Sources, presence and potential effects of contaminants of emerging concern in the marine environments of the Great Barrier Reef and Torres Strait, Australia

A systematic approach of method development for analysis of multiple classes of emerging contaminants in wastewater: a case study of a biological nutrient removal based plant

Pharmaceuticals, personal care products, synthetic hormones, and industrial manufacturing additives are used worldwide, and their residues are frequently detected in wastewater. In this study, a sensitive and selective method was developed and validated for the detection and quantification of 14 Emerging Contaminants (ECs) with various physico-chemical properties frequently found in wastewater. Solid Phase Extraction (SPE) allowed for extraction and concentration of the compounds. Liquid chromatography-mass spectrometry in both positive and negative electrospray ionization mode was used for the analysis. Three different combinations of mobile phase, water + 0.1% formic acid : acetonitrile + 0.1% formic acid (3 compounds), water + 0.1% formic acid : methanol (5) and 10 mM ammonium acetate buffer : acetonitrile + 0.1% formic acid (6) gave the best chromatographic conditions to analyze the contaminants in real wastewater samples. Four different eluents at acidic and basic sample pH values were tested to optimize the SPE methodology, and three different dilution ratios (1 : 1, 2 : 1, and 5 : 1) were tested to reduce the matrix effect. Data validation was conducted using linearity, intra and inter-day repeatability, LOD/LOQ, percentage recovery, and percentage process efficiency studies. As a case study, a biological nutrient removal (BNR) based plant was tested for the presence of ECs using the developed method. Removal efficiency at different treatment stages was assessed. Most of the treatment occurred at the secondary treatment stage, whereas primary treatment and disinfection had little effect on removal. All the contaminants were found in the inlet wastewater. Estrone (E1), an endocrine disrupting compound, was reported for the first time in Indian wastewater at 376.2 ng L-1. Seven, four, and two ECs were removed at high, medium, and low efficiencies, respectively. Carbamazepine showed negative removal. This study enhanced our understanding of the occurrence and fate of several ECs in BNR based treatment systems.

Marine litter arrived: Distribution and potential sources on an unpopulated atoll in the Seaflower Biosphere Reserve, Caribbean Sea

The Albuquerque atoll was studied as a representative natural laboratory to explore the role of sea-based sources of marine litter. This work aimed to identify the small-scale spatial distribution of marine litter (i.e., plastic, glass, paper, and others) as well as to explore the connectivity among the atoll habitats (sand beach, water surface, and reef) to give insights of potential sources of marine litter (>5 cm), mainly plastics. Marine litter was dominated by plastic items, as expected, with an average value of 0.5 items/m². Large microplastics (1-5 mm) were also sampled on beaches with an average value of 90 particles/m². In the atoll inner lagoon, marine litter was also composed by plastic, mainly fragments (average 0.059 items/m³). The predominance of plastic fragments on both the sea surface and beaches of the atoll makes inferences on sources limited. However, o fishing activities and sea-based sources might be relevant since local sources are very limited.

Atmospheric Trace Metal Deposition near the Great Barrier Reef, Australia

Aerosols deposited into the Great Barrier Reef (GBR) contain iron (Fe) and other trace metals, which may act as micronutrients or as toxins to this sensitive marine ecosystem. In this paper, we quantified the atmospheric deposition of Fe and investigated aerosol sources in Mission Beach (Queensland) next to the GBR. Leaching experiments were applied to distinguish pools of Fe with regard to its solubility. The labile Fe concentration in aerosols was 2.3–10.6 ng m−3, which is equivalent to 4.9%–11.4% of total Fe and was linked to combustion and biomass burning processes, while total Fe was dominated by crustal sources. A one-day precipitation event provided more soluble iron than the average dry deposition flux, 0.165 and 0.143 μmol m−2 day−1, respectively. Scanning Electron Microscopy indicated that alumina-silicates were the main carriers of total Fe and samples affected by combustion emissions were accompanied by regular round-shaped carbonaceous particulates. Collected aerosols contained significant amounts of Cd, Co, Cu, Mo, Mn, Pb, V, and Zn, which were mostly (47.5%–96.7%) in the labile form. In this study, we provide the first field data on the atmospheric delivery of Fe and other trace metals to the GBR and propose that this is an important delivery mechanism to this region.

