Environmental impacts of landfills: perspectives on bio-monitoring

Environmental regulations on landfills contain detailed instructions for monitoring the impacts of pollution from leachate on water, air and soil. However, references to the impact of landfills on the landscape and the need to monitor the surrounding vegetation are described only in general terms. Studies have indicated that near-surface pollution events, which are not necessarily captured by existing regulatory monitoring schemes, have affected the vegetation in the vicinity of landfills. Indications for the effects of pollution emanating from landfills include the retreat of sensitive and native plant species, the abundance of halophytes or nitrophilous plants and the prevalence of other invasive plant species, which can spread to adjacent ecosystems. To the best of the authors' knowledge, a comprehensive synthesis of landfill plant-based biomonitoring results has not yet been reported. The advantage of biomonitoring lies in its ability to assess the quality of the environment as perceived by living organisms. This would facilitate the determination of the response of plants to departures from natural conditions, detection of trends occurring in ecosystems and adoption of management practices to prevent or mitigate degradation of the environment. Thus, to detect such effects on the flora surrounding a landfill, this paper recommends that biomonitoring be utilised in environmental regulations to complement existing monitoring techniques.