Water Quality Assessment of Ekulu and Asata Rivers in Enugu Area, Southeastern Nigeria, Using Physico-Chemical and Bacteriological Parameters

This study was aimed at assessing the impacts of human activities on the quality of Ekulu and Asata Rivers in Enugu Area, Southeastern Nigeria. Twelve (12) water samples six (6) from Ekulu River and (six 6) from Asata River) were collected at different points along the regime of the two rivers and their physico-chemical and bacteriological characteristics/parameters determined. Results of the study indicate that the two rivers do not satisfy the Drinking Water Quality Standard of World Health Organization (WHO) and Federal Ministry of Environment (FMENV) in terms of pH/acidity (values between 4.5 and 7.0 and outside the WHO Standard of 6-5-8-5); turbidity (values between 7.88 and 294NTU units and greater than WHO standard of 5.0NTU units); iron (values between 3.10 and 7.35 mg/1 and greater than WHO standard of below 0.30mg/l; and coliform (values between 20 and 180 counts per 100ml and greater than WHO Standard of 3 counts per 100ml). Though Ekulu River is more acidic (lower pH values), more turbid (higher NTU units) and contains higher concentration of iron than Asata River. On the other hand, only Asata River do not satisfy the WHO Standards in terms of nitrate concentration (values between 8.9 and 25.9mg/l and greater than WHO Standard of 10 mg/1): and chromium (heavy metal, values between 0.189 and 0.429 mg/1 and greater than WHO Standard of 0.00lmg/1) Human activities of mining at abandoned Onyeama Coal Mine, car watch and disposal of industrial/domestic wastes are believed to be responsible for poor water quality of the two rivers in Enugu area. On the basis of Piper Diagram Classification, Ekulu River may be classified as Calcium Chloride Type, while Asata River may be classified as Mixed Water Type. Water from the two rivers, to be used for domestic and industrial purposes, should be adequately treated; and there is need to institute regular water quality monitoring programme for the two rivers.

characterised by folding, faulting and volcanism which resulted in the formation of Abakiliki ridge/anticlinorium.
The depositional process resumed in the Campanian with the deposition of Nkporo Shale (Anambra Basins) (with lateral equivalent of Enugu Shale); and continued into the Maastrichtian with the deposition of Mamu, Ajali and Nsukka Formations. The Nsukka Formation has the same lithological characteristics as the Mamu Formation. The two formations are sometimes referred to as the upper coal measures and Lower Coal Measures respectively. The coal-bearing Mamu Formation is one of the sedimentary formations of South-eastern Nigeria and consists of alternating beds of shale, claystone, mudstone, siltstone, sandstone and coal seams. The Mamu Formation was formed by series of transgression and regression that dominated the process of sedimentation during Maastrichtian (Upper Cretaceous) (Reyment, 1965;Mebradu, 1990;Obi et al., 2001).
The Mamu Formation is the most important geological formation with respect to coal formation, occurrence and mining in Enugu Area. The Mamu Formation underlies Ajali Sandstone (aquiferous unit) (Okeke and Okogbue, 2010). The Area is richly endowed with sub-bituminous coal seams within the Mamu Formation. Enugu Area also experiences much groundwater contamination due to coal mining activities. It also lacks prolific and potable groundwater due to the thinning-out of the Ajali sandstone aquifer through Udi town and Ninth-mile into Enugu Metropolis.
The rivers (Ekulu and Asata) flows through three geological formations namely the False Bedded Sandstone Ajali Sandstone (Ajalli Formation), the Lower Coal Measures (Mamu Formation) and Enugu Shale that constituted the largest formation in terms of area. The table below shows the generalized stratigraphic sequence of Southeasthern Nigeria. Table1:Generalized Stratigraphic Sequence of Southeasthern Nigeria (Modified from Ofodile, 1975 analyzed for their geochemical and bacteriological contents. These points ware designated E1, E2, E3, E4, E5, E6 and A1, A2, A3, A4, A5, A6 respectively for Ekulu and Asata Rivers ( Table 1). For River Ekulu, a control sample E1 was collected from the river before the mine. E2 is run off from Onyeama underground mine. Sample E3 was collected from Iva Bridge, E4, was from Trans Ekuku brigde, E5 was collected from Air Force Bridge along Abakpa and sample E6 was collected from Emene bridge. For Asata River, the control sample A1, was collected at Udi / Ngwo, A2 was taken from Akwata/Ogbete coal camp area, A3 was taken at Asata river, Agangwu (CIC Road). Sample A4 was taken at Asata river, O'Connor Street along Presidential Road Enugu. Sample A5 was collected from Asata river at Asata river Layout and sample A6 from Asata river at New Artisan Market Independence Layout. The sample locations and their coordinates are shown in the table (Table 2) and the drainage map (Fig 3) below.

