The production and disposal of leachate from municipal landfill sites is an important environmental problem. Water passing through a landfill carries with it a variety of dissolved and suspended materials mobilised from the decomposing waste. This effluent, if released raw into the environment, poses a severe threat to aquifer potability, surface water habitats, and terrestrial ecosystems subjected to run-off and / or flooding. As a result of its potential impact, landfill leachate remediation strategies are an important aspect of landfill management. A number of techniques have been developed to reduce its pollutant loading, including land treatment of landfill leachate. This practice involves irrigating leachate over grassland / woodland, and relying on the remediatory potential of the soil-plant system to dilute and disperse the effluents polluting impact. In this study, the aims were to critically assess the environmental effects of sustained and periodic landfill leachate application to land, and to develop guidelines to reduce the risk of application rates exceeding ecotoxicological thresholds. Results from experiments found that leachate was phytotoxic at elevated irrigation rates, and that management guidelines on appropriate leachate quality and soil-type were paramount to a successful irrigation scheme. The quality of leachate composition was found to fluctuate considerably, spatially and temporally around the landfill site, which could have serious ramifications on an irrigation scheme. Vegetation grown in soil was significantly more tolerant of landfill leachate irrigation than hydroponically cultured plants, and certain soil properties were found to enhance amelioration, in particular a clay-loam texture and high organic matter content. Prolonged land-spreading of leachate may not be a sustainable waste management option however due to environmental modifications occurring over time. Periodic landfill leachate disposal could provide a viable option in an emergency situation, or for occasional nutrient reuse. This would benefit the landowner by improving crop yield and forage palatability to ruminants. Nevertheless, a cautious approach must be adopted when considering this form of waste disposal, especially with regards to applying for a waste management licence, and in light of impending changes to the Special Waste Regulations in January 2002.