Impact of human activities on the quality of river water: The case of Evrotas River catchment basin,Greece

The impact of point (domestic and industrial effluents) and non-point (agricultural land runoff) pollution sources on the quality of the receiving waters of the Evrotas River (Laconia, Greece) was investigated during a monitoring study from August 1991 to August 1992. The part of the river which was located near the city of Sparta was seasonally influenced by the discharge of effluents from orange juice plants (operating during winter) and by the discharge of septage for the emptying of cesspools which are serving part of the city. The low dilution of incoming pollutants (septage) during the low water flow in summer lead to the decreasing self-purification capacity of the river and the development of septicity conditions in some of its parts. In the vicinity of intensively cultivated areas, the high concentrations of nitrogen and phosphorus which were detected in the river water during winter and spring may be partly attributed to the leaching of the applied fertilizers because of nirogen mobilization and soil erosion, following the season's precipitations. The protection of the Evrotas River water Quality must therefore include adequate treatment of the septage produced in the area, as well as the construction of wastewater treatment plants for the major industries of the area. The non-point pollution could be controlled by the restoration of the Evrotas riparian vegetation, together with a more rational use of fertilizers in the area.     

Water quality test based on dielectrophoretic measurements of fresh water algae Selenastrum capricornutum

A method is described whereby dielectrophoresis of algal cells is used to perform rapid water quality analysis, specifically detecting the presence of CuSO4. The dielectric collection spectrum of the fresh water alga Selenastrum capricornutum was determined for a range of concentrations of CuSO4 from 25 mg L(-1) to 0.25 mg L(-1) for exposure times of 15 min and 18 h. In all cases increasing the concentration of CuSO4 reduced cell collection, but a step reduction was observed in collection between 2 mg L(-1) and 5 mg L(-1). This method has potential for forming a rapid, low-cost test for water quality with broad specificity and significantly reduced analysis time compared to current methods.     

A new device for measuring fluctuations in plant stem diameter: Implications for monitoring plant responses

An electrical device capable of continuously measuring micronsized changes in stem diameter of woody and herbaceous plants is described. Fumigation of sunflowers with automotive exhaust was used to test the ability of the device to detect short-term plant responses.     

Determination of biomass burning emission factors: Methods and results

Biomass burning, in a broad sense, encompasses different burning practices, including open and confined burnings, and different types of vegetation. Emission factors of gaseous or particulate trace compounds are directly dependent both on the fuel type and the combustion process. Emission factors are generally calculated by stoichiometric considerations using the carbon mass balance method, applied either to combustion chamber experiments or to field experiments based on ground-level measurements or aircraft sampling in smoke plumes. There have been a number of experimental studies in the last 10 years to investigate wildfires in tropical, temperate, or boreal regions. This article presents an overview of measurement methods and experimental data on emission factors of reactive or radiatively active trace compounds, including trace gases and particles. It focuses on fires in tropical regions, that is, forest and savanna fires, agricultural burns, charcoal production, use of fuelwood, and charcoal combustion.     

Ammonia uptake by plants

The paper considers the methodology and results of experimental determination of dry deposition and ammonia uptake by isolated plant leaves. Analytical expressions are proposed which allow a transition from rates obtained in an isolated chamber to dry ammonia deposition by standing crops leaves.     

Characterizing soils for hazardous waste site assessments

This paper provides a review and justification of the minimum data needed to characterize soils for hazardous waste site assessments and to comply with the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Scientists and managers within the regulatory agency and the liable party need to know what are the important soil characteristics needed to make decisions about risk assessment, what areas need remediation and what remediation options are available. If all parties involved in characterizing a hazardous waste site can agree on the required soils data set prior to starting a site investigation, data can be collected in a more efficient and less costly manner. Having the proper data will aid in reaching decisions on how to address concerns at, and close-out, hazardous waste sites.This paper was prepared to address two specific concerns related to soil characterization for CERCLA remedial response. The first concern is the applicability of traditional soil classification methods to CERCLA soil characterization. The second is the identification of soil characterization data type required for CERCLA risk assessment and analysis of remedial alternatives. These concerns are related, in that the Data Quality Objective (DQO) process addresses both. The DQO process was developed in part to assist CERCLA decision-makers in identifying the data types, data quality, and data quantity required to support decisions that must be made during the remedial investigation/feasibility study (RI/FS) process. Data Quality Objectives for Remedial Response Activities: Development Process (US EPA, 1987a) is a guidebook on developing DQOs. This process as it relates to CERCLA soil characterization is discussed in the Data Quality Objective Section of this paper.     

Heavy metals in the SPM of air in the environment surrounding a ferro-alloy industrial plant in India

Prices for ferro-alloys have hardened due to the closure of plants in developed countries on account of increasingly stringent pollution control legislation, resulting in a higher cost of production. A ferro-alloy industry with a capacity of 80000 MT per annum was selected to study the nature of pollution. Because of the objectionable nature of polluting air in and around the plant it was located in a rural area where there was no other industry. The area was agriculturally active and there was no effective control system for this plant.The quality of ambient air around the plant site is discussed in this paper along with the meteorological conditions. The maximum concentration of suspended particulate matter (SPM) was 768 µg/NM³ downwind of the plant, minimum 184 µg/NM³, and the average was more than 446 µg/NM³. The presence of heavy metals, viz. Fe, Mn, Cr and Pb, was also assessed. The concentration of Fe was 50 µg/NM³ downwind and 10 µg/NM³ upwind. The concentration of other metals followed a similar trend.     

Matrix diffusion effects in the cleanup of heterogeneous aquifers

Simple mathematical models are developed to account for the rather slow mass transport of nonaqueous phase liquid (NAPL) into aqueous solution in groundwater during flushing operations. The models are based on the assumption that this bottleneck in the process is associated with diffusion in the aqueous phase in the porous medium from the location of the NAPL drops/ganglia in a region of relatively low permeability out into a region of substantially higher permeability, somewhat analogous to diffusion from a block of porous rock into a nearby fracture, where the fracture system overwhelmingly dominates the overall permeability. The models include batch flushing, flushing in a laboratory column, and a one-dimensional model for flushing by means of a single recovery well.     

Patchy distributions: Optimising sample size

A method for estimating sample size which does not require an a priori definition of desired precision, or the assumption that the population is normally distributed with constant variance, has recently been proposed. This paper discusses this method and presents five modifications which make the method easier to use and reduce the probability of estimating a larger sample size than is actually required. The method is extended and used to estimate the mean abundance of patchily distributed benthic organisms. The technique can be used to guide the design of any environmental sampling programme, be it physical, chemical or biological, where comparisons between times and/or locations are required. Trade-offs between numbers of replicates and numbers of levels/sites are discussed.     

Chromium redox speciation in natural waters

Dissolved hexavalent chromium concentrations were determined in river, estuarine and coastal waters of the Humber catchment in north-east England. Samples were collected, filtered, extracted on site and after storage for up to eight days. Hexavalent chromium concentrations did not change by more than 0.05 microg l(-1) (not significant, p = 0.05) over this period. Total chromium concentrations in the catchment were less than 1.0 microg l(-1). This is low in relation to the proposed Environmental Quality Standard. Hexavalent chromium accounted for between 27% and 100% of the total dissolved concentration, with an average of approximately 50%. The proportion of Cr(III) and Cr(VI) in the rivers and estuary were of the same range as previously measured in 1993. The addition of Cr(III) and Cr(VI) to fresh and saline water samples illustrates the complexity of the factors controlling chromium speciation in natural waters. The presence of oxidisable organic matter and the stabilising role of complexing organic ligands are proposed as the main controlling influences of redox speciation in filtered samples.