Sokoine University of Agriculture

Saltwater intrusion and nitrate pollution in the coastal aquifer of Dar es Salaam, Tanzania.

Show simple item record Mtoni, Yohana Mjemah, Ibrahimu Chikira Bakundukize, Charles Van Camp, Marc Martenes, Kristine Walraevens, Kristine 2022-12-19T14:47:10Z 2022-12-19T14:47:10Z 2013-11-03
dc.description Journal Article en_US
dc.description.abstract Dar es Salaam Quaternary coastal aquifer is a major source of water supply in Dar es Salaam City used for domestic, agricultural, and industrial uses. However, groundwater overdraft and contamination are the major problems affecting the aquifer system. This study aims to define the principal hydrogeochemical processes control- ling groundwater quality in the coastal strip of Dar es Salaam and to investigate whether the threats of seawater intrusion and pollution are influencing groundwater qual- ity. Major cations and anions analysed in 134 groundwater samples reveal that groundwater is mainly affected by four factors: dissolution of calcite and dolomite, weathering of silicate minerals, seawater intrusion due to aquifer over- exploitation, and nitrate pollution mainly caused by the use of pit latrines and septic tanks. High enrichment of Na ? and Cl - near the coast gives an indication of seawater intrusion into the aquifer as also supported from the Na–Cl signature on the Piper diagram. The boreholes close to the coast have much higher Na/Cl molar ratios than the boreholes located further inland. The dissolution of calcite and dolomite in recharge areas results in Ca–HCO 3 and Ca–Mg–HCO 3 groundwater types. Further along flow paths, Ca 2? and Na ? ion exchange causes groundwater evolution to Na–HCO 3 type. From the PHREEQC simu- lation model, it appears that groundwater is undersaturated to slightly oversaturated with respect to the calcite and dolomite minerals. The results of this study provide important information required for the protection of the aquifer system. en_US
dc.language.iso en en_US
dc.publisher Springer, Environimental Earth Science. en_US
dc.subject Dar es Salaam en_US
dc.subject Coastal aquifer en_US
dc.subject Hydrogeochemical processes en_US
dc.subject nitrate contamination en_US
dc.subject Salinization en_US
dc.subject Cation exchange en_US
dc.title Saltwater intrusion and nitrate pollution in the coastal aquifer of Dar es Salaam, Tanzania. en_US
dc.type Article en_US
dc.url DOI 10.1007/s12665-012-2197-7 en_US

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