Journal of Analytical & Bioanalytical Techniques
Open Access

Environmental pollution results undesirable change in hydrosphere and lithosphere when wastes does not avoid in well management manner [1]. Advanced industrialization and urbanization processes have provided comforts to human beings, on the other hand, it has also resulted in indiscriminate release of gases and liquids, which polluted the environment of biological system. Now a day, large amount of untreated municipal sewage/industrial wastewater is being discharged in to surface bodies for disposal and high concentration of pollutant found in wastewater are a combination of pollutant load and the amount of water with which the pollutant is mixed [2,3]. A material is becoming waste when it is discharged without expecting to be compensated for its inherent value and mainly comprised of water (99.9%) together with relatively small concentrations of suspended and dissolved organic and inorganic solids [3]. Those wastes may pose a potential hazard to human and environment particularly its contaminated ground water when improperly treated, stored, transported or disposed of [4,5].

Growing industrialization or urbanization and anthropogenic activities has an important negative impact on water quality in the downstream section of the major rivers and started to affect human health [6]. With the establishment of Universities in suburban area, the wastewater is mixed with municipal effluents and big culverts are coming out from the cities. These culverts are drains not only contain heavily polluted water but also give noxious and off smell gases. The polluted water even there is still used for growing vegetables in the nearby area of the cities without knowing their adverse impact on the life of consumers [7]. Effluents generated by industries, municipals and household activities are source of pollution [8]. Contaminated air, soil and water by industrial/municipal effluents are associated with disease burden and this could be reason for the current shorter life expectancy in developing countries when compared with developed nations [9,10].

The discharge of wastewater from industries, municipals, agricultural and urban areas carried by drains and channels to rivers worsen and broadens water pollution. High levels of pollution and the decay of water quality in river water can be causes an increase in biological oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS), total nitrogen (TN), total phosphores (TP), toxic metals such as Cd, Cr, Ni and Pb and fecal coliform and hence make such water unsuitable for drinking, irrigation and aquatic life and requires treatment before discharged into water bodies [11-13].

The liquid wastes were usually discharged untreated to a river or the ocean but, with the increasing world population, improved sanitary systems and the adventure of more stringent standards on wastewater treatment, this option has become increasingly untenable [14-16]. Thus, inadequate treatment and discharging of untreated wastewater can result in the accumulation of pollutants in the aquatic environment [17]. The consequence of this accumulation could result in loss of lively hood, increase in oxygen demand, promoting toxic algal blooms, loss of biodiversity, and degradation of water quality and destabilization of the ecosystem [18]. In order to comply with environmental legislation and to improve the competitiveness of the municipal sewage, the treatment of wastewater is not only desirable but also necessary to correct wastewater characteristics in such a way that the use or final disposal of treated effluents can take place without causing an adverse impact on the receiving water bodies [19]. The aim of this study is to analyze the level of some physicochemical parameters present in wastewater effluents discharged from Wolkite University at different sampling site.

Description of sampling site

Samples were collected from temporarily constructed treatment plant exist in the University and Megecha river, which is located approximately 171 km from Addis Ababa and 13 km from Wolkite city, in a specific place called Gubre. Wolkite is a town and administrative center of the Gurage Zone of the Southern Nations, Nationalities and Peoples' Region (SNNPR). The town do have 8°17°N37°47'E latitude and longitude and elevation between 1910 and 1935 meters above sea level.

Instrumentation and apparatus

pH Meter (WTW, Inolab Germany), mercury thermometer, vacuum analytical balance (0.0001 g accuracy), Hot air oven, polyethylene plastic bottles, volumetric flask, Erlenmeyer flask, pipettes, beakers, evaporating dish, desiccator, Whatman GF/C filter papers were used during sampling and analysis.

Chemicals and reagents

Chemicals and reagents used in this procedure were all analytical grade. 69-70% conc. Nitric acid (Spectra^®, BDH, England), silver nitrate, distilled and deionized water, potassium chromate, buffer solution.

Cleaning of apparatus

Volumetric flasks, measuring cylinders, evaporating dishes, and Erlenmeyer flask were washed with non- ionic detergents and tap water, rinsed with deionized water. Beakers and volumetric flasks were soaked with 10% (v/v) HNO3 for 24 hours followed by rinsing with deionized water, dried in oven and kept in dust free place until analysis was begins. Prior to each use, all the apparatus was soaked and rinsed in deionized water.

