ASSESSMENT OF POLLUTANTS LEVELS OF SURFACE WATER SEDIMENT AND FISHES FROM MBO RIVER SYSTEM AKWAIBOM STATE NIGERIA

1.1Background of the Study

Surface water bodies such as lakes, streams and rivers are the earth’s most vital renewable and widely distributed natural resources of providing man’s comfort, means of livelihood, circulation of the earth’s moisture (Barlkrishan, 2011). Mbo River system contribute significantly to food availability and security, income generation, trade and improved living standard as well as preservation of biodiversity. Mbo river system water is being used for drinking in the study area. Mbo River system is also a nursery ground for cultivation and breeding of different fish and seafood species for fishermen. Its water ways are used as transportation route for ferrying people and goods to the fishing settlements. Mbo River system is a source of major income earner as tourists flood the area during it fishing and boat regatta festival. The flooded shoreline is loaded with alluvial sediments that irrigate the adjourning soils and improves the yield of planted Okro, pepper and all sorts of vegetables (AKSG 2008).

In recent time, Mbo River system is deteriating in quality due to heavy metal pollution. Heavy metal pollution of surface and underground water (Islam et al 2012) sediment (Jared 2002) and fishes (Udosen et al 2014) are among the most central environmental problem of this century.

Generally, heavy metals have been defined as those classes of metals that are electropositive, transition, chemical elements having a relative high

specific gravity greater than (>5) (Roebuck 1992, Sorensen, 1991 and Deuffus, 2002).

Heavy metals like zinc, copper, iron, manganese, cobalt, chromium and nickel are beneficial when it comes to their use in plants, animals and human nutrition, This is because, they are required for metabolic activities in organs (Hossain, 2001). Others such as Mercury, Cadmium, and Lead have no known biological functions in living organism whatsoever. They exhibit extreme toxicity at low concentration (Hu, 2002).

When heavy metals are introduced into fresh river water or sea water they degrade (Ajibola et al 2008) the natural quality for water. It also affects negatively (Dahilia et al 2003) the organisms living in it. This is because they are stable and non-biodegradable (Offem and Ayotunde, 2008), persistent (Tam and Wong, 2011), toxic (Koto et al 2008). Other water pollutants are urine, feaces, bath water, cloth washing water (Lloyd, 1992). They also include leaves, grass chippings nitrates and phosphates (Oguzie, 1996) detergent, salts (NaCI), crude oil film and hot coloured dye (Purves, 1985). Water pollutants have their sources. They are generated mostly from anthropogenic sources (Udosen et al 2006). These include manufacturing activities (Ogbeibu and Ezennwa 2002, agricultural activities Eja et al, 2003), dumpsite (Moodley et al 2007, Okoyo and Agbo 2011). Others are untreated domestic sewage, municipal waste water discharges (Shriedah 1998), boat construction, accidental spills, combustion of fossil fuels (Agbugai et al 2012). Occasionally, heavy metal pollution also comes from natural source

through atmospheric deposition (Nriagu 1989), erosion (Ojiako et al, 2010) weathering (Asaolu and Olaifa 2004).

Heavy metals can alter the quality of water body by increasing the odour, pH, BOD and PO43- (Davies and Abowei et al 2009) by distrupting sediment nutrients,the natural quality of fish and fish tissue (Abu et al, 2012). This can lead to increasing fish disease and mortality, (Saxena et al 2005) and also influence physiological rates of fish reproduction (Korisiakpere and Ubogu 2001 Abu et al 2012). Previous cases of endemic exposure of heavy metals reported from the time of Iraq mercury poisoning (Harrison, 1999) to the time of Ita-Itai disease (Lister and Renshaw, 1991) to the time fo Zamfara metal poisoning (Nigeria Daily Thrust, 2010), all the cases had always result to health problems and death. Apart from few physiochemical parameters reported by (Essien-Ibok et al, 2010) on Mbo river, bioaccumulation of five metals in fish from Ibaka river reported by Akpanyung, (2006) and occupational distribution studies by AKSG (2009), there is no known history of assessment of environmental samples that is linked to people’s health and welfare in the study area as is done in this work.