Rick van Dam

• PhD (Aquatic Toxicology, RMIT University, 1998)
• Aquatic Ecosystem & Water Quality Specialist at Independent Consultant

Treated effluent from wastewater treatment plants (WWTPs) contains a diverse array of anthropogenic and natural contaminants. These contaminants have the potential to pose environmental and/or human health risks. While targeted chemical analysis is an indispensable tool for monitoring WWTP discharge, its limited chemical domain highlights the need...

The scientific knowledge that enables the prediction of potential aquatic ecological risks due to exposure of metals based on freshwater chemistry data have been available for several decades. As a result, ecosystems can be protected, using frameworks and procedures incorporated into regulatory approaches. Yet, when evaluating how freshwater risks...

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...

The derivation of sediment quality guideline values (SQGVs) presents significant challenges. Arguably the most important challenge is to conduct toxicity tests using contaminated sediments with physico-chemistry that represents real-world scenarios. We used a novel metal spiking method for an experiment that ultimately aims to derive a uranium SQGV...

The current study aimed to derive site-specific guideline values (SSGVs) for nitrate toxicity that are relevant to high hardness surface waters of the Pilbara region, north-western Australia, many of which receive nitrate-rich mine water discharges. The approach involved deriving SSGVs from a species sensitivity distribution (SSD) based on candidat...

Six tropical freshwater species were used to assess the toxicity of mine waters from a uranium mine adjacent to a World‐Heritage area in northern Australia. Key contaminants of potential concern for the mine are uranium (U), magnesium (Mg), manganese (Mn) and total ammonia nitrogen (TAN). Direct toxicity assessments were carried out to assess wheth...

Many international guidance documents for deriving water quality guideline values recommend the use of chronic toxicity data. For the tropical fish, Northern Trout Gudgeon, Mogurnda mogurnda, a 96-h acute and a 28-d chronic toxicity test have been developed but both tests have drawbacks. The 96-h toxicity test is acute and has a lethal endpoint and...

The species sensitivity distribution (SSD) is a statistical approach that is used to estimate either the concentration of a chemical that is hazardous to no more than x% of all species (the HCx) or the proportion of species potentially affected by a given concentration of a chemical. Despite a significant body of published research and critical rev...

Magnesium (Mg) is a mining‐related contaminant in the Alligators Rivers Region of tropical northern Australia. A mesocosm experiment was used to assess Mg toxicity to aquatic freshwater assemblages. Twenty‐five 2700 L tubs were arranged stratified‐randomly on the bed of Magela Creek, a seasonally‐flowing, sandy stream channel in the Alligator River...

From 27–29 March 2019, a technical workshop was held at the Australian Institute of Marine Science (AIMS) in Townsville, Queensland, Australia to discuss key issues associated with the derivation of water quality guideline values (GVs). This report summarises the discussion around many of the identified key issues and makes recommendations on the n...

Magnesium (Mg) is a common contaminant in mine water discharges. Although Mg is an essential element in biological processes, increased concentrations from anthropogenic sources can stress aquatic ecosystems. Additionally, studies evaluating the effects of Mg on north Australian freshwater species have indicated that in very soft waters there is a...

Existing prescriptive guidance on the derivation of local water quality benchmarks (WQBs; e.g. guideline values, criteria, standards) for protecting aquatic ecosystems is limited to only three to four specific approaches. These approaches do not represent the full suite available for deriving local WQBs for multiple types of water quality‐related i...

Freshwater mussels play key roles in aquatic ecosystems, but are experiencing a global decline. Although studies have reported high acute sensitivity of mussels to some contaminants, there is a lack of chronic toxicity data available for deriving high reliability water quality guideline values (GVs). Ammonia is a contaminant of potential concern in...

The chronic toxicity of ammonia to tropical freshwater species is under‐represented, leading to the use of temperate species to derive water quality guideline values (GV) for tropical regions. Such practices may lead to under‐protective GVs due to differences in toxicities observed between tropical and temperate species. Additionally, there are lim...

As part of the revision of the Australian and New Zealand Water Quality Guidelines (ANZECC/ARMCANZ 2000a, b; referred to herein as the 2000 Guidelines), a number of working groups were established to review particular sections of the guidelines. The Toxicants and Sediments Working Group was asked to investigate necessary revisions for the toxicant...

Summary As part of Phase 1 of the revision of the Australian and New Zealand Water Quality Guidelines for Fresh and Marine Water Quality (ANZECC/ARMCANZ 2000, referred to herein as the 2000 Guidelines), the Toxicants and Sediments Working Group was asked to investigate necessary revisions for the toxicant section. A workshop held at CSIRO Land and...

