We present the first evidence of accumulation of organochlorine compounds (DDTs, PCBs, HCB) and polycyclic aromatic hydrocarbons (PAHs) in Indo-Pacific humpback and Australian snubfin dolphins from the central and southern Great Barrier Reef. These dolphins are considered by the Great Barrier Marine Park Authority to be high priority species for management. Analyses of biopsy samples, collected from free ranging individuals, showed PAHs levels comparable to those reported from highly industrialized countries. DDTs and HCB were found at low levels, while in some individuals, PCBs were above thresholds over which immunosuppression and reproductive anomalies occur. These results highlight the need for ongoing monitoring of these and other contaminants, and their potential adverse effects on dolphins and other marine fauna. This is particularly important given the current strategic assessment of the Great Barrier Reef World Heritage Area being undertaken by the Australian Government and the Queensland Government.

Acid mine drainage (AMD) is one of the major environmental problems impacting aquatic ecosystems globally. We studied changes in the community composition of macroinvertebrates and amino acid (AA) profiles of dominant taxa along an AMD contamination gradient within the Dee River, Queensland, Australia to understand how AMD can affect the biomolecular composition of macroinvertebrates. Taxa richness and community composition of macroinvertebrates changed widely along the AMD gradient with significantly lower taxa richness recorded at the polluted sites compared to upstream and downstream sites. The Dipteran families: Chironomidae and Ceratopogonidae, the Odonata family Gomphidae, and the Coleoptera family Dytiscidae were the only families found at all sampling sites and were used here for AA analysis. There were significant variations in the AA profiles among the studied taxa. The AA profile of each taxon also varied among upstream, polluted and downstream sites suggesting that contamination of a river system with acid mine drainage not only alters the overall macroinvertebrate community composition but also significantly influences the AA profile of organisms that are tolerant to AMD. This study highlights the potential of using AA profiling to study the response of aquatic organisms to contamination gradients such as those associated with AMD.

This paper details the distribution of Cu, Pb and Zn in aquatic systems draining Mount Isa Ag-Cu-Pb-Zn Mine in arid northern Queensland, Australia. Sediment-metal concentrations in the <2 mm grain-size fraction adjacent to and downstream of the mine significantly exceed background concentrations (Cu, 159; Pb, 36; Zn, 86 ppm) as well as Australian government sediment quality low trigger guidelines (Cu, 65; Pb, 50; Zn, 200 ppm). Overbank sediments are more contaminated than channel sediments with mean values of Cu, 480; Pb, 540; Zn, 750 ppm. Mean concentrations in cut riverbank samples from the <2 mm fraction were Cu, 195; Pb, 724; Zn, 807 ppm. Corresponding <180 μm samples returned concentrations of Cu, 321; Pb, 995; Zn, 1110 ppm. Delivery of contaminants during wet seasons from Mount Isa Mine and historically contaminated riverbanks remains an ongoing issue. The ease of dust entrainment in arid zones means that sediments enriched in toxic concentrations of metals may be widely dispersed and ultimately ingested and absorbed by biota.

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.

Polyhalogenated 1,1′-dimethyl-2,2′-bipyrroles (PDBPs) are halogenated natural products (HNPs) previously shown to bioaccumulate in marine mammals and birds. Since their discovery in 1999, six hexahalogenated and a few lesser halogenated congeners have been identified in diverse marine mammal samples. Here we report the identification of 17 additional hexahalogenated PDBPs in the blubber extract of a humpback dolphin (Sousa chinensis) from Queensland, Australia. Thirteen of these new PDBPs were also detected in an Australian sea cucumber (Holothuria sp.). Additional samples were also tested positive on several new PDBPs, including an Australian venus tuskfish (Choerodon venustus) as well as a white whale (Delphinapterus leucas) and a sperm whale (Physeter macrocephalus) from the Northern Hemisphere. GC/ECNI-MS-SIM quantification of the molecular ions was carried out with the help of synthesized standards. The sum concentration of PDBPs was 1.1 mg/kg lipid in the humpback dolphin and 0.48 mg/kg lipid in the sea cucumber.

