Special Edition on Geohazards - Editorial

No Abstrac

Groundwater Vulnerability Map for South Africa

Vulnerability of groundwater is a relative, non-measurable and dimensionless property which is based on the concept that some land areas are more vulnerable to groundwater contamination than others. Maps showing groundwater vulnerability assist with the identification of areas more susceptible to contamination than others. They are useful in planning, policy formulation and decision-making for groundwater management and protection. Overlaying these maps with maps showing the location of contamination sources and land use enables the creation of risk maps.There are various methods for assessing groundwater vulnerability and from these the DRASTIC approach has been highlight in various studies as the most appropriate. This is mainly due to the fact that it is suitable for regional applications and the required input data are readily available. The DRASTIC index can be modified to incorporate anthropogenic influences on groundwater contamination and the modified form is called the DRASTIC Specific Vulnerability Index (DSVI). This paper discusses the creation of a groundwater vulnerability map for South Africa using the DSVI approach. The data used include the depth to groundwater, recharge, aquifer types, soil types, topography, the vadose zone, hydraulic conductivity and land use. These parameters were rated, weighted and combined to create the final map. The result was compared to groundwater quality data and similarities were found between the maps

Phytochemicals, antioxidant and antibacterial properties of a lichen species Cladonia digitata

Antioxidant activity assessment was performed using the free radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and reducing power assay. Phytochemical screening was done using chemical tests. Antibacterial activities of Cladonia digitata were determined by a disk diffusion method at concentrations of 0, 10, 50 and 100% (v/v) against pathogenic bacteria, Eschericia coli, Clostridium perfringens and Staphylococcus aureus. Standard cotrimoxazole (10 μg/ml) was used as a positive control. C. digitata revealed the presence of alkaloids, tannins, saponins, cardiac glycosides, flavonoids, anthraquinones and steroidal terpenes. The results of antioxidant activity indicate a concentration dependent activity. C. digitata extract showed better free radical scavenging activity than ascorbic acid and quercetin. There was no significant difference (T-test, p = 0.05) in the antioxidant activity between the extract and those of ascorbic acid and quercetin as assessed by the reducing power assay. The highest antibacterial activity was 16.1 mm diameter of zone inhibition observed against Clostridium perfringens followed by 15.5 mm against Staphylococcus aureus at the concentration of 100 and 50%, respectively. The results reveal that the tested extract consisted of several bioactive compounds, significant antioxidant and antimicrobial activity. The present results scientifically authenticate the use of C. digitata in folk medicine.Keywords: Phytochemicals, antioxidant, antibacterial, Cladonia digitat

A systematic review of evidence-based workplace prevention programmes that address substance abuse and HIV risk behaviours

The purpose of the systematic review was to determine the effectiveness of workplace substance abuse prevention programmes that also address substance-related HIV risks. A search of major electronic databases was conducted. Two authors independently applied eligibility criteria, assessed study quality, and extracted data using a standardised data extraction form. Due to the heterogeneity of study results, a qualitative approach was applied in assessing the effectiveness of the programmes. The search yielded 14 studies. All studies presented mixed results, with the majority reporting improvements in selfreported substance abuse measures. The review highlighted paucity in the availability of good quality workplace prevention programmes and none that addressed substance abuse and HIV risk behaviours in such settings.Keywords: Substance abuse, evidence-based, prevention programmes, workplace, industr

Remote sensing and geochemistry techniques for the assessment of coal mining pollution, Emalahleni (Witbank), Mpumalanga.

Environmental degradation associated with coal mining is one of the serious environmental issues in South Africa that is expected to continue with increasing energy demands. Mapping and monitoring contamination in mining areas are necessary to guide rehabilitation activities. Rapid monitoring systems are needed to develop effective rehabilitation plans. The advent of multispectral remote sensing data has proven to be effective in mapping and detecting mine related soil contamination. An integrated approach of soil geochemistry and remotely sensed data to characterise contamination in Emalahleni coal fields is presented in this study. Aster data was acquired and several band combinations were developed to identify patterns and occurrence of soil contamination. For geochemical assessment, the Nemerow index and the pollution loading index were calculated to evaluate the mining activity contamination. The classified aster images showed that contamination varies with land use. Residential areas and mining areas showed similar trends of contamination. Geochemical results showed that iron, vanadium and chromium are the most abundant elements in the study area. The findings of contamination indices reveal that the overall level of metal contamination in the study area is between moderate to heavily contaminated. The most polluted areas are concentrated in mining areas and along major transport intersections. The ASTER band ratios for silica and clay phases correspond with classified contamination indices indicating that remote sensing can successfully be used to assess pollution

An assessment of coastal vulnerability for the South African coast

Coastal vulnerability is the degree to which a coastal system is susceptible to, or unable to cope with, adverse effects of climate change. One of the most widely used methods in assessing risk and vulnerability of coastlines on a regional scale includes the calculation of vulnerability indices and presenting these results on a vulnerability map. These maps can assist coastal managers, planners, landowners and stakeholders identify regions of greater risk to coastal hazards and ultimately better inform mitigation and development strategies.This paper discusses the creation of a coastal vulnerability map for South Africa. The criteria used included elevation to chart datum, beach width, tidal range, wave height, geology, geomorphology, anthropogenic activities, distance to 20m isobaths and relative sea level change. The values of these parameters were divided into classes and the various classes ranked on a scale of 1 (very low vulnerability) to 5 (very high vulnerability) using examples from literature and expert knowledge. The layers were combined using the spatial overlay (map algebra) technique to create the final map. The results highlight the most vulnerable areas along the coastlines as the areas surrounding the City of Cape Town (the west coast) and the regions close to East London and Port St. Johns on the east coast. This can be mainly attributed to the type of geology and the anthropogenic activities in these areas

