DETERMINATION OF THE LEACHING TENDENCIES OF VARIOUS ROOFING SHEETS MODELLED AS RAIN WATER HARVESTERS IN IMO STATE NIGERIA

Abstract

Runoff rain water from roofing materials is a predominant channel for obtaining drinking water for most inhabitants in Imo State Nigeria as such water is even kept in storage tanks for later usage.. Analysis of four different roofing materials used in the area- Zinc, Aluminum Metro tiles and Galvanized iron roofing sheets (Zinc) was carried out to determine their chemical content and leaching abilities. 5gms of each sheet was separately ground to powder and elemental analysis using a compact multi-element bench top Energy Dispersive X-ray Fluorescent (EDXRF) EDX3600B by Skyray Instrument (precision: 0.0% deviation; detection limit: 0.0001% (1ppm) - 99.99%) was carried out. The research showed the metro tile roofing sheet contains toxic metals like lead; Pb(0.0962 mg/kg), Al (2.1380 mg/kg), Cr (0.1988 mg/kg) and Mn(0.2163 mg/kg) unlike the rest which roughly contain Al (1.0407 mg/kg), Zn (0.9000 mg/kg), Mn(0.1057 mg/kg) and Fe (1.0008 mg/kg). Leaching capability of the four sheets was determined.Rainwater was harvested into clean plastic container previously washed and rinsed severally. Simple leaching experiment was carried out. The sheets were cut into sizes of (4 by 4)cm and the surface areas measured. Each was introduced into a separate beaker with 150ml rainwater (mentioned) for 24 hours. The sheets were then removed from the rainwater and their surface areas re-measured. The resultant waters and the unused rainwater- the control, were analysed using Agilent 240 AA Atomic Absorption Spectrophotometer. The result detected that the metro tile roofing sheet decreased by 0.01cm in its surface area and was observed to have leached out Al (0.028mg/kg) and Pb(0.0060mg/kg) into the water. This can be hazardous by accumulation if proven.More work on this is still in the pipeline.