Darren Koppel

• Doctor of Philosophy
• Research Scientist at Australian Institute of Marine Science

The paucity of ecotoxicological data for Antarctic organisms is impeding the development of region-specific water quality guidelines. To address this limitation, toxicity testing protocols need to be developed to account for the unique physiology of polar organisms, in particular their slow growth rates. In this study, a toxicity test protocol was...

There is a growing need to understand the potential ecological impacts of contaminants in offshore oil and gas infrastructure, especially if that infrastructure is to be left in situ as a decommissioning option. Naturally occurring radioactive material (NORM) is one type of contaminant found in solid deposits on internal surfaces of infrastructure...

Multiple linear regression (MLR) models were developed for predicting chronic zinc toxicity to a freshwater microalga, Chlorella sp., using three toxicity modifying factors (TMF): pH, hardness, and dissolved organic carbon (DOC). The interactive effects between pH and hardness, and pH and DOC were also included. Models were developed at three diffe...

Bioavailability models e.g., multiple linear regressions (MLRs) of water quality parameters, are increasingly being used to develop bioavailability-based water quality criteria for metals. However, models developed for the Northern Hemisphere cannot be adopted for Australia and New Zealand without first validating them against local species and loc...

A range of new statistical approaches is being developed and/or adopted in ecotoxicology, that when combined, have the potential to greatly improve the estimation of no-effect toxicity values from Concentration-Response (CR) experimental data. In particular, we compare the existing No-Effect-Concentration (NEC) threshold-based toxicity metric with...

Offshore oil and gas infrastructure must be decommissioned at the end of its operational life. The base case approach for decommissioning under Australia’s regulatory framework is the complete removal of all infrastructure. However, alternative decommissioning approaches, such as leaving some infrastructure in situ, may deliver better environmental...

Anthropogenic activities in Antarctica have led to contamination of terrestrial sites, and soils in ice-free areas have elevated concentrations of metals, particularly around current and historic research stations. Effective management of Antarctic contaminated sites depends on the assessment of risks to a representative range of native terrestrial...

This modelling study uses the ERICA Tool and Bateman's equation to derive sediment threshold values for radiation protection of the marine environment relevant to NORM-contaminated products (radium-contaminated scales, ²¹⁰Pb films and ²¹⁰Po films) found in subsea oil and gas infrastructure. Threshold values are calculated as the activity concentrat...

Subsea pipelines carrying well fluids from hydrocarbon fields accumulate mercury. If the pipelines (after cleaning and flushing) are abandoned in situ, their degradation may release residual mercury into the environment. To justify pipeline abandonment, decommissioning plans include environmental risk assessments to determine the potential risk of...

Zinc is a contaminant of concern in aquatic environments and is a known toxicant to many aquatic organisms. Dissolved organic matter (DOM) is a toxicity modifying factor for zinc and is an important water chemistry parameter. This study investigated the influence of DOM concentration, source, and water pH on the chronic toxicity of zinc to a freshw...

Environmental context The oil and gas industry has a significant liability in decommissioning offshore infrastructure. Following decommissioning, subsea pipelines could be left on the seabed to provide artificial reefs. Mercury is a contaminant of concern which could remain within pipelines. There are gaps in our knowledge on how mercury moves thro...

Environmental context Having appropriate and robust models used for developing water quality guidelines is critical for sound environmental management. Methods used to validate models have only been demonstrated appropriate for a small portion of data types used in these models. This study has found that models using certain data types would be mor...

Scale residues can accumulate on the interior surfaces of subsea petroleum pipes and may incorporate naturally occurring radioactive materials (NORM). The persistent nature of ‘NORM scale’ may result in a radiological dose to the organisms living on or near intact pipelines. Following a scenario of in-situ decommissioning of a subsea pipeline, mari...

Many oil and gas fields are nearing production cessation and will require decommissioning, with the preferred method being complete infrastructure removal in most jurisdictions. However, decommissioning in situ, leaving some disused components in place, is an option that may be agreed to by the regulators and reservoir titleholders in some circumst...

Zinc is an essential element for aquatic organisms, however, activities such as mining and refining, as well as zinc's ubiquitous role in modern society can contribute to elevated environmental concentrations of zinc. Water hardness is widely accepted as an important toxicity modifying factor for metals in aquatic systems, though other factors such...

Predicting the toxicity of effluent exposures, which vary in duration, composition, and concentration, poses a challenge for ecological risk assessments. Effluent discharges may frequently result in the exposure of aquatic organisms to high concentrations of mixed contaminants for short durations. In the receiving environment effluents will undergo...

Thousands of offshore oil and gas facilities are coming to the end of their life in jurisdictions worldwide and will require decommissioning. In-situ decommissioning, where the subsea components of that infrastructure are left in the marine environment following the end of its productive life, has been proposed as an option that delivers net benefi...

Mercury is naturally present in the environment but has also been associated with the offshore oil and gas infrastructure. Environmental parameters govern its speciation and will influence its risk to marine organisms and humans, as e.g., methylmercury is a very lipophilic species which will bioaccumulate through the food web. Moreover, methylmercu...

Toxicity risk assessments of short-term discharges of contaminated waters to the aquatic environment have shown that receptor organisms can tolerate higher pulse-exposure than continuous-exposure concentrations of some contaminants. However, these observations are influenced by the mode of toxicity of the contaminants present and the concentration-...

Effluent discharges can potentially result in high concentrations of metals entering aquatic environments for short durations, ranging from a few hours to days. The environmental risks of such exposures are challenging to accurately assess. Risk assessment tools for effluent discharges include comparison of toxicant concentrations with guideline va...