A groundwater-planning toolkit for the main Karoo basin: Identifying and quantifying groundwater-development options incorporating the concept of wellfield yields and aquifer firm yields

This paper provides an overview of groundwater-planning tools that were developed during a Water Research Commission project that was initiated due to the need to place the significant knowledge on groundwater of the Karoo Basin within the realms of water resource planning. In essence, the project aimed to identify favourable areas of groundwater potential forbulk municipal water supplies, to provide a method to quantify them, and to package the information so that it is assessable for planning purposes. In identifying favourable groundwater areas, the focus turned to developing a detailed transmissivity map of the Main Karoo Basin. In order to present yields in an accessible manner to water-supply planners, the same concept used in surface-water resource assessments and dam or reservoir design were adapted and applied to groundwater. Two methods were developed, namely the Aquifer Assured Yield Model and the Aquifer Firm Yield Model (the latter of which was developed into a software package together with the other products). The Aquifer Firm Yield Model provides the historical firm yield and uses historical monthly rainfall data together with recharge, evapotranspiration and baseflow to determine aquifer storage in any given month. The firm yield can be considered to define the upper limit of the groundwater resource. In order to establish possible wellfield yields, the C-J Wellfield Model (based on the  Cooper-Jacob approximation of the Theis groundwater-flow equation) was developed whereby borehole spacing can be optimised after inputtingestimated transmissivity values from the transmissivity map. To aid the planning process, groundwater-quality maps were produced together with the Wellfield Cost Model which provides an easy way to obtain first-order cost estimates of the wellfield options. This paper briefly describes these ‘tools’ that were produced and provides slightly more detail on how thetransmissivity maps were developed

Factors associated with repeat genital symptoms among sexually transmitted infection service attendees in South Africa, 2015 - 2016

Background. South African guidelines recommend a syndromic approach for the management of sexually transmitted infections (STIs), based on the presence of genital symptoms. However, the guidelines do not prescribe specific indications for microbiology testing for patients presenting with or without repeat genital symptoms.Objectives. To describe the prevalence of and factors associated with repeat genital symptoms among STI service attendees at primary care facilities.Methods. This was a cross-sectional study at 7 STI primary care facilities participating in the aetiological surveillance of STIs between January 2015 and December 2016. Demographic and clinical information and appropriate genital specimens were collected from participants presenting with vaginal discharge syndrome (VDS), male urethral syndrome (MUS) and/or genital ulcer syndrome (GUS). Repeat genital symptoms were defined as self-reported history of the same STI-related genital symptoms in the preceding 12 months. Multivariable logistic regression identified factors associated with repeat genital symptoms.Results. Of 1 822 eligible participants, 480 (30%) had repeat genital symptoms (25% and 75% in the preceding 3 months and 12 months, respectively). Of those with repeat genital symptoms, the median age was 28 (interquartile range (IQR) 24 - 32) years, and 54% were females. The most common aetiological agents among participants with VDS, MUS and GUS were bacterial vaginosis (n=132; 55%), Neisseria gonorrhoeae (n=172; 81%) and ulcers (n=67; 63%), respectively. One hundred and seven (20%) participants had no detectable common STI aetiology. In the multivariable analysis, repeat genital symptoms were associated with HIV co-infection (adjusted odds ratio (aOR) 1.43; 95% confidence interval (CI) 1.14 - 1.78), VDS diagnosis (aOR 1.39; 95% CI 1.10 - 1.76), self-reported condom use (aOR 1.56; 95% CI 1.20 - 2.03) and age 25 - 34 years (aOR 1.33; 95% CI 1.03 - 1.71).Conclusions. Our study found a high prevalence of repeat genital symptoms ‒ a significant proportion without STI aetiology. Identified factors of repeat genital symptoms highlight the need for improved integration of HIV and STI prevention and management. Further research is needed to determine the aetiology of repeat genital symptoms and the contribution of non-STI causes

Utilization of the Standardized Assessment for Clinical Trial Enrollment (SAFE) Template to Improve Clinical Trial Screening and Enrollment

Amanda Brink pictured. Department of Investigational Cancer Therapeutics Presented at JADPRO Live 2021.https://openworks.mdanderson.org/aprn-week-22/1003/thumbnail.jp

Decentralization in Africa and the resilience of traditional authorities: Evaluating Zimbabwe’s track record

Zimbabwe has undergone various phases of institutional reform during colonial and post-colonial times either co-opting, distorting or denying the presence of traditional authorities, but somehow none of these institutional engineering episodes managed to uproot them. What in fact happened is successive waves of political institutions designed and put in place during these reforms withered away. Zimbabwe’s traditional authorities are still there and they continue to play a big role in the daily lives of rural populations.This paper looks at one of the most important endogenous factors influencing the workings of decentralization in Zimbabwe. Successive waves of formal institutional change that took place during Zimbabwe’s colonial and post-colonial history have been unable able to uproot the influence of traditional leaders. Due to their home-grown legitimacy, various traditional authorities continue to play an ever-present role in the lives of people in rural areas. But, as it is the case throughout most of Africa, the powers of traditional leaders have mostly been uncodified under modern law and these power relations tend to be rather informal and culturally inaccessible to most outsiders. Consequently, the scholarly literature has not been able to systematically acknowledge their pervasive influence. The article concludes with a reflection on how the influence of traditional authorities can be translated into the democratic and progressive empowerment of rural populations in the developing world