Magnesium (Mg) is a primary contaminant in mine water discharges from the Ranger Uranium Mine (north Australia). Site‐specific Water Quality Guideline Values (WQGVs) for Mg have been derived from laboratory and field studies. Contaminated groundwater with elevated electrical conductivity and metals (Mg, manganese, uranium, sulfate and calcium) was...

A novel bioassay is presented that allows for the estimation of the chronic toxicity of contaminants in receiving tropical marine environments. Relevant procedures to identify contaminants of concern and evaluate hazards associated with contamination in these environments have long remained inadequate. The 6-day bioassay is conducted using freshly...

Revised water quality guideline values (WQGVs) are presented for the metals aluminium (Al), gallium (Ga) and molybdenum (Mo) in receiving marine environments. These elements are commonly found in elevated concentrations in alumina refinery waste streams, yet current WQGVs fail to accurately assess the environmental risk. Here, chronic biological ef...

Australian freshwaters have relatively low water hardness and different calcium to magnesium ratios compared with those in Europe. The hardness values of a substantial proportion of Australian freshwaters fall below the application boundary of the existing European nickel Biotic Ligand Models (NiBLMs) of 2 mg Ca/L. Toxicity testing was undertaken u...

Ammonia is recognised as a major pollutant worldwide, originating from natural and anthropogenic sources. Studies have reported that freshwater mussels are amongst the most sensitive taxa to ammonia, but there is a lack of data available on ammonia toxicity for the early life stages of freshwater mussels from tropical regions. This paper reports th...

Key ecological processes must be present and maintained in ecosystems to ensure the success of ecological restoration and conservation programs. The present paper identifies and defines key ecological processes operating at various spatial scales within aquatic ecosystems of the Magela Creek catchment, within Kakadu National Park, and prioritises t...

There is limited data concerning the toxicity of ammonia in fresh soft-waters. Ammonia toxicity is largely dependent on pH and temperature. The USEPA have derived equations to adjust species toxicity estimates based on changes in pH and temperature. It has been reported that the pH-ammonia toxicity relationship, derived by the USEPA, may differ in...

The internationally important river–floodplains of the Kakadu Region in northern Australia are at risk from invasive species and future sea-level rise–saltwater inundation (SLR–SWI), requiring assessments of multiple cumulative risks over different time frames. An integrated risk-assessment framework was developed to assess threats from feral anima...

The world's most productive bauxite mines and alumina refineries are located in tropical or sub-tropical regions. The discharge water from alumina refineries can contain elevated aluminium (Al, <0.45µm fraction), from 30 to 1000μg/L. There is a need for additional information on the toxicity of Al to aquatic organisms to improve the environmental r...

Protection of the environment and people from the potential impacts of uranium mining and milling is a global issue as the world's demand for power generation derived from uranium increases. We present a framework for deriving multiple stressor-pathway causal models for an operational uranium mine that can be used to identify research and monitorin...

Water quality guideline values (GVs) are a key tool for water quality assessments. Site-specific GVs, which incorporate data relevant to local conditions and organisms, provide a higher level of confidence that the GV will protect the aquatic ecosystem at a site compared to generic GVs. Site-specific GVs are, therefore, considered particularly suit...

A need exists for appropriate tools to evaluate risk and monitor potential effects of contaminants in tropical marine environments, as currently impact assessments are conducted by non-representative approaches. Here, a novel bioassay is presented that allows for the estimation of the chronic toxicity of contaminants in receiving tropical marine en...

As part of the revision of the 2000 Australian and New Zealand Water Quality Guidelines (ANZECC/ARMCANZ 2000; referred to herein as the 2000 Guidelines) a number of Working Groups were established to review particular sections of the Guidelines. The Toxicants and Sediments Working Group was asked to scope necessary revisions in the section on toxic...

As part of Phase 1 of the revision of the 2000 ANZECC/ARMCANZ Water Quality Guidelines (ANZECC/ARMCANZ 2000; referred to herein as the 2000 Guidelines), the Toxicants and Sediments Working Group was asked to scope out a range of topic areas where revisions were required. A workshop held at CSIRO Land and Water at Lucas Heights, NSW in April 2010 id...

As part of Phase 1 of the revision of the 2000 ANZECC/ARMCANZ Water Quality Guidelines (ANZECC/ARMCANZ 2000; referred to herein as the 2000 Guidelines), the Toxicants and Sediments Working Group was asked to scope out a range of topic areas where revisions were required. A workshop held at CSIRO Land and Water at Lucas Heights, NSW in April 2010 id...

