Hazardous waste disposal in New Zealand

The quantities of hazardous wastes generated in New Zealand are relatively small, both in total volume and on a per capita basis: they consist principally of liquids and solids derived from primary industries such as horticulture and forestry, and from the Petroleum, chemical and manufacturing industries. There is no satisfactory inventory of hazardous waste quantities or relative toxicity at the national level, nor is there any central coordinating organisation responsible for the implementation of sound management strategies. Current legislation involves several Government departments in statutory or advisory roles connected with hazardous waste management, but administration of disposal practices devolves to regional and local authorities. The occasional uncontrolled discharge of chemical wastes, unsatisfactory past practices regarding landfill siting and leachate management, and the development of major petrochemical industries, together require better coordinated and enforced policies concerning hazardous waste disposal. The most widely advocated method of hazardous waste disposal for New Zealand is codisposal in appropriately sited and controlled landfills, with particular emphasis on protection of freshwater resources, both surface and subsurface. The secure landfill solution adopted for the Waireka chemical dump site near New Plymouth demonstrates that containment is a necessary management strategy in particular situations: alternative methods of disposal such as incineration of certain intractable wastes should also be promoted as technically feasible and environmentally acceptable. Greater use of replacement, recycling or reprocessing must be encouraged in order to minimise the quantities, and toxicity of hasardous wastes requiring disposal in New Zealand.