IDENTIFYING SUSTAINABLE OPTIONS FOR THE MITIGATION OF DIFFUSE AGRICULTURAL POLLUTION
There was no evidence of major diffuse agricultural pollution problems in the two study catchments. Water quality was generally within the appropriate national and international standards, with the exception of bacteriological quality and salinity, neither of which is specifically related to agrochemical pollution. Nitrate levels were slightly elevated in some instances, with some concern regarding possible eutrophication in coastal lagoons and, in particular, its impact on fisheries. Pesticides were detected, however, in some water, fish and sediment samples at certain locations at extremely low concentrations, but with probable undetected short-term peaks. The potential ecological and human risks are serious, making it important to improve routine monitoring of water quality in agricultural catchments and expand it to include rapid biological assessment, as well as to reduce sources of risk.
Environmental considerations were found to be less important than productivity factors in current agricultural policy and legislation. Fertiliser use is still increasing in both countries, leading to a growing pressure on the environment, and pesticide use is not systematically recorded and thus difficult to evaluate. The limited evidence suggests a steady decline in agrochemical use, though, with a gradual shift to less toxic compounds, offset in some instances by changes in cropping patterns to more agrochemical-intensive crops. Both countries have effective systems for registering permissible pesticides and have banned many persistent organochlorine pesticides and others believed to be particularly harmful (although these are still detected in the environment). Integrated pest management programmes operate and organic agriculture is growing in popularity.
Livelihoods were not yet affected by diffuse pollution in the case study sites and agrochemicals were not a limiting factor for reuse. Irrigation canals (and streams) provide the main source of water for multiple human uses, particularly resulting in highly significant bacteriological contamination which was perhaps the overriding concern in terms of human health.
Recommendations were made on technical training, best management practices, legislation and monitoring and compliance. For example, many improvements in agricultural practices were considered to also reduce pollution risk (better timing of fertiliser applications, improved techniques for using pesticides, reducing excess water release to drains) and misuse of pesticides could be addressed through measures including the pesticide registration process, promotion of alternative pest control methods, and better and more rapid access to information on new agrochemical products.