Article Subject
Environmental
Abstract

This study reveals that the electrical conductivity of groundwater in the study area ranges from 4.5 – 4400 mho/cm. 16% of the locations have conductivity in excess of 1000mho/cm. Therefore the values for Umuoji (2300mho/cm), Idama (3000mho/cm), Toru Ndoro (3000mho/cm) Oloma (3800mho/cm) and Kalaibiama (4400mho/cm) are objectionable. pH is therefore a major issue in the groundwater samples from the study area. In fact all the 112 datasets studied have values for pH. The values range from very acidic (3.8 at Toru Ndoru) to permissible (8.4 at Kalaibiama).  46% of the samples (51 datasets) have values within WHO standards while 65% have values outside WHO scale. The alkalinity values range from 0.09 – 180mg/l. 65 water samples had values for hardness. 75% of this has values <75mg/l while 9% has values between 75 and 180mg/l. It is therefore expected that the waters will be chemically aggressive to iron and carbonate surfaces. Few cases of high hardness values at Idama, Kalambiama and Oloma are in the mangrove swamp and coastal ridges. Iron is a more common problem in groundwater samples from the freshwater swamps/back swamp/meander belt region as well as the mangrove swamps and coastal ridges. Chloride concentration is high particularly in the coastal areas and parts of Port Harcourt city bordering saltwater creeks and tidal channels which have influent relationship with the local groundwater table. The chloride content in groundwater appears generally to decrease from north to south ie from the hinterland to the coast. The localized chloride enrichment around the Old GRA, Port Harcourt, Borokiri, Moscow road and Central Police Station in Port Harcourt could be as a result of brackish water invasion from nearby creeks and tidal channels. Chloride again is a major quality issue especially in groundwater in these areas as well as in the mangrove swamps and the coastal beaches and ridges. Salinity values range from 2mg/l at Beeri to 2500mg/l at Idama. Oloma and Kalaibiama have 2200mg/l and 220mg/l respectively.  WHO appears to be silent on specifications of limit for salinity, it tends to increase in a southerly direction. Least values of salinity are more common in the hinterland. The salinity values of groundwater in the study area appear to be generally tolerable. Excessive abstraction of groundwater appears to have resulted in a decreased seaward flow of fresh groundwater causing saline water to enter and penetrate inland through submarine outcrops. This phenomenon will progressively displace the freshwater thereby increasing the salinity depth.

 

Keywords
Deep Aquifers
groundwater
Chemistry
Quality
Niger Delta
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