Physical and chemical characteristics of water from Okamini Stream, Obio/Akpor, Rivers State, Niger Delta, Nigeria

Water samples were collected from Okamini stream and analyzed for some physicochemical parameters. The values showed that electrical conductivity, total dissolved solids, total suspended solids, chlorides, sulphates, nitrates and phosphates were within the range of values acceptable for domestic water use by WHO. Others such as turbidity, pH and salinity were not within acceptable range in water for human consumption. Although, the water from the stream at the time of evaluation may not be at an alarming situation, but calls for adequate surveillance and protection to avert possible decay that looks eminent.


Introduction
Aquatic environments in the past few years have been subjected to deleterious environmental attack. This attack is due to the rising number of population, rise in industrial activities and human quest for monumental arts (Kinsiclounon et al., 2013). Deterioration of water bodies is an issue that is presently worrisome, especially among city dwellers, since the provision, distribution and maintenance of water within the requirement for quality uses and maintenance of sanitation infrastructure is relatively scares when compared to human population and spread (Edori and Edori, 2021a).
The value given to any river water is dependent on the worth of nourishing sources. These natural nourishing sources are superficial runoff water, glaciers, wetland, rainfall and ground water seepages, and nature of discharged liquid waste from homes and industries and size of population living within the immediate environment (Al-Zubaidi, 2012). The term quality of water mostly talk about to the constituent of water that is desired at the optimal level for the development of plants and animals. The quality of water is affected by different environmental dynamics such as pH, temperature, opacity or turbidity, amount of nutrients, hardness, alkalinity and the amount of oxygen present in water (Edori, 2020).
The assessment of physicochemical parameters are necessary to ascertain the level to which the quality of water can be appreciated by individuals, homes and cooperate bodies. Also they are readily available tools to determine the level of water acceptability for consumption and irrigation purposes (Solomon and Kehinde, 2017;Banunle et al., 2018). Under natural conditions river system, the different chemical constituents that may be present in water usually occur at very low concentration. However, these concentrations are raised when there is an upsurge of population growth, urban drift, enlargement of industrial activities, taking of undue advantage of natural resources, absence or weak environmental regulatory laws and intense use of the water for irrigation (Mehedi et al., 1999).
Plants and animals which dwell in water require a healthy environment to inhabit which can equally provide the necessary food and mineral requirement for growth. For optimum aquatic productivity, there must be a corresponding balance in the characteristic constitution of the physicochemical components of the water (Onyegeme-Okerenta et al., 2016). Therefore, when considering the quality of water for maximum output, the physicochemical parameters cannot be neglected. This is the reason that in pollution control and management, water quality is very important (Kamal et al., 2007;Adewuyi et al., 2017).
This research, therefore investigated the levels of some physicochemical parameters in Okamini Stream, an important water source for rural communities in Egbelu and Elioparanwo communities in Obio/Akpor local Government Area of Rivers State, Nigeria.

Materials and methods
Sampling of water was done in the morning period between 7:00-8:00 am. Water sampling was done at three different positions with plastic vials, which had been previously washed and dried. The depth of water sampling was maintained at 20 cm below the water surface and covered immediately. The obtained samples were placed in iced packed vessel and moved to the laboratory where the analysis were carried out. Sampling was done in January and March.
The conductance of the water samples and total dissolve solids (TDS) were determined on site using a portable handheld meter (Mettler Toledo MC-226). The meter has selections buttons which represents each of the parameters. When the probes are inserted into the water samples, the meter reads of the conductivity or the total dissolved solids depending on the button pressed. Reading were taken after the meter has stabilized for at least five seconds. The photometric method was used to measure the turbidity of the water samples. This was achieved through the passage of a stream of light through the water and light which scattered at right angles to the stream of light were measured photometrically. The total suspended solids (TSS) were measured by first recording the weight of a filter paper and thereafter, the water was passed through the filter paper and the filter paper was allowed to dry to constant weight. The increase in weight was taken as TSS (Bertram and Balance, 1996).
The Thermo Orion pH meter was used to measure the water pH on site. The procedure follows the manner which conductivity and TDS were measured. The method of Cataldo et al. (1985) was used to analyze nitrate concentrations. A volume of water 2 mL and 8mL (5% w/v) salicylic acid in concentrated sulphuric acid were mixed together and put in 250 mL conical flask and kept standing for twenty minutes. A volume of 190 mL of 2M sodium hydroxide were slowly dropped into the mixture until the pH was raised beyond 12 and allowed to cool. The proportion of the nitrate sample to salicylic acid-H2SO4 was maintained at 1:3 (v/v). The absorbance of the nitrate spectrophotometrically evaluated at a wavelength of 410 nm and concentrations determined through calibration curve.
To determine the concentration of phosphates in the water samples, the method of APHA (1995) was used. To a clear colourless water of 100 mL volume was added a drop of 0.05 mL phenolphthalein indicator. Further added to this mixture was 2 drops of 2M sulphuric acid and a pink colour was formed. Drops equal to 4 mL molybdate and 0.5 mL of stannous chloride were mixed together and allowed to react. The mixed solutions were left standing for 11 min. Thereafter, the concentrations of phosphates were determined with a Spectrophotometer (Model 752 Shimadzu, Japan) at a wavelength of 690 nm.

