Douala, situated between latitude 4.00 - 4.15 and longitude 9.65 - 9.95, is the economic capital of Cameroon in the Littoral Region and it hosts more than 80% of the industries in the Country. Increased urbanization and agricultural activities have a potential for trace metal contamination as such, the trace metal evaluation of groundwater in Douala begs our attention. This study investigated the trace metal content of groundwater sources; determined estimates of the health hazard and pollution risk indices; assessed the health hazard and level of risk to trace metal pollution in Douala. Measurement of 153 hand-dug wells for physicochemical parameters and chemical analysis of 10 representative groundwater samples was carried out to determine their trace metal content using Inductively Coupled Plasma Mass Spectroscopy ICP-MS. R-mode statistical analysis; Hierarchical Cluster Analysis (HCA) and Pearson’s correlation analysis (PCA) of the trace metals to the physico-chemical parameters were done. Four pollution hazards were estimated; the average daily dose ADD, carcinogenic risks CR, non-carcinogenic risk hazard quotient HQ and hazard index HI. Six pollution risks indices were determined: the Degree of contamination DC, Enrichment factor EF, Ecological risk factor Er, Ecological risk index RI, Pollution load index PLI, and geo-accumulation index Igeo. The trace elements detected in groundwater in Douala and their relative abundance in decreasing order are: Si > Al > Sb > Sr > Ba > Mn > Li > Zn > As > Bi > Cr > Fe > Se > Ag > Mo > Ni > Pb > Sn > Ti > TI > V. HCA distinguishes trace metals into two clusters: Cluster1; Li, Zn, Sr, Sb, Al, TI, V, Ti, Sn, Pb, Mo, Ni, Ag, Cd, Co, Cu, U, Y, Ba, Mn, Cr, Se, Bi, As, Fe and Cluster2 Si. The values of groundwater pollution hazard indices ranged; ADD (0 - 60 mg/kg/day), CR (0 - 13), HQ (1.0E05 - 1.1E05) and HI (1.05E04 - 1.2E04). The values of the pollution risk indices are DC (-1.93 - 1.91), EF (0.0 - 1.2), Er (-5 - 0), RI (-17.58 - -17.64), PLI (-0.13 - 0.13) and Igeo (0 - 1.16). The Health risk assessment qualified groundwater in Douala as unsafe and intolerable for human consumption but without carcinogenic effects. Pollution indices placed groundwater in Douala in the low degree background contamination with minimal enrichment, low potential ecological risk and geogenically unpolluted to moderately polluted. Very strong correlations were observed among some of the trace element pairs, suggesting common sources, mutual dependence and identical behaviour from provenance and during transport. The severity of trace element toxicity is governed by several factors, such as dose, nutrition, age, and life style. Therefore, these low trends might not guarantee human health due to an increasing level of environmental pollution that might be imposed by increasing human activity on Douala City and environs which might contaminate the groundwater; this demand for monitoring of groundwater sources for drinking purposes.
Cite this paper
Ntube, N. S. , Nyangang, A. J. , Agbor, M. N. and II, A. R. A. (2022). Trace Element Evaluation of Groundwater in Douala, Cameroon. Open Access Library Journal, 9, e8267. doi: http://dx.doi.org/10.4236/oalib.1108267.
Akoachere, R.A., Egbe, S.E., Eyong, T.A., Edimo, S.N., Longonje, S.N., Tambe, D.B. and Nelly, N.B. (2019) Seasonal Variations in Groundwater of the Phreatic Aquiferous Formations in Douala City-Cameroon: Hydrogeochemistry and Water Quality. Open Access Library Journal, 6, e5328.
Guevart, E., Noeske, J., Ekambi, A., Solle, J. and Bita Fouda, A. (2006) L’améliora- tion de la qualité par l’analyse des décès au cours de l’épidémie de choléra de 2004 à Douala. Cahier de Santé, 16, 49-154. (in French)
Akoachere, J.F.T.K., Lundi, A. and Njinuwo, M.T. (2013) Assessment of the Relationship between Bacteriological Quality of Dug-Wells, Hygiene Behaviour and Well Characteristics in Two Cholera Endemic Localities in Douala, Cameroon. BMC Public Health, 13, Article No. 692. https://doi.org/10.1186/1471-2458-13-692
Eneke, G.T., Ayonghe, S.N., Chandrasekharam, D., Ntchancho, R., Ako, A.A., Moun- cherou, O. and Thambidurai, P. (2011) Controls on Groundwater Chemistry in a Highly Urbanised Coastal Area. International Journal of Environmental Research, 5, 475-490.
Mural, R.C. (1972) Stratigraphy and Paleogeography of the Cretaceous and Lower Tertiary in Southern Nigeria. In: Dessauvagie, T.F.J. and Whiteman, A.J., Eds., African Geology, University of Ibadan Press, Ibadan, 251-266.
Petters, S.W. (1980) Biostratigraphy of Upper Cretaceous Foraminifera of the Benue Trough, Nigeria. Journal of Foraminiferal Research, 10, 191-204.
https://doi.org/10.2113/gsjfr.10.3.191
Abbot, B.M., Walker, J.W. and Prissorsky, J.A. (1978) An Evaluation of the Douala Permit, Cameroon, as an Aid to the 1978 Relinquishment. HTSC Report No. 442- A1822, 25 p.