Sampling and sample collection

The primary step in the application of experimental methodology towards environmental analysis consists of sampling and storage, followed by sample treatment and analysis. Although sampling appears to be a relatively straightforward matter, it is generally a problematic stage of analysis. So, it is considered to be an important and corner stone of analysis. A preliminary survey of sampling point was done for two days, based on the objective of the study, availability of the potential sources of waste. For the analysis of some physicochemical parameters in wastewater effluent, available points were selected. Three different units of wastewater samples were collected using composite sampling from the wastewater channels. A control sample was collected from the river before the effluent meet with the river water.

Sample pre-treatment

Some parameters were analyzed directly (i.e., pH and temperature), but for the determination of most of the parameters, the samples have to be prepared for analysis. A variety of sample treatment methods are used depending on the analyte to be determined and the kind of analytical method to be used. Hence, the sample should be preserved properly until analysis.

Physicochemical analysis

In all sampling stations of the wastewater, pH [20] and temperatures [21] were measured on-sites with pH/Ion- Meter and mercury thermometer (0-50°C) respectively. In the laboratory, Total dissolved solids and Total suspended solid were determined gravimetrically using method [22], chloride was determine using Mohr’s titration [23].

Statistical analysis

Standard deviation, list significance difference (LSD) and Analysis of Variance (ANOVA) were analyzed using Statistical Package for Social Scientists (SPSS) 13.0, Microsoft Office Excel Program. ANOVA is used to test the hypothesis about the differences between three or more means [24]. The significance variation of the concentration of the parameters in each sample were tested at 95% confidence levels.

Physicochemical parameters distribution

Mean and standard deviation values for physicochemical variables (temperature, pH, TDS, TSS, and Cl-) along each sampling units are shown in Table 1.

Table 1: Mean ± SD values of TDS, TSS and Cl- in mg/L and temperature (°C) and pH in wastewater samples.

Temperature

Is an important indicator of water quality in regards to existence and survival of aquatic organisms. Temperature is basically do have direct effect on other parameters of wastewater such as pH, redox potentials, solubility of metals and a variation in temperature and influences the metabolic rate of organisms etc. The recorded values of temperature for wastewater samples at S₁, S₂, S₃, and control sample is 26.67 ± 0.780, 25.37 ± 0.453, 25.23 ± 0.563 and 25.03 ± 0.662°C respectively (Table 1).

pH

The value of pH is also do have direct influence on other physicochemical parameters and the availability of metal ion in the water. According to Fakayode [25], the pH of a water body is very important in determination of water quality since it affects other chemical reactions such as solubility and metal toxicity. In the present study, the levels of pH are varied between 8.227 ± 0.058 and 8.833 ± 0.058 in the wastewater samples and 8.127 ± 0.087 in controlled samples. The value of pH at S₁ is higher than the other sampling points and followed by S₂. The higher value of pH is may be due to the usage of alkaline materials for different activities.

Total Suspended Solid (TSS)

Suspended solid do not mean that they are floating matters and remain on top of water layer. They are under suspension and remain in water sample. Total suspended solids play an important role in water and waste water treatment. Their presence in water sample cause depletion of oxygen level [26]. The current study shows the concentration of TSS at S₁, S₂, S₃, and control sample is 1501.68 ± 1.629, 1002.79 ± 2.895, 558.63 ± 2.761 and 324.03 ± 2.983 mg/L respectively (Table 1). The highest value in S1 may the use of much amount of water for cleaning and removing dirty materials from cafeteria, clinic, laboratory, etc. Results suggest that these effluents may cause handling problem, if directly applied to agricultural field or if discharged into river or stream it will not be suitable for aquatic life. According to literature, the effluent discharged from Wolkite University were categorized under strong wastewater that should not be discharged into stream.

Total Dissolved Solid (TDS)

TDS can be taken as an indicator of water quality parameter because it directly affects the aesthetic value of the water by increasing turbidity and results pollution. TDS tell us the amount of both organic and inorganic dissolved compounds which may remain persistent and result in a cumulative toxic effect [27]. The average concentration of TDS at S1, S2, S3, and control sample is 2002.42 ± 3.173, 1589.66 ± 0.825 mg/L, 985.68 ± 0.848 and 399.08 ± 1.323 mg/L respectively. Effluents with high TDS value may cause salinity problem if discharged to irrigation water. Some dissolved organic matter may contribute to increased level of TDS which also indicates that water is polluted [28]. The results of TDS decreasing in concentration through the sampling points indicating that, the solids were either adsorbed on the surface of the earth or desorbed in to it. High concentration of TDS may reduce the water clarity leading to a decrease in photosynthesis and when added with toxic compounds and heavy metals, leads to increase in temperature.