As part of Phase 1 of the revision of the 2000 ANZECC/ARMCANZ Water Quality Guidelines (ANZECC/ARMCANZ 2000; referred to herein as the 2000 Guidelines), the Toxicants and Sediments Working Group was asked to scope out a range of topic areas where revisions were required. A workshop held at CSIRO Land and Water at Lucas Heights, NSW in April 2010 id...

A need exists for appropriate tools to evaluate risk and monitor potential effects of contaminants in tropical marine environments, as currently impact assessments are conducted by non-representative approaches. Here, a novel bioassay is presented that allows for the estimation of the chronic toxicity of contaminants in receiving tropical marine en...

Reproductive inhibition (egg production) of the aquatic snail, Amerianna cumingi, over 4 d has been used to derive toxicity estimates for toxicants of concern in tropical Australia. Toxicity estimates from this test have been used as chronic data points in Species Sensitivity Distributions (SSD) for deriving site-specific guideline values (GVs). Ho...

As part of the revision of the 2000 Australian and New Zealand Water Quality Guidelines (ANZECC/ARMCANZ 2000; referred to herein as the 2000 Guidelines) a number of Working Groups were established to review particular sections of the Guidelines. The Toxicants and Sediments Working Group was asked to scope necessary revisions in the section on toxic...

Chronic toxicity test methods for assessing the toxicity of contaminants to tropical marine organisms are generally lacking. A 96-h chronic growth rate toxicity test was developed for the larval stage of the tropical dogwhelk, Nassarius dorsatus. Growth rates of N. dorsatus larvae were assessed following exposures to copper (Cu), aluminium (Al), ga...

Elevated Manganese (Mn) is a common contaminant issue for mine water discharges and previous studies have reported that its toxicity is ameliorated by H + , Ca2+ and Mg2+ ions. The toxicity of manganese (Mn) was assessed in a high risk scenario, i.e. the slightly acidic, soft waters of Magela Creek, Kakadu National Park, Northern Territory, Austral...

There is a shortage of established chronic toxicity test methods for assessing the toxicity of contaminants to tropical marine organisms. We tested the suitability of the tropical microalga Isochrysis galbana for use in routine ecotoxicology and assessed the effects of 72-h exposures to copper (Cu, a reference toxicant), aluminium (Al), gallium (Ga...

The time taken for organisms to recover from a pulsed toxicant exposure is an important consideration when applying water quality guidelines to intermittent events in the environment. Organisms may appear to have recovered using standard toxicity testing methods but could carry residual toxicant or damage that may make them more sensitive to subseq...

Mining operations commonly treat mine water prior to discharging it to the environment. Results of biological toxicity tests and Toxicity Identification Evaluations have shown that environmental risks can still exist for these highly treated waters. We present examples for mine waters that were treated using high density sludge–microfiltration–reve...

Elevated major ions (or salinity) are recognised as being a key contributor to the toxicity of many mine waste waters but the complex interactions between the major ions and large inter-species variability in response to salinity, make it difficult to relate toxicity to causal factors. This study aimed to determine if the toxicity of a typical sali...

Environmental hazard assessments for chemicals are performed to define an environmentally 'safe' level at which, theoretically, the chemical will not negatively affect any exposed biota. Despite this common goal, the methodologies in use are very diverse across different countries and jurisdictions. This becomes particularly obvious when internatio...

Six freshwater species (Chlorella sp., Lemna aequinoctialis, Amerianna cumingi, Hydra viridissima, Moinodaphnia macleayi and Mogurnda mogurnda) were exposed to 4, 8 & 24-h Mg pulses in natural creek water. Mg toxicity to all species increased with exposure duration, however, the extent of increase and the nature of the relationship differed greatly...

Generic water quality guidelines (WQGs) are developed by countries/regions as broad scale tools to assist with the protection of aquatic ecosystems from the impacts of toxicants. However, since generic WQGs cannot adequately account for the many environmental factors that may affect toxicity at a particular site, site-specific WQGs are often needed...

The Ranger Uranium Mine, in northern Australia, is monitored by the Supervising Scientist Division (SSD) of the Australian Government to ensure that it does not impact on the highly valued aquatic ecosystems of Kakadu National Park. In 2010, the SSD adopted the continuous monitoring of electrical conductivity (EC) and turbidity, in combination with...

The Australian and New Zealand Guidelines for Fresh and Marine Water Quality are a key document in the Australian National Water Quality Management Strategy. These guidelines released in 2000 are currently being reviewed and updated. The revision is being co-ordinated by the Australian Department of Sustainability, Environment, Water, Population an...