Njike, N.P.R. (1984) Contributions a l’etude geologique, stratigraphic et structural de la bordure, thèses. Department of Geology, University of Yaounde, Yaounde, 61.
Nguene, F.R., Tanfu, S., Loule, J.P. and Nhassa, C. (1992) Paleoenvironment of the Douala/Kribi Campo Sub-Basins in Cameroon, West Africa. African Geology, University of Yaounde, Yaounde.
Njoh O.A., Essien J.A. and Tembi, A. (2014) Albian-Turonian palynomorphs from the Mundeck and Logbajeck Formations, Ediki River, North-Western Part of the Douala Sub-, Cameroon. Science, Technology and Development, 15, 66-77.
Ji, Y., Feng, Y., Wu, J., Zhu, T., Bai, Z. and Duan, C. (2008) Using Geo-Accumula- tion Index to Study Source Profiles of Soil Dust in China. Journal of Environmental Sciences, 20, 571-578. https://doi.org/10.1016/S1001-0742(08)62096-3
Akoachere II, R.A., Hosono, T., Eyong, T.A., Ngassam, M.C.P., Nkongho, R.N., Okpara, S.O. and Oben, T.T. (2019) Evaluation of Trace Metals in Groundwater of Ekondo-Titi and Environs, Onshore Rio Del Rey, Cameroun. Open Access Library Journal, 6, 1-25.
Hu, X., Zhang, Y., Ding, Z.H., Wang, T.J., Lian, H.Z. and Sun, Y.Y. (2012) Bio-Ac- cessibility and Health Risk of Arsenic and Heavy Metals (d, Co, Cr, Cu, Ni, Pb, Zn and Mn) in TSP and PM2.5 in Nanjing, China. Atmospheric Environment, 57, 146- 152. https://doi.org/10.1016/j.atmosenv.2012.04.056
Koki, I.B., Bayero, A.S., Umar, A. and Yosuf, S. (2015) Health Risk Assessment of Heavy Metals in Water, Air, Soil and Fish. African Journal of Pure and Applied Chemistry, 9, 204-210. https://doi.org/10.5897/AJPAC2015.0654
Kamunda, C., Mathuthu, M. and Madhuku, M. (2016) Health Risk Assessment of Heavy Metals in Soils from Witwatersrand Gold Mining Basin, South Africa. International Journal of Environmental Research and Public Health, 13, Article No. 663.
https://doi.org/10.3390/ijerph13070663
Song, D., Zhuang, D., Jiang, D., Fu, J. and Wang, Q. (2015) Integrated Health Risk Assessment of Heavy Metals in Suxian County, South China. International Journal of Environmental Research and Public Health, 12, 7100-7117.
https://doi.org/10.3390/ijerph120707100
Kim, E.J., Herrera, J.E., Huggins, D., Braam, J. and Koshowki, S. (2011) Effect of pH on the Concentrations of Lead and Trace Contaminants in Drinking Water: A Combined Batch, Pipe Loop and Sentinel Home Study. Water Research, 45, 2763-2774.
https://doi.org/10.1016/j.watres.2011.02.023
Boateng, T.K., Opoku, F., Osafo, S.A. and Osei, A. (2015) Pollution Evaluation, Sources and Risk Assessment of Heavy Metals in Hand-Dug Wells from Ejisu-Juaben Municipality, Ghana. Environmental Systems Research, 4, Article No. 18.
https://doi.org/10.1186/s40068-015-0045-y
Adebowale, K.O., Agunbide, F.O. and Olu Owolabi, B. (2009) Trace Metal Concentration, Site Variations and Partitioning Pattern in Water and Bottom Sediments from Coastal Area: A Case Study of Ondo Coast, Nigeria. Environmental Research Journal, 3, 46-59
Ayantobo, O.O., Awomeso, J.A., Oluwasanya, G.O., Bada, B.S. and Taiwo, A.M. (2014) Non-Cancer Human Health Risk Assessment from Exposure to Heavy Metals in Surface and Groundwater in Igun Ijesha, Southwest Nigeria. American Journal of Environmental Science, 10, 301-311.
https://doi.org/10.3844/ajessp.2014.301.311
World Health Organization (2017) Guidelines for Drinking-Water Quality: 4th Edition Incorporating the First Addendum. World Health Organization, Geneva.
U.S. Environmental Protection Agency (2013) 2011 Toxics Release Inventory: Public Data Release Report. U.S. Environmental Protection Agency, Washington DC.
Akoachere, R.A., Etone, E.N., Mbua, R.L., Ngassam, M.P., Longonje, S.N., Oben, P.M. and Engome, R.W. (2019) Trace Metals in Groundwater of the South Eastern Piedmont Region of Mount Cameroon: Quantification and Health Risk Assessment. Open Access Library Journal, 6, 1-21
Ian Ridley, W. (2012) Chap 15. Petrology of Associated Igneous Rocks. In Volcanogenic Sulphide Occurrence Model, U.S. Geological Survey, Reston, 227-262.
Hakanson, L. (1980) An Ecological Risk Index for Aquatic Pollution Control: A Sedimentological Approach. Water Research, 14, 975-1001.
https://doi.org/10.1016/0043-1354(80)90143-8
