CRC CARE brings together industry, government, science and engineering to prevent, assess and clean up environmental contamination
Menu

Log in

×

Technical reports

Share

CRC CARE's technical report series comprises a comprehensive collection of work carried out by CRC CARE and its partners. This work is done to address technical issues of importance to industry and government.

CRC CARE Technical Report 26: Phosphorus management in soils using coal combustion products

Large quantities of coal combustion products (CCPs) are being generated worldwide annually and dumped in large piles as landfills. These products are residues from the combustion of coal, largely used for electricity generation. The economic availability of coal and the burgeoning demands of the rising population are set to increase the coal-fuelled electricity generation in the future. Australia, being amongst the top nations in using coal for production of electricity, generates enormous quantities of CCPs. There is an increasing concern among the power stations and environmental agencies on the mobility of heavy metals from the CCPs, which may result in contaminating our land resources and water bodies.

+ Read More

Large quantities of coal combustion products (CCPs) are being generated worldwide annually and dumped in large piles as landfills. These products are residues from the combustion of coal, largely used for electricity generation. The economic availability of coal and the burgeoning demands of the rising population are set to increase the coal-fuelled electricity generation in the future. Australia, being amongst the top nations in using coal for production of electricity, generates enormous quantities of CCPs. There is an increasing concern among the power stations and environmental agencies on the mobility of heavy metals from the CCPs, which may result in contaminating our land resources and water bodies.

Although the coal-fired power generation has evolved a long way towards clean coal processing technologies, resulting in higher energy production and value addition, there has not been any breakthrough in reducing the volume of combustion wastes i.e., the CCPs generated. Consequently, the ash dumps are fast inflating and envisaged for more expansion in the impending years. This is mainly due to the under-utilisation of these waste materials in some countries, where the concerns towards environmental health and public well-being had not been addressed. The possible uses of CCPs in the construction industry as a cement substitute; in agriculture as a liming agent; and in environmental remediation have reaped benefits round the globe. Current utilisation levels of these resources in Australia are low, considering their actual potential in environmental remediation.

Most Australian soils are inherently deficient in phosphorus (P) and many sandy soils are not efficient in the retention of P, thereby results in leaching and (surface) runoff losses. Agricultural application of fertilizer P and wastes including farm effluents, manures and biosolids (BS) have been the most significant contributors of P build-up in soils and consequent accumulation in water bodies causing eutrophication. The immobilisation of P in soils using CCPs has been a significant area of research over the past decade not only for the potential of CCPs in minimising the loss of P, but also making the P bioavailable for agronomic utilisation.

Transformation [(im)mobilisation] of P in soil is closely associated with the pH and the concentrations of iron (Fe), aluminium (Al) and calcium (Ca) in the soil. An increase in soil pH generally increases the potential of inorganic P immobilisation in soil via P adsorption, especially to acidic and neutral soils. However, Ca concentration also influences adsorption of P. At very high pH and high Ca concentration, inorganic P gets precipitated with Ca and it becomes strongly immobile. However, at low pH, P adsorbs to the surface of Fe and Al oxides. The pH also influences the breakdown of organic P into inorganic P in soil, due to phosphatase activity and the resultant P mineralisation. The CCPs are generally alkaline and are rich in these cations and hence can serve as potential amendments for P management in soil, which will be explained in this report using immobilisation, transformation and bioavailability experiments. Also, this report will serve as an effective guide for the farming communities and a source of information for industries and researchers related to CCPs.

 

- Read Less

Technical Report 25 - PRBs - front cover

CRC CARE Technical Report 25: A framework for selecting, designing and implementing a permeable reactive barrier system

This report addresses the use of permeable reactive barriers (PRBs) at contaminated sites. It includes guidance on suitability assessment, design, operation, monitoring and decommissioning while taking into consideration existing international guidance, protocols and research.

CRC CARE Technical Report 24: Analytical methods for priority and emerging contaminants - a literature review

The availability of analytical methodology with sufficient detection sensitivity and selectivity is crucial to effective management of environmental contaminants. This review has considered the analytical methodology available for a range of Contaminants of Emerging Concern (CECs) and assessed the measurement-related needs on the basis of two key criteria: the relevance of each contaminant to the Australian environment and the degree to which appropriate analytical capability is available in Australia. Quality assurance tools essential for ensuring comparability of results between laboratories, such as availability of proficiency testing (PT) studies and reference materials were also considered.

