Assessment of the Impact of Effluents Discharge from Murang’a Town and Its Environs on the Water Quality of River Mathioya, Murang’a County, Kenya

Effect of effluents into rivers is of great economic, environmental and health concern. Chemical fertilizers are used extensively in modern agriculture, in order to improve yield and productivity of agricultural products. However, nutrients, leaching through the soil from agricultural activities, sewerage effluents and runoff from residential areas reaching river water resources are causing serious pollution. The purpose of this study was to determine the impact of effluent discharges on water quality of River Mathioya in Murang’a County, Kenya. Samples were collected upstream and downstream of Murang’a town along the Mathioya River. The pH, dissolved oxygen, electrical conductivity, total dissolved solid, total suspended solids and temperature were determined using the respective meters. Heavy metals were determined using flame atomic absorption spectrometry while sodium and potassium were determined using flame photometry. Nitrates and phosphates were determined using UV/Visible spectrophotometry. Fluoride ion selective electrode was used to determine fluoride. The study has shown that there was considerable amount of heavy metals in the water samples of Mathioya River, though the levels were below WHO maximum permissible levels for zinc 0.05 - 0.08, chromium 0.02 - 0.03, lead was below the limit of detection and copper 0.03 - 0.04 while iron 0.73 - 1.16 and manganese 0.88-2.24 mg/L exceeded this limit. The concentrations of the physicochemical parameters pH 6.94 - 7.76, TDS (37.84 - 54.59 mg/L), TSS (42.78 - 53.84 mg/L), DO (4.75 - 8.27 mg/L) and EC 63.89 - 80.17, nitrates (6.40 - 13.66 mg/L), phosphates (0.29 - 0.91 mg/L) and fluoride (0.68 - 0.88 mg/L). Keywords: AAS, AES, UV/VIS, ISE, physico-chemical parameters, nutrients levels, heavy metals

Prospecting For Iron and Titanium Using Termitaria

Mining activities begin with mineral prospecting and exploration, which can be quite expensive.  A number of mineral prospecting methods are known such as excavation of soil for analysis, phyto- prospecting, and hydro-geochemical prospecting among others.  Ants and termites are known to burrow up to 55 meters to water tables. In the process, they bring up debris, which may contain traces of minerals in mineralized areas. Qualitative and quantitative analysis of anthills’ and termite mound soil samples can be used as preliminary tests for prospects of finding a given mineral. Termitaria sampling has been used in other parts of the world such as Australia, India and Ghana. The study sought to find out whether there are significant levels of iron and titanium in anthills soil samples compared to top soil samples from Kwale, Kathwana and Kithiori, which are mineralized areas in Kenya. Flame atomic absorption spectroscopy was used to determine the metals under study after acid digestion. The control samples had lower concentrations of iron for all the three areas; 20.63±0.09 mg/g compared to mean concentration of anthill of 25.3±0.06 mg/g in Kwale, 90.53±0.00 mg/g compared 98.53±0.29 mg/g at Kathwana and 82.63±0.22 mg/g compared to 89.46±0.00 mg/g at Kithiori. Titanium content in termitaria samples was higher than the control for all the three areas; 14.94±0.24 mg/g compared14.72±0.00 mg/g at Kwale, Kithiori18.47±0.03 mg/g compared to15.93±0.03 mg/g at Kithiori and 14.52±0.03 mg/g compared to13.13±0.00 mg/g at Kathwana. These results demonstrate the potential for use of termitaria soil sampling in mineral prospecting. For conclusive results of iron and titanium mineralization, multimedia sampling is recommended. Keywords: Termitaria, Mineral Prospecting, Flame Atomic Absorption Spectroscopy

Analysis of the Levels of Phosphates, Nitrates and Sulfates in the Wheat Growing Area of Ntulele in Narok County, Kenya

This study sampled wheat farms in Ntulele area of Narok county to determine the levels of nitrate, phosphate and sulfate using UV-VIS spectrophotometer and data analyzed using MSTAT-C, SPSS and student t-test. Nitrates were found to be sufficient whereas phosphates and sulfates were found to be deficient in most of the farms sampled. Sulfate had the least CV% of 8.54 followed by nitrates with 14.23% and phosphate had the highest with 21.91% an indication that all the nutrients were applied in similar rates by the farmers of Ntulele. The nutrients before and after planting were significant (p<0.05). Keywords: Nitrate, Sulfate, Phosphate, UV-VIS, Soil, Ntulele

In vitro determination of Sun Protection Factor on Clays Used for Cosmetic Purposes in Kenya

Ultraviolet radiation is a real problem to human health and it’s said to cause skin cancer and related skin ailments. These diseases are of economic burden in terms of diagnosis, treatment and prevention in low and middle level countries. Commercial sunscreens are considered as the most effective way of preventing the incidences of skin cancer, however they are costly, unavailable and they contain toxic ingredients, which can in the end be cancerous. Sunscreens from natural sources like plants and clay are currently being explored as cheap, reliable, and available and may offer simple alternative health benefits. The purpose of this study was to evaluate the amount of sun protection factor (SPF) offered by cosmetic clays used in Kenya by different communities. The SPF was determined in vitro using 3 M transpore adhesive tapes on twelve clay samples collected randomly from sites used in three counties namely Narok, Bomet and Bungoma. Using a spreading protocol of 2 µg/cm2 transmittances between 280 to 400 nm were measured using a UV 1800 Shimadzu, Japan spectrophotometer. A commercial sunscreen with known SPF was incorporated in the study as a positive control. The SPF values of the clays were found to be between 1.46 and 40.98. The SPF value obtained for the commercial sunscreen differed from the SPF cited by the manufacturer. A second method was used on the commercial sunscreen and values obtained were in close agreement with those used in the first method. This study revealed that clays used for cosmetic purposes offer some form of sun protection to its users. Determination of SPF using Transpore tape is cheap, easy to handle, readily available and rapid. Keywords: Sun Protection factor, Clay

BIOSORPTION OF SELECTED HEAVY METALS BY THE BIOMASS OF THE GREEN ALGA SPIROGYRA SP.

