The stable isotope mixing model in R (SIMMR) proves to be a robust method for quantifying the relative contributions of multiple sources to a mixture. In this study, we integrated the stable isotopes of NO3- and hydrochemical data into the SIMMR model to assess the proportional sources of NO3- in groundwater samples at the Granvillebrook and Kingtom dumpsites. The bi-plot analysis of delta N-15 versus delta O-18-NO3- revealed that the NO3- in the dumpsites predominantly originated from manure and leachate (MAL), soil organic-N (SON) and domestic wastewater (DW) confirming the prevalence of denitrification and ammonia volatilization. Furthermore, SIMMR analysis of delta N-15 versus delta O-18-NO3- provided detailed insights. At the Granvillebrook dumpsite, SON emerged as the primary contributor (43.6%) to NO3- in groundwater, followed by MAL (31%) and DW (17%). In the Kingtom area, significant contributions came from MAL (32.2%), SON (28.0%), and DW (26.3%). Additionally, SIMMR analysis of delta N-15 versus dissolved oxygen (DO) indicated that MAL played a predominant role (61.1%) in contributing NO3- to the groundwaters of the Granvillebrook dumpsite, followed by SON (23.8%) and DW (15.1%). In the Kingtom dumpsite, DW (55.0%), SON (29.1%), and MAL (15.9%) were identified as the major contributors to NO3- in groundwater. The study underscores that coupling delta N-15 and DO in the SIMMR model is a more efficient method for quantifying the contributions of NO3- sources from MAL, SON, and DW. This research bridges a knowledge gap by providing novel insights into NO3- source analysis, serving as a foundational resource for future NO3- isotope studies in groundwaters near dumpsites. Assessing the temporal variations and sources of NO3- can support the development of improved agricultural management practices and sewage disposal programs, to sustain water quality in wells near dumpsites.

Monitoring the nutrient levels of the dam water on the Bui hydropower project (Ghana) is vital for understanding its ecological health. The purpose of this study is to evaluate current (2021) nutrient levels and examine the irrigational water quality. The novelty of this research lies in the combination of nutrient analysis and irrigational water quality index (IWQI) as tool to understand the ecological health of the dam water. Bui dam water is slightly acidic (pH of 6.6) which partly influences nutrient bioavailability in the dam water. The composition of water in terms of ion dominance follow the order of Ca2+>Na+>Mg2+>K+ and that of anions followed the order of HCO3->Cl->SO42->NO3-, with signatures of Ca2+- Mg2+- HCO3– water type. Pearson's correlation plot shows pH, TDS, and EC influences sulphate distribution in the dam. EC mean level of 78.06 µS/cm is below acceptable ranges (150 and 500 µS/cm) known to sustain freshwater fish species (e.g., Alestidae, Anabantidae and Bagridae family) present in the Bui dam. Historical nitrate, phosphate and sulphate measured 2.01mgL-1, 0.16mgL-1 and 20.96mgL-1 as against 0.79mgL-1, 0.60mgL-1 and 2.22mgL-1 caused by the impoundment. The nutrient decrease shows improved water quality over time. The spatial plot shows low phosphate levels in the northwestern and southeastern part of the dam indicating rapid uptake and sediment trapping. IWQI shows the water has no toxicity risk for any plant. This study provides a basis for further monitoring to ensure the observed nutrient decrease is not altered by human-induced activities. Strengthening management policies is therefore encouraged to sustain the dam's ecological health.

Investigating sources and evolution of groundwater in the Black Volta River basin is vital for understanding aquifer chemical configuration. Though resettlement has made groundwater in the region an important water supply source, its hydrochemical origin is poorly understood. Therefore, hydrochemistry was coupled with stable isotope (delta H-2 and delta O-18) techniques to improve knowledge for effective groundwater resource management. For this purpose, 23 boreholes were sampled in the Black Volta River basin of Ghana. Major ion dominance is in the order: Na+ > Ca2(+) > Mg2(+) >K+ and HCO3 > Cl > SO42 -> NO3- respectively. Hydrochemical facies indicates the presence of soluble silicate minerals within aquifer. Hierarchical cluster analysis showed higher ionic concentration within aquifers which decreases towards discharge areas. This is attributed to longer residence time at lower elevations leading to interaction of water with silicate and accessory minerals. Oxygen-18 spatial plot shows recharge occurs along subsurface fractured zones which is confirmed by the water table contour of the study area. Natural geochemical processes, anthropogenic influences and the dissolution of silicate/albite components were extracted using Principal component analysis/factor analysis. These two components which explains the hydrochemistry constituted 79.5% of the total variance in the hydrochemical data and have eigen values > 1. Isotopic composition of groundwater indicates is of meteoric origin and the aquifers were recharged by precipitation. The outcome of this study provides theoretical support for the monitoring and management of groundwater, and its implication on the migration of people in arid/semi-arid regions.