+ Read More

The availability of analytical methodology with sufficient detection sensitivity and selectivity is crucial to effective management of environmental contaminants. This review has considered the analytical methodology available for a range of Contaminants of Emerging Concern (CECs) and assessed the measurement-related needs on the basis of two key criteria: the relevance of each contaminant to the Australian environment and the degree to which appropriate analytical capability is available in Australia. Quality assurance tools essential for ensuring comparability of results between laboratories, such as availability of proficiency testing (PT) studies and reference materials were also considered.

The first task of this project was to develop a shortlist of contaminants for detailed investigation using a combination of CRC CARE end-user input and international peer-reviewed literature. The former included the findings of a CEC Forum held by the CRC in February 2012 which generated a ‘first tier priority’ list of contaminants (Priority 1: methyl tertiary butyl ether (MTBE), perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), weathered hydrocarbons, benzo(a)pyrene (BaP) and polybrominated diphenyl ethers (PBDEs)). Another four classes of contaminants determined from the literature and discussions with Australian and international experts to be important emerging contaminants were selected for review as Priority 2. These were perfluorinated alkyl substances (PFASs) other than PFOS and PFOA, novel flame retardants (FRs), short-chain chlorinated paraffins (SCCPs) and methylsiloxanes. Other contaminants nominated by CRC CARE end-users or found in literature reports were selected as Priority 3, requiring further investigation regarding their relevance in the Australian remediation context, based on their likely use and environmental prevalence. The Priority 3 contaminants were 1,4-dioxane, benzotriazoles, ionic liquids, benzidine dyes, musk fragrances, microbicides, organoboron, organoplatinum, arsenic species and nanoparticles.

The project team then undertook a more detailed literature review into each of the Priority 1, Priority 2 and Priority 3 contaminants. As part of the review, a voluntary and anonymous survey of NATA-accredited laboratories was also conducted to assess the availability of analytical capabilities in Australia.

The key findings of the review were that:

  • Significant analytical methodology gaps were not found for any of the Priority 1 compounds, although tools to assess laboratory performance such as easily accessible proficiency testing (PT) schemes are lacking. This may seem surprising in view of their identification by the CEC Forum as a ‘first tier priority’. It should be noted, however, that the research requirements specified by that Forum were much more wide-ranging than the analytical methodology focus of this review and that in the cases of MTBE and BaP, the research needs identified by the Forum were explicitly focussed on areas other than measurement. In addition, there has already been considerable research into all the Priority 1 compounds in recent years, which has in turn resulted in substantial progress in analytical method development for these compounds.
  • Analytical capability gaps in Australia were identified for SCCPs, PFASs other than PFOS and PFOA, novel FRs other than PBDEs, synthetic musks, benzidine dyes, benzotriazoles, methylsiloxanes, organoplatinum compounds and nanomaterials. There appear to be suitable methods in the literature for PFOS, PFOA, PBDEs, novel FRs including tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDD), and synthetic musks. Development of local analytical capability for SCCPs, PFSAs and selected FRs including TBBPA and HBCDD appears to present the most significant priority for Australia given the relatively high level of usage in this country.
  • Gaps in the availability of matrix reference materials in areas where analytical capability exists or where it has been recommended were identified for PFASs including PFOS and PFOA, SCCPs, TBBPA and HBCDD, benzotriazoles, synthetic musks and arsenic species.
  • Gaps in the availability of proficiency testing studies by Australian providers in areas where analytical capability exists or where development has been strongly recommended were identified for MTBE, PAHs including BaP, PFASs including PFOS and PFOA, PBDEs, arsenic species, SCCPs, HBCDD and TBBPA.

The recommendations from the review were that:

  • For the very diverse groups of PFASs and novel FRs, especially TBBPA and HBCDD, analytical methodology is not adequate in Australia. Many of these compounds will be used in Australia as they have important commercial applications, and many are subject to long-range transport and may be found in the Australian environment whether they are used here or not. Further investigation into which analytes will be most significant for the Australian environment is recommended. The development of methods, production of reference materials and coordination of PT schemes can then be considered for the more relevant analytes.
  • The development of methods, production of reference materials and coordination of PT schemes for short-chain chlorinated paraffins (SCCPs) is strongly recommended.
  • The development of analytical methods for benzotriazoles and synthetic musks is recommended, to allow the distribution and environmental impact of these contaminants in Australia to be assessed.
  • The production of reference materials and coordination of PT schemes for arsenic species in environmental matrices is strongly recommended.
  • Activities of interest would be the development of methodology to allow studies to be conducted into the extent of contamination by methylsiloxanes, benzidines arising from dyestuffs and organoplatinum anticancer drugs.

