Environmental Impact of Scrap Metal Industries: Examination of Vertical Seepage of Scrap Metal Effluents (Heavy Metals) into the Aquifer

Abstract

Research was carried out to determine the extent of damage caused by
the release of heavy metals from scrap metal dump sites into the aquifer
in Benin City, Nigeria. The nine scrap metal dump sites investigated
were located at; i) Osasogie Street by Total Filling Station, Off Benin
Sapele Road, ii) Omoragbon Agho, Off Benin Sapele Road, Etete, iii)
Evbuotubu Junction by Ekehuan Road iv) Asoro Hill by Upper Ekehuan
Road v) Christopher Osewengie Street, Ekae Quarters, off Sapele Road,
vi) Akugbe Street, off Saint Saviour Road, vii) Upper Iwehen, off Lagos
Street, Oba Market, viii) Evbienwen Street, off Wire Road and ix)
Iduowina Road, Iduowina Quarters, off Benin Auchi Road. The control
site was located at Uniben Reserved Area, University of Benin, Benin
City. Water samples were obtained from hand dug wells, private
boreholes and rivers closest to scrap metal dump sites. The distance
between the sites and water sources were measured using a global
positioning satellite (GPS) device. The Atomic Adsorption
Spectrophotometer (AAS) was used to analyze the six heavy metal
concentrations of copper (Cu), chromium (Cr), cadmium (Cd), zinc (Zn),
lead (Pb) and iron (Fe) in the soil and water. The soil samples were
obtained from three (3) depths (0 - 10, 10 - 20 and 20 - 30 cm)
respectively, from the nine scrap metal dump sites investigated, using a
strategic quadrat random sampling method. Results showed that all the
heavy metals investigated except Zn, exceeded the WHO / FEPA limits
for drinking water in at least five (5) locations from all the water sources.
Presence of the heavy metals at varying concentrations in all the three
soil depths was reported in the soil samples. The concentrations of heavy
metals in soil samples taken from the scrap metal dump sites exceeded
the corresponding soil sample from the control sites at the three depths
under investigation. Soil Chromium (Cr) levels exceeded the Ecotoxicity
limit (1 mg/kg) in all the three depths at the nine sites. This confirms that
the seepage of heavy metals from the scrap metal dump sites lead to soil
pollution and consequently the degradation of the soil quality, creating a
hazardous environment for man, plants and animals in the Ecosystem.
This study thus confirms that the scrap metal industries has a long term
negative impact on the environment by the releasing of heavy metals into
the environment, and also shows that the sustainability of the
environment in the face of this trade is an issue that should be addressed.