Laboratory Analysis of Water Samples
The laboratory analysis of the water samples were carried out at Enugu State Water Corporation Water Analysis Laboratory. The physical and chemical parameters used for the water quality assessments in the study include temperature, turbidity, colour, conductivity, pH, dissolved oxygen content (DOC), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solute (TDS), total suspended solids, total hardness, total alkalinity, nitrate, nitrite, ammonia, silicate, manganese, calcium, phosphate, sulphate and chloride. The bacteriological parameters were also measured. All the analyses were carried out according to guidelines of APHA, (2012) and Bartram and Balance (1996). pH concentrations of the water were determined in situ using a portable pH digital meter, HANNA 211 model. The electrodes were rinsed with distilled water. The instrument was standardized against a buffer solution with pH 4 and 7. The electrode (sensor) sends signal to the digital meter, the meter converts the signal to pH and dispays the result. pH measurements run on a scale from 0 to 14, with 7.0 considered neutral. Solutions with a pH below 7.0 are considered acids. Solutions with a pH above 7.0, up to 14.0 are considered bases. After each Journal of Environment and Earth Science www.iiste.org ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online) Vol.11, No.4, 2021 measurement, hydrochloric acid was added to neutralize alkaline solutions while sodium hydroxide was used for acidic solutions followed by rinsing with distilled water. Turbidity was measured by the use of Hack Turbidimeter. The Turbidimeter measures the light scattered and absorbed by particles present in the water sample as light travels in a straight line through the water sample. It is measured in nepheloturbidimetric units (NTU). Turbidimeters have scattered-light detectors located at 90 o to the incident beam called nephelometers. For each range of NTU, calibration was done using silicon oil after which verification was done, Total dissolved solids (TDS) was measured by gravimetric method. The two principal methods of measuring total dissolved solids are gravimetry and conductivity methods. The gravimetary method involves weighing the residue that remains after evaporation and drying the liquid solvent. The Total Suspended Solids, TSS was determined by filtering a well mixed sample through a weighted glass-fibre filter and the residue retained in the filter was dried to a constant weight at 103 to 110 0 C. Increase in weight of the filter represents the total suspended solids Electrical conductivity was determined by Electrical conductivity meter. Dissolved Oxygen (DO) was measured with DO meter. Biochemical Oxygen Demand (BOD) was determined following the procedure of American Public Health Association, (APHA) (2012). The BOD test involves taking an initial dissolved oxygen (DO) reading and a second reading after five days of incubation at 20 o C. Chemical Oxygen Demand COD was determined titrimetrically using open reflux method according to American Public Health Association, (2012). This involves a two hour digestion at high heat under acidic conditions in which potassium dichromate acts as the oxidant for any organic material present in a water sample. Hardness was determined using the Ethylene diaminetetra acetate (EDTA) titrimetric method. The apparatus include Burette, Graduated cylinder, Erlenmer Flask, Pipette. The buffer solution was prepared using HCI and distilled water. While shaking well and carefully the solution is titrated with standardized 0.0Im EDTA solution until the red colour changes to clear blue colour and the burette reading is recorded. The concentration of Nitrate and Nitrite in the study area was determined using the Phenoldisulporic acid method. Chloride analysis was carried out according to the methods of American Public Health Association, (2012) which involves silver nitrate (AgNO3) titration with chromate indicator (K2CrO4).

