The study investigated the effects of industrial effluents discharges on stream water quality in Onitsha urban area of Anambra State. Effluents quality assessment was carried out on samples collected at eight (8) locations of the sampled industries while water quality assessment was carried out first on three (3) samples collected  upstream or at control sites  as well as on eight (8) samples collected at discharge locations in Onitsha urban area in 2015. The control sites were located upstream 500 meters before contact with discharge effluents. The physico-chemical and microbiological parameters analyzed were Temperature (T), pH (Hydrogen ion concentration), Total Dissolved Solids (TDS), Dissolved Oxygen (DO), Turbidity, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Magnesium (Mg), Nitrate (NO3), Iron (Fe), Calcium (Ca), Zinc (Zn), Sodium (Na), Copper (Cu), Lead (Pb), Chromium (Cr), Total Heterotrophic Counts (THC) and Total Coliform Group (TCG). The results of the analyses revealed significant concentration of many dissolved salts, heavy metals and pathogenic organisms in the water samples due to effluents intrusion. Discharged effluents deviate radically from the WHO(2011) standards: Temperature ranged from 290C to 360C,  TDS ranged from 0.7mg/l to 6.10mg/l, DO ranged from 35mg/l to 143.6mg/l, Turbidity ranged from 100ntu to 400ntu, BOD ranged from 2.06mg/l to 41.9mg/l, COD ranged from 2.08mg/l to 53.9mg/l, Mg ranged from 0.12mg/l to 3.09mg/. These values were above WHO (2011) standard limits for drinking water while others like pH which ranged from 5.5 to 12.0, Ca which ranged from 0.60mg/l to 8.24mg/l, Zn ranged from 0.01mg/l to 0.70mg/l, Na ranged from 0.14mg/l to 2.69mg/l, and Cu which ranged from 0.02mg/l to 1.68mg/l were below WHO (2011) recommended standards for drinking water. The microbiological parameters like Total Heterotrophic Counts and Total Coliform Groups are highly above WHO standards. The analysis revealed statistical significant differences between the water samples at control and the water samples at discharge locations. MANOVA was used as a test instrument in this study because it allows for maximum interactions between all the variables.Taken together the findings show that there are contaminations of the streams investigated by industrial effluents and that the stream waters are not safe for drinking purposes. Appropriate management measures were suggested to minimize effluents contamination of surface water in the study area.




            Governments and organizations all over the world recommend industrialization as the quickest track to economic development (UNDP, 2010). The major advantages of industrialization as a short and quick path to economic development are the massive production of goods and services, short gestation of investments, high net worth yield of capital and near total economic independence (Uchegbu, 2002). In addition, employments are created by direct linkage and trickle down effects in the national economies (Ajayi, 2007). Industrialized countries generate more funds directly from their manufacturing industries which they use to procure other items needed in their countries. These advantages commend industrialization to all the countries of the world as a quick means to economic development (Uchegbu, 2002). Based on this, various countries create laws and policies that favour and promote industrialization (Bichi and Anyata, 1999).

            But industrialization, though beneficial, has quite a lot of environmental problems that result from the manner of the production streams in the various industries, as each type of production process and the nature of the inputs in the production process, yield diverse types of industrial wastes (Uchegbu, 2002). Industrial wastes and effluents refer to the wastes that are generated from industries as a result of the production processes of the industries (Uchegbu, 2002). Industrial wastes and emissions contain toxic and hazardous substances most of which are detrimental to human and animal health (FEPA, 1991). Some of these substances are lead, cadmium and mercury (heavy metals), and toxic organic chemicals such as pesticides, polychlorinated biphenyls (PCBs), dioxins, polyaromatic hydrocarbons and phenotic compounds. The Federal Environmental Protection Agency (FEPA) in 1990 identified industrial waste as a major environmental problem requiring urgent attention in Nigeria and noted that many chemical industries in the coastal areas contribute to increases in the amount of chemical effluent load pollution in the Nigerian coastal waters.