Stable Isotope (& delta;2H and & delta;18O) technique is employed to investigate the Dam water-groundwater interaction on the Bui hydropower project in Ghana, to ascertain; if surface water from the dam recharges the groundwater or if there is balance flow relationship between the two systems. The hydrochemical results showed that the pH of the groundwater (5.51-7.18) was slightly acidic to basic, predominantly due to lithology. The pH of the surface water (6.13-6.98) suggests decomposition of submerged organic matter at the impoundment of the dam. The hydrochemical facies showed signatures that result from groundwater interaction with soluble aquifer materials (feldspars, micas, and quartz). Stable isotope in the study area showed surface water is more enriched (& delta;18O = -2.46%0; & delta;2H -21.48%0) than rainwater (& delta;18O = -3.36%0; & delta;2H = - 17.83%0), which is slightly enriched than groundwater (& delta;18O = -3.58%0; & delta;2H = - 17.48%0). The stable isotope (& delta;2H-& delta;18O) biplot indicates that no interaction occurred between the groundwater and the Black Volta River; the groundwater in the catchment is of meteoric origin. D-excess confirms mineralization due to water-rock interaction while the biplot of Cl- versus & delta;18O delineated three (3) groups of water i.e., water being bridged by rocks; groundwater recharged by rainfall with little or no evaporation and evaporated groundwater. Residence time influences groundwater's ionic configuration which imparts aesthetic characteristics over time. The study confirms the feasibility of complimenting geochemistry with the isotope technique to investigate flow relationships between dam water and groundwater systems.

Introduction Pesticide and heavy metals are persistent and nonbiodegradable and they can be bioaccumulated through the biologic chains: soil-plant-food and seawater-marine organismfood (Shawi et al., 1999). So, the presence in high amount of pesticide and heavy metals in environment represents a potential danger for human health and for environment due to their extreme toxicity. For this reason, accurate monitoring of their concentration plays an important role. Population can be contaminated with organic pollutants and heavy metals by ingestion of contaminated or polluted food and water. The gravity of toxic effect depends on nature, concentration, body resistance and presence of other contaminants. The concentration of these elements in food products is varied, depending of their origin, storage conditions and processing technologies (Stanciu et al., 2005). Food safety is a major public concern worldwide. During the last decades, the increasing demand of food safety has stimulated research regarding the risk associated with consumption of foodstuffs contaminated by pesticides, heavy metals and/or toxins (D’Mello, 2003). Farmers around the world including Ghana use pesticides as a preventive policy against the possibility of a devastating crop loss from pests and diseases. Accordingly in Ghana, for several decades now, pesticides have been employed in agriculture not only to control and eradicate crop pests but also in the public health sector for disease vector control. Nevertheless, heavy metals are also among the major contaminants of food supply and may considered the most important problem to our environment (Zaidi et al., 2005). Such problem is getting more serious all over the world especially in developing countries. During the last decades, the increasing demand of food safety has stimulated research regarding the risk associated with consumption of fruit and vegetables as they constitute major part of human diet contributing nutrients, vitamins, minerals and fibers. However, these plants contain both pesticide residues and heavy metals over a wide range of concentration. Therefore, residues of pesticides and heavy metals could affect the ultimate consumers especially when these commodities are freshly consumed. The total dietary intake of pesticides residues that remain on agricultural commodities are known as carcinogens/or toxins and therefore it is desirable to reduce these residues (Zawiyah et al., 2007). In general, food is the main exposure route. Exposure to pesticide residues and heavy metals through the diet is assumed to be five orders of magnitude higher than other exposure routes, such as air and drinking water (Juraske et al., 2009). According to the World Health Organization (WHO), food consumption consists on averaged for 30 % (based on mass) of fruit and vegetables, and fruit and vegetables are the most frequently consumed food group (WHO, 2003). Furthermore, because fruit and vegetables are mainly consumed raw or semi-processed, it is expected that they contain higher pesticides residue and heavy metal levels compared to other food groups of plant origin, such

A study was conducted to obtain systematic monitoring data on the contamination levels of selectedorganochlorine and organophosphorous pesticide residues in fruits and vegetables sold on Ghanaian markets. Atotal of 309 samples of fruits and vegetables were purchased from the main urban markets and supermarkets inGreater Accra through the months of July, 2009 to May, 2010. The analysis was carried out on GC-ECDemploying multi residue analytical technique. The obtained results showed the predominance of methoxychlorin most of the analyzed samples. The detected concentrations of it in pineapple, lettuce, cabbage, cucumber andonion exceeded the European Commission Maximum Residue limits (EC MRLs), as did the concentrations oflindane in papaya, pineapple, cabbage and onion as well as dieldrin in papaya, banana, pineapple and cabbage.Residues of endrin in lettuce and carrot were higher than the EC MRL, as was chlorpyrifos in pineapple. Basedon the observations made in these studies, it is proposed that more extensive investigations covering allfoodstuffs in Ghana be carried out so as to generate data for policy making, development of consumerinformation laws and curtailment of the use of some of these pesticides.

