[1] Lenntech Water Treatment and Air Purification. Water Treatment, Published by Lenntech, Rotterdamseweg, Netherlands (2004).(www.excelwater.com/thp/filters/Water-Purification.htm).
[2] Hutton M, and Symon C. The Quantities of Cadmium, Lead, Mercury and Arsenic Entering the U.K. Environment from Human Activities. Sci. Total Environ. 57:129-150(1986).
[3] Battarbee R , Anderson N, Appleby P, Flower RJ, Firtz S, Haworth E, Higgit S, Jones V, Kresier A, Murno MA, Natkanski J, Oldfield F,Patrick ST, Richardson N, Rippey B, Stevenson AC(1998). Lake Acidification in the United Kingdom, ENSIS, London. http://WWW.geog.ucl.ac.uk/-spatrick/f_r_pubs.htm.
[4] Niragu Jo , Pacyna J. Quantitative Assessment of Worldwide Contamination of Air, Water and Soil by Trace Metals , Nature , 333:134-139(1988).
[5] Niragu Jo. A global Assessment of Natural Sources of Atmospheric Trace Metals, Nature, 338:47-49(1989).
[6] Garbarino JR, Hayes H, Roth D, Antweider R, Brinto TI, Taylor H. Contaminants in the Mississippi River, U.S. Geological Survey Circular 1133, Virginia, U.S.A(1995). (WWW.Pubs.usgs.gov/circ/circ1133/).
[7] Hawkes JS. Heavy Metals, J. Chem. Educ.74(11):1374(1997).
[8] Lindsay WL. Micronutrient soil testing for the tropics. In Vlek, P. L.G. (ed.). Macronutrients in Tropical Food Crop Production. International Fertilizer Development Center, Muscle Shaols, PP(169-200) (1985).
[9] Ayeni, O. O. Metal contamination of soils collected from four different sites along the lower Diep River, Cape Town. International Journal of the (2010).
[10] Duruibe, J. O., Ogwuegbu, M. O. C. and Egwurugwu, J. N. Heavy metal pollution and human biotoxic effects. International Journal of Physical Sciences Vol. 2 (5), pp. 112-118(2007).
[11] David, P. Trace Element Contamination of the Environment. London: Elsevier Science Publishing Company(1997).
[12] Dara S.S. Environmental Chemistry and Pollution control. New Delhi: s. Chand and company Ltd, India(2004).
[13] Ogbuene E. B. Analysis of Rainfall Disparity on Land degradation and Biodiversity loss in Southeastern Nigerian Environment. Ist West Africa International Workshop and Conference on Landslides and Other Geo-Hazards(2010).
[14] Mabogunje, A.L. “The Debt to Posterity: Reflections on a National Policy on Environment Management”, in Sada, P.O. and Odemarho, F.O. (eds.), Environmental Issues and Management in Nigerian Development, Evans Brothers Nigeria Publishing Limited(1988).
[15] Urbinato D. London's Historic Pea-Soupers, United States Environmental Protection Agency Intergovernmental Panel on Climate Change (IPCC) (2007), Impacts, consequences, adaptation and vulnerability Cambridge University Press: Cambridge(1994).
[16] BAI Jun-hong, XIAO Rong, GONG A-du, GAO Hai-feng, HUANG Lai-bin. Assessment of heavy metal contamination of surface soils from typical paddy terrace wetlands on the Yunnan Plateau of China [J]. Physics and Chemistry of the Earth, 2011, 36(9): 447−450.
[17] Akpoveta, O.V, Osakwe, S.A, Okoh, B E; Otuya, B O. Physicochemical Characteristics and Levels of Some Heavy Metals in Soils around Metal Scrap Dumps in Some Parts of Delta State, Nigeria J. Appl. Sci. Environ. Manage. December, 2010.
[18] Muller G. Index of geoaccumulation in sediments of the Rhine river [J]. Geo Journal, 1969, 2(3): 108−118.
[19] Hakanson L. Ecological risk index for aquatic pollution control —A sedimentological approach [J]. Water Research, 1980, 14(8): 975−1001.