Evaluation of Landfill Effects on Soil and Water Sources, A Case Study of the Whein Town Sanitary Land Fill, Montserrado County-Liberia.

Abstract

The study investigated the perceptions of the inhabitants of Whein Town on the effects of the activities of Whein Town Sanitary landfill in Monrovia, Liberia, and evaluated real time health hazards posed on the community. The Whein Town Engineered Landfill was developed with an integrated solid waste management motive. Even though the landfill lifespan expired at the end of 2016, active landfill activities are still ongoing. Liners may have deteriorated, thereby resulting in infiltration of leachates into ground and surface water sources, resulting in their contamination and consequent health attendants. Frequent flooding of adjoining agriculture lands by leachates from the landfill is perceived to have reduced the quality of the land for its intended purpose. Inhabitants of Whein town therefore have every justification to believe that the improperly sited landfill, which is currently over-aged and ill-managed, is responsible for most of their predicaments. The study was therefore conducted to verify the effects of the landfill on soils, water sources as well as health of inhabitants of Whein Township. Questionnaires were distributed to ascertain citizens’ perceptions on the effect of the landfill activities in the study area. Total Dissolved Solids (TDS), pH, Electrical Conductivity (EC) and 5-day Biochemical Oxygen Demand (BOD5) were analysed on samples of potable water sources from hand-dug well and stream water (surface water) as well as leachates from the landfill’s wastes stabilization ponds. Calorimetric method was used to analyse the levels of 6 heavy metals (Zn, Cu, Pb, Cd, Cr, Fe) in the samples while Atomic Absorption Spectrophotometer was used to determine the levels of the same heavy metals in soils samples.

The potential ecological risk assessment method by Hakanson. L, (1980) was used to determine the level of contaminations of the soils by the heavy metals. The BOD and TDS levels were higher than WHO permissible limits while the heavy metals studied had appreciable levels to constitute contamination. It was inferred that leachates discharges were responsible for the contamination of the water sources. The results of heavy metal pollution assessment indicated that the mean contamination factor (Cf) values recorded for all the elements had a range of 0.0219mg/kg – 19.9506mg/kg and follows the descending order of: Cd > Pb > Cu > Zn > Cr. The degree of contamination (CD) index was 20.12mg/kg which indicated that there was considerable contamination by the heavy metals. The potential ecological risk assessment indices of single elements was in the descending order of Cd > Pb > Cu > Cr > Zn. Cadmium was the key influence factor causing the risk with its mean value as high as 601.73mg/kg. The range of the comprehensive potential ecological risk (RI) was 555.147mg/kg – 651.063mg/kg and which indicated a very strong degree of ecological pollution and damage in the soil. It is therefore recommended that a critical assessment of the performance of the landfill be performed to possibly enable its urgent decommissioning since it has over-lived its useful life span. Also, safe drinking pipe borne water should be supplied to the community to discourage inhabitants from harvesting from their present sources of drinking water and further, blood analysis should be conducted to evaluate heavy metals body burdens of the inhabitants of the study area and its environs. This will help to diagnose and prepare for the on-set of any heavy metal-associated disease.