             Industrial wastes exist in three forms; – solid wastes, liquid and gaseous effluents (Uchegbu, 2002). Liquid industrial effluents are liquid wastes which are produced in the course of industrial production activities (Echiegu and Liberty, 2013). These wastes are residues of either uniform or diverse composition which have been found to be of various degrees of toxicity (Echiagu and Liberty, 2013).  There are, in many countries, policies and laws which guide and control the production and management of industrial wastes because of their hazardous nature (Uchegbu, 2002; Ubachukwu, 2012).

             Nigeria has laws and policies on industrial waste production, control and disposal (Uchegbu, 2002).  The laws are the Federal Hazardous Waste Management Regulation of 1991; The Environmental Impact Assessment (EIA) Act of 2004; The Harmful Waste Act of 2004; The National Environmental Standards and Regulation Enforcement Agency (NESREA) Acts of 2007 etc. According to Mozie (2011), the problem in Nigeria is not the absence of regulatory laws but the low obedience to and the poor or the near non-enforceability of the many environmental laws of the country.  The non-enforcement of the environmental laws over the years, has led to the improper disposal of industrial effluents and this has now become a major problem and a source of concern to both governments and industrialists in Nigeria (Mozie, 2011).

            In many developing countries, such as Brazil and India, the disposal or discharges of effluents, (even when these are technologically and economically achievable for particular standards) do not always comply with pre-treatment requirements (Echiegu and Liberty, 2013). When this happens, the human society pays a great price for improper disposal of industrial wastes. In Amazon, Brazil for instance, Di-Mario (2004) reports that prospecting for gold has resulted in rivers and fish being severely contaminated with mercury used in the refining process in the country while Charles and Margaret, (1993) and Mason, (1998) also describe the effects of acetaldehyde and chloride discharged from a factory into Mina-Mata Bay in Japan in 1950s which killed many animals such as dogs, cats and pigs involved in the consumption of water extracted from Mina-Mata Bay in Japan.  In 1958, when the number of victims exceeded 50 people, 21 of whom died, a ban was placed on the sale of fish from Mina-Mata Bay, though there was no restriction on disposal of industrial effluent on surface waters. The effects of industrial effluents on surface water can remain a threat for long period of time because of bioaccumulation of toxins in animal or human tissues.

There is at present general lack of information on the effects of effluents discharged by these industries on the water quality of the streams crossing the urban areas in Nigeria. The choice of Onitsha for this study is based on the fact that many effluents producing industries are located in the urban area. Onitsha urban area is slopy which means that runoff water can easily drain the effluents and discharged them into nearby streams. The drainage pattern and topography make the available streams in the urban area vulnerable to pollution from industrial activities particularly by effluent discharges. Still, the urban residents depend on the urban streams for domestic and related purposes. See plates 1, 2 and 3.

Therefore, to effectively and properly protect the available streams and their uses in the study area, it is crucial to assess the effects of effluents discharge chemistry and translate the information (which is currently lacking) into reliable and sustainable management strategy that will guide urban planners, policy makers, stream end users and water resources providers to prevent or minimize harmful impacts of stream water contamination and ensure sustainability of fresh water resource availability for urban users and the ecosystems. Based on these therefore, this work seeks to characterize the liquid effluents discharged by industries in Onitsha urban area and establish their deleterious effects on the water quality of streams in the study area. Uchegbu (2002) reports high incidence of diseases and deaths in the study area and noted that the causes of such deaths may not be unconnected with the use of contaminated surface waters in the area for domestic and other purposes.