Salinity in the Antarctic nearshore marine environment is seasonally dynamic and climate change is driving greater variability through altered sea ice seasons, ocean evaporation rates, and increased terrestrial ice melt. The greatest salinity changes are likely to occur in the nearshore environment where elevated metal exposures from historical was...

Increased focus on the development and application of bioavailability‐based metal water quality guideline values requires increased understanding of the influence of water chemistry on metal bioavailability and toxicity. Development of empirical models, such as multiple linear regression models, requires the assessment of the influence of individua...

Antarctic melt streams are important ecosystems that increasingly face contaminant pressures from anthropogenic sources. Metal contaminants are often reported in the limno-terrestrial environment but their speciation is not well characterised, making environmental risk assessments difficult. This paper characterises labile metal concentrations in f...

There have been limited studies on the effects of toxicity modifying factors, such as dissolved organic matter (DOM), on the toxicity of metal mixtures to aquatic biota. This study investigated the effects of DOM concentration (low: 2.8 ± 0.1 mg C/L; high: 11 ± 1.0 mg C/L) and DOM source (predominantly terrestrial or microbial) on the chronic toxic...

Nickel is often a metal of interest in regulatory settings given its increasing prevalence in disturbed freshwaters and as a known toxicant to fish and algae. Dissolved organic matter (DOM) is a toxicity modifying factor for nickel and a ubiquitous water physicochemical parameter. This study investigated the effect of DOM concentration and source o...

Metal contaminants in Antarctic soils are typically found around research stations which are concentrated in ice-free coastal areas. The risk of these contaminants to the Antarctic environment is not well understood, given Antarctica’s unique organisms and climate. This study assessed the use of diffusive gradients in thin-films (DGT), a passive sa...

Australian tropical freshwaters can experience extreme seasonal variability in rainfall and run off, particularly due to pulse events such as storms and cyclones. This study investigated how seasonal variability in dissolved organic matter (DOM) quality impacted the chronic toxicity of copper to a tropical green alga (Chlorella sp.) in the presence...

Fertilizers containing phosphate (PO4 3−) are commonly used within the agricultural industry and are known to increase the bioavailability and mobility of metalloids like arsenic (As). This may increase plant uptake of As and hence pose a risk to human health. Arsenic and antimony (Sb) often co‐occur in contaminated soils, however, little is known...

Antimony (Sb) is an emerging contaminant and until recently it was assumed to behave in a similar way to arsenic (As). Arsenic and Sb often co-occur in contaminated sites, yet most investigations consider their toxicity to plants singly. More research is needed to understand the interactions between As and Sb in soils and plants. This study investi...

Robust environmental assessments and contaminant monitoring in Antarctic near-shore marine environments need new techniques to overcome challenges presented by a highly dynamic environment. This study outlines an approach for contaminant monitoring and risk assessment in Antarctic marine conditions using diffusive gradients in thin-films (DGT) coup...

Firefighting is an occupation with exposure to a wide range of chemicals by means of inhalation, ingestion or dermal contact. Although advancements in personal protective clothing and equipment have reduced the risks for acute exposure during fire suppression operations, chronic exposure may still be present at elevated levels in fire stations. The...

Localised sites in Antarctica are contaminated with mixtures of metals, yet the risk this contamination poses to the marine ecosystem is not well characterised. Recent research showed that two Antarctic marine microalgae have antagonistic responses to a mixture of five common metals (Koppel et al., 2018a). However, the metal accumulating potential...

Anthropogenic contamination in the Antarctic near‐shore marine environment is a challenge for environmental managers because of its isolation, high costs associated with monitoring and remediation activities, and the current lack of Antarctic‐specific ecotoxicological data. This study investigated the application of diffusive gradients in thin‐film...

Metal contaminants are rarely present in the environment individually, yet environmental quality guidelines are derived from single-metal toxicity data. Few metal mixture studies have investigated more than binary mixtures and many are at unrealistically high effect concentrations to freshwater organisms. This study investigates the toxicity of fiv...

Contaminants predominantly occur in mixtures, posing a challenge to environmental management which is predominately based on single-contaminant toxicity. Chemical interactions of the contaminants and non-specific biological responses to these mixtures may result in effects that differ from the sum of the toxicity of individual components. These dif...

Over one hundred years of anthropogenic activity in Antarctica has resulted in historic waste sites that contaminate the near-shore marine ecosystem with metals. This contamination adversely affects the community structure and diversity of algae in these environments. To prevent further contamination and facilitate the remediation of this unique en...

Over one hundred years of anthropogenic activity in Antarctica has resulted in areas of contamination in near-shore marine ecosystems. Such contamination has been shown to adversely affect community structure and the diversity of algae in these environments. To better manage impacts and to facilitate the remediation of this unique environment, a ro...

The Antarctic environment is considered the last pristine wilderness. However, a hundred years of anthropogenic activity, including research, fishing, and tourism has resulted in pervasive and localised contamination to the Southern Ocean . This contamination has been shown to adversely affect the community structure and diversity of algae in the m...

Prior to the productive use of iron- and steel-making slags as environmental amendments, a risk assessment supported by material characterization concomitant with leaching and ecotoxicological testing is necessary. Five iron- and steel-making slags were characterized geochemically and the leachability of their elemental constituents assessed. The t...

Thorough examination of the physico-chemical characteristics of a Ti processing residue was undertaken including mineralogical, geochemical, and radiochemical characterisation, and an investigation of the environmental toxicity of softwater leachate generated from the residue. Concentrations of most metals measured in the leachate were low; thus, t...