 

- Read Less

CRC CARE Technical Report 23: Petroleum hydrocarbon vapour intrusion assessment - Australian guidance

This document provides a clear decision framework for the conduct of petroleum vapour intrusion assessments resulting from contamination of soil and groundwater by petroleum hydrocarbons.

+ Read More

This document provides a clear decision framework for the conduct of petroleum vapour intrusion assessments resulting from contamination of soil and groundwater by petroleum hydrocarbons.

Drawing on the best available guidance and science relating to the current understanding of petroleum vapour intrusion from Australia and other jurisdictions, this document outlines approaches that should be considered in the assessment of acute and chronic risks. These approaches may be on the basis of either an initial screening or a more detailed assessment as appropriate.

This decision framework incorporates flow diagrams and “decision boxes”, with additional detail provided in appendices. It is expected that this decision framework will assist the user in making appropriate and sound decisions in the assessment of petroleum vapour intrusion, including the collection and evaluation of vapour data.

The potential for petroleum vapour intrusion may vary considerably with different situations, as petroleum hydrocarbons readily biodegrade in the subsurface when sufficient oxygen is available, and this guidance provides the means to take such variability into account.

While several aspects of this guidance are general and can be applied to a range of volatile compounds, the guidance is intended to specifically address petroleum vapour intrusion, and should not be applied to sites contaminated with other compounds not sourced from petroleum, such as chlorinated hydrocarbons and landfill gas.

While the decision framework and the methods and approaches listed or presented in the guidance are specifically oriented towards assessment of petroleum vapours, this does not mean that methods and approaches not presented in the guidance cannot be utilised. Rather, other approaches can be used, where relevant, and adequately justified and agreed with regulators, auditors or third party reviewers prior to use.

By following the guidelines outlined in this document, the assessment of petroleum vapour intrusion will be adequately robust and will meet regulatory (and auditor/third party reviewer) requirements for the completion of such assessments.

 

- Read Less

CRC CARE Technical Report 22: Developing a national guidance framework for Australian remediation and management of site contamination - Review of Australian and international frameworks for remediation

This project is the first of several projects required to deliver an accepted national remediation framework (NRF) and guidance.

+ Read More

The Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE) carries out research into the assessment and clean-up of contaminated sites. During the preparation of its successful bid for funding to 2020, the need for a nationally consistent approach to remediation of contaminated sites was identified by:

  • representatives of environmental regulatory bodies from across Australia
  • major corporate entities which operate and clean-up sites across multiple jurisdictions.

It was acknowledged that current guidance for the remediation and management of contaminated sites comprises some high quality, but dated, national documents, and high quality, but non-harmonised, guidance issued by some jurisdictions. Early discussions regarding the purpose, benefits and limitations of a new remediation framework identified the following elements as important in the consideration of the approach, structure and content of the document – the framework should:

  • enable a nationally consistent approach to remediation of contaminated sites
  • be established under the umbrella of the Standing Council on Environment and Water (SCEW)
  • NOT impinge on the policy and decision-making prerogatives of the states and territories
  • NOT be legally binding
  • distil and utilise existing documentation and experience, and
  • provide practical guidance within an overall framework which establishes the context for remediation in Australia.

 

This project

This project is the first of several projects required to deliver an accepted national remediation framework (NRF) and guidance. It is essentially an initial and exploratory scan of national and international sources in order to identify:

  • international remediation and management frameworks which may be suitable for adoption or adaption in an Australian context
  • current regulation of remediation and management of site contamination in Australia, and
  • barriers to the adoption of an Australian NRF and management of contaminated sites.

The focus of the project was the gathering of information that may assist the national remediation framework steering group (NRFSG) as it considers:

  • effective ways to approach the development of the framework in the Australian regulatory context
  • the potential structure of the framework and the areas to be covered within the framework, and
  • content to be included in the framework.