The Effects of Crude Oil and Dispersant on the Larval Sponge Holobiont

Larvae of the sponge R. odorabile survived exposure to high concentrations of petroleum hydrocarbons; however, their ability to settle and metamorphose was adversely affected at environmentally relevant concentrations, and these effects were paralleled by marked changes in sponge gene expression and preceded by disruption of the symbiotic microbiome. Given the ecological importance of sponges, uncontrolled hydrocarbon releases from shipping accidents or production could affect sponge recruitment, which would have concomitant consequences for reef ecosystem function.

Accidental oil spills from shipping and during extraction can threaten marine biota, particularly coral reef species which are already under pressure from anthropogenic disturbances. Marine sponges are an important structural and functional component of coral reef ecosystems; however, despite their ecological importance, little is known about how sponges and their microbial symbionts respond to petroleum products. Here, we use a systems biology-based approach to assess the effects of water-accommodated fractions (WAF) of crude oil, chemically enhanced water-accommodated fractions of crude oil (CWAF), and dispersant (Corexit EC9500A) on the survival, metamorphosis, gene expression, and microbial symbiosis of the abundant reef sponge Rhopaloeides odorabile in larval laboratory-based assays. Larval survival was unaffected by the 100% WAF treatment (107 μg liter⁻¹ polycyclic aromatic hydrocarbon [PAH]), whereas significant decreases in metamorphosis were observed at 13% WAF (13.9 μg liter⁻¹ PAH). The CWAF and dispersant treatments were more toxic, with decreases in metamorphosis identified at 0.8% (0.58 μg liter⁻¹ PAH) and 1.6% (38 mg liter⁻¹ Corexit EC9500A), respectively. In addition to the negative impact on larval settlement, significant changes in host gene expression and disruptions to the microbiome were evident, with microbial shifts detected at the lowest treatment level (1.6% WAF; 1.7 μg liter⁻¹ PAH), including a significant reduction in the relative abundance of a previously described thaumarchaeal symbiont. The responsiveness of the R. odorabile microbial community to the lowest level of hydrocarbon treatment highlights the utility of the sponge microbiome as a sensitive marker for exposure to crude oils and dispersants.

IMPORTANCE Larvae of the sponge R. odorabile survived exposure to high concentrations of petroleum hydrocarbons; however, their ability to settle and metamorphose was adversely affected at environmentally relevant concentrations, and these effects were paralleled by marked changes in sponge gene expression and preceded by disruption of the symbiotic microbiome. Given the ecological importance of sponges, uncontrolled hydrocarbon releases from shipping accidents or production could affect sponge recruitment, which would have concomitant consequences for reef ecosystem function.

Microplastic Contamination Has Limited Effects on Coral Fertilisation and Larvae

Microplastics are ubiquitous throughout the world’s oceans and contaminate coral reef ecosystems. There is evidence of microplastic ingestion by corals and passive contact with coral tissues, causing adverse health effects that include energy expenditure for particle removal from the tissue surface, as well as reduced growth, tissue bleaching, and necrosis. Here, it was examined whether microplastic contamination impairs the success of gamete fertilisation, embryo development and larval settlement of the reef-building coral Acropora tenuis. Coral gametes and larvae were exposed to fifteen microplastic treatments using two types of plastic: (1) weathered polypropylene particles and (2) spherical polyethylene microbeads. The treatments ranged from five to 50 polypropylene pieces L−1 and 25 to 200 microbeads L−1. Fertilisation was only negatively affected by the largest weathered microplastics (2 mm2), but the effects were not dose dependent. Embryo development and larval settlement were not significantly impacted by either microplastic type. The study shows that moderate–high levels of marine microplastic contamination, specifically particles <2 mm2, will not substantially interfere with the success of critical early life coral processes.