This study was conducted to determine the uptake of trace elements by the emergent wetland plant species Eleocharis equisetina at the historic Jumna tin processing plant, tropical Australia. The perennial emergent sedge was found growing in acid waters (pH 2.45) and metal-rich tailings (SnAsCuPbZn). E. equisetina displayed a pronounced acid tolerance and tendency to exclude environmentally significant elements (Al, As, Cd, Ce, Co, Cu, Fe, La, Ni, Pb, Se, Th, U, Y, Zn) from its above-substrate biomass. This study demonstrates that geobotanical and biogeochemical examinations of wetland plants at abandoned mined lands of tropical areas can reveal pioneering, metal-excluding macrophytes. Such aquatic macrophytes are of potential use in the remediation of acid mine waters and sulfidic tailings and the reclamation of disturbed acid sulfate soils in subtropical and tropical regions.

Microplastic abundance and characteristics were assessed in five decapod crustaceans purchased from seafood markets and collected in coastal waters around Australia (South Australia, New South Wales, Queensland, Northern Territory, and Western Australia). Three species of prawns (king, banana and tiger prawns) and two species of crabs (blue-swimmer and mud crabs) were analysed. Muscle tissues and gastro-intestinal tracts in prawns, and gastro-intestinal tracts in crabs, were chemically digested, with microplastic identification verified using Fourier Transform Infrared spectroscopy. Forty-eight percent of crustaceans contained microplastics. Prawns and crabs had 0.8 ± 0.1 and 1.6 ± 0.1 pieces per individual, respectively, with spatial patterns evident. Microplastics were predominantly fibres (98%) of blue (58%) and black (24%) colours with polyolefin including polyester the most prevalent polymers. Overall, compared to a systematic review we performed of microplastics in decapod crustaceans worldwide, microplastic loads in crustaceans from Australia were in the lower range of plastic contamination.

To protect and improve water quality in the Great Barrier Reef, the Queensland Government's Reef 2050 Water Quality Improvement Plan targets that 90% of sugarcane, horticulture, cropping and grazing lands in priority areas be managed using best management practices for sediment, nutrient and pesticides by 2025. Progress towards this target is insufficient and variable across catchments and industries. The motivation to adopt improvements in management practices is heavily influenced by social, economic, cultural and institutional dimensions. In this paper we synthesise the literature on how these human dimensions influence decision making for land management practice and highlight where future investment could be focussed. We highlight that focussing on —1) investigating systems to support landholder decision making under climate uncertainty (risk); 2) generating a better understanding of the extent and drivers of landholder transaction cost; 3) understanding if there are competing ‘right’ ways to farm; and 4) improving understanding of the social processes, trust and power dynamics within GBR industries and what these means for practice change— could improve practice change uptake in the future.

The detection rates of pharmaceuticals (Ps), personal care products (PCPs), current-use pesticides (CUPs) and a food additive (FA) in Brisbane River estuary (Queensland), Sydney estuary (New South Wales) and the Yarra River estuary (Melbourne, Victoria) were: Ps: 16/25, 7/25 and 12/25, respectively, CUPs; 28/53, 5/53 and 23/53, respectively, PCPs: 1/3, 0/3 and, 1/3, respectively and FA; 1/1, 1/1 and 1/1, respectively. Diuron was measured in all estuarine samples, simazine, MCPA and 2,4 D were also commonly measured. Pharmaceuticals: carbamazepine, iopromide paracetamol tramadol and venlafaxine were also commonly measured across the estuaries. Generally, analytes were prominent in Brisbane River estuary, followed by Yarra River/Sydney estuary. Inputs of Ps are likely from leakages or effluents of WWTPs; CUPs are potentially from agricultural and parklands via surface run-off in Brisbane River estuary, while for Sydney and Yarra estuaries, which have separate stormwater and sewer systems, sources are likely to be ingression and leakage.

Water quality monitoring is important to assess changes in inland and coastal water quality. The focus of this study was to improve understanding of the spatial component of spatial-temporal water quality dynamics, particularly the spatial variability in water quality and the association between this spatial variability and catchment characteristics. A dataset of nine water quality constituents collected from 32 monitoring sites over a 11-year period (2006–2016), across the Great Barrier Reef catchments (Queensland, Australia), were evaluated by multivariate techniques. Two clusters were identified, which were strongly associated with catchment characteristics. A two-step Principal Component Analysis/Factor Analysis revealed four groupings of constituents with similar spatial pattern and allowed the key catchment characteristics affecting water quality to be determined. These findings provide a more nuanced view of spatial variations in water quality compared with previous understanding and an improved basis for water quality management to protect nearshore marine ecosystem.