Information was gathered regarding frameworks that are used to guide the remediation and management of contaminated sites in a number of international jurisdictions. Information was also gathered regarding general approaches taken to remediation and management in the six states and two territories of Australia. Some national documents, approaches and processes for dealing with assessment of contaminated sites were also considered for their potential for adaptation to a management and remediation context.

A number of common elements exist in the structure and content of framework documents scanned for this project. There is also commonality in the way that remediation and management of contaminated sites is approached generally in jurisdictions in Australia and internationally.

In order to synthesise the information gathered in this project in a useful way, an example framework has been provided, including possible elements of a framework document. The particular priorities, requirements and content for the Australian national remediation and management framework will, of course, be developed over the coming years.

The example framework is offered simply as a tool to summarise the elements common to remediation and management as found in this scanning project, and to organise, in framework style, some of the elements and issues that could be addressed as part of the harmonisation process. In summary, the example framework comprises two distinct parts which are themselves comprised of particular elements as briefly described as follows:

Part 1: Philosophy

  • Context

-      includes background and jurisdictional arrangements, as well as the purpose and intended audience for any framework documentation

  • Policy and principles

-      includes discussion of agreed principles and policy approaches that do or will guide activities related to remediation and management, e.g. precautionary principle, liability, risk management, green remediation

Part 2: Practice

  • Guidance

-      includes practical guidance for practitioners, provided either as specific advice or techniques outlined within the text of the framework document, or as references to tools and guidance available elsewhere.

Guidance could relate to all steps of the remediation and management process from the setting of remediation objectives to post-remediation auditing and the use of institutional controls.

A full description of the example framework is provided in Section B of this report.

 

Addressing barriers to a national approach on remediation and management

Barriers to a national approach toward remediation and management of contaminated sites are most likely to arise from the lack of an existing legislative and regulatory framework through which such matters can be addressed. Unlike the development of the National Environment Protection (Assessment of Site Contamination) Measure (NEPM), which provides a framework for the assessment of contaminated sites and was undertaken using processes established under law, the development of a national remediation and management framework is not provided for in existing legislation.

The Australian experience in developing a national approach to the assessment of contaminated sites does demonstrate the success of cooperative efforts across states and territories in the past. That this cooperation is an ongoing asset has been demonstrated during the recent review and proposed variation of the NEPM. Recent restructuring of the ministerial council system may also assist the process of developing a national framework for remediation and management of contaminated sites.

Following the 2010 review of the ministerial council system by the Council of Australian Governments (COAG), the SCEW Council was established with a number of priorities, the first being to pursue seamless environmental regulation and regulatory practice across jurisdictions.

A seamless environmental regulation thematic oversight group (SERTOG) has
been established to further the Council’s aims, and the development of a national remediation and management framework has been selected as a pilot project. Comprising representatives from jurisdictions across Australia, SERTOG has the potential to be a key resource, given the relationship its members have to regulatory practice in the states and territories. The group’s membership and structure should enable it to become an effective mechanism for the identification, management and resolution of potential paths and barriers to the adoption of a national framework. 

 

- Read Less

CRC CARE Technical Report 21: Sampling strategies for biological assessment of groundwater ecosystems

The effective management of groundwater resources across Australia is essential to meet current and future national water needs. At the same time, the significance of groundwater ecosystems in terms of their biodiversity and ecosystem services is increasingly being recognised such that surveys of groundwater ecosystems are now often a part of development applications and environmental impact assessments.

+ Read More

The effective management of groundwater resources across Australia is essential
to meet current and future national water needs. At the same time, the significance
of groundwater ecosystems in terms of their biodiversity and ecosystem services is increasingly being recognised such that surveys of groundwater ecosystems are now often a part of development applications and environmental impact assessments.

Despite the growing awareness of the value of groundwater ecosystems, there is currently little guidance available to assist practitioners in their assessment. Accordingly, the aim of this document is to provide guidance on methods and strategies for the biological assessment of groundwater ecosystems, specifically in
the context of localised environmental threats or impacts. Within the context of contaminated site assessment, routine investigation of groundwater ecosystems may not be required, but should be considered in areas of ecological significance or conservation value.

The groundwater environment is characterised by total darkness. As a result, there
are no photosynthetic primary producers and (usually) only low concentrations of organic carbon as an energy source for the ecosystem. The biota of the ecosystem
is comprised of two major components: the microbes (including bacteria and fungi), and the larger mostly crustacean macro- and meiofauna (stygofauna). Accordingly, groundwater ecosystems are very different from surface water ecosystems, and so require different strategies for their biological assessment.