Plate 1.                        Spiritual bathing in Idemili River

Source:            Author’s fieldwork, (2015)

Plate 2:            Processing of Bitter Leaves in Nkisi River

Source:            Author’s fieldwork, (2015)


Indiscriminate disposal of municipal and industrial wastes remains a major threat to surface water pollution globally. Studies carried out in Nigeria and elsewhere on the effects of industrial effluents on water pollution include those of Odokuma and Okpokwasili (1993); Dada (1997), of Grove(2000),  Ekiye and Zejiao, (2010); Taiwo, (2011); Amadi, (2012); Onuigbo, (2013) and Daniel, (2015). Dada (1997), in a study carried out in Nigeria, was of the view that high phosphate concentrations in the discharged effluents result in nutrient enrichment of the receiving water bodies thereby leading to ecological disaster. Grove (2002), in his own study notes that domestic use, agricultural production, mining, industrial production, power generation, forestry and other factors can alter the chemical, biological and physical characteristics of water in ways that can threaten ecosystem integrity and human health. Miller, Farrel and Egelund (1998) in a study of the impact of dairy production on Utah Waterways in India identified bacteria pollution as the major source of waterways pollution in the area. Similarly, Colcanap and Dufour (1982) discovered that most of the chemical industries in Ivory Coast contribute significantly to increases in the amount of chemical effluent pollution loads in the coastal and estuarine waters. Taiwo, (2011) also reported that in most cases, sewage and wastewater from homes are routed into the rivers and streams.

             Industrial effluents when discharged directly into the rivers without prior treatment have the capacity to increase some water quality parameters (Dada, 1997). Less than 10% of industries in Nigeria treat their effluents before being discharged into rivers (Dada, 1997). This has led to high loads of inorganic and hazardous metals such as Lead (Pb), Chromium (Cr) and Iron (Fe) in many of the receiving water bodies. Taiwo (2011) discovers that the resultant effects of effluents in the receiving streams and rivers are many, including water quality impairment, reduction in fish abundance and effects on water usage for recreation, industrial and domestic purposes. Dada (1997) adds that high phosphate concentrations in these effluents result into nutrient enrichment of the receiving water bodies thereby leading to ecological disaster. 

            Oghenekobaroh, (1997), who worked on implications of the accidental discharge of water containing high ammonia level in Okrika River from National Fertilizer Company of Nigeria (NAFCON), near Port Harcourt, Rivers State, reported that the incidence caused massive fish deaths and socio-economic problems for artisanal fishing industry in the surrounding villages. In Lagos, most industrial plants are located along the water fronts and streams. Amadi (2012) found out that these industrial plants discharge their wastes into the streams near their premises. The urban poor in Lagos rely on these polluted surface waters for water supply. The implication of the continued consumption of the polluted water is that the consuming population could be sick endemically or continue to be sick until it gets to epidemic proportions.          

            In Onitsha, almost all industries discharge their liquid effluents into streams. Many of these liquid effluents include dye, mercury, cadmium, silver nitrate, and sulphur compounds etc which pollute the water in the stream channels. Reliable information on the effects of such discharges is almost non-existent. The disposal of liquid effluents from industries into streams needs to be continuously investigated because they may pose serious environmental problems that need to be monitored and analyzed for characterization. The liquid effluent laden rivers may contain suspended matter, odour, oil and paint, foaming and excessive acidity and alkalinity. These properties may impair or rather deter beneficial uses of the receiving streams for domestic, industrial and agricultural water uses.

            Some of the industries operating in the study area use large volume of water but are without waste water treatment plants and so routinely discharge their waste water directly into nearby streams. The physical and chemical water quality indicators of the water bodies are not monitored periodically. As a result of this, there is great uncertainty about the changes in stream water quality as well as how to respond to stream water deterioration as a result of frequent discharges of effluents into surface waters by the nearby industries.

This study, therefore, seeks to fill these existing gaps in knowledge. It seeks to characterize the liquid effluents discharged by industries in Onitsha urban area and establish their deleterious effects on the water quality of the receiving water bodies. It is hoped that the result of this study will assist the relevant industries and authorities in designing mitigation measures to ensure that the water quality in the streams of Onitsha urban area is protected. The study will also provide useful information to Onitsha urban dwellers and government officials responsible for planning and cleaning of the urban space.                                                                                                     

Plate 3:             Washing of meat (Hides and skin) in Idemmili River

Source:            Authors fieldwork, (2015)


The aim of this study is to examine the effects of industrial effluents on stream water quality in Onitsha urban area of Anambra State, Nigeria. To achieve this aim, the following objectives will be pursued to;

1. Identify the sources of effluents and describe how effluents are disposed by the industries in Onitsha urban area.

2. Characterize the physico-chemical and microbiological properties of the effluents generated by the industries in the study area.