Laboratory Measurement of Heavy Metals
Heavy metal analysis was conducted using Varian AA220 Atomic Absorption Spectrometer according to the method of American Public Health Association, (APHA) (2012). Atomic absorption spectroscopy (AAS) is a spectroanalytical procedure for the quantitative determination of chemical elements using the absorption of optical radiation (light) by free atoms in the gaseous state. The electrons of the atoms in the atomizer can be promoted to higher orbital (excited state) for a short period of time (nanoseconds) by absorbing a defined quantity of energy (radiation of a given wavelength). This amount of energy, i.e., wavelength, is specific to a particular electron transition in a particular element.
Atomic absorption spectrometer working principle is based on the sample being aspirated into the flame and atomised when the AAS's light beam is directed through the flame into the monochromator, and unto the detector that measures the amount of light absorbed by the atomised element in the flame. Since the metals have their own characteristic absorption wavelength, a source lamp composed of that element is used, making the method relatively free from spectral or radiation interferences. The amount of energy at the characteristic wavelength absorbed in the flame is proportional to the concentration of the element in the sample over a limited concentration range.

Measurement of Bacteriological Parameters (Microbial Analysis)
There are two basic methods for analyzing water samples for bacteria; the membrane filtration method and the multiple-tube fermentation method. The material required for membrane filter coliform tests include filtration units, filter membrane, absorbent pads, forceps and culture dishes. The membrane filtration method was used for bacteriological analysis. In the membrane filteration method, samples to be tested are passed through a filter. 100 ml of a water sample is drawn through a membrane filter (0.45 µm pore size) through the use of a vacuum pump. The microorganisms present in the water remain on the filter surface. When the filter is placed in a sterile petri dish and saturated with an appropriate medium, incubating the plates at a specified temperature (44.5°C or 112.1 0 F) for a specified time period (24 hours). This elevated temperature heat shocks non-faecal bacteria and suppresses their growth. Hence, growth of the desired organisms is encouraged, while that of other organisms is suppressed. Each cell develops into a separate colony, which can be counted directly, and the results calculated as microbial density. This method varies for different bacteria types (variations might include, for example, the nutrient medium type, the number and types of incubations, etc.).
Discrete bacterial colonies were isolated immediately after counting. The isolates were characterized by Indole Production Test. This test is important in the identification of enterobacteria. Most strains of E. coli, P. vulgaris, P. rettegeri, M. morgani and Providenca species break down the amino acid tryptophan with the release of indole. The test organism was inoculated in a bijou bottle containing 3 ml of sterile tryptone water and incubated at 35-37°C for up to 48 hours. Kovac's reagent (0.5 ml) was added to the test solution, shaken gently and examined for red colour at the surface layer within 10 minutes. The red surface layer indicates positive test while no red colour indicates negative test for E. coli

Results and Discussion 4.1 Results
Comprehensive results of measured parameters are shown in the tables below   3 and 4). The water appears cloudy and muddy at most of the locations except for A1 (River Asata at source) which was colourless. The Cloudy appearance is reflected in the increasing turbidity values recorded in the study area. Temperature values range between 27 o C and 31 o C with highest temperature value recorded at Ekulu River Agu-Abor Bridge (31 o C). The result shows that surface water samples taken from River Ekulu and Asata recorded pH values ranging from 4.5 to 7.0. The pH of the water samples taken from River Ekulu ranges from 4.5 to 6.0. These values fall below permissible limits with gradual tendencies towards acidity. A pH value of 4.50 was recorded at E2-Journal of Environment and Earth Science www.iiste.org ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online) Vol.11, No.4, 2021 80 Onyeama coal mine. This is a clear indication that the water has strong acidic content and therefore cannot be considered for consumption. The Onyeama abandoned coal mine, agricultural activities, block industry, car wash, hotels and other activities around Ekulu contributes to the pollution of River Ekulu. A pH of 5.8 was recorded at Akwata bridge Asata River. Akwata bridge is very close to Ogboete Market; waste generated from commercial activities, car parks and other activities are dumped at the river bank. Generally, Ekulu River has more acidic content than Asata River, this can be attributed to the presence of Iron Sulphide (Pyrite) associated with coal deposits.