In this paper, the influence of contact time, initial pH and metal ion concentrations on the adsorption properties of a freshwater green alga (Spirogyra sp.) biomass was studied. Several model solutions of selected heavy metals (Cd, Cu, Cr, Pb) were put into contact with the green algae-based sorbent for different time periods. After the treatment, the concentrations of heavy metals in model solutions were determined using flame atomic absorption spectrometry (FAAS) and inductively-coupled plasma-optical emission spectrometry (ICP-OES). Fourier transform infrared spectroscopy (FTIR) was used to reveal which functional groups were responsible for the green algae biosorption properties. Adsorption capacities were found to be 22.52, 38.19, 35.59 and 94.34 mg/g for Cd, Cr, Cu and Pb, respectively, at contact times of 15-50 minutes and initial metal ion concentrations of 500-700 µg/g. The optimum pH for biosorption of Cd, Cr, Cu and Pb were 5.5, 5.8, 5.9 and 5.0, respectively. The biosorption process followed second order kinetics and fittedthe Langmuir isotherm model. Biomonitoring studies suggested the possible use of this freshwater green algaas a bioindicator, with mean concentration factors for the selected elements in the range of 367-7154. BIOSORPCIJA ODABRANIH TEŠKIH METALA POMOĆU BIOMASE ZELENE ALGE SPIROGYRA sp.   U ovom radu je proučavan uticaj kontaktnog vremena, početnog pH i početne koncentracije metalnih jona na sorpcione karakteristike slatkovodne zelene alge Spirogyra sp. Nekoliko model-rastvora odabranih teških metala (Cd, Cu, Cr, Pb) je tretirano, u različitim vremenskim intervalima, sorbentom pripremljenim od zelenihalgi. Plamena atomska apsorpciona spektrometrija (FAAS) i induktivno kuplovana plazma sa optičkom emisionom spektrometrijom(ICP-OES) su korišćene za određivanje sadržaja teških metala u model-rastvorima Nakon tretmana. Furijeova transformacion ainfracrvena spektroskopija (FTIR) je pokazala koje funkcionalne grupe su nosioci biosorpcionih osobina zelenih algi. Pri kontaktnim vremenima u opsegu 15-50 minuta i polaznoj koncentraciji metala 500-700 µg/ml, sorpcioni kapacitet je iznosio 22,52, 38,19, 35,59 i 94,34 mg/g za Cd, Cr, Cu i Pb. Optimalni pH za biosorpciju Cd, Cr, Cu i Pb je bio 5,5, 5,8, 5,9 i 5,0. Proces biosorpcije prati kinetiku drugog reda i zakonitosti Lengmirovog izotermalnog modela. Rezultati biomonitoringa ukazuju da zelene alge imaju veliki potencijal kao bioindikatori; srednji koncentracioni fakori za proučavane metale su bili u opsegu 367-7154.

VOLTAMMETRIC INVESTIGATION OF THE DISTRIBUTION OF HYDROXO-, CHLORO-, EDTA AND CARBOHYDRATE COMPLEXES OF LEAD, CHROMIUM, ZINC, CADMIUM AND COPPER: POTENTIAL APPLICATION TO METAL SPECIATION STUDIES IN BREWERY WASTEWATER

This paper reports results on complex formation reactions between OH-, Cl-, EDTA and carbohydrate ligands with Pb2+ ions at various [LT]:[MT] ratios and at different pH values (1.5-13.0). Differential pulse anodic stripping voltammetry (DPASV) employing an ex situ plated thin mercury film electrode (TMFE) was used to measure the shifts in peak potentials. Formation of simple, polyligand as well as mixed ligand complexes are reported. The reactions between the Pb(II) and the carbohydrate ligands showed pronounced pH dependency on metal forms compared to reactions with simple inorganic ions such as chloride. Modeling of the experimental data obtained with the DPASV method was done using computer software (3D-VISE). The calculated complex formation curves (CCFC) based on mass balance equations were fitted to the experimental complex formation curves (ECFC) and the goodness of the fit evaluated (RSD < 5%). These studies were applied to Pb, Cr, Zn, Cd and Cu speciation in brewery wastewater in which differences between total metal determined by flame atomic absorption spectrometry (FAAS) after acid digestion and labile fraction determined by DPASV were used to estimate the percentage of non-labile fraction (mainly metal-organic complexes). Up to 90% of the metal was found to exist as the “inert” fraction, implying that the effluent system from the brewery industry poses minimal health risks to the environment with regard to toxic forms of the metals as the organically bound metal forms are generally known to have low toxicity compared to the aquo or labile metal forms. KEY WORDS: Metal speciation, Carbohydrates, Brewery wastewater, Differential pulse voltammetry Bull. Chem. Soc. Ethiop. 2005, 19(1), 125-13