Environmental radiological impact associated with non-uranium mining industries: a proposal for screening criteria

Niobium, phosphate, coal and gold mining facilities have been selected as case studies with the aim of identifying possible sources of radiological impact during and after cessation of industrial operations. The results have shown that acid drainage, as well as chemical processing of mineral ores, constitute relevant impact indicators for present-day and future scenarios. The possible use of solid wastes abandoned at the end of the operations represents a long-term radiological concern. Therefore, it is necessary that Brazilian legislation for environmental licensing be revised taking into account the potential environmental and radiological impacts caused by these industries and establishing remedial procedures for waste storage areas in the existing sites. The indicators developed and procedures carried out can be used in screening for decisions on the adoption of regulatory requirements for practices at such types of installations.     

Arsenic poisoning in groundwater: health risk and geochemical sources in Bangladesh

Of the 2508 water samples analyzed in 10 districts of Bangladesh, 51%, on an average, contained arsenic levels of 0.05 to 2.50 mg/l. 95% of nail, 96% of hair, and 94% of urine samples contained arsenic above the normal level. Approximately 3.58 million people out of a total of 17.92 million who are drinking water containing arsenic levels >0.20 mg/l are potentially exposed to high risk of health hazard. Eight thousand and five hundred arsenic patients are identified; they are suffering from various skin lesions, gangrene in leg, skin, lung, bladder, liver, and renal cancer. A big portion of the total population is highly vulnerable to various internal cancers. Lowest arsenic concentration in drinking water producing dermatological disease is found to be 0.103 mg/l. However, the exposure time to develop arsenicosis varies from case to case reflecting its dependence on arsenic level in drinking water and food, nutritional status, genetic variant of human being, and compounding factors. This study has determined the high intensity of fluorescent humic substances in drinking water containing elevated concentrations of arsenic and very low concentrations of heavy metals. The synergistic/antagonistic effect of fluorescent compounds present in drinking water may aggravate the toxicity of arsenic. Geochemical study suggests that arsenic may be released from both reductive dissolution of Fe and Mn (oxy)hydroxide and microbial oxidation of organic matter.     

Characteristic levels of heavy metals in sediments and dredged sediments of a municipal creek in the Niger delta, Nigeria

Characteristic levels of metal ions in post dredged sediment and dredged sediments materials of a municipal creek in the Niger Delta show that significant concentrations of heavy metals are found to be accumulated more on the surface (0–15cm depth) of the dredged material as compared to the sub surface (15–30cm) and post dredged sediments. The distribution patterns were in the following order Fe > Mn > Zn > Cu > Pb > Ni > Cd and Fe > Mn > Zn > Pb > Cu > Ni > Cd for the post dredged sediment and dredged sediment materials respectively. The levels of the various metals were far below the EPA screening levels for open water disposal, consequently total levels of heavy metal found in these sediments pose no problem by open-water or upland disposal     

Effect of Agave attenuata extracts on detoxification enzymes of Biomphlaria alexandrina

The toxicity and rising costs of synthetic molluscicides have led to interest in compounds derived from locally growing plants that can be used as molluscicides. The aim of the present work was to study the effect of extracts of some Egyptian plants having lethal effect on snails of medical importance (Biomphlaria alexandrina) as well as on antioxidant and glutathione detoxification enzymes. Ethanolic extracts of locally growing plants Agave attenuata, Agave sislana, Phytolaca dodecandra and Euphorbia spllendens were applied as a contact poison to B. alexandrina, the intermediate host of Schistosoma mansoni. The LC₅₀ of A. attenuata, A. sislana, P. dodecandra and E. spllendens are 82, 101, 98 and 98 mg/L, respectively. Glutathione and the enzymes involved in protection of the snail from reactive oxygen species namely, glutathione peroxidase, glutathione reductase, glutathione S-transferase, catalase, gamma glutamyl transferase increased in the survival snails exposed to high concentrations of A. attenuata. Glucose-6-phosphate dehydrogenase indirectly affecting glutathione reductase and the oxidation, reduction of glutathione significantly decreased in snails exposed to A. attenuata extracts. Superoxide dismutase level tend to decrease in snails exposed to A. attenuata of action. In conclusion A. attenuata is preferable when compared with synthetic molluscicides. The enzymes involved directly or indirectly in protection mechanism of the snail against A. attenuata are mainly responsible for snails survival.     

Not seeing eye to eye: differences in supervisor and subordinate perceptions of and attributions for psychological contract breach

This study examines supervisor and subordinate perceptions of and attributions for psychological contract breach. The data suggest that supervisor and subordinate perceptions are most likely to differ on the extent to which the organization violated its obligations to provide fair pay, advancement opportunities, and a good employment relationship. In addition, the results indicate that the greater the degree of psychological contract breach reported by subordinates, the less committed they are to the organization and the lower their job performance (as rated by their supervisor). Moreover, when psychological contract breach is perceived, supervisors' and subordinates' attributions regarding the reasons for the breach are likely to differ. Specifically, the findings suggest that subordinates are more likely to attribute breach to the organization's intentional disregard for the commitments that it had made to the employee, while supervisors are more inclined to attribute breach to situations beyond the organization's direct control. Copyright © 2001 John Wiley & Sons, Ltd.     