The surface water turbidity of the study area was within 7.8NTU to 294NTU with highest values recorded around River Ekulu indicating a high level of physical disturbance. River Ekulu recorded extremely high turbidity values (105-294NTU) compared to River Asata (7.88-40.1NTU). These values exceed the 5NTU recommended limit by WHO and FMEN. The values recorded at River Asata are quite minimal but above recommended limits too. This indicates a high extent of pollution in line with the cloudy appearance of the river. River Ekulu at Agu Abor Bridge (E2) had the highest turbidity value of 294 NTU. This is evident from series of house construction activities, block industries and other human activities going on very close to the river in this environment. The water from the river is being utilized for this purpose. River Asata has relatively low turbidity when compared to River Ekulu.
Records of River Asata reveal higher Electrical conductivities, Total Dissolved Solids and Total Solids values than those of River Ekulu. The electrical conductivity values measured in the study area ranges from 10.4 to 435.0µS/cm, TDS values between 6.76mg/l to 282.75mg/l, and total solids between 6.78mg/l to 282.78mg/l. Generally, the values obtained from all locations are within WHO and FMENV permissible limit indicating low level of pollution by dissolved contaminants. Dissolved oxygen level in the surface water of the study area was found to have concentration ranging from of 4.81 to 7.81mg/l, with highest values around Asata Rivers. The DO levels in both rivers are high enough to support aquatic life with concentrations above 5.0 mg/l except that of River Asata at Akwata/ Ogbete area which is below 5.0g/ml. The Biochemical Oxygen Demand (BOD) of the sampled Ekulu and Asata River ranges from 0.30 to 5.8mg/l with highest concentration around Asata River at Zik Avenue Bridge, Ogui. The BOD level in all the locations was lower than the WHO standard value of 5.0mg/l except for A3 -Asata River at Zik Avenue Bridge (5.8mg/l). This can be attributed to the presence of a waste dump at this location. High BOD is an indication of significant bacteriological activity on the river.
The values of hardness for the two rivers ranges from 2 to 88 mg/l, with the highest values occurring around River Asata. This is evident from higher concentrations of Calcium (17-81mg/l) and Magnesium (2-7mg/l) in River Asata than River Ekulu (Calcium 2-26mg/l; Magnesium 0-3mg/l). The results are tolerable for Calcium (WHO limit of 200mg/l and FMENV limit of 180mg/L) and beyond limit for Magnesium WHO permissible limit of 1mg/l. Total hardness for the two rivers are within limits, the result shows that the River Ekulu is soft while River Asata is moderately hard.
Salinity level observed in the study samples ranged from 138.00mg/l to 404.25mg/l with the highest concentration around River Asata. High Sodium Chloride content in water may be as a result of the fact that Sodium Chloride constitutes the bulk of amount of wastes deposited in the river by households. Also, River Asata has highest concentrations of Calcium (81mg/l), Magnesium (7mg/l) and Carbonate (80mg/l) than River Ekulu (26mg/l, 3.0mg/l, 0.003mg/l respectively), though all the values are within permissible limits. The presence of a considerable content of Calcium, Magnesium and Carbonate increases the pH value of water, and raises the alkalinity as seen in River Asata.
The recorded value for Phosphate in the study area ranges from (0.0 -0.09mg/l), Ammonia (0.29 -4.87mg/l), Nitrate (1.2 -25.90mg/l) and Nitrite (0.0 -4.53mg/l). The concentrations of these parameters are higher in River Asata when compared to River Ekulu. The values fall within the set limits by World Health Organization (WHO) drinking water standard except for Ammonia and Nitrite. The value for Ammonia at River Asata ranges from 0.28mg/l to 4.87mg/l which is above the set limit of 0.05mg/l by FMENV. This concentration was highest (4.87mg/l) at A4 (O'Connor Bridge Asata). This could be due to the activities of a nearby car, agricultural activities taking place along the river bed, and other uses such as bathing and washing in the river. Highest concentration of Nitrite was at Asata River New Artisan Bridge. This can be attributed to the waste materials generated from a piggery farm located close to the river at this point. Generally, Phosphate, Ammonia and Nitrate in surface waters may result from discharge of domestic, industrial and agricultural runoff that contains excess Phosphate, Ammonia and Nitrates introduced into the soil as fertilizers.
