ABSTRACT

Water samples from ground water and some rivers from Owerri Local Government Area of Imo state Nigeria, were investigated for contaminants and heavy metals. The results obtained showed that in the month of April 2009, the ground water had mean maximum concentration 1.303 mg/dm3 of Pb, 1.048mgldm3 of Pb,1.488mgldm3 of Pb,for Otamiri and Oramiriukwa rivers respectively.For the month of May 2009, the ground water results showed maximum mean concentration 1.016mg/dm3 of Pb,1.069mg/dm3 of Pb, 1.7mg/dm3of Pb and 1.488mg/dm3 of Pb,for Otamiri and Oramiriukwa rivers respectively.The underground waters had mean concentration of 3.636mg/dm3 Cu,which exceeded WHO standard of 3.0mg/dm3 for drinking water.In the month of may Oramiriukwa river had Mn with a maximum mean concentration of 3.334mg/dm3 which exceeded the WHO standard of 2.0mg/dm3. The results showed lead of values 2.852mg/dm3 for the ground waters, 0.255mg/dm3 of lead , 1.045mg/dm3 of Lead and 0.855mg/dm3 of Lead for Otamiri,Nworie and Oramiriukwa rivers respectively. The correlation coefficient matrix for the element of 0.500 was taken to be significant. For the ground waters, Fe2+, Zn2+ were strongly correlated during April/June 2009 periods. The Otamiri river results showed that the heavy element Cu2+, Fe2+, Mn2+ and Zn2+ were strongly correlated in the month of April/May 2009 . The samples from Nworie River had strong correlation for the element Fe2+ Mn2+ and Zn2+ for the period of April/May 2009.Cu2+had strong correlation in the period April/May 2009. Oramiriukwa River had strong correlation for elements Cu2+, Fe2+, Pb2+ and Zn2+ in the period April/May 2009. Pb+ had strong significance in the April/May 2009 period. Mn24+ had very strong correlation in April/May 2009. A histogram chart of the frequency distribution of the heavy metal concentrations in the period,the pollution index of the water bodies were determined using Horton’s rule. The above results indicate that some of these water bodies should not be taken orally without treatment.Nworie river was founded most polluted of all the water bodies, followed by Oramiriukwa river,Otamiri river had mild pollutions, one of the ground water site’s was reported as heavily polluted with the element copper with a concentration of 3.636mg/dm3.It was discovered that none of the water sources investigated met WHO standards for safe water.

ii

CHAPTER ONE

1.0 INTRODUCTION

Water is an essential raw material for human life and a vital factor to the establishment of industries. Without water no life [1].

Water in its natural environment is characterized by impurities. Being a universal solvent, water contains dissolved solids, gases and hosts a number of microorganisms.

Hence the quality of water is defined by the level of its physical, chemical and biological impurities. [2]

Different sources of water include stream, lakes, ponds, rain, springs and wells. Sources of water in Old Owerri LGA of Imo State include rivers like Otamiri, Nworie and Oramiriukwa; and the underground waters (Boreholes). These rivers and underground waters (boreholes) supply water for the daily activities of the people living along the banks, tributaries and environs. Well asFor example Nworie River discharges intoOtamiri river as a tributary while Oramiriukwa River has a number of streams discharging into it as crossed many communities on its course.

Pure, safe and clean water can only exist briefly in nature but is polluted immediately by human activities and environmental factors. Industrial effluents, fertilizers from farm lands, diesel from pleasure boats, are possible pollutants of rivers and thier environ.[3]

The use of surface water by man is as old as the existence of human beings. Water is a natural resource, and indispensable to life. Water supplies for human consumption should be adequate and free from bacteria harmful to humans. The quality of river water depends on the quality of the feeding sources which include surface run off water, glaciers, swamp, rain and underground water.

Underground water, like springs, boreholes are better quality water

1

than surface water, such as lakes, rivers, streams, due to the purification of the former prior to distribution. The underground water is rarely polluted by both man and animals [4,5,6].

