Risk and Toxicity Assessments of Heavy Metals in Tympanotonus fuscatus and Sediments from Iko River, Akwa Ibom State, Nigeria

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U. U. Ubong
I. O. Ekwere
E. E. Ikpe


This study evaluates the physico-chemical parameters and heavy metals in water, sediments and Tympanotonus fuscatus obtained from three sample sites along Iko River in Eastern Obolo LGA, AkwaIbom State. The heavy metal analysis results on Pb, Cd and Ni in sediments and Tympanotonus fuscatus were used to estimate the human health and ecological risk assessment of the study area. The human health risk assessment tools utilized in this study were estimated dietary intake (EDI), total hazard quotient (THQ) and hazard index (HI) while sediment pollution parameters evaluated were contamination factor (CF), contamination degree (CD), pollution load index (PLI) and geoaccumulation index (Igeo). Results obtained showed that EDI of Cd in periwinkle in the study sites ranged from 0.2 – 6.4 µg/kg-bw/day and exceeded the provisional tolerable dietary intake (PTDI), while EDI for Pb (0.0004 – 2.6 µg/kg-bw/day) and Ni (0.32 – 2 µg/kg-bw/day) was within the limit for all sites, except Ni in site II (34 µg/kg-bw/day) which was higher than the PTDI of 5 µg/kg-bw/day. The THQ of Cd in all sites was greater than 1, while Pb and Ni generally recorded THQ < 1. The hazard index (HI) was as follows: site I (2.36), sites II (24.44) and site III (6.5), highlighting a potential hazardous effect to humans as a result of the consumption of Tympanotonus fuscatus obtained from site II and III. The sediment pollution assessment revealed that the contamination factor (CF) and geoaccumulation index, Igeo of Cd were far above the permissible limits while Pb and Ni were mostly within limits. The estimated contamination degree (CD) and pollution load index (PLI) showed a high degree of pollution, which can be mainly attributed to the high degree of Cd contamination in the sediment. Therefore, the area under investigation is highly polluted and the periwinkle obtained from Iko river in the study area is unfit for human consumption.

Heavy metals, Tympanotonus fuscatus, risk assessment, total hazard quotient, contamination, pollution

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Ubong, U. U., Ekwere, I. O., & Ikpe, E. E. (2020). Risk and Toxicity Assessments of Heavy Metals in Tympanotonus fuscatus and Sediments from Iko River, Akwa Ibom State, Nigeria. International Journal of Environment and Climate Change, 10(3), 38-47. https://doi.org/10.9734/ijecc/2020/v10i330186
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Raja P, Veerasingam S, Suresh G, Marichamy G,Venkatachalapathy R. Heavy metals concetration in four commercially valuable marine edible fish species from Parangipettai Coast, South East Coast of India, Int J. of Animal and Vet. Adv. 2009; 1(1):10-14.

Ademoroti CMO Standard methods for water and effluents analysis. Foludex Press Ltd., Ibadan. 1996;3:29-118.

Bower HJ. Heavy metals in Sediments of Founary cover cold spring, New York, Environ Sci. Technol. 1979;13:683-687.

Farombi EO, Adelowo OA, Ajimoko YR. Biomarkers of oxidative stress and heavy metals levels as indicator of environmental pollution in African Catfish (Clarias gariepinus) from Nigeria Ogun River. Int. J. of Environ. Res. and Pub. Health. 2007; 4:158-165.

Wang Y, Yang Z, ShenZ, Tang Z, Niu J,Gao F.Assessment of heavy metals in sediments from a typical catchment of the Yangtze River, China Environ Monit. Assess. 2011;172(1-4):407-417.

Fu J, Tao X, Yu H, Zhang X. Risk and Toxicity Assessments of Heavy metals in sediments and fishes from the Yangtze River and Taihu Lake, China, Chemosphere,2013;93(9):1887-1895.

Davies OA, Allison ME, Uyi HS. Bioaccumulation of Heavy Concentration of Lead in Perwrinkle (Tympanotonos fuscatus) and River Sediments in Eagle Island River, Rivers, American. J. Environ. Prot. 2006;2:37-40.

AOAC. Official Methods of Analysis of the Association of Analytical Chemists. Edited by Kenneth Helrich; 1990.

USEPA. Mercury update: impact on fish advisories.US Environmental Protection Agency, Washington DC; 2001.

USEPA.Risk-based concentration table. United State Environmental Protection Agency, Washington, DC; 2001.

FAO/WHO. Joint Food Standards Program Codex Committee on contaminants in foods. Fifth session, the Hague, Netherlands; 2011.

Li X, Liu L, Wang Y. Heavy metal contamination of urban soil in an old industrial city (Shenyang) in Northeast China. Geoderma. 2013;192(1):50-58.

Benson NU, Enyong PA, Fred-Ahmadu, OH. Trace metal contamination and health risks assessment of commelina Africana L. and psammiticsandflats in the Niger Delta, Nigeria. App. and Environ. Soil Sc; 2016.
Article ID 8178901

Hakanson L. Ecological risk index for aquatic pollution control: A sedimentation approach. Water Res. 1980;14:97–100.

Tomlison DC, Wilson JG, Harris CR, Jeffrey DW. Problems in the assessment of heavy metals levels in estuaries and the formation of pollution index. Helgoland Mar. Res. 1980;3:566–575.

Muller G. Index of geoaccumulation in sediments of Rhine River. GeoJournal. 1969;2:108–118.

Turekian KK,Wedepohl KH. Distribution of the elements in some major units of the earth’s crust.Geol. Soc. of Amer. Bull.1961;72(2):175–192.

Araoye PA. The seasonal variation of pH and dissolved oxygen (DO2) concentration in Asa lake Ilorin, Nigeria, Int. J. of Phy. Sc.2009;4(5):271-274.

Jenyo-Oni A,Oladele AH. Heavy Metals Assessment In Water, Sediments And Selected Aquatic Organisms In Lake Asejire, Nigeria.European Scient.Journ. 2016;12(24):339–351.

WHO. Guideline for drinking water quality(3rded). Incorporating 1st and 2nd Agenda. Vol. 1: Recommendation. World Health Organisation, Geneva; 2008.

National Institute for Occupational Safety and Health (NIOSH). Report to congress on workers’ home contamination study conducted under the workers’ family protection Act (29 U.S.C. 671a), 1995; DHHS (NIOSH) Publication No. 95-123; 1995.

WHO. Evaluation of certain food additives and contaminants.41st Report of the Joint FAO/WHO Expert Committee on Food Additives. Tech. Report Series. 1993;837.

Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological profile for Nickel. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service; 2005.

Pierron F, Baudrimont M, Boudou A, Massabuau JC. Effects of salinity and hypoxia on cadmium bioaccumulation in the shrimp Palaemonlongirostris.Environ. Toxicol. Chem. 2007;26(5):1010-1017.

Fritoff A, Kautsky L, Greger M. Influence of temperature and salinity on heavy metal uptake by submerged plants. Environ. Poll.2005;133(2):265–74.

Joint FAO/WHO Expert Committee on Food Additives (JECFA). Evaluation of certain Food additives and contaminants: Summary and conclusion on the Seventy-third meeting. World Health Organization, Geneva; 2010.

World Health Organization (WHO). Guideline for drinking water quality, 2nd ed., Recommendations. World Health Organization, Geneva. 1997;1.