Heavy Metals Levels in Fish Samples from North Central Nigerian Rivers

Most aquatic organisms are capable of accumulating heavy metals to concentrations much higher than those present in water and sediments in their environment. In this piece of work, the concentrations of heavy metals were determined in fish organs of Albula vulpe and Tilapia zilli obtained from rivers in six different states within the North-Central metropolitan area using Atomic Absorption Spectrometry. The results showed that the liver of Tilapia zilli has the highest level of heavy metals with the concentration of Mn as 435.1mg/kg and the gills have the lowest concentration of Cd as 0.3mg/kg. Also the liver of Albula vulpe have the highest concentration with Mn as 292.6mg/kg and the muscles have the lowest concentration with Pb as <LOD. The trend for heavy metal accumulation is Mn>Cr>Pb>Cd>Ni in Albula vulpe and Mn>Cr>Pb>Ni>Cd in all the organs of Tilapia zilli. This indicates that the fish samples could be used to monitor Mn and Cr pollution levels in the North-Central Rivers.Keywords: Albula Vulpe, Heavy metal, North Central Nigeria, Tilapia Zilli, Rive

Analysis of Heavy Metals Contamination and Quality Parameters of Groundwater in Ihetutu, Ishiagu

The levels of some quality parameters and heavy metals in groundwater inIhetutu minefield of Ishiagu were analyzed in four seasons (rainy, late rainy,dry, and late dry), in order to evaluate the deterioration of the groundwaterqualities in the area. Pb-Zn mining and several other related activities havebeen going on for several decades in Ihetutu, and thus render the groundwater resources in the area less available for consumption, through toxic chemical substances expected to be constantly discharged to the groundwater bodies from the mines and other domestic wastes. The aim of this study was thus to determine the levels of heavy metals and other physico-chemical properties in the groundwater, to assess its suitability for drinking and other domestic purposes in Ihetutu. Samples were collected from dug-wells and underground water platforms, and analyzed using standard procedures, for their physico-chemical properties and heavy metals levels. Results obtained for the various seasons ranged as pH = 6.80-8.72, EC = 190.00-1120.00 µS/cm, alkalinity = 4.20-30.60 mg/L, TDS = 105.00-567.00 mg/L, TH = 8.00-44.00 mg/L, Cl- = 26.00-126.00 mg/L, Cu = 0.00-0.30 mg/L, Zn = 0.00-0.42 mg/L, Fe = 0.00-3.93 mg/L, Mn = 0.00-0.59 mg/L, and Pb = 0.00-0.43mg/L. Average levels of analyzed parameters in study area were: pH = 7.56,EC = 424.06 µS/cm, alkalinity = 17.88 mg/L, TDS = 218.69 mg/L, TH =21.88 mg/L, Cl- = 54.31 mg/L, Cu = 0.20 mg/L, Zn = 0.51 mg/L, Fe = 2.55mg/L, Mn = 0.32 mg/L, Pb = 0.38 mg/L. Mean levels of most parameters were found to be within standard guidelines/limits but were above control levels, giving an indication of deterioration of the groundwater qualities in the area. Also, seasonal concentrations of most parameters, including the heavy metals were in the order of LDS>DRS>LRS>RNS. Heavy metals mean concentrations also trended in the order of Fe>Zn>Pb>Mn>Cu. Correlations among heavy metals were all positive, with the strongest between Cu and Pb (r = 0.921) while the least was between Cu and Mn (r = 0.176).ANOVA showed no statistically significant differences among sampling stations in study area, as p-values (0.757) was higher than the significance level (α=0.05). Comparison of the results with control values, indicated cases of deterioration of the groundwater quality in the study area. This confirmed that the groundwater resources in the area were adversely affected by wastes and discharges from the mining activities and several other sources including domestic wastes

A review on the use of chelating agents as an alternative to promote photo-Fenton at neutral pH: Current trends, knowledge gap and future studies

In this review, we have critically examined the alternatives to conventional photo-Fenton process such as the strategies to perform it in circumneutral pH in the so-called photo-Fenton like process. They include iron chelation, iron replacement with another metal and use of iron immobilized on surfaces of solid materials, use of iron oxides, among others. The use of such strategies can be employed to overcome the challenges identified in conventional photo-Fenton, moreover, advantages and drawback of each technique must be clarified and the recent achievements should be shared with the scientific community. The use of a chelating agent to make iron soluble at circumneutral pH presents many advantages when compared to other current techniques. However, the correct understanding of the chelating process, complex activity and the complex resistance along with the mechanism of radical production should be taken into account to prepare an effective photo-Fenton with complexed iron. The review also identifies the current trends in chelate assisted photo-Fenton process and the unexplored areas in this field of study. A discussion about the environmental and safety issues in the application of these methods, with emphasis to the Fe chelation strategy, was also considered with detailed review over the past ten years710CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP308914/2017-1; 424395/2016-92014/17774-