Abstract

This study is set out to build a conceptual framework model (CFM) for risk assessment of contaminated lands and dumping sites that is comprehensive, convenient to use, and easily accessible. Mahmood Booti Open Dumping Site (MBODS), the oldest (1996-2016) allowed dumping site in Lahore, was chosen as the research area for the practical demonstration and application of the created conceptual framework model. Site inspections, approved departments, and field surveys were used to gather baseline data. Leachate (n=20), soil samples (n=20), and groundwater (n=14) were gathered for concentration evaluation and risk estimation, and their physio-chemical characteristics and heavy metal contents were examined.

The landfill gas emissions calculation tool of choice was LANDGEM. EASEWASTE was used on MBODS in order to assess the site's chosen environmental effects. A MBODS scenario has been built based on the current inquiry into the dumping site, and relevant data regarding trash composition and generation have been gathered and included to evaluate the environmental implications. The thorough risk assessment of the Mahmood Booti Dumping Site reveals that improper waste management techniques were used while disposing of waste, leaving the site highly polluted. Despite being closed in 2016, the facility lacked a leachate, gas, or liner collecting system. The data and information from the baseline study parameters proved to be quite beneficial in the subsequent phases of risk assessment.

The concentration assessment determines that the soil and groundwater have been significantly contaminated by leachate from the disposal site. The soil fertility was changed by the disposal of garbage, according to physico-chemical study. The study region also included the presence of pollutants and heavy metals at the receptor (soil and water), route (leachate), and source (the actual dumping site). In contrast, the research area's e-values for manganese (27), chromium (1.34), copper (1.75), and zinc (30.4) indicated a low ecological danger. The e-values for nickel (936.25), lead (3506), and cadmium (4744.9) indicated a significant potential risk to ecological entities. In a similar vein, the site's prospective ecological risk index results demonstrated a significant risk to the local population and ecological components. The research region was determined to be heavily contaminated by anthropogenic sources.

The analyzed heavy metals' reported quantities were compared to the WHO's permissible limits. It was discovered that there is no carcinogenic danger to human health from Cd and Pb. An evaluation of the carcinogenic risk of lead from drinking water revealed that it exceeded USEPA standard values. Even though the MBODS has reached the post-closure stage, the surrounding populace is still at risk from this latent source of harmful chemicals. The Mahmood Booti Open Dumping Site's landfill gas emissions have been calculated using the LANDGEM model. The first year after the garbage was accepted by the dumping area, 1997, saw the generation of 1.150E+03 (Mg/year) of methane from solid waste; nevertheless, the largest methane production rate was observed between 1996 and 2016, indicating the peak of generation by roughly 4.17E+03 (Mg/year). The potential effects of ozone depletion (OD) (4.44E+06), spoiled groundwater resources (SGR) (5.14E+12), human toxicity via soil (HTs) (9.14E+09), human toxicity via water (HTw) (7.03E+10), and ecotoxicity in water chronic (ETwc) (6.25E+11) were evaluated by the EASEWASTE model. Global warming, human toxicity through soil and water, ecotoxicity, and contaminated groundwater resources were deemed to have the greatest potential for impact.