A study was conducted to investigate the magnitude of heavy metals (arsenic [As], copper [Cu], cadmium [Cd] and mercury [Hg]) contamination that may be present in some Ghanaian medicinal herbs/plants available in local markets and also to compare the levels with recommended levels by the International Organization. A total of 267 samples of herbal plants representing 18 different plants collected from several markets in Ghana were tested for heavy metals contamination. Atomic Absorption Spectrophotometry was used for the analyses, and content of metals per sample was expressed as percent mu g/g. The study showed differences in metal concentrations according to the parts analysed (leaf, fruit, root bark and crown). The obtained results which showed the predominance of Cd in almost all the analysed parts of the samples followed by Zn, Cu, As and Hg. However, Hg was the least predominant metal detected in the analyzed samples. All the monitored metals in the herbal plants were within the safe limit approved by Codex Alimentarius Commission and FAO/WHO limit for spices. The findings generally suggest that consumers of these herbal products would not be exposed to any risk associated with the intake of herbal plant products for the management of diseases.

A study was conducted to investigate the organochlorine, organophosphorus and synthetic pyrethroid pesticide residues in fruits and vegetables from markets in Ghana. For this purpose, a total of 309 fruits and vegetable samples, were collected and analyzed by gas chromatography with electron capture detector. The obtained results showed that the predominance of organochlorine followed by organophosphorus and synthetic pyrethroid pesticides in most of the analyzed samples. The detected concentrations of them were most significant in vegetable samples. The results obtained showed that 39.2 % of the fruits and vegetable samples analyzed contained no detectable level of the monitored pesticides, 51.0 % of the samples gave results with trace levels of pesticide residues below the maximum residue limit (MRL), while 9.8 % of the samples were above the MRL. The findings point to the urgent need to establish reliable monitoring programs for pesticides, so that any exceedance in concentration over environmental quality standards can be detected and appropriate actions taken.

A B ST R A C T The seeds of Azadirachta indica A. Juss. popularly known as neem collected from five cities of Accra metropolis was studied. Trees with wide girth and different seed weight were observed. Maximum residual oil content was noticed in trees from Haatso. Weight of the seeds had no effect on the oil yield. Seed oil content in most of the cities was not significantly correlated with morphological parameters of seeds. A.indica seed oil extracted was analyzed for their physicochemical properties such as viscosity at 28 o C (0.07 kg/ms), pH (5.7), acid value (1.102 ml/g), iodine value (71.0 gI 2/100g) and free fatty acid value (48.35 ml/g). The maximum mean percentage oil obtained (52.5 %) makes the commercialization of the seeds of Azadirachta indica in Ghana a possible and profitable venture. The result also confirms the oil to be good quality and can find application in industrial purposes.

The objective of present research study was to assess the concentration of pesticide residues in fruits and vegetables from markets in Kumasi and to generate awareness about the lethal effects of these pesticides on human beings as well as to estimate the potential health risks associated with the pesticide residue with regard to consumers. A total of 350 locally produced fruits and vegetables were purchased from six main markets in Kumasi and analyzed by gas chromatography equipped with electron capture detector for organochlorine (gamma-HCH, methoxychlor, aldrin, dieldrin, endrin, p,p'-DDE, p,p'-DDT) and pyrethroid (permethrin, cyfluthrin, cypermethrin, fenvalerate, deltamethrin) residues. The residual concentrations of selected pesticides in the various fruit and vegetable samples and the potential health risks associated with the exposure to these pesticides were also assessed. The results obtained showed that 37.5% of the fruit and vegetable samples analyzed contained no detectable level of the monitored pesticides, 19.0% of the samples gave results with levels of insecticides residues above the MRL, while 43.5% of the samples showed results below the MRL. The analysis of health risk estimates revealed that none of the pesticides exceeded the reference dose in both fruit and vegetables except endrin which exceeded reference dose in vegetables, suggesting a great potential for systemic toxicity in children considered the most vulnerable population subgroup. Based on observations made in these studies, it is proposed that more extensive monitoring investigation covering all fruits and vegetables in all the ten regions of Ghana be carried out to find the exact position of pesticide residues.