John O. Odiyo

The health implications of wastewater reuse in vegetable irrigation: a case study from Malamulele, South Africa

Malamulele is located in an arid region where small-scale irrigation with wastewater is rife. A study was conducted to investigate the health implications of wastewater reuse in vegetable irrigation. Results showed that there are potential health hazards associated with this practice. The wastewater contained 103 helminth eggs/100 ml and zero helminth eggs for control group; vegetable wash water had 3 helminth eggs/100 ml for the exposed group and zero for control. The wastewater results exceeded the WHO guidelines whereas the vegetable wash water counts were within the guideline. Stool samples of farmers and their children indicated common infections with hookworm and Giardia lamblia. Hookworm infections were high (42%) among exposed group in comparison to the control group (27.5%). The farmers were able derive their livelihood from the sale of vegetables. The findings suggest that the health risks of using wastewater are real but can be managed by using the incomes that the farmers earn.

Determination and Distribution of Polycyclic Aromatic Hydrocarbons in Rivers, Sediments and Wastewater Effluents in Vhembe District, South Africa

Polycyclic aromatic hydrocarbons are very toxic and persistent environmental contaminants. This study was undertaken to assess the concentrations and possible sources of 16 PAHs (Polycyclic aromatic hydrocarbons) classified by the United State Environmental Protection Agency as priority pollutants in water and sediments of the Mvudi and Nzhelele Rivers. Effluents from Thohoyandou wastewater treatment plant and Siloam waste stabilization ponds were also investigated. Diagnostic ratios were used to evaluate the possible sources of PAHs. PAHs in the water samples were extracted using 1:1 dichloromethane and n-hexane mixtures, while those in the sediment samples were extracted with 1:1 acetone and dichloromethane using an ultrasonication method. The extracts were purified using an SPE technique and reconstituted in n-hexane before analyses with a gas chromatograph time of flight—mass spectrometer. The results obtained indicate the prevalence of high molecular weight PAHs in all the samples. PAHs concentrations in water and sediment samples from all the sampling sites were in the range of 13.174–26.382 mg/L and 27.10–55.93 mg/kg, respectively. Combustion of biomass was identified as the major possible source of PAHs. Effluents from wastewater treatment facilities were also considered as major anthropogenic contributions to the levels of PAHs found in both river water and sediments. Mvudi and Nzhelele Rivers show moderate to high contamination level of PAHs.

Synthesis and Characterization of Biopolymeric Chitosan Derived from Land Snail Shells and Its Potential for Pb2+ Removal from Aqueous Solution

Pb2+ is considered to be a very toxic pollutant in the aquatic environmental media. Biopolymeric chitosan synthesized from snail shell has been studied for its potential to remove heavy metals from aqueous solution. The experiments were conducted in the range of 1–50 mg/L initial Pb2+ concentration at 298 K. The effects of pH, adsorbent dosage and contact time on the adsorptive property of the adsorbent were investigated and optimized. The derived chitosan was characterized using Fourier transform infrared spectrometer (FT-IR) and X-ray florescence (XRF). The experimental data obtained were analysed using the Langmuir and Freundlich adsorption isotherm models. The Langmuir model and pseudo second order kinetic model suitably described the adsorption and kinetics of the process with regression coefficients of 0.99 and 1.00, respectively. Sodium hydroxide was a better desorbing agent than hydrochloric acid and de-ionized water. From the results obtained, it is concluded that synthesized biopolymers from land snail shells has the potential for the removal of Pb2+ from aqueous solutions.