3. Assess the effects of the industrial effluents on the stream water quality within the study area

4. Highlight the health implications of surface water contamination by industrial effluents and suggest management strategies which can prevent or minimize stream water contamination by industrial effluents in the study area.


We subjected the tests to a hypothesis: Null Hypothesis

Null hypothesis stated that there is no statistically significant variation between the mean parameters of the discharged effluents and the WHO standards (p < 0.05).

1.5       THE STUDY AREA:

1.5.1    Location:

Onitsha urban area is geographically located between latitude 6°07’- 6°09’N and longitude 6° 47’- 6°48’E. (Fig.1). It is situated at the bank of River Niger in Anambra State. It is the gateway to eastern Nigeria and the economic nerve center of Nigeria. Onitsha lies at the major east-west crossing point of the Niger River and occupies the northern end of the river that is regularly navigable by relatively large vessels. These factors have historically made Onitsha a major centre for trade between eastern and western Nigeria.

The study area covers about 251 square kilometers and is accessed through the east west national main road from Lagos through Benin which links the eastern-north-south route via the Niger Bridge at Onitsha (Okala, 2013). Mozie, (1992) explains that such favourable site at a meeting point of two contrasting regions, providing the link between the savanna of north and the delta region of the south enables Onitsha to develop into an important commercial centre. The city is split up into two local government areas namely, Onitsha North and Onitsha South local government areas. Onitsha is bounded by Ogbaru in the south and Idemmili North in the east (Fig. 1)

Fig. 1: Anambra State, Showing Onitsha Urban Area.

Source: Ministry of Lands and Surveys Anambra State. (2015)

Figure 2: Onitsha Urban Area

Source: Google Earth Image, 2015 (Author’s modification)

1.5.2   Climate

The climate of the study area belongs to Thornthwaite’s (1948) humid forest megathermal climate which Iloeje (1971) regards as sub-equitorial and Inyang (1975) classifies as 8-month rainy season climate. The climate of the study area has the following characteristics: an annual rainfall of 1500-2000mm. Monanu (1975) classifys the area as having a rainfall variability of 3 percent. The wet months are from April to October and the dry period lasts from November to March. About ninety percent of the rains fall in the months of April and August, while the remaining ten percent fall in the months of September to October. The temperatures are uniformly high. The mean daily maximum for the year is 300C. The daily maximum is highest in March at 32.0C and lowest in late September of 280C. The mean daily minimum average is 220C for the year, 280C in August when cloud cover is experienced and 240C in February and March. The monthly mean is 26.30C, 270C in July and 280C August and 320C in February and March . All average monthly temperature for Onitsha is greater than 180C. (Meteorological Office, Onitsha).

The mean relative humidity is between 80 percent and 90 percent in July, and between 40 to 60 percent in January (Monanu, 1975). Laddel (1956) puts the climatic conditions as comfortable in terms of human physiology.

1.5.3 Geology

The main geologic units of the area are the recent deposits of the Holocene (Quatenary) occupying the active floodplains of the Rivers Niger and Anambra and the sandstone formations of the Upper-Middle Eocene (Tertiary) occupying the sandstones plains lying above and adjacent to the Niger-Anambra floodplains. The sandstone formations are subdivided into the Bende-Ameke sandstone and the Nanka formations. These formations have been described at various times by groove (1951), Reymet (1959), Orajaka (1975), Egboka and Nwankwo (1985), Mbanugo (1987) and Mozie (1992). The stratigraphic succession of the study area appears to be that of the Bende-Ameke formation and the sandstone formations of the Nanka group lie in an unconformity from the cretaceous beds beneath them. Above the sandstones are found the lignites of the Asaba-Ogwuashi formations and on them the recent deposits of the Holocene. In the vicinity of the Niger valley proper, the Asaba-Ogwuashi and the recent deposits pinch off and the sandstone rests on the Imo Clay shale further inland.