The effect of chelating agents on the uptake and accumulation of cadmium by Mytilus edulis

The uptake, storage and excretion of cadmium by the common mussel Mytilus edulis (L.) has been studied at sub-lethal concentrations using the radioactive isotope ^115mCd as a marker. After an initial lag period, the uptake at low concentrations in sea water is linear with time and directly proportional to the sea water concentration, with a maximum concentration factor of 165 at 0.7 g Cd/ml sea water. A decrease occurs at higher concentrations indicating saturation of the available binding capacity. Prior complexation of the cadmium with either EDTA, humic and alginic acids or pectin doubles both the rate of accumulation and the final tissue concentrations (order: kidneyviscera>gillsmantle>muscle) and eliminates the lag period, suggesting that ionic cadmium must first be complexed before uptake can occur. A mechanism for this effect, which may involve thionein, is described. The rate of excretion of cadmium is 18 times slower than that of uptake, with the major route via the kidney but not via the byssal threads as with particulate iron. The need to detoxify and store cadmium by an immobilization mechanism is a consequence of this slower rate of elimination.     

AN EXTENSION INFORMATION PROGRAM TO IMPROVE RESIDENTIAL WELL WATER QUALITY1

ABSTRACT: Older inland lake communities in Wisconsin are more likely than many areas to have degraded water supplies. Many home sites are on sandy soils with high water tables and have shallow wells close to their own or a neighbor's septic system. Yet unless major rehabilitation is undertaken, these homes are relatively exempt from local codes and regulations. They also are beyond the application of the federal Clean Drinking Water Act. An Extension education program was created in response to the problem. At a community's request, home drinking water “screening tests” are conducted for at least coliform bacteria, chlorides, and nitrate/nitrite-N. Test results, together with explanations and recommendations are reported at a local meeting. Public response has been positive, and a surprising number of wells appear to be contaminated to some degree.     

Evaluation of indoor radon measurements in Hungary

The RAD Laboratory measured annual means of radon activity concentrations in 15 277 first-floor rooms of dwellings and in 325 rooms on upper floors in Hungary (1994-2004). The original purpose of the survey was to find radon-prone area in Hungary. The maximum measured value was 5800 Bq m(-3), while the minimum was 10 Bq m(-3). Due to geological diversity and different structures of buildings, the data set of first-floor rooms did not follow the lognormal distribution. Therefore, strata were chosen so that the measured data fitted the lognormal distribution. The numbers of dwellings above a given radon level were determined in each stratum. The national distribution was then taken as the sum of the individual distributions of all strata. This distribution was not lognormal. The parameters of the best fitting lognormal distribution were GM = 58 Bq m(-3), GSD = 2.2. The weighted averages of strata values GM = 62 Bq m(-3), GSD=2.1 were obtained corresponding to 92% of Hungarian dwellings.     

Applying radioecology in a world of multiple contaminants

This paper presents a review of the current status of radioecology and how it might be applied to contribute to a broader range of environmental pollution and contamination problems. In many respects radioecology is a unique and specialised branch of environmental science. However, radioecologists could be much more aware of the similarities and differences between their field and other fields of environmental pollution science. Areas of common interest described herein are exposure and risk assessment, and the problem of the bioavailability of potentially toxic substances in environmental media. It is concluded that radiometric methods and radioecological modelling methods can assist significantly with understanding and quantifying both these issues. The existence of multiple contaminants at many locations around the world dictates that assessment and remediation exercises should be carried out in an integrated fashion, as a partnership between scientific disciplines.     

Evaluation of the pollution of the surface waters of Greece from the priority compounds of list II, 76/464/EEC directive, and other toxic compounds

The pollution of the surface waters of Greece from the priority compounds of 76/464/EEC Directive was evaluated. The occurrence of 92 toxic compounds, 64 of which belong to priority compounds of List II, candidates for List I, of 76/464/EEC Directive, was studied in surface waters and wastewater through the developed network of 62 sampling stations, which covers the whole Greek territory. The analytical determination was performed by Purge and Trap-Gas chromatography-Mass spectrometry for volatile and semivolatile organic compounds (VOCs), Gas Chromatography-Electron Capture Detection for organochlorine insecticides, Gas Chromatography-Nitrogen Phosphorous Detection for organophosphorous insecticides, High Performance Liquid Chromatography-Photodiode Array Detection for herbicides, and Electrothermal Atomic Absorption Spectrophotometry and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) for metals and the toluene extractable organotin compounds. The concentrations of VOCs and insecticides detected in the surface waters of Greece were very low, whereas the concentrations of herbicides and metals ranged generally at moderate levels. VOCs were detected almost exclusively in the rivers and very rarely in the lakes, while the frequency of occurrence of insecticides, herbicides and metals was similar for rivers and lakes. Water quality objectives (WQO) and emission limit values (ELV) have been laid down in national legal framework for a number of compounds detected in the samples, in order to safeguard the quality of surface waters from any future deterioration.     

Food,feed, and fuelwood resources of Nepal: A GIS evaluation

A GIS-based land evaluation model was developed to determine the food, feed, and fuelwood sufficiency of all districts in Nepal. Resource surpluses or deficits were calculated for each district for 1981, the year for which the national land resource data were available. Of the three resources, feed supplies were found to be the most critical. Feed deficits occurred in 57% of all districts in 1981, while food and fuelwood deficits occurred in less than 10% of all districts. Different scenarios were carried out for the year 2000 to estimate the magnitude of future resource deficits, assuming resource use and yields in Nepal remain constant in the face of growing population and livestock numbers. Linking resource data with spreadsheet and GIS systems provides a new way to understand and evaluate resources at the district and national levels. To more fully capture the usefulness of this approach, information on rates of change in productivity and land use is needed.     

Estimating maquiladora hazardous waste generation on the U.S./Mexico border

Maquiladoras, manufacturing plants that primarily assemble foreign components for reexport, are located in concentrations along the northern frontier of the US/Mexico border. These plants process a wide variety of materials using modern industrial technologies within the context of developing world institutions and infrastructure. Hazardous waste generation by maquiladoras represents a critical environmental management issue because of the spatial concentration of these plants in border municipalities where the infrastructure for waste management is nonexistent or poor. These border municipalities contain rapidly increasing populations, which further stress their waste handling infrastructure capacities while exposing their populations to greater contaminant risks. Limited empirical knowledge exists concerning hazardous waste types and generation rates from maquiladorsas. There is no standard reporting method for waste generation or methodology for estimating generation rates at this time. This paper presents a method that can be used for the rapid assessment of hazardous waste generation. A first approximation of hazardous waste generation is produced for maquiladoras in the three municipalities of Nogales, Sonora, Mexicali, Baja California, and Cd. Juarez, Chihuahua, using the INVENT model developed by the World Bank. In addition, our intent is to evaluate the potential of the INVENT model for adaptation to the US/Mexico border industrial situation. The press of border industrial development, especially with the recent adoption of the NAFTA, make such assessments necessary as a basis for the environmental policy formulation and management needed in the immediate future.