**6. Results and discussion**

### **6.1 Discussion**

**Table 1** shows the conductivity values for January samples analyzed at five different points: 593.00, 618.00, 828.00, 507.00, and 690.00 μohms/cm. The conductivity values were generally greater than the WHO maximum permissible limit of 500.00 μohms/cm. This is evident from the measured mean of 647.20 ohms/cm. Point 3 had the highest conductivity of 828.00 μohms/cm, while point 1 had the lowest conductivity of 593.00 μohms/cm. Furthermore, when compared to the other points, the conductivity at point 4 (507.00 μohms/cm) was slightly higher than the WHO standard limit.

**Table 2** shows the conductivity (μohms/cm) values for February samples analyzed at five different points: 511.00, 499.00, 497.00, 500.00, and 513.00 μohms/cm. In comparison to the mean of 504.00 μohms/cm recorded, the conductivity values were generally greater than the maximum value of 500.00 μohms/cm of WHO standards limits. Points 5 and 1 had the highest conductivities of 513.00 μohms/cm and 511.00 μohms/cm, respectively, while points 3, 2, and 4 were all within the WHO standard limits.

The pH values for January, February, and March samples at five different points are as follows: 7.60, 6.53, 7.52, 6.89, 6.50, 6.66, 6.86, 6.56, 6.76, 6.84, 6.93, 7.10, 7.09, 7.25, and 7.06, as shown in **Tables 1** and **2**. The pH values were found to be generally within the WHO acceptable limits of 6.50–9.20. This is evident from the mean pH value of 7.01, which falls within the WHO threshold range of 6.50–9.20. This implies that the effluent discharged into the river by Kaduna Refining and Petrochemical Company has no effect on the river's pH concentration.

The temperature values recorded for the five different samples over three consecutive months (January, February, and March) at five different points are as follows: 21.30, 20.80, 20.20, 20.90, 20.30, 20.80, 20.50, 20.40, and 20.70°C, which are all less than the room temperature of 25.00°C. While those of March were 27.60, 29.30, 29.80, 30.10, and 30.00°C higher than the room temperature, as shown in **Tables 1**–**3**. The mean temperature values of 20.80°C, 20.54°C, and 29.36°C demonstrate this. The increase in temperature values observed in March could be attributed to seasonal changes rather than Kaduna Petrochemical and Refining Company's activities.

As shown in **Table 1**, the turbidity values for January samples at five different points are: 28.70, 14.45, 43.69, 103.00, and 14.01 NTU, which are higher than the maximum limits of WHO and Federal Environmental Protection Agency (FEPA) acceptable standards of 10.00 NTU. Considering the recorded mean turbidity value of 40.77 NTU, which is significantly higher than the acceptable value.

As shown in **Table 2**, the turbidity values for February samples at five different points are: 26.35, 18.36, 23.85, 25.93, and 31.93 NTU, which are higher than the maximum limits of WHO and Federal Environmental Protection Agency (FEPA) standard acceptable standards of 10.00 NTU. Taking into account the recorded mean turbidity value of 25.28 NTU, which is higher than the acceptable value.

The turbidity values for March samples at five different points, as shown in **Table 3**, are greater than the maximum limits of WHO and Federal Environmental Protection Agency (FEPA) standard acceptable standards of 10.00 NTU. Considering the recorded mean turbidity value of 34.16NTU, which is significantly higher than the acceptable value. As a result, the increase in mean turbidity values of 40.77, 25.28, and 34.16 NTU above the acceptable standard in January, February, and March could be attributed to effluents released by the Kaduna Petrochemical and Refining Company.

### **6.2 Chromium (Cr)**

The amount of chromium (Cr) in the five (5) different samples at different points in January, February, and March samples was less than 0.0100 mg/kg (<0.0100 mg/ L), as shown above. This is evidence from the mean (<0.0100), standard deviation (0.0112), and variance (0.0001), which show how far apart each metal is from its arithmetic mean. The coefficient of correlation between the three (3) months was discovered to be zero (0), indicating that there was no correlation between them. The WHO and FEPA drinking water standards were 0.05–2.00 mg/L (**Table 4**).

### **6.3 Iron (Fe)**

The iron (Fe) content of these five samples at various points is shown in **Table 5** for January samples in mg/L. At point 1, the amount is high, but at point 2, the amount decreases, while at point 3, the amount increased dramatically, and at point 4, the amount was very low, while at point 5, the amount decreased dramatically.

For February samples, the amount decreases at points 1, 2, and 3, but increases slightly higher at point 4, and dramatically increases at point 5.

For March samples, the amounts at points 1, 2, 3, and 4 decrease, but the amount at point 5 increases to be greater than the amounts at points 3 and 4 but less than the amounts at points 1 and 2. This is evidenced by the three-month mean of 0.2587, 0.8663, and 1.5467, the standard deviation of 0.1996, 0.2585, and 0.0605, and the variance of 0.0398, 0.668, and 0.668. The coefficient of correlation for January and February was found to be +1, indicating a perfect positive correlation between the two months, whereas the correlation for January and March and February and March was found to be zero (0), indicating no correlation between the months.

The amount of Iron (Fe) allowed by the American Public Health (APH) and World Health Organization [14] for drinking water was 0.30 mg/L.