Designating Air Quality Management Areas (AQMAs) in the UK Implications for Securing UK Air Quality Objectives

Across the United Kingdom, the majority of local authoritieshave now completed their first phase of local air qualityreview and assessment work, as required under the AirQuality Strategy for England, Scotland, Wales and NorthernIreland (DETR, 2000a). Emerging from this first phasework is an anticipated suite of over 110 Air QualityManagement Areas (AQMAs). These areas are identifiedlocations where one or more of the national air qualityobjectives are predicted to exceed by specific target dates,and their spatial extent and shape is emerging as highlyvariable. Local authorities are guided to use a variety ofscientific tools to underpin the scientific assessments, anda consideration of uncertainty in both the tools used andsubsequent delineation of AQMAs is likely to affect theemerging management areas significantly. With subsidiarity underpinning the process of local air qualitymanagement (LAQM), local decision-making is anticipated toinfluence the outcome of the LAQM process in its entirety,with the declaration of AQMAs necessitating the preparationand implementation of air quality action plans. UKexperience of the effective management of local air quality,through the designation of AQMAs, demonstrates a valuableframework for other European countries developing mechanismsto manage air quality locally.     

Use of Natural 35S to Trace Sulphate Cycling in Small Lakes,Flattops Wilderness Area,Colorado, U.S.A.

Measurements of the cosmogenically-produced ³⁵S, a radioisotope of sulphur (t_1/2 = 87 days), are reported for the Ned Wilson Lake watershed in Colorado. The watershed contains two small lakes and a flowing spring presumed to be representative of local ground water. The watershed is located in the Flattops Wilderness Area and the waters in the system have low alkalinity, making them sensitive to increases in acid and sulphate deposition. Time series of ³⁵S measurements were made during the summers of 1995 and 1996 (July–September) at all three sites. The system is dominated by melting snow and an initial concentration of 16–20 mBq L^-1 was estimated for snowmelt based on a series of snow samples collected in the Rocky Mountains. The two lakes had large initial ³⁵S concentrations in July, indicating that a large fraction of the lake water and sulphate was introduced by meltwater from that year's snowpack. In 1995 and 1996, ³⁵S concentrations decreased more rapidly than could be accounted for by decay, indicating that other processes were affecting ³⁵S concentrations. The most likely explanation is that exchange with sediments or the biota was removing ³⁵S from the lake and replacing it with older sulphate devoid of ³⁵S. In September of 1995 and 1996, ³⁵S concentrations increased, suggesting that atmospheric deposition is important in the sulphate flux of these lakes in late summer. Sulphur-35 concentrations in the spring water were highly variable but never higher than 3.6 mBq L^-1 and averaged 2 mBq L^-1. Using a simple mixing model, it was estimated that 75% of the spring water was derived from precipitation of previous years.     

Deposition and Storage of Spheroidal Carbonaceous Fly-Ash Particles in European Mountain Lake Sediments and Catchment Soils

Spheroidal carbonaceous particles(SCPs) are produced only from high temperaturecombustion of fossil-fuels. In mountain lakesystems, they provide an unambiguous indicator ofatmospheric deposition. In order to comparedepositional fluxes of SCPs between mountainareas experiencing various pollutant regimes,intensive bulk deposition sampling was undertakenat five sites across Europe. Catchment soil coresand lake sediment cores were also taken at eachsite to compare SCP storage over the post-industrial period. Atmospheric, sediment and soilSCP data showed similar patterns. Highestcontamination was found in Scotland, Slovakia andSpain with the Austrian site intermediate and themid-Norwegian site least contaminated. A highproportion of accumulated SCPs were found to bestored in catchment soils at each site.Therefore, a significant increase in soilerosion, possibly as a result of future climatechange, could lead to the input of largequantities of catchment stored SCPs and, byimplication, other atmospherically depositedcontaminants to the lake ecosystem.     

Trends in the Water Chemistry of High Altitude Lakes in Europe

Here we present the chemical trends of seven high altitude lakes, analysed within the AL:PE and MOLAR Projects of the EU (1999) and selected on the basis of the availability of complete and reliable data for the period 1984–1999. The lakes are representative of the Scandinavian Alps, the Cairngorm Mountains in Scotland, the Alps and the Pyrenees. Significant trends were identified for some indicators of acidification, for instance pH and alkalinity, but not all lakes reacted similarly to decreasing depositions of sulphate and base cations. Differences in lake response are discussed in relation to recent variations of atmospheric deposition chemistry and associated changes in climatic conditions. Beside individual variations of the studied lakes, depending, among other things, on altitude and morphology, catchment characteristics and climate trends play a major role for the reaction of high altitude lakes on changes in atmospheric depositions.