Evaluation of Contamination and Ecological Risk of Heavy Metals Associated with Cement Production in Ewekoro, Southwest Nigeria.

Temitope Ayodeji Laniyan,Adeniyi Johnpaul Adewumi

doi:10.5696/2156-9614-10.25.200306

Temitope Ayodeji Laniyan, Adeniyi Johnpaul Adewumi

Open Access

https://doi.org/10.5696/2156-9614-10.25.200306

Copy DOI

Abstract

Background.Exposure to heavy metals emanating from cement production and other anthropogenic activities can pose ecological risks.Objectives.A detailed investigation was carried out to assess the contamination and ecological risk of heavy metals associated with dust released during cement production.Methods.Sixty samples, including 30 soils and 30 plants, were collected around Lafarge Cement Production Company. Control samples of soil and plants were collected in areas where human activities are limited. Samples were dried, sieved (for soil; 65 μm), packaged and analyzed using inductively coupled plasma mass spectrometry at Acme Laboratory in Canada.Results.The average concentration of heavy metals in soils of the area are: copper (Cu): 41.63 mg/kg; lead (Pb): 35.43 mg/kg; zinc (Zn): 213.64 mg/kg; chromium (Cr): 35.60 mg/kg; cobalt (Co): 3.84 mg/kg and nickel (Ni): 5.13 mg/kg. Concentrations of Cr in soils were above the recommended standards, while other metals were below recommended limits. The average concentrations of heavy metals in plants were: Cu: 26.32 mg/kg; Pb: 15.46 mg/kg; Zn: 213.94 mg/kg; Cr: 30.62 mg/kg; Co: 0.45 mg/kg and Ni: 3.77 mg/kg. Levels of heavy metals in plants were all above international limits. Geo-accumulation of metals in soils ranged between −0.15 and 6.32, while the contamination factor ranged between 0.53 and 119.59. Ecological risk index of heavy metals in soils ranged between 49.71 and 749.Discussion.All metals in soils of the study area except for Cr were below the allowable limits, while the levels of metals in plants were above the permissible limits. Levels of heavy metals reported in this study were higher than those from similar cement production areas. Soils around the Ewekoro cement production area were low to extremely contaminated by toxic metals. Cement production, processing, transportation in conjunction with the abandoned railway track in the area greatly contribute to the high degree of contamination observed in the area. Metal transfers from soil to plant are a common phenomenon. The metals pose low to considerable ecological risk.Conclusions.Anthropogenic sources, especially cement processing activities, release heavy metals which leads to progressive pollution of the environment and poses high ecological risk.Competing Interests.The authors declare no competing financial interests

Highlights

IntroductionEmission of toxic metals from industries is a source of environmental degradation, and can affect human heath.[1,2,3,4,5,6,7,8,9,10] Cement production emits dust particles of various sizes, volatile substances and dangerous metals, harming the environment.[11,12] Cement dust reduces crop yield (through stomata clogging), gaseous exchange, rate of transpiration and inhibits intercellular processes, and affects surrounding ecosystems.[13,14,15,16,17] The main materials used in the production of cement are limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore.[18]
The highest concentration of Pb was found around sample 23, while the least values were found in sample 1 (Figure 4)
The present study was carried out to assess the extent of heavy metals contamination and their potential ecological risk in soils and plants of Ewekoro, southwest Nigeria

Summary

Introduction

Emission of toxic metals from industries is a source of environmental degradation, and can affect human heath.[1,2,3,4,5,6,7,8,9,10] Cement production emits dust particles of various sizes, volatile substances and dangerous metals, harming the environment.[11,12] Cement dust reduces crop yield (through stomata clogging), gaseous exchange, rate of transpiration and inhibits intercellular processes, and affects surrounding ecosystems.[13,14,15,16,17] The main materials used in the production of cement are limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore.[18]. Exposure to heavy metals emanating from cement production and other anthropogenic activities can pose ecological risks. A detailed investigation was carried out to assess the contamination and ecological risk of heavy metals associated with dust released during cement production. Sixty samples, including 30 soils and 30 plants, were collected around Lafarge Cement Production Company. Control samples of soil and plants were collected in areas where human activities are limited. Levels of heavy metals reported in this study were higher than those from similar cement production areas. Soils around the Ewekoro cement production area were low to extremely contaminated by toxic metals. Anthropogenic sources, especially cement processing activities, release heavy metals which leads to progressive pollution of the environment and poses high ecological risk. Cement production, contaminated, ecological, heavy metals mobilized, soil.

Methods

Results

Discussion

Conclusion