The heavy metals analysed include Lead, Iron, Copper, Chromium, Manganese Arsenic and Cadmium. Some of the Heavy Metals had very low concentrations as some of them were below detection limits at almost negligible concentrations. Iron, Chromium and Cadmium are shown to be of significant concentrations, and above the set limit. The concentration of Iron (3.1-7.35mg/l) and Manganese (0.07-0.079mg/l) in River Ekulu was higher than that of River Asata (1.09-2.58) and (0.00-0.021) respectively. These figures are within limits for Manganese (0.5mg/l) but far above WHO limit of 0.3mg/l and FMENV 0.5mg/l for Iron. The highest concentration of Manganese (0.079mg/l) was recorded at E2 (Onyeama Mine). High Iron and Manganese Journal of Environment and Earth Science www.iiste.org ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online) Vol.11, No.4, 2021 81 concentrations are associated with acidic water as shown by high acidic content of Ekulu River. The Onyeama abandoned coal mine and other activities around River Ekulu accounts for very high concentration of Iron recorded within the area evident from high concentration of Iron (6.28mg/l) recorded at location E2; the Onyama Coal Mine. Sample taken at all twelve sample locations exceed the WHO standard of 0.3mg/l and FMENR 0.5 standards for Iron, though Asata River had lower values compared to Ekulu River.
The sampled water in the study area shows that Lead concentrations ranges from 0.010 to 0.047 mg/l with the highest concentration around Asata River. This range is below WHO Standard of 0.05mg/l indicating that the communities around the study area do not have any threat of Lead toxicity. The concentration of copper within the study area ranges from 0.00 to 0.032, with the highest values around River Ekulu . Copper concentration within the study area fall within WHO and FMENV standards of 1.00 and 0.5 respectively. Arsenic was completely not detected in any of the locations; therefore there is no threat of Arsenic toxicity in the area.
The concentrations of Chromium in the study area was quite alarming, above the set limit of 0.01mg/l. Seven points out of the twelve sample points had high concentrations of Chromium ranging from 0.06 to 0.429mg/l with highest concentrations at River Asata. Chromium is a naturally occurring heavy metal that is commonly used in industrial processes and can cause severe health effects in humans. Although it can be released through natural forces, the majority of the environmental releases of chromium are from industrial sources.
Total Coliform values rank above comparing standards. From the table, the Total Coliform count in the study area ranges from 20 to 180mg/l with River Ekulu accounting for the highest concentrations. Also, the presence of E-Coli at most of the locations indicates faecal pollution. The values show high level of human activities that result in faecal pollution of the surface water bodies. The concentration of coliform bacteria was observed in all the sampling locations with River Ekulu being seriously faecally polluted. This is not surprising as the neighbourhood where the river runs through is highly populated when compared to Asata neighbourhood. E3 -Agu-Abor Bridge, E5-Air Force Bridge Abakpa Nike and Emene Bridge (near Orie Emene Market) had the highest records and these are all high population density areas, majorly lower to medium class. The presence of coliform bacteria in water usually indicates that the water is unsuitable for drinking. Microbes in water can cause water-borne diseases such as dysentery, cholera, and typhoid fever if the water is consumed untreated. However, water at Ngwo source has the lowest concentration of Total Coliform. It also shows that settlement receiving supply from the aforementioned will be potable.
The table below shows a comparative assessment of the average concentrations of each parameter as analysed for each river.

.2.2 Statistical Analysis of Geochemical and Bacteriological Parameters Using Histogram Diagram
The histogram as represented in the diagram shows the concentration distributions of geochemical parameters within various locations around River Ekulu and Asata. Measured values of water samples collected around both rivers recorded high salinity concentration as represented in figures below. This validates the Piper Classification below which places them at Calcium Chloride Type. Other parameters that show high concentrations include TDS, Total Hardness and Total Coliform.