Many jurisdictions around the globe have well-developed regulatory frameworks for the derivation and implementation of water quality guidelines (WQGs) or their equivalent (e.g. environmental quality standards, criteria, objectives or limits). However, a great many more still do not have such frameworks and are looking to introduce practical methods...

Mining operations often use passive and/or active water treatments to improve water quality prior to environmental release. Key considerations in choosing a treatment process include the extent to which the water quality is actually improved, and the potential residual environmental risks of the release of such water. However, there are few publish...

The present study reanalyzed 46 existing uranium (U) chronic toxicity datasets for four freshwater species to generate consistent toxicity measures and explore relationships between U toxicity and key physicochemical variables. Dissolved organic carbon (DOC) was consistently the best predictor of U toxicity based on 10% inhibitory concentration (IC...

The use of the no observed effect concentration (NOEC) and lowest observed effect concentration (LOEC) in ecotoxicology has been consistently criticized for over 30 years. A search of the literature from the past 30 years found 22 articles challenging the validity and/or appropriateness of NOEC/LOEC data compared to only one in defense of such data...

The influence of dissolved organic carbon (DOC) on the toxicity of aluminum (Al) at pH 5 (relevant to acid mine drainage conditions), to the tropical green hydra (Hydra viridissima), green alga (Chlorella sp.), and cladoceran (Moinodaphnia macleayi) was assessed. Two DOC sources, a natural in situ DOC in soft billabong water (SBW) and Suwannee Rive...

The influence of dissolved organic carbon (DOC), in the form of Suwannee River fulvic acid (SRFA), on uranium (U) toxicity to the unicellular eukaryote, Euglena gracilis (Z strain), was investigated at pH 6. In a background medium without SRFA, exposure of E. gracilis to 57 μg L−1 U resulted in a 50% reduction in growth (IC50). The addition of 20 m...

The Relative Risk Model (RRM) was used to undertake a spatially explicit regional ecological risk assessment at a continental scale for the 1.1 million km Northern Tropical Rivers (NTR) region of Australia, and at a catchment scale for the Daly River, Northern Territory. The NTR RRM assessed risks of 18 threats to three aquatic habitats and four ec...

The Ranger uranium mine is surrounded by the World Heritage Kakadu National Park, Australia, and is upstream of the Ramsar-listed wetlands of the Magela Creek floodplain. We present the results of a Quantitative Ecological Risk Assessment (QERA) for the floodplain that combines both point source mining risks and diffuse non-mining landscape-scale r...

The influence of dissolved organic carbon (DOC), in the form of Suwannee River fulvic acid (SRFA), on uranium (U) toxicity to the unicellular eukaryote, Euglena gracilis (Z strain), was investigated at pH 6. In a background medium without SRFA, exposure of E. grac-ilis to 57 lg L-1 U resulted in a 50% reduction in growth (IC 50). The addition of 20...

The influence of dissolved organic carbon (DOC), in the form of Suwannee River fulvic acid (SRFA), on uranium (U) toxicity to the unicellular eukaryote, Euglena gracilis (Z strain), was investigated at pH 6. In a background medium without SRFA, exposure of E. grac-ilis to 57 lg L-1 U resulted in a 50% reduction in growth (IC 50). The addition of 20...

Flocculant blocks are commonly used as a component of (passive) water treatment systems to reduce suspended sediment loads in the water column. This study investigated the potential for aquatic biological impacts of a flocculant block formulation that contained an anionic polyacrylamide (PAM) active ingredient and a polyethylene glycol (PEG) based...

The influence of dissolved organic carbon (DOC) on the toxicity of uranium (U) to three Australian tropical freshwater species, the Northern Trout Gudgeon (Mogurnda mogurnda), green hydra (Hydra viridissima) and unicellular green alga (Chlorella sp.) was assessed. Exposures were conducted in synthetic soft water without DOC and with DOC added in th...

Fulvic acid (FA) from a tropical Australian billabong (lagoon) was isolated with XAD-8 resin and characterized using size exclusion chromatography, solid state cross-polarization magic angle spinning, 13C nuclear magnetic resonance spectroscopy, elemental analysis, and potentiometric acid-base titration. Physicochemical characteristics of the billa...

Mining represents one of the threats to the quality and biodiversity of freshwater ecosystems in northernAustralia. Uranium (U), aluminium (AI)and arsenic (As) are priority metals of ecotoxicological concern for the region's mining industry for which insufficient toxicity data exist (6). Few existing studies (see reviews 8, 3 and 4 for uranium, alu...

The discharge of catchment-management water from the Ranger uranium (U) mine into Magela Creek upstream of the Ramsar-listed Magela Floodplain in Kakadu National Park is an important part of the mine's water-management system. Because U is one of the primary toxicants associated with this water, a receiving-water trigger value (TV), based on chroni...