Evaluation of Microbiological and Physicochemical Parameters of Alternative Source of Drinking Water: A Case Study of Nzhelele River, South Africa

Background: Access to clean and safe drinking water is still a problem in developing countries and more pronounced in rural areas. Due to erratic supply of potable, rural dwellers often seek for an alternative source of water to meet their basic water needs. The objective of this study is to monitor the microbiological and physicochemical water quality parameters of Nzhelele River which is a major alternative source of drinking water to villages along its course in Limpopo province of South Africa. Methods: Membrane filtration method was employed in evaluating the levels of E. coli and Enterococci in the river water from January-June, 2014. Specialized multimeter was used to measure the pH, electrical conductivity and turbidity of the river water. Ion Chromatograph was used to measure major anions such as fluoride, chloride, nitrate and sulphate in the water. Results: High levels of E. coli (1 x 102 - 8 x 104 cfu/100 mL) and enterococci (1 x 102 – 5.7 x 103 cfu/100 mL) were found in the river water and exceeded their permissible limits of 0 cfu/100 mL for drinking water. Turbidity values ranged from 1.12-739.9 NTU. The pH, electrical conductivity, chloride, fluoride, nitrate and sulphate levels were below their permissible limits for drinking water. Conclusion: The river water is contaminated with faecal organisms and is unfit for drinking purposes. However, the levels of the major anions accessed were within the permissible limits of drinking water.

Evaluation of temporary seasonal variation of heavy metals and their potential ecological risk in Nzhelele River, South Africa

Abstract Surface water is often used as alternative source of drinking water in many regions of the world where the potable water supply is erratic or not present. The concentration of heavy metals was assessed using an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). The impact of temporary seasonal variation on the contamination level was also assessed. Contamination factor (CF) and Hakanson’s potential ecological risk (Er and RI) indices were used to evaluate the toxicity levels of the metals in the sediments of the river. Higher concentrations of Fe, Mn, Pb, Cu and Zn were determined in the dry season in the river water whereas in the sediments higher levels were recorded for Al, Fe, Cd, Cr, Cu and Zn in the wet season. The average CF values for all the metals showed a low contamination level in the sediment, except for Cu and Cd which had moderate and considerable contamination levels, respectively. Similarly, Cu showed a moderate ecological risk level (Er = 62.90) only in March 2014, for other months Cu and the other metals investigated had Er values < 40 which implies low ecological risk. The mean relative abundance of heavy metals in the sediments follows the trend Al>Fe>Mn>u>Zn>Cr>Pb>Cd.

Challenges to Sustainable Safe Drinking Water: A Case Study of Water Quality and Use across Seasons in Rural Communities in Limpopo Province, South Africa

Consumption of microbial-contaminated water can result in diarrheal illnesses and enteropathy with the heaviest impact upon children below the age of five. We aimed to provide a comprehensive analysis of water quality in a low-resource setting in Limpopo province, South Africa. Surveys were conducted in 405 households in rural communities of Limpopo province to determine their water-use practices, perceptions of water quality, and household water-treatment methods. Drinking water samples were tested from households for microbiological contamination. Water from potential natural sources were tested for physicochemical and microbiological quality in the dry and wet seasons. Most households had their primary water source piped into their yard or used an intermittent public tap. Approximately one third of caregivers perceived that they could get sick from drinking water. All natural water sources tested positive for fecal contamination at some point during each season. The treated municipal supply never tested positive for fecal contamination; however, the treated system does not reach all residents in the valley; furthermore, frequent shutdowns of the treatment systems and intermittent distribution make the treated water unreliable. The increased water quantity in the wet season correlates with increased treated water from municipal taps and a decrease in the average contaminant levels in household water. This research suggests that wet season increases in water quantity result in more treated water in the region and that is reflected in residents’ water-use practices.

Mineral Constituents and Kaolinite Crystallinity of the <2 μm Fraction of Cretaceous-Paleogene/Neogene Kaolins from Eastern Dahomey and Niger Delta Basins, Nigeria

Abstract This study examines the mineral composition and kaolinite crystallinity of Cretaceous and Paleogene/Neogene kaolins from Nigeria based on X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy data of the <2 μm fraction. The purpose of this was to assess the minerals present, structural order, and possible industrial applications of the kaolins. A total of twenty-eight (28) samples comprising of fifteen (15) Cretaceous and thirteen (13) Paleogene/Neogene kaolins were analysed. The XRD results showed that both the Cretaceous and Paleogene/Neogene kaolins have kaolinite as the dominant phase followed by quartz with anatase, hematite, and goethite occurring in minor quantities. Based on the mineralogical composition, the Paleogene/Neogene deposits were classified as sandy kaolin and the Cretaceous deposits were classified as pure kaolin. The kaolinite structural order for the Cretaceous pure kaolin was higher than that obtained for the Paleogene/Neogene sandy kaolin with more quartz, iron, and titanium oxides. The economic consideration of the deposits showed that the sandy kaolin type can be used in pigment industrial applications whereas the pure kaolin type can be used in refractory, fiberglass, and ceramic industrial applications.

