Environmental risk assessment of cement dust on soils and vegetables in an urban city of South Western Nigeria

Abstract

The negative consequence of industries in urban cities has become a major concern. Environmental risk assessment of heavy metals in the cement factories around Ewekoro environ was evaluated to deduce its risk on public health.Soil samples and consumable vegetables (Sugar-cane (Saccharumofficinarum), Soko (Celosia argentea), Cocoyam (Colocasiaesculerita) and Ewedu (Corchoruos olitorius) were collected 200m apart around the cement factory. Soil samples were dis-aggregated and sieved through a 65µ mesh sieve, then analyzed using inductively coupled plasma-emission spectrometry (ICP-ES), while plant samples were crushed and pulverized before being analysed using inductively coupled plasma-mass spectrometry (ICP-MS), all analyses were done at Acme laboratories Canada. Geochemical result of soils showed that most of the metals have values above the USEPA standard except Ni, V, Cr, and Ba, due to the effect of cement factory. Contamination factor and degree (C deg ) revealed extreme contamination of Zn and Mn. Inter elemental analysis showed a strong correlation between Cr-As ('r' = 0.872) and Ga-v ('r' = 0.936), which reflects the same anthropogenic source. Geochemical results in vegetables revealed Zn to be the highest metal accumulated, and that which is most contaminated is Ewedu (Corchoruos olitorius). A strong and positive correlation was found in Ba-Sr, and Cd-Zn with r > 0.9 showing the same anthropogenic source.Transfer factor(TF) revealed accumulation of metals by the vegetables. Analysis of the health implications of these heavy metals was carried out in some clinics around the area and the common diseases recorded are the ones generally associated with cement dust inhaling. Soils and vegetables Risk Analysis IX 133 of areas around the cement factory are contaminated with metals especially Zn and Mn, with a severe effect on the public health.

Assessment of Health Risk Associated with Heavy Metal Contamination of Edible Vegetables in Cement Contaminated Area

“…In this study, the Mn, Fe, Zn, Cu, Se, Pb, and Cd content of vegetables in all the locations studied were below the recommended safe limits for vegetables. Contrary to our findings Zn, Cu and Pb content of the vegetables around Ewekoro cement factories were reported to be above permissible levels for both the soils and the plants samples [20]. However, the Cr and As levels of some vegetables at location closest to the factory (camp) was observed to be higher than the recommended safe limit ( [17]).…”

“…This indicates that the metal content of these vegetables is safe with no risk to human health. Bio-accumulation of Mn has also been described in some plants grown around cement factories [20]. The reason for slightly higher HQ for Mn in Telfaria Occidentalis (1.11 compared to <1.0) is not known but may be related to the higher daily intake since this vegetable is the most consumed on daily basis in the population studied.…”