Analysis of pesticide mixtures discharged to the lagoon of the Great Barrier Reef, Australia

Organisms and ecosystems are generally exposed to mixtures of chemicals rather than to individual chemicals, but there have been relatively few detailed analyses of the mixtures of pesticides that occur in surface waters. This study examined over 2600 water samples, analysed for between 21 and 47 pesticides, from 15 waterways that discharge to the lagoon of the Great Barrier Reef in Queensland, Australia between July 1, 2011 and June 30, 2015. Essentially all the samples (99.8%) contained detectable concentrations (>limit of detection) of pesticides and pesticide mixtures. Approximately, 10% of the samples contained no quantifiable (>limit of reporting) pesticides, 10% contained one quantifiable pesticide and 80% contained quantifiable mixtures of 2–20 pesticides. Approximately 82% of samples that contained quantifiable mixtures had more than two modes of action (MoAs), but only approximately 6% had five or more MoAs. The mode, average and median number of quantifiable pesticides in all the samples were 2, 5.1 and 4, respectively. The most commonly detected compounds both individually and in mixtures were the pesticides atrazine, diuron, imidacloprid, hexazinone, 2,4-D, and the degradation product desethylatrazine. The number of pesticides and modes of action of pesticides in mixtures differed spatially and were affected by land use. Waterways draining catchments where sugar cane was a major land use had mixtures with the most pesticides. Waters entering the Great Barrier Reef were analysed for pesticides, 80% of samples contained 2 to 20 quantifiable pesticides with a mean of 5.1. Land use can predict the number of pesticides in mixtures.</p

Including management policy options in discrete choice experiments : a case study of the Great Barrier Reef

Rolfe, JC ORCiD: 0000-0001-7659-7040Information about the management policy used to achieve environmental protection outcomes is rarely included as variables in choice experiments. In cases where people have very different preferences for the types of input measures used, the utility of environmental protection options may be sensitive to the choice of inputs used to achieve the protection. The discrete choice experiment reported in this paper to value protection measures for the Great Barrier Reef in Australia is interesting in two important ways. First, different management policies to increase protection have been included as labels in the choice experiment to test if the mechanisms to achieve improvements are important to respondents. Second, the level of certainty associated with predicted reef health has been included as an attribute in the choice alternatives, helping to distinguish between outcomes of different management policies. The results show that protection values vary with the policy scope of the improvements being considered. Values are sensitive to whether protection will be generated by improving water quality entering the reef, increasing conservation zones or reducing greenhouse gas emissions, and the level of certainty of outcomes

Australia's Great Barrier Reef

Australia’s Great Barrier Reef (the GBR) is an iconic natural ecosystem, globally renowned for its majesty and grandeur. The GBR encompasses a vast array of unique and important marine and terrestrial habitats, from deepwater reefs to archetypal barrier reefs, as well as vast seagrass and algal meadows, intertidal mud flats, sand cays, and continental islands. The variety of environments and habitats encompassed within the GBR gives rise to extraordinary biodiversity. The GBR is also unusual compared with most reef systems around the world because the islands and adjacent coastal areas are sparsely populated. Moreover, Australia is a developed economy and does not generally rely heavily on subsistence or artisanal extraction of reef resources. That said, the GBR is being increasingly threatened by anthropogenic activities, such as land clearing and agricultural runoff, coastal development, pollution, and above all, increasing global carbon emissions that are rapidly changing environmental conditions. Sustained and ongoing global climate change has culminated in unprecedented and recurrent mass coral bleaching in recent years, which now represents the foremost threat to the integrity, functioning, and biodiversity of coral reef environments. Significant investment and effort is committed to conserving the GBR, both to maintain the ecological function and human benefits derived from the various natural systems, but the effectiveness and longer-term benefit of established and renewed management actions are conditional on immediate and effective action to reduce global carbon emissions