| || || Rabo, Karalaini|
| || || An investigation into trace metal contamination in the closed Lami landfill |
Institution: University of the South Pacific.
Subject: Pollution -- Risk assessment -- Fiji -- Lami, Heavy metals -- Environmental aspects -- Fiji -- Lami
Call No.: pac TD 189 .5 .F5 R33 2014
Copyright:10-20% of this thesis may be copied without the authors written permission
Abstract: The Lami landfill received solid wastes from the greater Suva area from 1945 until its closure in late 2005. It was a dump site with no pollution control facility. The site is located near a residential area and surrounded by several types of water bodies (sea, swamp). This study was conducted to determine the sediment, leachate and pore water quality of the disposal site. Sediment, leachate and pore water samples were investigated for concentrations of six trace elements (cadmium, chromium, copper, iron, lead and zinc) using the Atomic Absorption Spectroscopy technique. Results show considerable pollution of metals in the closed dumpsite. Iron concentrations in sediments were high throughout the dumpsite, having a concentration range of 1.99 – 8.06% and having a median of 4.32%. This was followed by zinc with concentrations ranging from 67 – 3527 mg/kg and a median of 508 mg/kg. Cadmium recorded the lowest concentration throughout the dumpsite having concentrations ranging from 0.1 – 4.74 mg/kg and a median of 0.55 mg/kg. With the exception of cadmium, all metal concentrations in sediments exceeded the Effects Range-Medium (ERM) of the Sediment Quality Guidelines (SQG) of the National Oceanographic and Atmospheric Administration (NOAA) and are considered to be highly contaminated with potential adverse ecological effects on the local benthic communities. The high levels of metals found in sediments suggest there was little or no control on the acceptance of hazardous wastes and materials at the dumpsite whilst in operation for more than fifty years. These results agree with literature indicating the highly contaminated area around the Suva harbor and significant enrichment from the closed dumpsite as a major source of metal pollution in the area. The concentrations of the six metals in pore water exceeded the US EPA recommended levels for natural waters. Iron recorded the highest concentrations with values ranging from 0.99 – 3.21 mg/L and a median value of 2.18 mg/L. This was followed by zinc having a concentration range of 24 – 426 μg/L and a median of 143 μg/L. Cadmium and chromium recorded the lowest concentrations with some stations reading below the method detection limits. IV The elevated levels of metals in pore water are strongly attributed to the high metal content in sediments. Comparison of pore water values with literature could not be conducted due to lack of studies and data on soil pore water. Leachate samples collected at the closed Lami dump have metal concentrations less than the effluent standards set by the Fiji government and the US EPA. This could be due to the dilution factor provided by the high annual rainfall. Similar to sediments and pore water, iron recorded the highest concentrations followed by zinc and lead. Iron concentration in leachates ranged from 2.8 – 4.7 mg/L and having a median of 3.9 mg/L. Zinc values ranged from 111 – 438 μg/L with a median value of 316 μg/L. Chromium recorded the lowest concentrations with values ranging from 0.9 – 12.6 μg/L and a median value of 4.51 μg/L. The potential adverse environmental effects of a closed landfill/dumpsite are in many respects similar to those of operating landfills. This study shows the degradation of sediment as well as water quality caused by uncontrolled open dumping and unmanaged landfills.