MACROINVERTEBRATE DIVERSITY AND WATER QUALITY PATTERN OF A MUNICIPAL STREAM IN DOKO DISTRICT, NIGER STATE, NIGERIA

Abstract

Macroinvertebrates organisms form significant part of an aquatic ecosystem which are of ecological and economic importance because they maintain various levels of interaction within aquatic environment. Emikpata stream in Doko district, Niger State, Nigeria is used for a variety of purposes such as irrigation, cattle drinking and domestic purposes. The macroinvertebrate diversity and water quality patterns of the stream were evaluated for a period of eight months using the standard experimental techniques. Four different study stations were selected along the course of the stream designated as Stations 1, 2, 3, 4, respectively. A total of 625 individuals from 28 species and 19 families of invertebrate were recorded. Significantly higher (P<0.05) macro-invertebrate abundance was recorded from dry season than in the wet season. The results of the physicochemical parameters showed that temperature (23.0 – 27.0 0C), flow velocity (0.29-0.30 m/s), conductivity (49.1 – 110.0 us/cm), dissolve oxygen (5.97 – 6.35 mg/L), total hardness (12.3-18.0 mg/L), total alkalinity (13.0-20.5 mg/l), phosphate (0.60 – 1.12 mg/L) , potassium (1.74 – 1.92 mg/L) was not significant (P>0.05) among the sample stations  while  biological  oxygen  demand  (3.25-3.87  mg/L), pH  value  (6.0  –  6.32), chlorine (10.71 – 32.79 mg/L), nitrate (1.83 – 3.69 mg/L), sodium (7.24 – 9.02 mg/L), showed significant differences (P<0.05) between the sample station.. The CCA result showed strong relationships between species abundance and measured environmental variables. Emikpata Stream is found to be under minimum anthropogenic impact and is impaired in the downstream sections. Higher population of pollution tolerant macroinvertebrates groups and the tasting water quality of the surface water during the sampling  period  were  implications  of  pollution  stress  caused  by  anthropogenic activities, decomposing domestic wastes and inorganic fertilizer washed into the stream from various nearby farms.

CHAPTER ONE

1.0 INTRODUCTION

1.1 Background to the Study

Macroinvertebrates organisms are significant part of an aquatic ecosystem which are of ecological and economic importance because they maintain various levels of interaction within aquatic environment (Dobson et al., 2002). Biomonitoring of this organism may help to conserve and making management decision in an area. Macroinvertebrates have limited mobility and can stay in an area for some time without moving away easily. The type of the macroinvertebrates species obtained may be used as indicator of the status of the water quality of that environment at that location in a particular time (Arimoro and Keke 2016). Macroinvertebrates have high variability and are significant to predict the effect of short term environmental variation which are used to distinguish some characteristics of rivers and streams across the globe (Barbour et al., 1999). According to  Uwem  and  Edet  (2016)  substrate  is  among  the  most  important  factor  in  the distribution of macrobenthic invertebrates, although alterations in physico-chemical parameters such as temperature and salinity and food availability also play vital role in determining the extent of distribution and abundance of macrobenthic invertebrates species in aquatic ecosystem and they plays a critical role in the functioning of aquatic environment. Also, they constitute a major link in the aquatic food chain (Olomukoro et al., 2013; Uwem and Edet., 2016).

Freshwater pollution by human activities is becoming a matter of urgent concern threatening environmental productivity, sustainability and further social economic development in sub-Saharan Africa (Arimoro and Ikomi., 2008; Nyenje et al., 2010; Arimoro and Keke., 2016). Several uses of aquatic ecosystems, includes laundry, water source for drinking, irrigation, hydropower generation as well as riparian activities on rivers’ catchments such as unregulated land use and landscape alteration, have led to both biotic and physical deterioration of aquatic environment (Nyenje et al., 2010). In Nigeria, land use changes on various catchments, agro-industrial activities and rapid urbanization pose threats to the well-being of aquatic environment and alters the composition and abundance of macroinvertebrates (Arimoro and Ikomi, 2008; Andem et al., 2014; Arimoro et al., 2015). Also, human population and industrial activities are increasing; hence there is greater threat of water pollution. Diverse inputs of pollutants in most metropolitan area of Nigeria include domestic, industrial waste waters and rainwater surface effluents which flows through the urban waterways primarily into the three main river systems (Ayoade and Olusegun, 2012). The spatio-temporal functional and structural compositions of macroinvertebrate assemblage in any stream system can be influenced by human activities (Arimoro and keke 2016). In the face of changing and intensifying human activity in catchments draining into the stream, there is a need to assess the current status of water quality and benthic invertebrate fauna assemblage in the river and to test protocols for future monitoring.

