqueous phase liquids (DNAPLs) trapped in the subsurface can act as long-term sources of contamination by dissolving into flowing groundwater. If the components have different solubilities then dissolution will alter the composition of the remaining DNAPL. We theorized that a multicomponent DNAPL pool may become mobile due to the natural dissolution process. In this study, we focused on two scenarios: (1) a DNAPL losing light component(s), with the potential for downward migration; and (2) a DNAPL losing dense component(s), with the potential for upward migration following transformation into a less dense than water nonaqueous phase liquid (LNAPL). We considered three binary mixtures of common groundwater contaminants: benzene and tetrachloroethylene (PCE), PCE and dichloromethane (DCM), and DCM and toluene. A number of physical properties that control the retention and transport of DNAPL in porous media were measured for the mixtures, namely: density, interfacial tension, effective solubility, and viscosity. All properties except density exhibited nonlinear relationships with changing molar ratio of the DNAPL. To illustrate the potential for natural remobilization, we modelled the following two primary mechanisms: the reduction in pool height as mass is lost by dissolution, and the changes in fluid properties with changing molar ratio of the DNAPL. The first mechanism always reduces the capillary pressure in the pool, while the second mechanism may increase the capillary pressure or alter the direction of the driving force. The difference between the rate of change of each determines whether the potential for remobilization increases or decreases. Static conditions and horizontal layering were assumed along with a one-dimensional, compositional modelling approach. Our results indicated that for initial benzene/PCE ratios greater than 25:75, the change in density was sufficiently faster than the decline in pool height to promote DNAPL breakthrough into the adjacent porous medium. In contrast, there was no potential for natural remobilization of a PCE-DCM mixture, primarily because the densities of the components are not sufficiently different. Dissolution of a DCM-toluene mixture decreased the density, reducing the tendency for downward displacement. However, the ultimate transformation from a DNAPL to an LNAPL may induce upward displacement. These results suggest that at sites with DNAPL pools containing a mix of components of sufficiently different densities and relative solubilities, natural remobilization may be an active mechanism, with implications for site evaluation and remediation.     

Impacts of swine manure pits on groundwater quality

Manure deep-pits are commonly used to store manure at confined animal feeding operations. However, previous to this study little information had been collected on the impacts of deep-pits on groundwater quality to provide science-based guidance in formulating regulations and waste management strategies that address risks to human health and the environment. Groundwater quality has been monitored since January 1999 at two hog finishing facilities in Illinois that use deep-pit systems for manure storage. Groundwater samples were collected on a monthly basis and analyzed for inorganic and bacteriological constituent concentrations. The two sites are located in areas with geologic environments representing different vulnerabilities for local groundwater contamination. One site is underlain by more than 6 m of clayey silt, and 7-36 m of shale. Concentrations of chloride, ammonium, phosphate, and potassium indicated that local groundwater quality had not been significantly impacted by pit leakage from this facility. Nitrate concentrations were elevated near the pit, often exceeding the 10 mg N/l drinking water standard. Isotopic nitrate signatures suggested that the nitrate was likely derived from soil organic matter and fertilizer applied to adjacent crop fields. At the other site, sandstone is located 4.6-6.1 m below land surface. Chloride concentrations and delta15N and delta15O values of dissolved nitrate indicated that this facility may have limited and localized impacts on groundwater. Other constituents, including ammonia, potassium, phosphate, and sodium were generally at or less than background concentrations. Trace- and heavy-metal concentrations in groundwater samples collected from both facilities were at concentrations less than drinking water standards. The concentration of inorganic constituents in the groundwater would not likely impact human health. Fecal streptococcus bacteria were detected at least once in groundwater from all monitoring wells at both sites. Fecal streptococcus was more common and at greater concentrations than fecal coliform. The microbiological data suggest that filtration of bacteria by soils may not be as effective as commonly assumed. The presence of fecal bacteria in the shallow groundwater may pose a significant threat to human health if the ground water is used for drinking. Both facilities are less than 4 years old and the short-term impacts of these manure storage facilities on groundwater quality have been limited. Continued monitoring of these facilities will determine if they have a long-term impact on groundwater resources.