Leachate seepage from landfill: a source of groundwater mercury contamination in South Africa

Abstract

Mercury has been used for many centuries in the production of consumer products such as thermometers, electrical switches, fluorescent light bulbs, batteries, biocides and pesticides, cosmetics and dental amalgam filling, among others. After use, these mercury-containing consumer products form part of the municipal solid waste (MSW). As a result of an unseparated solid waste collection system, mercury-containing wastes tend to end up in landfills where mercury and other pollutants can leach out of products into landfill leachates. The present study, therefore, was conducted with the aim of determining the total mercury (THg) concentrations in leachate and sediment samples collected from 4 selected landfill sites (3 sites in Gauteng Province – Soshanguve, Hatherly, Onderstepoort and 1 site in Limpopo Province – Thohoyandou). Groundwater samples were collected from the monitoring boreholes at the four selected landfill sites in the summer and winter periods. An acid digestion method was employed for sample preparation and this was followed by analysis using cold vapour atomic absorption spectrophotometry (CVAAS). The concentration range of total mercury in the Thohoyandou leachate, sediment and groundwater samples was 0.12–2.07 μg/L, 0.03–0.48 μg/g and 0.09–2.12 μg/L, respectively. In Soshanguve, the concentration range of total mercury in leachate, sediment and groundwater samples was 0.10–1.20 μg/L, 0.04–0.62 μg/g and nd –1.66 μg/L respectively, Hatherly concentration range was 0.42–1.31 μg/L and 0.06–0.78 μg/g in leachate and sediment, respectively and in Onderstepoort the concentration range was 0.12–2.41 μg/L, 0.03–0.50 μg/g and 0.05–2.44 μg/L, in leachate, sediment and groundwater, respectively. The findings from this study suggest that there is a likelihood of groundwater pollution by mercury from landfill leachate seepage, particularly for landfills that are not lined with a geomembrane.

Tetracycline Removal from Water by Adsorption on Geomaterial, Activated Carbon and Clay Adsorbents

“…The pH effect was investigated; 100 mg • dm -3 of tetracycline solutions were prepared in the pH range (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). After adjustment, the solutions were mixed with 0.3 g of adsorbent during 24 h at 298 K. The pH was adjusted by using 0.1 N of HCl or KOH according to the desired pH value.…”

“…Therefore, the composition of leachates is very difficult to determine. Despite the complexity of the effluent, it is 1 Scientific and Technical Research Center in Physico-Chemical Analysis, PO box 384, Headquarters ex-Pasna Industrial area Bou-Ismail, zip code 42004 Tipaza, Algeria, phone +213(0)24325774, fax +213(0)24325774, ORCID: 0000-0002-1432-7237 2 LPCEMAE Laboratory, Faculty of Chemistry, Houari Boumediene University of Science and Technology (USTHB), PO box 32 ELALIA, Bab Ezzouar Algiers, Algeria, email: bhamdi_99@yahoo.fr, ORCID: 0000-0002-5502-1605 3 Controlled Porosity Materials Team, Institute of Materials Sciences of Mulhouse UMRCNRS 7361, University of Strasbourg, University of Haute Alsace, ENSCMu, 3 rue Alfred Werner, 68093 Mulhouse Cedex, France, email: jocelyne.brendle@uha.fr, ORCID: 0000-0001-5266-6224 possible to identify these xenobiotic compounds [9][10][11][12][13][14][15][16]: phenols, chlorinated aliphatic compounds, aromatic hydrocarbons, tetracycline, pesticides, and plasticizers.…”

Hazardous Waste Management: An African Overview

“…This landfill lacks a leachate collection system, and thus frequent groundwater pollution is recorded [106]. This is similar to the Granville Brooke and Garankuwa landfills in Sierra Leone and South Africa, respectively [101,107].…”

An updated review of the salient geomedical aspects of mercury for enhancement of data quality in simulation modelling and other prognostic applications: Africa case descriptions

“…In the study by Panichev et al (2019), five provinces of South Africa were sampled between 2013 and 2017; and the lichens analysed to provide time-integrated data, which correspond to the mean Hg concentration in air at a specific location over a long time period. Nevondo et al (2019) suggested that Hg coming from contaminated groundwater from landfill leachate seepage could carry significant amounts of Hg, especially in landfills that are not lined with a geomembrane. Bieser et al (2020) investigated sources and sinks of Hg at Cape Point, South Africa by combining atmospheric Hg data with a trajectory model; and found that continent is the major sink, and the ocean, especially its warm regions (i.e., the Agulhas Current), is the major source for Hg.…”