ABSTRACT
This study was carried out to assess the levels of coppers in the pond water of the Jimi Dam in Ozoro over a four-month period from April to July, 2020. Copper concentrations in the water were found to be very low, and in the cases of Arsenic and Cadmium, concentrations were found to be in trace amount and below detection.
Copper levels at all the sampling stations on the other hand were found to be low throughout the study period. The study also revealed very highly measurable concentrations of the studied coppers, especially in the bottom sediments and in the flesh of the two sampled fish species Tilapia zillii and Oreochromis niloticus harvested from the Dam. With the exception of Lead, all the copper concentrations in the bottom sediments of the Dam were found to be above the USEPA Safety Reference Standards for all or some of the sampling month. Arsenic concentrations in the bottom sediments at all the sampling stations were all well-above the threshold value of 30 mgkg-1. The mean Arsenic concentrations at some of the sampling station were almost 3 times higher than the safety reference standard. Cadmium levels recorded in the bottom sediments were above the Safety Reference Value of 3 mgkg-1 at all the sampling points and fell within the levels for moderately polluted sites. The fish samples of the two species were categorized into two size classes, small (<10cm) and large (>10cm) for the metal analysis. The observed metal concentrations in the bottom sediments and fish were similar to those observed in areas under moderate to heavy pollution. The concentrations of As, Cu and Pb in the flesh of the two fish species were found to be above safety reference standards for human consumption stipulated by the WHO, and hence can pose a serious health threat to people who consume the fish from the Dam. It is imperative that fishing from the Jimi Dam is prohibited and consumption of fish from it discouraged because of the high levels of the coppers in the flesh of the two fish species. The study revealed no significant spatio-temporal variations in the concentrations of the four studied coppers as far as the water and biota were concerned indicating an even distribution of the metals in the dam.
CHAPTER ONE
INTRODUCTION
1.1 Background of study
Coppers may occur in aquatic environments from natural processes and from discharges or leachates from several anthropogenic activities (Connell et al., 1999; Franca et al., 2005). Concentration of natural waters by coppers negatively affects aquatic biota and poses considerable environmental risks and concerns (Cajaraville et al., 2000; Ravera, 2001). Monitoring programmes and research on coppers in aquatic environment have become important due to concerns of over accumulation and toxic effects to aquatic organisms and to humans through the food chain (Otchere, 2003). Contaminants can persist for many years in sediments where they hold the potential to affect human health and the environment (Mackevičiene et al., 2002).
Sediments are an important sink of a variety of pollutants, particularly coppers and may serve as an enriched source of these contaminants for benthic organisms (Wang et al., 2002). Metals may be present as dissolved species, as free ions or forming organic complexes with humic and fulvic acids. Additionally, many metals e.g. Pb associate readily with particulates and become adsorbed or co-precipitated with carbonates, oxyhydroxides, sulphides and clay minerals. Exposure of sediment- dwelling organisms to metals may then occur via uptake of interstitial waters, ingestion of sediment particles and via the food chain (Luoma, 1989). The occurrence of elevated levels of coppers in sediments found at the bottom of the water column can be a good indicator of man-induced pollution rather than natural enrichment of the sediment by geological weathering (Davies et al. 1991, Chang et al. 1998).
1.2 Problem Statement
Mining operations usually results in the release of waste materials (tailings) into the environment and consequently cause problems for the growth and performance of flora and fauna (Montgomery et al., 2003). Moreover, some mine tailings contain arsenic, lead, mercury, cadmium and that are harmful to human and other living organisms (Enger et al., 2004). In addition, the use of toxic chemicals such as cyanide in separating valuable mineral components from the ores and the formation of Acid Mine Drainage (AMD) from the waste also cause pollution in soils and water.
1.3 Objective of the Research
In the light of the above problems this study was carried out;
- To measure the concentration of Copper in pond of the Jimi pond in Ozoro
- To examine the spatial and temporal trends of Copper in pond water in Ozoro
1.4 Significance of Study
Coppers are non-biodegradable and undergo a biogeochemical cycle in which natural waters are the main pathways (CIFA, 1994; Ukpebor et al., 2005) and fish species can accumulate these coppers in their tissues at concentrations greater than the ambient water and pose a health threat to humans who consume them.
In the human body, toxic metals attack the proteins notably the enzymes (Ademoroti, (1996) and their toxic effects are cumulative and cause slow poisoning of the system over a period of time (Nriagu, 1988; Ukpebor et al., 2005). Coppers have been implicated in the upsurge of liver and kidney diseases, and is believed to be responsible for a high proportion of mortality caused by kidney and liver morbidity (Friberg, et al., 1986; Herber et al., 1988; Ndiokwere, 2004), pains in bones (Tsuchiya, 1978), mutagenic, carcinogenic and teratogenic effects (Fischer, 1987; Friberg et al., 1986, Kazantzis, 1987, Heinrich, 1988), neurological disorders, especially in the foetus and in children which can lead to behavioral changes and impaired performance in IQ tests (Lansdown, 1986; Needleman, 1987).
1.5 Limitations of the Study
The study had no control of other contaminants of the pond. Also the researcher was short on time as he was engaged in other academic works in school.
Finances too was a great challenge in carrying out this work, mainly on transportation to the selected schools.
1.6 Scope of the Study
The study was limited to the pond water in Delta state, Ozoro. The study used descriptive analysis and experiments were carried out in the pond to collect data for the analysis. The findings of the study cannot be generalized to other ponds unless a similar study is done in ponds with similar characteristics.
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