Results and Discussion
The  (Edori, 2020), but higher than the values observed at effluents discharge points along the mangrove stretch of New Calabar River, Rumuolumeni, Port Harcourt, Rivers State (Edori and Nna, 2018). Conductivity measures the ability with which aqueous solutions transmits electricity. This is based on the mobility rate of a number of current carrying species available in the medium, the environmental temperature, the nature and type of ions present and the charges of the species present (Sharma and Walia, 2017). When conductivity is high, it can be inferred to have resulted from elevated concentration of heavy metals in the water (Edori, 2020). Conductivity of an important factor when considering the number of dissolved ionic species or electrolytes in water and also play a role the examination of hardness and alkalinity of water. According to Karato and Wang (2013), ions of sodium, potassium and chloride enhances conductance of water and are associated with mining pollution and or other elated anthropogenic interference. The low conductance of the water from the stream may be interpreted from the angle of low anthropogenic influence or that the associated influence may not be related to input of conductivity enhancers. This observation is in agreement with those of Banunle et al., 2018). Although turbidity may not a major source of health concern, but it is related to lake eutrophication, aesthetics, disinfection and medium for microbial growth, through supply of nutrients available from the turbid particles. The evaluation of the status of water based on TDS take into consideration the levels of organic and inorganic that is present in the water solution (Rahmanian et al., 2015). The magnitude of aquatic pollution is a function of amount of dissolved solids existent. It was observed that the values of TDS was slightly higher in March when compared to January. This situation is not unconnected with the beginning of rainfall in March, which through runoffs carry soluble particle from the adjoining lands to the stream. This observation is inconsonance with thee observation of (Abdar, 2013). The importance of TDS as a water parameter cannot be undermined because it controls both biotic and abiotic conditions of water system and also very vital when considering treatment procedures (Thirupathaiah et al., 2012). Total suspended solids is a parameter that is linked to turbidity of water. Increase in TSS is directly proportional to turbidity of water (Edori et al., 2019). Turbidity of water is influenced by human induced factors which include land tilling and other forms of land loosening, which enhances erosion and transportation of surface soil particles into the stream through runoffs (Songa et al., 2015). Natural enhancer of TSS are algae and re-suspended particles of silt and sediments. The major causes of re-suspension of sediment particles include turbulent movement of water and disturbance of shallow water through boat engines. At elevated levels, TSS introduces smell, colour and taste to water (Edori and Nna, 2018).
The chemical characteristics of water from Okamini Stream is give in Table 2. The pH of the waterbody in January varied from 5.60 -5.63 and a mean value of 5.64±0.03. In March, the observed range fall between 5.80 -6.42 and a mean of 6.18±0.27. These values are lower than the required value for drinking water by WHO, which is in the range of 6.5 -8.5.
The results of pH in the Okamini Stream is in consonance with the observation of (Onyegeme-Okerenta et al (2016) in Otamirioche River in Etche, Rivers State, Nigeria, where the pH values were in the acidic range. The acidic nature of the water from Okamini Stream is not unconnected with slow flowing nature due to tidal effects which allows organic waste to remain at a position for a long time and therefore continue to add up. This cannot be farfetched because of the presence of waste dumps, abattoir and fish farms along the stream coupled with drainage discharge point that discharges directly to the stream. According to Keith (2013), aerobic organisms which degrades organic wastes produces carbon dioxide, which solubilize in water to produce carbonic acid, thus keeping the water in acidic form. Adequate aquatic pH is necessary for all human industrial, domestic and physiological activities. Its importance is based on the fact that several chemical and biological processes is related to the pH of the system, of which when it is at the extreme causes a lot of physiological impairment and damage to manufacturing equipment. Most changes in aquatic pH is caused by presence of industrial contaminants, pollutants and or agents, photosynthesis and respiration of algae which feeds on the contaminants (Dorleku, 2013). Salinity can be used to define the amount of salt present in a medium. High salinity increases the density of water and lead