Contaminants and the soil environment in New Zealand

In the last decade or so there has been escalating concern worldwide regarding the quality of the environment as affected by human activity. For agriculture, this has meant that many of the modern cultural practices have come under ever-increasing scrutiny by the public at large. Issues of importance to the consumer include the nutrient value of foodstuffs as well as any contamination by toxic substances, principally those arising from the farm production system itself. There is widespread distrust, much of it ill-informed, regarding the use of modern agrichemicals such as pesticides, fertilisers and animal health remedies and the effect of their use on food quality. However, any soil contamination (because soil is fundamental to most land-based plant or animal production systems) is extremely serious because the contaminant or its breakdown products may accumulate in food products ultimately for human consumption. In New Zealand (NZ), there is currently much activity in determining the causes and effects of heavy metal additions and pesticide residues on the quality of the agricultural environment. Additionally, there is increasing pressure from the public, both domestic and international, concerning the impact of agriculture on the wider environment. For example, off-farm water quality may be adversely affected and the important soil-mediated and other processes which might be involved are the subject of several major studies in NZ.