Physicochemical Properties and Macronutrients Status of Water From Mukumbura and Zhoubvunda Rivers’ Floodplain Shallow Wells In The Zambezi Valley, Northern Zimbabwe

 

Chimweta Moreblessing and Nyakudya Innocent Wadzanayi

 

Full Length Research Paper I Published March,2019

 

Journal of Physical Science and Environmental Studies Vol. 5 (1), pp.14-20

 

ABSTRACT

Floodplains are a sink of pollutants from surrounding areas, yet they provide sources of water for irrigating crops, and human, livestock and wildlife drinking. In semi-arid areas, floodplains are usually the only sources of water particularly during the dry season when upland wells dry up. The objective of this study was to determine the suitability of the water from shallow wells for crop use and drinking. Total dissolved solids (TDS), pH, electrical conductivity (EC) and selected macronutrients concentrations in shallow wells’ water in Zambezi Valley floodplains, northern Zimbabwe were determined. Water samples were collected at depths between 2.7 and 3.3 m in November 2015. Water pH was measured using Adwa pH/mV/ISE and temperature meter; EC and TDS using Adwa EC/TDS and temperature meter; Mehlich 3 extracted Ca, Mg, K, and Na concentrations were determined using atomic absorption spectrometry, phosphates were measured using the ascorbic acid procedure, while sulphates were determined using the barium sulphate method. Data from water analyses were subjected to ANOVA. Water pH ranged from 6.94 to 7.73; EC ranged from 137.67 to 220.00 µScm-1; and TDS ranged from 114.67 to 173.43 mgl-1. Macronutrient concentrations (mgl-1) were: 23.33 to 64.23 for Ca; 19.23 to 23.60 for Mg; 0.34 to 1.50 for K; 14.46 to 19.05 for Na; 3.03 to 5.87 for phosphates and 1.12 to 6.12 for sulphates. Plant nutrient concentrations were very high for phosphates, normal to high for Ca, normal for the rest. Electrical conductivity, TDS and pH were within normal range for crop use. The water quality met the World Health Organization and the Standards Association of Zimbabwe specifications for drinking water. Satisfactory crop productivity is achievable using the water for irrigation purpose but measures should be taken to minimize accumulation of phosphates and Ca.

Key words:Capillary rise, Groundwater, Smallholder farming and Water quality.

 

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