.2.2.1Statistical Analysis of Heavy Metals Concentration within the Study Areas using Histogram
The histogram for the heavy metals concentration within both rivers shows the distribution of the heavy metals. The heavy metals analysed include Lead, Iron, Copper, Chromium, Manganese and Arsenic. Iron and Chromium are shown to be of significant concentrations. Highest concentrations of Iron (7.35mg/l) was recorded at Ekulu River while highest concentration of Hexavalent Chromium (0.429mg/l) was recorded at Asata River as shown in the histogram. Hexavalent Chromium value of 0.429mg/l is far above the FMENV limit of 0.001mg/l, and Iron concentration of 7.35mg/l exceedingly high when compared with WHO and FMENV standards of 1mg/l and 0.5mg/l respectively. Also, high level of Cadmium (0.078mg/l) was recorded at Akwata bridge Asata River above WHO standard of 0.01mg/l. The rest of the Heavy Metals recorded low concentrations as some of them were below detection limits. Arsenic was not detected in any of the locations.

.2.2 Analysis of Piper Diagram for Ekulu and Asata Rivers
A piper diagram is a graphical representation of the chemistry of a water sample or samples. The Piper diagram is used to infer hydro-geochemical facies (Piper, 1948). Facies are recognizable parts of different characters belonging to any genetically related system. Hydrochemical facies are distinct zones that possess cation and anion concentration categories.
The piper plots include two triangles, one for plotting cations and the other for plotting anions. The cations and anion fields are combined to show a single point in a diamond-shaped field, from which inference is drawn on the basis of hydro-geochemical facies concept. These tri-linear diagrams are useful in bringing out chemical relationships among water samples in more definite terms rather than with other possible plotting methods. Water types are designed according to the domain in which they occur on the diagram segments (Sadashivaiah et al 2008).
The relative ionic composition of the surface water samples in the study area in milli-equivalent per litre (meq/l) were calculated and employed in plotting the piper trilinear diagram in which the ions in milli-equivalent per litre are expressed in percentages of total cations and anions as shown in the figures below The ternary plot at the left hand side indicates that the water samples are rich in calcium ions while the right ternary plot indicates richness of water samples in Chloride ions. River Ekulu has concentration points for cations falling within Calcium type (50%), while the anions fall within the Chloride (85%) type. The corresponding sub divisions of surface water can be classified as Calcium Chloride Type, meaning that the samples are high in Ca 2+ + Mg 2+ and Cl -+ SO4 2-. River Asata has concentration points for cations falling within Calcium type (85%), while the anions fall within the Chloride (90%) type. The corresponding sub divisions of the surface water can be classified as Mixed Type.
Journal of Environment and Earth Science www.iiste.org ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online) Vol.11, No.4, 2021 87 The stiff diagram for River Asata shows dominance of Calcium cations and Na+K ions in the water samples. Therefore the chemical species are present thus, Ca 2+ >Na+K> Fe 2+ > Mg 3+ . This result conforms to that of piper plot for the river with dominance of calcium ion.

Assessment of Sodium Adsorption Ratio (SAR)
Sodium-adsorption ratio (SAR) describes the tendency for sodium cations to be adsorbed at cation-exchange sites in soil at the expense of other cations, calculated as the ratio of sodium to calcium and magnesium in the soil. SAR is used to assess the relative concentrations of sodium, calcium, and magnesium in irrigation water and provide a useful indicator of its potential damaging effects on soil structure and permeability.
Plants are detrimentally affected both physically and chemically by excess salts in some soils and by high levels of exchangeable sodium in others. A saline soil contains excess soluble salts that reduce the growth of most plants. These soluble salts contain cations such as sodium (Na + ), potassium (K + ), calcium (Ca 2+ ) and magnesium (Mg 2+ ) along with anions chloride (Cl -), sulfate (SO4 2-), nitrate (NO3 -), bicarbonate (HCO3 -) and carbonate (CO3 2-). Salinity may be as a result of land use, saltwater intrusion, and saline industrial waters. Accumulation of salts can result in sodic soil conditions. When SAR is greater than 15, the soil is called a sodic soil. Soil sodicity is caused by high sodium levels in soils at concentrations greater than 15 percent of the cation exchange capacity. Sodic soils tend to have poor structure with unfavourable physical properties such as poor water infiltration and air exchange, which can reduce plant growth (Munshower, 1994). Excess sodium in sodic soils causes soil particles to repel each other, preventing the formation of soil aggregates. This results in a very tight soil structure with poor water infiltration, poor aeration and surface crusting, which makes tillage difficult and restricts seedling emergence and root growth (Munshower, 1994, Seelig, 2000Horneck et al. 2007).
