The wreck of the MV <i>Rena</i>: spatio-temporal analysis of ship-derived contaminants in the sediments and fauna of Astrolabe Reef

<p>The October 2011 sinking of the container ship MV <i>Rena</i> on Astrolabe Reef, New Zealand, provided a rare opportunity to examine the fate of shipwreck-derived contaminants on an offshore rocky reef and food chain. Analyses of trace metals, polycyclic aromatic hydrocarbons (PAHs) and organotins indicated significant but localised contamination of Astrolabe Reef but not of nearby Mōtītī Island. Three years after the grounding, PAH concentrations were greater in sediments at Astrolabe (up to 131 mg kg⁻¹) than at control locations, while organotins from the ship's antifouling hull paint were found exclusively in Astrolabe Reef sediments and biota. Over 80% of Astrolabe sediment samples contained tributyltin at concentrations above guideline sediment levels (>0.07 mg kg⁻¹). Tributyltin and its decomposition products were also recorded in sea urchins, gastropods, lobster and fishes at concentrations up to 0.2 mg kg⁻¹. Wreck and cargo-derived metals, particularly copper, tin and zinc, were present in some Astrolabe sediment samples above Australia and New Zealand Environment and Conservation Council guideline concentrations. However, there appeared to be only limited transmission of metals through the food chain. Copper, tin and zinc were recorded at greater concentrations in Astrolabe sea urchins and gastropods compared to control specimens, while metal concentrations in other biota were comparable across impact and control sites. Despite over 3 years having passed since the <i>Rena</i> grounding, the data series does not show any upward or downward trends in contaminant concentrations on Astrolabe Reef. Consequently, there is uncertainty about the long-term implications of the <i>Rena</i> grounding for the ecology of Astrolabe Reef.</p

Measurement of shipwreck-derived waterborne trace metals using DGT samplers

<p>A contemporary approach to the assessment of metal pollutants in aquatic environments has been to measure contaminant concentrations in biological indicator species (mussels, oysters). However, for environments in which such indicator species do not occur naturally and cannot be deployed, alternative approaches for monitoring trace-metal pollution are required. Three years after the 2011 grounding of the MV <i>Rena</i>, diffusive gradients in thin films (DGT) samplers were deployed at Otaiti (the offshore reef where the <i>Rena</i> grounded) to assess levels of waterborne trace-metal contamination. Although the probability of detecting waterborne contaminants within a dynamic open ocean reef environment would seem low, due to mixing and dilution, our analyses confirmed the presence of copper (≤0.43 vs ≤0.27 nmol kg⁻¹), iron (≤6.3 vs ≤4.2 nmol kg⁻¹), aluminium (≤8.9 vs ≤1.3 nmol kg⁻¹), zinc (≤2.8 vs ≤2.0 nmol kg⁻¹) and manganese (≤0.11 vs ≤0.09 nmol kg⁻¹) at elevated concentrations in the <i>Rena</i> debris field relative to reference sites. The results demonstrate the utility of DGTs as a tool for measuring waterborne contaminants and suggest further research is required to characterise the contaminant plume and determine what effect it might have on the recovery of Otaiti's impacted biological communities.</p

Introduced macroalgae: a growing concern

Introductions of non-indigenous species to new ecosystems are one of the major threats to biodiversity, ecosystem functions and services. Globally, species introductions may lead to biotic homogenisation, in synergy with other anthropogenic disturbances such as climate change and coastal pollution. Successful marine introductions depend on (1) presence of a transport vector, uptake of propagules and journey survival of the species; (2) suitable environmental conditions in the receiving habitat; and (3) biological traits of the invader to facilitate establishment. Knowledge has improved of the distribution, biology and ecology of high profile seaweed invaders, e.g. Caulerpa taxifolia, Codium fragile ssp. tomentosoides, Sargassum muticum, and Undaria pinnatifida. Limited, regional information is available for less conspicuous species. The mechanisms of seaweed introductions are little understood as research on introduced seaweeds has been mostly reactive, following discoveries of introductions. Sources of introductions mostly cannot be determined with certainty apart from those directly associated with aquaculture activities and few studies have addressed the sometimes serious ecological and economic impacts of seaweed introductions. Future research needs to elucidate the invasion process, interactions between invaders, and impacts of introductions to support prevention and management of seaweed introductions

Role of active metabolites in the use of opioids

The opioid class of drugs, a large group, is mainly used for the treatment of acute and chronic persistent pain. All are eliminated from the body via metabolism involving principally CYP3A4 and the highly polymorphic CYP2D6, which markedly affects the drug's function, and by conjugation reactions mainly by UGT2B7. In many cases, the resultant metabolites have the same pharmacological activity as the parent opioid; however in many cases, plasma metabolite concentrations are too low to make a meaningful contribution to the overall clinical effects of the parent drug. These metabolites are invariably more water soluble and require renal clearance as an important overall elimination pathway. Such metabolites have the potential to accumulate in the elderly and in those with declining renal function with resultant accumulation to a much greater extent than the parent opioid. The best known example is the accumulation of morphine-6-glucuronide from morphine. Some opioids have active metabolites but at different target sites. These are norpethidine, a neurotoxic agent, and nordextropropoxyphene, a cardiotoxic agent. Clinicians need to be aware that many opioids have active metabolites that will become therapeutically important, for example in cases of altered pathology, drug interactions and genetic polymorphisms of drug-metabolizing enzymes. Thus, dose individualisation and the avoidance of adverse effects of opioids due to the accumulation of active metabolites or lack of formation of active metabolites are important considerations when opioids are used.Janet K. Coller, Lona L. Christrup, Andrew A. Somogy