The effects of chronic uranium (U) exposure on larval Northern trout gudgeon, Mogurnda mogurnda, were assessed in two experiments using a newly-developed 28d survival and growth toxicity test. Significant effects were observed in both tests, but toxicity was markedly higher in Test 2 than Test 1. The LC50s for Tests 1 and 2 were 2090microgL(-1) and...

The toxicity of magnesium sulfate (MgSO(4)), and the influence of calcium (Ca), were assessed in very soft freshwater (natural Magela Creek water [NMCW]) using six freshwater species (Chlorella sp., Lemna aequinoctialis, Amerianna cumingi, Moinodaphnia macleayi, Hydra viridissima, and Mogurnda mogurnda). The study involved five stages: toxicity of...

The Australian Government's Supervising Scientist Division (SSD) is the entity responsible for the independent supervision, monitoring and audit of uranium mines in the Alligator Rivers Region (ARR) of Australia's Northern Territory. The Ranger uranium mine, one of the world's largest producers of uranium oxide (5,000 tpa or 10% of world production...

The decommissioned Mount Todd gold mine, located in the wet-dry tropics of northern Australia, consists of a large waste water inventory and an acid rock drainage problem, which has the potential to impact upon freshwater ecosystems of the Edith River catchment. The toxicity of retention pond 1 (RP1) water was determined using six local freshwater...

The aquatic ecosystems of the Northern Tropical Rivers catchments are still relatively intact and, for this reason, represent an internationally significant asset. Whilst we know much about the aquatic ecosystems, particularly for specific areas (eg. Alligator Rivers Region, Ord River, Daly River), much knowledge still remains unknown and/or unquan...

Developmental pressure across Australia's northern coastal catchments will increase rapidly in the near future. These areas are important strongholds for marine biodiversity and contain some of the least impacted marine habitats in the world. Consequently, such development must take place in an environmentally sustainable manner and needs to be und...

Warne and van Dam O P I N I O N P I E C E In ecotoxicology we generate either hypothesis-based or point estimate toxicity data. The former consist of no observed effect concentrations (NOECs), lowest observed effect concentrations (LOECs) and maximum acceptable threshold concentrations (MATCs – the geometric mean of a NOEC and a LOEC). Examples of...

The Ranger Mine has been used as a case study to illustrate how field biological indicators of ecosystem status and results from ecotoxicological studies can be combined with a water quality record from downstream of a minesite to derive water quality guideline values that are not as conservative as would be produced by the default approach of conf...

The objective of the Tropical Rivers Inventory and Assessment Project (TRIAP) ecological risk assessment sub-project is to develop a framework applicable to key focus catchments and significant locations that meet stakeholder needs. A broad overview of the major pressures on tropical Australia's aquatic ecosystems will be provided through this sub-...

Uranium is one of the metals of ecotoxicological concern for the uranium mining industry in tropical Australia. In order to more fully assess the risk that U in waters discharged from mining activities poses to tropical freshwater ecosystems, the role of dissolved organic carbon (DOC) must be quantified. DOC is one of the key determinants of the bi...

The scope of the TRIAP program, however, does not allow detailed quantitative ecological risk assessments (QERA) to be undertaken for all four focus catchments. Hence, the Daly River catchment in the Northern Territory (NT) was chosen to test the utility of various QERA approaches that could be applied to the other focus catchments to assess thre...

This chapter focuses on the application of the Relative Risk Model (RRM) as a regional risk assessment tool at two scales: the Northern Tropical Rivers; and the Daly River catchment. The RRM has not previously been applied to a large region such as at the Northern Tropical Rivers scale, and results suggest that it is the most appropriate tool to co...

The tropical rivers of northern Australia are under increasing pressure due to environmental threats and human activities. The objective of this sub-project (sub-project 2) of the Tropical Rivers Inventory and Assessment Project (TRIAP; www.nctwr.org.au/publications/tropical­ rivers) is to develop a risk assessment framework applicable to the key...

The chronic toxicity (72-h cell division rate) of uranium (U) to the unicellular alga, Chlorella sp., was assessed in natural Magela Creek water (NMCW) to provide data for the derivation of a site-specific water quality trigger value for U in Magela Creek, NT, Australia. In addition, the data were compared to those for Chlorella sp. when tested for...

The present study assessed the ecological risks of the herbicide tebuthiuron to freshwater fauna and flora of northern Australia's tropical wetlands. Effects char-acterization utilized acute and chronic toxicity data of tebuthiuron to local fresh-water species (three animals and two plants) as well as toxicity data derived from northern hemisphere...