to water stratification . The amount of salts present in water (ie level of salinity) enables fast deterioration of manufacturing and structural equipment. This is due to the ability of the saline water to provide charged species thus creating room or medium of electron movement and exchange, thus causing oxidation-reduction reaction into play within the equipment on contact. High salinity discourages some biotic processes. For example, some fishes migrate away from salty environment, worms and leeches do not in any way come in contact with saline environment or else instant death is recorded and at extreme levels affects the osmotic behaviour of some aquatic plants and animal and lead to death of such if the situation is prolonged. Thereby causing changes to natural biodiversity of aquatic vegetation and fauna (water ecologies) (Godfrey, 2000). The presence of influence of brackish water from the New Calabar River may have influenced the salinity of the stream under study. When the level of chloride is high in water, it promotes conductance behavior of the water and also enhances the corrosivity of the water on metallic materials (Gregory, 1990). The presence of chlorides in surface water results from different sources such as sediment re-suspension of chloride containing particles, manure and sewage discharges and industrial wastes (Gregory, 1990). The stream may have received chlorides input outside tidal incursions from discharge of agricultural wastes from nearby slaughter house, direct sewage and solid waste discharge and leached effluents from the dumpsite by the streamside. The concentrations of the nutrient parameters in the water are given in Table 3 Redox reactions in water undergone by ammoniacal nitrogen and nitrites give rise to nitrates in water. Another source of nitrates in water is through death and decay of organic matter and some inorganic processes which occur in river system. Application of nitrogen based fertilizers on nearby farmlands, which are washed in water bodies is another contributory factor of water nitration (USEPA, 2012). When nitrates is increased in water, the likely effects include decreased quantity of available oxygen in water, eutrophication and blue baby syndrome disease in children Sulphate contribute to water acidity if present at high concentration. Although it is not considered as a very toxic matter in water, yet it is related to different physiological effects when consumed above required concentrations (Omaka et al., 2014). These conditions include purgation, lack of fluids in the body and abdominal irascibility. At levels above 500 mg/L in domestic water, urgent action is required to remove it otherwise it will be disastrous health wise to consumers after short time intake (Bertram and Balance, 1996). Mining activities, manufacturing processes, paper milling and tanneries are major contributors of sulphate in water medium (Andrews et al., 2004 Edori andEdori, 2021b). Discharged sulphur dioxide during combustion processes reacts with oxygen in the atmosphere to form sulphuric acid, which is precipitated during rainfall back to the river of soil. Extremely elevated values of sulphate lead increased acidity of the water and increase bacterial bloom, for example, sulphate reducing bacteria (Edori and Edori, 2021b).
The values observed in the water for phosphate in the water from Okamini Stream ranged from 0.272 -0.524 and a mean of 0.424±0.11 mg/L. The values observed in March ranged from 0.361 -0.513 mg/L and a mean of 0.458±0.07 mg/L. The observed phosphate values were within the 0.5 mg/L requirement for domestic water use.
One of the major causes of lake-eutrophication is phosphate, which supply nutrients to microorganisms that culminates in algal bloom. (Wagner, 1974;Omaka et al., 2014). Phosphorous as an important element required for plant growth is often applied in farms for maximum yield. However they are sometimes carried to water bodies through runoffs and as such becomes deleterious to organisms and the general aquatic ecology. Phosphates in water combines with suspended particles to increase turbidity. Furthermore, due to its support for algal growth, the more algae present in water the more turbid the water is likely to be. Phosphate presence in water occasioned with a resultant decrease in the oxygen content or carrying capacity of the water, clog up the waterways, leading to decreased oxygen content and therefore death of living organisms (Katoski, 1997).

Conclusion
The physicochemical parameters examined in the Okamini Stream in Obio/Akpor, Rivers State showed that the water is not suitable for consumption. However, the values obtained generally showed danger signals in the immediate, but there is the likelihood that the situation might get worse in the near future of the conditions around the stream are not put under serious check or complete removal.