Industrial effluents like toxic chemicals and heavy metals pollute several surface waters. Mercury is one of the heavy metals, in a group that includes lead, cadmium, plutonium and others. A feature the heavy metals have in common is that they tend to accumulate in the bodies of organisms that ingest them, their concentrations increase up the food chain. Some marine algae may contain heavy metals of concentrations of up to one hundred times that of the water in which they are living, small fish eating the algae develop higher concentrations of heavy metals in their flesh, larger fishes who eat the smaller fishes concentrate the metal still further, and so on up to fish eating birds or animals [7]

Some non-metallic elements commonly used in industries are also potentially toxic to aquatic lives and to some extent to human beings. Chloride is widely used to kill bacteria in municipal water, sewage treatment plants and to destroy various microorganisms are found in plumbing lines in

water works stations. Chlorine can also kill algae and harm fish populations.[8]

Acids from industrial operations and acid mine drainages especially in coal and sulphide areas remain serious source of surface and ground water pollutions [9,10]

The run-off water from fertilized fields carries some of the fertilizers to rivers. In rivers and lakes the fertilizer provides nutrients that increase the growth of algae. The algae use up the oxygen dissolved in the water, and the lack of oxygen causes the death of fish and other aquatic lives. Phosphates in laundry detergents have the same effect. Hence the use of fertilizers as well

2

as detergents result in entrophication of water. Pesticides used on crops get into rivers in this way too [10,11] destroying aquatic lives.

Urbanization and industrialization develop countries economically but lead to environmental pollution. The main effect of urbanization is increased run-off, which causes increased erosion thereby making the water muddy which is a type of pollution. In addition many new and sometimes toxic chemicals are added to the environment, industrial activities unbalance the natural cycles with harmful substances such as heavy metals [10,12].

Many organic compounds occurring naturally and the synthetic ones are widely used as herbicides and pesticides, as well as in a variety of industrial processes. The negative effects in organisms vary with the particular type of compound, some are carcinogenic, toxic directly to humans or other organisms, and make water unpalatable, and some accumulate in organisms as heavy metals. Oil spills are a kind of organic compounds pollution of surface water. Vinyl chloride vapor used in the production of plastics is carcinogenic and it is not known how harmful traces of vinyl chloride in water may be. Laboratory tests conducted on animals revealed that polychlorinated biphenyl’s (PCBs) cause impaired reproduction, stomach and lower alimentary disorders and other problems [10,13].

Polluted water may contain pathogens and disease-producing organisms such as fungi, bacteria, viruses, protozoa, parasites and worms which are vectors that carry and spread disease like skin infections, dysentery, diarrhea, typhoid fever, malaria and other related diseases [14,

15].

Most industrial effluents contain non-biodegradable, toxic and hazardous wastes which bioaccumulate in living organism when consumed. These wastes pose high health risks as well as threatening coastal and estuarine fishes on which most rural populace especially in the riverine areas

3

depend on for their livelihood. [16,17].

The principal causes and sources of pollution in groundwater have been grouped into four categories, namely municipal, industrial, agricultural and miscellaneous [17].

Municipal sources – These include sewage leakages, liquid wastes and soil wastes. Industrial sources-include liquid wastes and leakages from tanks and pipelines as well as mining activities and oil field brines. Agriculture produces pollution as a consequence of irrigation return flows, animal wastes, pesticides etc. Under miscellaneous are listed spills and surface discharges, septic tanks and cesspools, roadway deicing, interchange through wells, etc [18].

Nitrates are important pollutants of groundwater and indeed of the environment in general. All over the world an increasing input of fertilizers aimed at increasing agricultural output is occurring and concomitantly there is a general deterioration in the quality of both surface water and ground water. Today, in most rivers there is an abnormal increase in nitrogen and phosphorus concentrations. There is evidence of a link between gastric cancer and high nitrate concentration in ingested water [11,19]

Such addition of nutritive elements induces entrophication with problems concerning the use of water by human populations. The leaching of nitrate from agricultural land is a great concern to the soil chemist. [5,19].

Mining operations produce many ground water pollution problems. The nature of the pollutant depends on the material actually being mined and also on the mining processes. Very important contributors are the coal, phosphate, uranium mines and bodies producing iron, copper, zinc and lead, etc. Since surface and subterranean mines usually extend below the water tables, expansion of mining activities necessitates de-watering. The water so removed is highly mineralized and referred to as acid mine drainage. Acid

4

mine drainage is characterized by low pH, high iron, aluminum and sulphate contents. Coal accumulations are usually associated with pyrite, which is stable for sub-water table conditions, but oxidizes if the water table is lowered. Oxidation succeeded by contact with water produces iron [III]sulphate and tetraoxosulphate (VI) acid in solution, and of course, if they reach ground water its pH will be reduced and its iron and sulphate contents will increase [2,5].