Chloride (Cl-)

Like that of other water quality parameters, chlorides are also important in detecting the contamination of ground water by wastewater. The mean concentration of chloride is 223.67 ± 2.644 mg/L for S₁, 128.37 ± 2.155 mg/L for S₂, 98.80 ± 2.637 mg/L for S₃, and 46.707 ± 1.117 mg/L for the controlled sample (Table 1). The values of Cl- ion in the first sampling point (S1) is high as compared to the other sites. This is due to natural processes such as the passage of water through natural salt formations in the earth or an indication of pollution from domestic/municipal sewage [29]. The results show a decrease in concentration along the channels this may be either through selftreatment, sedimentation, etc.

According to the current finding, the physicochemical parameters in the studied wastewater effluent showed a decrease in concentration from S₁ to S₃. This might be as a result of self-purification or absorption of these parameters within the wall of the discharged channel or in the storage tanker. However, the result shows are a need to properly manage wastes in the University compound and control and monitor workers activities in order to ensure that such activities have minimal negative effects on the surrounding water stream; even though the parameters concentrations were decrease as the distance increase, care must be taken by inhabitants to avoid eutrophication in the rivers.

Comparisons of observed results with international standards

When concentration of physicochemical parameters was compared with international standard for domestic wastewater discharged to the surrounding river, showed relatively higher concentrations except temperature and pH. The comparative results were presented in Table 2.

Table 2: Comparison of observed concentration (mg/L) of physicochemical parameters in with guidelines of wastewater discharged in to river [9,11,27,30].

As it has been indicated in the above table, the mean values of temperature pH and Cl- were lower than WHO, FEPA and NEQS standard under the specified standard ranges, for wastewater to be discharged into channels of river. In all sampling site the mean concentration of TSS were extremely higher than the permissible limits set by NEQS (200 mg/L) and EEPA (30 mg/L). The mean concentration of TDS at S₁ were higher than WHO and FEPA standard of 2000 mg/L for the discharged of wastewater into surface water but, the concentration at S₂, S₃ and controlled samples were below the maximum permissible limits of WHO and FEPA standards. However, according to the EEPA and NEQS standards (3000 mg/L and 3500 mg/L respectively) the results of TDS in all sampling points including the controlled sample were below the maximum permissible.

Statistical analysis

From one-way ANOVA, the statistic F-calculated was greater than F-critical value at p ≥ 0.05 significant level, for all the parameters under investigated except that of temperature and pH. This result reveals that there is inter-site variability of mean concentration of all parameters in wastewater and control sample and there is absence of inter-site variability of temperature and pH in wastewater and control samples. Absence of significant difference in temperature and pH in each wastewater and control samples may indicates that sampling sites are under the same geographical location and share common climatic conditions. Similarly, presence of significant difference in mean concentration for the rest of the parameters indicates that either the distance between sampling points, variation between measurements.

LSD value for temperature and pH shows that, there is no significance difference between means of each sampling points. On the other hand, LSD value also shows that, there is significance variation in mean concentration for the rest of the parameters between each sampling points. Thus, both the one-way ANOVA and LSD values shows there is statistically significant variation in mean concentration of each parameters along with at S1, S2, S3 and control sample. This implies that, the distribution of mean concentration of the analyte between the sampling points is big enough (i.e., the concentration of the analyte is scattered between the sampling points).

Even though the wastewater is not treated with treatment plant, the concentration of each parameters was decreased along sampling points. This is an indication that contamination levels of each parameter decrease along the sampling stages as the distance of the wastewater channel increases from the point of discharge. In addition, the concentrations of each parameters were higher at S₃ as compared to concentration in the controlled sample. This shows that effluent discharged from the university highly affect the nearby water body.

ANOVA at 95% confidence level suggests that, there were significant difference in the mean concentration of all parameters except temperature and pH between sampling sites. The variance among results of temperature and pH in three wastewater and control samples should not be attributed to anything more than random error in the analytical procedure. Even though the researchers could not able to analyze all water quality parameter due to limitation of budget and time, the research finding can alarm stockholders to construct treatment plant. However, further study should be conducted periodically on water quality parameters of the river water.

We would like to thank the Department of Chemistry, Wolkite University, Ethiopia, for providing the laboratory facilities and the necessary supports.