Northeast Australian experience in minimizing environment harm from waste recycling and potential pollutants of soil and water

Users of natural resources are increasingly required to identify and minimize environmental risks associated with their activities. Risks as perceived by the owner or operator (the industry), the general public, and the regulator need to reflect the actual risk, but in real life this goal is elusive. This article provides five examples on how environmental risks were assessed in the quest for sustainable sugarcane production systems in a region where around 80% of the industry's production occurs in river basins that drain to the Great Barrier Reef World Heritage Area of northeast Australia. Auditing and benchmarking, incorporating a range of chemical measurements, were features of these studies that covered heavy metals, organic waste recycling, acid sulfate soils (ASS), pesticides (particularly herbicides), and sugar juice lost during mechanical cane harvesting. It has been established that sugar juice can induce a significant 5-day biochemical oxygen demand (BOD5) if allowed to drain to adjacent waterways, stripping these of dissolved oxygen (DO). That is, it poses an occasional environmental risk. Evidence is also presented to suggest the actual environmental risk from pesticides may be lower than perceived. Environmental problems caused by strong acid drainage from ASS were addressed by participative research, ultimately delivering sugar industry self-regulation in New South Wales (NSW) of drain management on affected cane farms. Strategies now offered to make organic waste recycling more sustainable from a heavy metal loading perspective include recommendations to use lower application rates, to redistribute filter muds across all cane lands rather than only to those in close proximity to sugar mills, and to avoid repeated applications to the same paddocks.