High salt levels hinder water absorption, inducing physiological drought in the plant. The soil may contain adequate water, but plant roots are unable to absorb the water due to unfavourable osmotic pressure. This is referred to as the osmotic or water-deficit effect of salinity. The second effect of salinity is shown when excessive amounts of salt enter the plant in the transpiration stream and injure leaf cells, which further reduces growth. This is called the salt-specific or ion-excess effect of salinity (Greenway and Munns, 1980). Sodium Adsorption Ratio (SAR) equation and classification was developed by the United States Department of Agriculture (USDA, 1965) and stated thus; The concentrations of Na + , Ca 2+ and Mg 2+ are calculated in milliequivalent per litre (Meq/l). The table below shows the classification water based on SAR by USDA 1965 Sodium is commonly used to determine the stability of water for agricultural purpose because its reaction with soil reduces permeability. According to Lamond and Whitney (1992) water containing SAR values from 0-10 can be applicable on all agricultural soils, while water having SAR range of 18 -26 may produce harmful effect. SAR range of 26 -100 is unsuitable for irrigation purposes The sodium adsorption ratio concentrations for Asata and Ekulu Rivers were obtained as 1.1887meq/l and 0.2956meq/l respectively. From the Table above (Table 6), the SAR values obtained falls within the range of 0-10 known as excellent. This therefore implies that both surface waters in the study area are applicable to all soil types in terms of agriculture and equally excellent for irrigation purposes.

Conclusion
Measurements and analysis of geochemical and bacteriological characteristics of water samples from Ekulu and Asata rivers in Enugu Areas, collected from different points along their regimes indicate that the two rivers are not generally suitable for domestic/industrial uses because they do not satisfy the World Health Organization (WHO) and Federal Ministry of Environment (FMENV) Drinking Water Quality Standards, in terms of acidity, (Unacceptable pH Values); turbidity, (Unacceptable High Turbidity Values); and high coliform/nitrate, iron and chromium contents.
Ekulu river water is more acidic and contains more iron than Asata river. This is due to sand extraction from Ekulu river (source of iron) and mine waters from Onyema coal mine (source of acid/high pH values). On the  Vol.11, No.4, 2021 other hand, Asata river water contains more nitrate and chromium than Ekulu river water. Human activities of urban agriculture (including use of fertilizers), disposal of industrial/domestic wastes (Solid waste dump sites), motor mechanic workshops and sand extraction from the rivers and coal mining at Onyema coal mine are responsible for the poor water quality of the two rivers in Enugu Area. Though water quality from the two rivers satisfy the US Department of Agriculture (USDA) Sodium Adsorption Ratio (SAR) requirement for irrigation water. They are therefore good for agricultural uses.
On the basis of Piper Diagram classification, Ekulu river may be classified as Calcium Chloride Type while Asata river may be classified as Mixed Water Type. It is recommended that water from the two rivers, to be used for domestic and industrial purposes, should be adequately treated. It is also recommended that regular water monitoring programme should be instituted for the two rivers.

Recommendations
i. Appropriate water treatment measures are required to upgrade the water quality to domestic, recreational and industrial standards. ii. Automobile workshops and huge waste dump along the rivers should be relocated and cleaned up.
iii. Residents and factories should be regulated by the government and community leaders to ensure that no part of the river or its watershed is used to dump wastes. There should be effective enforcement of these regulations and offenders punished with equivalent fines or jail sentences. iv. The Onyeama mines should be adequately monitored and sustainably exploited for environmental sustainability. v. Public Awareness/Education should be intensified; the more people know about the causes and effects of pollution, the more they try to avoid the consequences. vi. People that make use of the water from the river for drinking, cooking and domestic uses should endeavour to locally treat it by boiling and filtering before use. vii. Water from both rivers is generally recommended for agriculture and irrigation purposes based on the SAR assessment of the two rivers. viii. Farming activities near the rivers must be such that will not be done with artificial fertilizer. ix. Industries located close to the river to ensure that wastes are treated before releasing them into the river water.