DETERMINATION OF PHYSICOCHEMICAL PROPERTIES AND HEAVY METAL CONTENTS IN WATER, SEDIMENT AND FISH IN WATER AND FOOD CROPS IN, ZAMFARA STATE, NIGERIA
DETERMINATION OF PHYSICOCHEMICAL PROPERTIES AND HEAVY METAL CONTENTS IN WATER, SEDIMENT AND FISH IN WATER AND FOOD CROPS IN, ZAMFARA STATE, NIGERIA
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Date
2018-09
Authors
SUNDAY, Moses
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Abstract
The physicochemical properties of water of the three major dams and rivers in Zamfara State were analyzed using standard analytical methods. The concentrations of heavy metals in the sediments, fish and food crops were also examined. The result revealed marked variations and non-uniform distribution of all the physicochemical parameters from one season to another for two years of study. pH, temperature, EC, TDS, TSS, alkalinity, DO, BOD, COD, Cl, SO4, PO4 and hardness have values that fall below the USEPA standard limit for drinking water with exception of turbidity (88.67 mg/l).Analysis of variance revealed that there were significant difference (P < 0.05) between the parameters based on locations and seasons. The concentration of heavy metals in the crops (tomatoes and cassava) grown around the vicinity of the dams and rivers determined using atomic absorption spectrometry (AAS) revealed, a spatial and non-uniform distribution in the concentration of the heavy metals (Zn, Cd, Cr, Pb and Hg) in the water, sediments, fish, and food crops in all six locations studied. The concentration of heavy metal determined in water, sediment, fish and food crops were generally high during the dry season with exception of Hg which recorded its highest concentration in year 2015. Zn and Cr levels in the water, sediment, fish and food crops were within international safe limits while Cd (0.1022 mg/l), Pb (0.2104 mg/l) and Hg (1.8818 mg/l) levels were far above (0.01, 0.01 and 0.001mg/l) USEPA safe limits respectively for drinking water. Two major indices such as contamination factor (CF) and pollution load index (PLI) were used for determining the contamination level of water, sediment, tomatoes, cassava and fish samples. The result revealed a high contamination factor for Cd, Pb and Hg across all the six locations and a general overall pollution load across all the locations. The direct effect of heavy metal was observed during the histological assessment of fish tissues such as gills, liver and skin. All gills showed common abnormalities in the Tilapia fish (Orechromis mossambicus)inhabited in all the six locations. Most common are desquamation of lamellar epithelium, hypertrophy of epithelial cells, lifting up of lamellar epithelium, intraepithelial oedema, aneurysm, hyperplasia, and haemorrhage in the gill filament. Histology of liverrevealed the presence of heterogeneous parenchyma characterized by vacuolization, foci of necrosis, hypertrophy ofnuclei and degenerated hepatocytes. Histological changes of the skin were mostly at the level of the epidermis, without major changes in the dermis and hypodermis; picnotic nuclei in the matrix layer of the epidermis are the most severe lesion recorded.
A four step sequential extraction was used to determine the chemical association of the metals (Zn, Cd, Cr, Pb and Hg). Major sedimentary phases in the sediments showed differences in the distribution of each metal among those phases. Of all the five elements studied, Cd (14.739- 39.931%) and Pb (0.105- 9.832%) appeared to be the most readily solubilized, thus making these elements the most potentially bioavailable.The evidence of pathological alterations in gills, livers and skin of Orechromis mossambicus appeared to be a useful bio-marker to assess the impact of metal pollution in water on the health of fish and higher levels of Cr, Cd, Zn, Pb and Hg in the fish are worrying as it may cause health related problems in the consumers of fish in the study area
Description
A DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES,
AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF DOCTOR OF PHILOSOPHY IN ANALYTICAL CHEMISTRY DEPARTMENT OF CHEMISTRY FACULTY OF PHYSICAL SCIENCE AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
Keywords
DETERMINATION OF PHYSICOCHEMICAL PROPERTIES,, HEAVY METAL CONTENTS IN WATER,, SEDIMENT,, FISH IN WATER,, FOOD CROPS,, ZAMFARA STATE,, NIGERIA,