Sampling of stygofauna is generally conducted by means of pumps, nets or traps, with the choice of method often having little impact on the variety of animals collected, but some influence on the abundance of those animals. Importantly, to adequately assess the diversity of stygofauna at a location, multiple bores must be sampled on multiple occasions. Samples from multiple bores on a single occasion, or from a single bore on multiple occasions, will not adequately assess stygofauna diversity. Our sampling indicates that at least five sampling locations and five sampling events may be required.

Microbial assemblages may be assessed by a variety of means including molecular or metabolic fingerprinting, direct measurement of biomass and microbial enzyme activity. Irrespective of the method chosen, repeat temporal and spatial sampling should be undertaken. While measures of microbial activity at relatively undisturbed sites may be variable over time, the effects of disturbance to an aquifer may cause a large and readily detectable shift in microbial activity, greatly exceeding the spatial and temporal variability among undisturbed sites.

Assessments of aquifer ecosystems in the context of environmental impact assessment should examine both microbes and stygofauna, reflecting the major biotic components of the ecosystem. Multiple samples over space and time are necessary, with the exact level of replication and sampling effort ideally determined by site-specific studies.

 

- Read Less

CRC CARE Technical Report 20: Guidance document for the revegetation of land contaminated by metal(loid)s

The revegetation of sites contaminated by metals (such as Cu, Zn, Ni, or Pb) and metalloids (such as As) is an important environmental challenge. On a global-scale, large investments are required in order to rehabilitate the soil to a productive and non-environmentally-damaging endpoint, and as a result, an ever increasing number of technologies have been developed.

+ Read More

The revegetation of sites contaminated by metals (such as Cu, Zn, Ni, or Pb) and metalloids (such as As) is an important environmental challenge. On a global-scale, large investments are required in order to rehabilitate the soil to a productive and non-environmentally-damaging endpoint, and as a result, an ever increasing number of technologies have been developed. However, the successful implementation of a revegetation system requires a true multi-disciplinary effort, with collaboration between soil scientists, agronomists, hydrologists, ecotoxicologists, and economists.

The overall revegetation process can be separated into three broad steps:

  1. assessment of soil contamination
  2. remediation, and
  3. revegetation / plant selection.

Although all three steps are considered here, an emphasis is placed on the first and last of these. This document provides a brief review of current knowledge, with a particular emphasis on Australian plants and landscapes.

 

- Read Less

CRC CARE Technical Report 19: Winery wastewater irrigation - effects of potassium and sodium on soil structure

Generation of wastewater is an inevitable component of the wine production process. Typically this wastewater has a high salt concentration, due mainly to chemical cleaning products and spent grape lees. Land application of winery wastewater is increasingly being advocated as a means to mitigate deteriorating water quality associated with surface water discharge. A major agricultural concern however, is the potential for monovalent cations, namely sodium (Na+) and potassium (K+) to accumulate in the soil profile and subsequently impact on soil structure.

+ Read More

Generation of wastewater is an inevitable component of the wine production process. Typically this wastewater has a high salt concentration, due mainly to chemical cleaning products and spent grape lees. Land application of winery wastewater is increasingly being advocated as a means to mitigate deteriorating water quality associated with surface water discharge. A major agricultural concern however, is the potential for monovalent cations, namely sodium (Na+) and potassium (K+) to accumulate in the soil profile and subsequently impact on soil structure.

Best management practice for managing nutrients in many wastewaters generally focuses on retaining constituents, such as nitrogen (N) and phosphorus (P), within the soil profile where they are assimilated into plant growth. However, the assimilation of Na+ by plants is low, and the best management approach to mitigate the potential effects of high soil Na+ concentrations is to leach this salt down the soil profile. Plant K+ requirements are generally high (i.e. similar to N), however, high loadings typical under winery wastewater (i.e. 600 kg K+ ha-1 yr-1) far exceed plant requirements. Although the relative effect of K+ on soil structure is less than that of Na+, an excess in the soil profile can contribute to a decline soil structure.   