Drainage from waste heaps produced by mining and run-offs contain agricultural and industrial wastes, water flowing through municipal and industrial wastes leaches soluble materials and these become contaminated. Leachate contains poisonous substances and if disposal sites are not carefully managed in other to collect and treat leachate effectively, it can enter the ground water system [19].

Other sources of ground water contamination include widely used substances such as highway salt, fertilizers that are spread across the land surface and pesticides. In addition, array of chemicals and industrial materials leak from pipelines, storage tanks, and holding ponds. Among these pollutants are classified as hazardous meaning they are either inflammable, corrosive, explosive or toxic. As rain water percolates through the soil, it carries pollutants to the water table. Here they mix with the ground water and contaminate the supply. Because groundwater movements are usually slow, polluted water may go undetected for a long time [20].

Another common source of groundwater pollution is sewage, which emanates from an ever-increasing number of septic tanks. Others are inadequate or broken sewer systems and farm wastes [21,22]

Sewage water, which is contaminated with bacteria, enters the groundwater system and gets it polluted. Sewage and manure contain both ammonia and acid, organic forms of nitrogen. Organic nitrogen may be

5

converted into ammonia in the soil. Nitrate is a problem as a contaminant in drinking water due to its harmful biological effects. High concentration of nitrates causes methamoglobinemia which causes gastric and intestinal cancer [19,23]. Several human activities have indirect or devastating effects on water quality and aquatic environment. Such activities include accidental or unauthorized release of chemical substances, discharge of untreated water or leaching of noxious liquids from solid waste disposal [24-26].

A recent work by Yahaya in 2006[27] revealed that the cat fish has been isolated as net accumulators or bio accumulators of pollutants such as zinc, Mn, Cr, Co, Ni, Rb, C, Cd etc. Zinc, an indispensable trace element, is essential for human and fish existence, and is as well regarded as a pollutant in several areas. Compared to the other bio-available metals, it was the second most abundant in the Shell fish . Industries producing pesticides, plastics, chlorine, caustic soda, pulp and paper introduce into the environment (soil, water) heavy metals such as mercury [28,29]. Acid rain breaks rocks, releasing heavy metals into streams, lakes and ground water, by this aquatic environments are heavily contaminated by these heavy metals. Heavy metals can not be degraded bio-chemically in nature. The stability of these metals therefore allows them to be transported to considerable distances by water. As a result of this process, the level of heavy metals in the upper member of the food chain can reach values significantly high to cause health hazards, when such organisms are used as food by man [26]. Some of these heavy metals are clearly in organic form at the time of discharge and do undergo further bio-transformation inside the fish, which render them extremely dangerous. For example mercury exists in zero, [O], plus one,[+], and plus two,[+2], oxidation states.Methyl mercury CH3Hg+ is an important feature of this cycle, particularly with regard to its uptake by fish and humans. Methyl mercury CH3Hg+ is the major mercury species found in fish and about

6

95% of the mono methyl mercury CH3Hg +          eaten is absorbed by human

[30,31].

Many cities in the developing countries have been developed without adequate and proper planning thus leading to indiscriminate actions including dumping of wastes in and around water, washing and taking baths in rivers etc. The use of rivers varies from one locality to another and so are the

involvements, demand for its use accordingly, from fish farming to transportation, laundry and convenient points of waste discharge from both home and industries, to recreation and do serve the domestic needs of the people for water [32].

Analysis on the use of whole organisms to evaluate the concentration of heavy metals in lower animals such as fish and crabs gave startling results [27,33].

Mining activities have been identified with the exposure of heavy metals that were once buried deep in the heart of the Earth to the surface from where they are easily leached to the nearby soil, rivers, streams and lakes. The toxic metals of lead have been known to bind with the active sites of enzymes, thus preventing the enzyme from carrying out its normal functions. Heavy metals, particularly mercury [Hg], lead (Pb), cadmium (Cd) ,are sulphur

seeking and easily bind to

S-CH3 and S–H (sulphydryl group) in enzymes,

protein, thus immobilize the enzyme[34].