Baseline Analysis of Ground Water Quality Around Open Dumpsites in Lagos, Nigeria: Focus on Polynucelar Aromatic Hydrocarbons ( PAHs) Baseline Analysis of Ground Water Quality Around Open Dumpsites in Lagos, Nigeria: Focus on Polynucelar Aromatic Hydrocarbons.By Mayowa Dayo
Introduction to Study Area • Lagos State (aka. Las Gidi, Eko) ~ 60% of Nigeria’s industrial and commercial centers (1). Situated on the Southwestern coast of Nigeria • It has the largest population of people (15-17million) and the smallest geographic area (1) • In 1996 Lagos State Environmental Protection Agency (LASEPA) was established. • Major dumpsites are located in neighborhoods of people with lower income.
Background Dumpsites Polynucelar Aromatic Hydrocarbons PAHs PAHs are a type of organic compounds that are produced when complex organic substances are exposed to incomplete combustion or high-pressure processes. PAHs occur naturallybut mostly produced through anthropogenic sources such as burning of refuse, tires, petroleum, coal, motor exhaust and smoking. Modes of exposure include ingestion, dermal contact & inhalation. The main pathway of carcinogenesis is through PAH metabolite interaction with DNA. Why PAHs: known carcinogens & chronic PAH toxicity may lead to increased risk for cancer such as skin, lung, bladder, liver & stomach cancer • Open dumps are the simplest and cheapest method of disposing of waste • Primarymeans of waste management especially in developing countries (3). • Water infiltrates and permeates through dumpsites producing leachate, which may contain undesirable and toxic chemicals. • Motivation: The need to categorize the long-term effects of environmental pollution on the health outcome of exposed people in nearby communities.
Aims and Hypothesis • Aims: • To determine spatial distances between major dumpsites and usable water catchments and to graphically depict populations at risk to PAH exposure due to geographic proximity to dumpsites in Lagos • To determine the baseline level of PAHs in groundwater aquifers around 2 dumpsites in Lagos, Nigeria • To determine the increased risk of cancer in people that consume polluted water. • To create a policy brief aimed at LASEPA and other responsible bodies in Lagos, Nigeria. • Hypothesis: • Ground water around open dumpsites in Lagos is contaminated with PAHs
Methods • Sampled wells & boreholes in houses around Olushosun and Solous dumpsites • 6 samples from Olushosun & 8 from Solous collected over two day period (July 9th and July 10th). And 2 control samples • GPS used to collect coordinates of each dumpsite and sampling site. • Data on temperature, pH, distance of well/borehole to dumpsite, water depth and well depth were collected on site. • Chemical analysis performed at LASEPA using GC/FID method for PAHs. • Samples were analyzed for the presence of 18 PAHs commonly found in drinking water.
Research in Progress • Continued statistical analysis • T-test to compare means of PAHs found in each site • 1-sample t-test with maximum contamination level of PAHs in drinking water (as proposed by EPA , 0.2 ppb) as predefined value. • Risk assessment modeling • Hazard - Can the Identified agents present a carcinogenic hazard to humans and under what circumstances? • Dose - At what level of exposure might effects occur? • Exposure – what are the conditions of human exposure • Risk – character of the risk? How well do data support conclusions? • Uncertainties
Questions? Translation: “May Lagos remain strong”