Fourier Transform Infrared Spectroscopy of Clay Size Fraction of Cretaceous-Tertiary Kaolins in the Douala Sub-Basin, Cameroon

Abstract The structural order of Cretaceous-Tertiary kaolins of the Douala Sub-Basin in Cameroon was determined in this study. This was achieved using Fourier Transform Infrared spectroscopy (FTIR) with attenuated total reflectance (ATR) on the Bomkoul, Dibamba, Ediki, Logbaba, Missole and Yatchika kaolins. Transmittance spectra of 20 samples were recorded in the mid-infrared regions (MIR). Results show that most of the kaolins had the four distinguishable bands in the hydroxyl (OH) stretching region, though the second transmittance band (3670 cm−1) had low intensities. The hydroxyl stretching of water bands (3457 and 3442 cm−1 for KGa-1b and KGa-2, respectively) were mainly observed in all Logbaba samples at 3443 cm−1 and 3445 cm−1. The two bands reflecting OH deformation of inner-surface hydroxyl and inner hydroxyl groups (937 and 915 cm−1) were quite visible in the Bomkoul, Dibamba, Logbaba and Missole II samples; slightly visible in all Yatchika and two of the Ediki; and not visible in Missole I and one of the Ediki samples. Therefore, based on the empirical classification of the degree of order of kaolinite, 10 of the studied samples had ordered structures. Three displayed partially ordered structures; four had poorly ordered structures, and three exhibited disordered structures. This study revealed that kaolins from Dibamba, Logbaba and Missole II in the Douala Sub-Basin had the best crystallinity, which is one of the important characteristics needed for industrial applications.

Impact of Wastewater on Surface Water Quality in Developing Countries: A Case Study of South Africa

Wastewater effluents are major contributors to a variety of water pollution problems. Most cities of developing countries generate on the average 30–70 mm3 of wastewater per person per year. Owing to lack of or improper wastewater treatment facilities, wastewater and its effluents are often discharged into surface water sources, which are receptacles for domestic and industrial wastes, resulting to pollution. The poor quality of wastewater effluents is responsible for the degradation of the receiving surface water body. Wastewater effluent should be treated efficiently to avert adverse health risk of the user of surface water resources and the aquatic ecosystem. The release of raw and improperly treated wastewater onto water courses has both short‐ and long‐term effects on the environment and human health. Hence, there should be proper enforcement of water and environmental laws to protect the health of inhabitants of both rural and urban communities. This study reports major factors responsible for the failing state of wastewater treatment facilities in developing countries, which includes poor operational state of wastewater infrastructure, design weaknesses, lack of expertise, corruption, insufficient funds allocated for wastewater treatment, overloaded capacities of existing facilities, and inefficient monitoring for compliance, among others.

Household Hazardous Waste Management in Sub‐Saharan Africa

Household hazardous wastes (HHWs) have not been given serious attention in sub‐ Saharan Africa. There is little or no information on HHWs in many developing countries of the world. This is regardless of the fact that they are very toxic and contain constit‐ uents which are persistent in nature. Once released into the environment, they can remain stable for exceptionally long periods of time. They have the potential to be harmful to public health and the environment if not handled, used, and disposed properly. This study reports the level of knowledge and management of HHWs in three tertiary institutions in sub‐Saharan Africa. Several factors were found to be responsible for poor management of HHWs. These include lack of awareness, inadequate treatment technologies, financial constraints, lack of realistic policies and legal frameworks, and unplanned settlements, among others.