Most rivers in Nigeria, particularly those in urban areas are now being used for dumping both solid and liquid wastes, these high-polluting activities are now threatening the sustainability and functionality of freshwater ecosystems in Nigeria (Arimoro and Oganah, 2010). Keke et al (2017) reported that most the vast Nupe flood plain and it tributaries  and  riparian  vegetation  in  Niger  State  are  used  for  extensive  fisheries activities and serve as spawning and nursery ground for a number of fish species, which depend largely on several macroinvertebrates organisms for survival. Also, they are used for irrigation of crops as well as sources of drinking water for both human and livestock.

Emere and Nasiru (2008) reported that most major cities contain a number of water ways such as drainages which are channeled directly into water bodies such as streams and rivers. Those water bodies have been subjected to increasing pollution from contaminated surface water runoff       from industrial, agricultural, residential, commercial, recreational areas and institutions such as schools and hospital.

Edegbene et al., (2015) revealed that River Chanchaga, in North central Nigeria is an important river flowing through several Local Government Areas in Niger State of Nigeria. It is a municipal river which is mainly used by the riparian communities and environs as source of potable water, irrigation and other domestic activities. Some stations of the river is presently faced with perturbation arising from car washing, bathing, illegal gold mining, and industrial activities at its catchment. All these anthropogenic activities affect the distribution and survival of macroinvertebrates across the river.

1.2 Statement of the Research Problem

Most uses of water in most part of Nigeria compromise water quality and the integrity of the aquatic ecosystems (Arimoro et al., 2015). With increase human activities such as industrialization and urbanization along Emikpata stream couple with other anthropogenic activities which include laundry, farming, bathing and drinking along the stream which is threatening the sustainability and integrity of biodiversity and water quality. However, since there is increase human activities on the streams thus there is need to assess the current health status of the water quality and macroinvertebrates assemblage of this  streams  which  will  serves  and  provide baseline information  on biomonitoring guides of Emikpata stream.

1.3 Justification of the Study

The result from this study will give a base line information on the macroinvertebrate diversity and water quality pattern of Emikpata stream. It will also give us insight on the level of anthropogenic activities which may cause the change in the physico-chemical parameters. The information from the study area will also justify whether the changes in physico-chemical parameters effect the level of macroinvertebrate.

Emikpata stream in Niger State is main source of water to the nearby settlements with the increase in population of the surrounding number of villages in which the water are mostly used for domestic activities such as drinking, laundry, bathing, washing of plates and also water from this stream is used for irrigation of crops in nearby farmland. In this regards, biological monitoring as proved to be an important tool in assessing the condition of this water body. Also, biological and chemical data are essential in understanding ecosystem integrity. This study will provide baseline information on the abundance and diversity of macrobenthic invertebrates in relation to physico-chemistry of Emikpata stream in Niger State.

1.3 Aim and Objectives of the study

This  study is  aimed  to  assess  the  macrobenthic invertebrate assemblage and  water quality status of Emikpata stream in Doko district of Niger state.

The objectives of the study are to determine the;

i         Macroinvertebrate species composition and distribution in Emikpata stream.

ii.        Physico-chemical parameters of Emikpata stream.   .

iii. Spatio-temporal variations of macroinvertebrate assemblage and physico-chemical parameters of Emikpata stream.

Related Project Topics :