CHARACTERISATION OF GROUNDWATER QUALITY IN AREAS AROUND THE LAKE CHILWA BASIN, ZOMBA

Groundwater quality is affected by human activities in the region and therefore the issue of groundwater contamination is common worldwide. High coliform above 50 CFU/100ml levels in drinking water can rise waterborne diseases like cholera, typhoid, and diarrhea and this problem has been reported in many sorts of research around Malawi and other countries. Other studies related to coliform contamination of groundwater are limited in the study area. The purpose of the study was to investigate the microbiological quality of groundwater in boreholes around the Chilwa Lake basin and the origin of contaminants. To complete the study, at each site, two water samples were collected from six sampling sites at Jali Police Station, Jali Epicentre, Jali Anglican, Chande, Dzinja, and Pilimiti. The physical parameters were measured using the multiparameter water quality probe except for pH, and the temperature was measured by pH meter and turbidity by photometric method, all the chemical parameters were measured using a photometric method by a photometer, and all the microbiological parameters were measured using membrane filtration method by membrane lauryl sulfate broth. Statistical analysis like One-way Analysis of Variance (ANOVA), and Pearson correlation were performed to assess the connection between the water quality parameters, regression analysis to predict dependent variables, and the Water Quality Index (WQI) was calculated to look at the status of water conditions. The results for Physico-chemical showed that temperature surpassed the permissible limit of national for untreated borehole waters while pH, EC, TSS, Turbidity, and TDS values were within the maximum permissible limit of MBS and MoIWD for untreated borehole water. Total coliforms counts were low at BH1 and for BH2, BH3, BH4, BH5, BH6 the values were above the maximum permissible limit and for fecal coliform zero concentrations at BH1 and BH5 while BH3, BH4, and BH6 the values surpassed the maximum limit for untreated borehole water. Furthermore, Pearson's correlation analysis showed a significant positive correlation between, EC and TSS and turbidity, nitrate and ammonia, faecal coliforms, TSS, ammonia, and total coliforms. The ANOVA showed that there were no statistically significant differences (p>0.05) in all water quality parameters measured within the six boreholes sampled at Mwambo T/A. The regression found that the fecal coliform dependent variable can be predicted with independent variables. The WQI found that the groundwater quality of T/A Mwambo is very poor and not suitable for human consumption. The study reflects a very bad quality of groundwater in the in T/A Mwambo. It was concluded that some indicators put into indication mostly microbial pollution because most of the boreholes were found to have high Coliforms as compared to maximum permissible limits for MoIWD and MBS. It was also concluded that the WQI method is a highly efficient tool for determining the quality of potentially polluted water bodies. Therefore, civic education is a need in these communities to reduce water-related diseases by telling people to disinfect water with either chlorine or heat before drinking as well as frequent monitoring activities using the water quality index approach so that the legislative makers can take appropriate action on the polluted water points.

The physical parameters were measured using the multiparameter water quality probe except for pH, and the temperature was measured by pH meter and turbidity by photometric method, all the chemical parameters were measured using a photometric method by a photometer, and all the microbiological parameters were measured using membrane filtration method by membrane lauryl sulfate broth. Statistical analysis like One-way Analysis of Variance (ANOVA), and Pearson correlation were performed to assess the connection between the water quality parameters, regression analysis to predict dependent variables, and the Water Quality Index (WQI) was calculated to look at the status of water conditions. Therefore, civic education is a need in these communities to reduce water-related diseases by telling people to disinfect water with either chlorine or heat before drinking as well as frequent monitoring activities using the water quality index approach so that the legislative makers can take appropriate action on the polluted water points. Water quality index, physical-chemical parameters, microbiological parameter, water quality.

Lake Chilwa wetland is situated at a latitude of 15o 20 S and longitude 35o 40E in southern Malawi and the east of Zomba plateau. It experiences a warm tropical climate, which is characterized by rainy and dry seasons. The rainy and dry seasons occur from November to April and May to October, respectively. The study area is relatively hot and humid due to low lying altitude 0f 2050 to 2200 (Hellens, 2013). The mean annual temperature is 24oC. The highest temperature of 29oC and the lowest temperature of 20oC are experienced in October and June, respectively (Missi & Atekwana, 2018). Rainfall variability has a significant impact on water availability and the discharge of particular catchments (Hellens, 2013). However, processes other than rainfall play a significant role in the hydrologic processes of any catchment (Hellens, 2013). The study was mainly conducted in T/A Mwambo specifically in the villages of Jali, Dzinja and Chande, which were all around Lake Chilwa basin. The area relies on boreholes for water supply on which most of them are located close to the pit latrines and agricultural lands.

Traditional authority: TA Mwambo

District: Zomba

Coordinates: -15.4653, 35.5092