Groundwater Pollution Vulnerability Research Articles

Investigation of the Hydrological Quality of Ethiope River Watershed, Southern Nigeria

The surface and groundwater resources of the Ethiope river watershed have been investigated for its hydrological and quality characteristics. The results indicate that Ethiope River is perennial and fed by groundwater seepages, precipitation and surface run-off from adjacent areas. The lowest discharge rate of the river is recorded inJune and increases steadily reaching its peak in October. The physico-chemical parameters of both water sources include, pH (5.28-7.06), turbidity (1.16 – 8.12 NTU), conductivity (65.00- 127.0 ìs/cm), dissolved oxygen (4.40-7.60 mg/l) and total hardness (25.50 – 45.0 mg/l). Others include, Na+ (3.91 – 27.05 mg/l), K+ (3.91 – 8.73 mg/l), Ca2+ (3.21 – 9.60 mg/l), Mg2+ (1.46- 5.84 mg/l), HCO3- (31.50-80.00 mg/l), Cl- (17.55 –35.10 mg/l), SO4 2- (0.25-0.58mg/l), NO3 2- (0.19-0.55 mg/l) and PO4 2- (0.20-19.00 mg/l). This physico-chemical quality is generally compatible with WHO guideline for domestic use. Nevertheless, the water samples consist of high microbial population including total coliform bacteria counts (39.00 – 1100 MPN/100ml) and Escherichia coli (21.00 – 305.00 MPN/100ml), which render both surface and groundwater unfit for domestic use without disinfection. An assessment of surface water-groundwater homogeneity using the parametric student’s t and F tests on selected constituents (chloride, nitrate, sulphate, phosphate, sodium, potassium, calcium and magnesium), indicate non-significance in thevariation within the tested parameters except for nitrate. This suggests some groundwater-surface water intermixing or communication, and the activity of denitrifying bacteria in surface water. A groundwater pollution vulnerability assessment using DRASTIC model indicates moderately high pollution risk level for the aquifer system

Assessment of groundwater pollution vulnerability and modelling of the Kanye Wellfield in SE Botswana—a GIS approach

Botswana is a semi-arid country with limited recharge to groundwater resources. Groundwater however is a major source of water for domestic, industrial and agricultural uses. There is therefore the need to ensure that the groundwater resources are of drinking quality, by protecting them against pollution sources such as landfills, pit latrines, industries, agricultural pesticides and waste. In this study a preliminary assessment of vulnerability of groundwater to pollution in Kanye well field in SE Botswana is undertaken. In order to assess the vulnerability of this aquifer to pollution, soils types, mapped geology and information from 82 boreholes were input into a GIS system to classify pollution vulnerability using Theissen polygons of the study area. Results indicate that 58% of the well field area is highly or very highly vulnerable to pollution, 34% is moderately vulnerable to pollution, and only 9% has low vulnerability. Estimates of the aquifer media characteristics in areas with only a few observations or few geological logs were considered to have higher uncertainty than areas with many observations. However, the use of the polynomial estimator enabled consideration of simple uncertainty for the aquifer media characteristics and pollution vulnerability modelling process.

Evaluation of waste disposal site using the DRASTIC system in Southern Korea

As a systematic approach to waste disposal site screening for groundwater pollution protection, the DRASTIC system developed by the US Environmental Protection Agency (USEPA), was introduced at Younggwang County in Korea. Hydrogeological spatial databases for the system include information on depth to water, net recharge, aquifer media, soil media, topographic slope, hydraulic conductivity and lineament. Using the databases, the DRASTIC system and a GIS, the regional groundwater pollution vulnerability of the study area was assessed. The fracture density extracted from lineament maps was added to the DRASTIC system to take into account the preferential migration of contaminants through fractures. From the results of the study, a degree of groundwater pollution vulnerability through the study area was easily interpreted, and waste disposal sites could be screened for groundwater protection.

Groundwater recharge and pollution vulnerability of British aquifers: a critical overview

Abstract The concept of aquifer pollution vulnerability, and the way it has been developed and incorporated as a central element in British groundwater protection policies, is reviewed in detail. A related question is: do we understand enough about groundwater recharge mechanisms to assess pollution vulnerability realistically and to define necessary protection measures efficiently? Some key remaining areas of uncertainty are analysed in the light of recent research results.