In many regions, Na+ and K+ are readily leached during winter rainfall events and, therefore, pose limited risk of accumulation or subsequent soil dispersion. In fine-textured soils that tend to drain poorly, or where loading rates of constituents are high, achieving adequate leaching may be problematic. A greater degree of management will, therefore, be required at locations where winery wastewater is applied to fine- textured soils with high clay content. Where accumulation of salts is likely, maintaining a sodium adsorption ratio (SAR) of winery wastewater below 6 (mmolc L-1)0.5 and potassium adsorption ratio (PAR) below 10 (mmolc L-1)0.5 is likely to prevent adverse soil structural changes.

There is a close relationship between winery wastewater electrical conductivity (EC) and soil dispersion, whereby adverse changes to soil structure under high net loading of Na+ or K+  is mitigated at higher EC. It is therefore valuable to include measurement of winery wastewater EC in routine analysis. Routine use of calcium (Ca2+) amendments including, yet not restricted to, lime, gypsum and calcium nitrate – either added directly to wastewater or to soils – will enable Ca2+ exchange and displacement of Na+ and K+. Winter application of Ca2+ amendments will ensure its percolation down the soil profile, thereby ensuring good distribution of Ca2+ and raising soil EC that is otherwise lowered under rainfall. 

Given the lesser effect of K+ on soil structure relative to Na+, a switch to potassium-based sterilisers will lower SAR in the final stream. In addition to this, the greater PAR in winery wastewater will further prevent Na+ retention in soils. 

The greatest volume of winery wastewater is generated immediately after vintage, during which time salt concentration tends to be at a maximum. The quantity of salt applied to soils with irrigation is influenced by the land area over which it is distributed. Because the period that winery wastewater is applied to land is relatively short, i.e. immediately following vintage, greater land area will be an effective means of minimising the net salt accumulation in soils. To avoid nutrient imbalances in crops grown with winery wastewater, loading rates could be determined based on meeting the K+ demand of the crop. With adequate management (namely, prevention of high ESP and EPP during consecutive seasons) the risk of soil dispersion can be mitigated.

 

 

 

- Read Less

CRC CARE Technical Report 18: Selecting and assessing strategies for remediating LNAPL in soils and aquifers

Light non-aqueous phase liquid (LNAPL) petroleum hydrocarbons are complex mixtures of chemicals that variably partition into water and gaseous phases when released into subsurface environments. They pose a range of concerns – from issues of aesthetics and nuisance to acute risks to human health and the environment.

+ Read More

Light non-aqueous phase liquid (LNAPL) petroleum hydrocarbons are complex mixtures of chemicals that variably partition into water and gaseous phases when released into subsurface environments. They pose a range of concerns – from issues of aesthetics and nuisance to acute risks to human health and the environment. The properties of LNAPL and its interaction with geological strata make effective removal of LNAPL contaminants difficult. Indeed, effective remediation and amelioration of concerns may not be possible in many situations. In addition, much uncertainty arises through an incomplete understanding of the potential effectiveness of LNAPL remediation strategies in different subsurface settings.

Major challenges in addressing LNAPL contamination include:

  • knowing enough about likely LNAPL behaviour in subsurface environments
  • building an adequate LNAPL conceptual site model
  • adequately assessing all concerns posed by LNAPL at a site
  • defining technology and site end points
  • balancing the need for action at a site with achievable end points
  • overcoming the lack of information on the field-scale effectiveness of remediation technologies in different settings
  • matching the capability of remediation technologies to desired remediation end points for a site
  • having adequate measures to quantify the performance of remediation technologies
  • knowing when and if remediation technologies reach their practicability limits
  • determining the net environmental and social benefits of LNAPL remediation.

This report seeks to provide information and a framework that would allow some of these challenges to be addressed. It provides guidance in selecting and matching the performance of remediation technologies to a range of subsurface settings, risk reduction targets and concerns. The emphasis here is on LNAPL that has infiltrated to the water table and in settings of major relevance to Australia. One of the aims is to identify the gaps in the current understanding of remediation process and performance in the various subsurface settings. Not all the information required is available or known. As such, this document provides a status report, which can be updated as research and additional experience fills the identified gaps.

We examine existing (and some past) approaches to LNAPL remediation in Australia and internationally. In the context of risk-based remediation, the process of identifying concerns (including risks) that may trigger LNAPL remediation is described. It is then shown how the identified concerns are used to formulate remediation objectives from which remediation end points may be defined. This process is set in terms of the overall goals and long-term vision for the condition and use of a site. It is these goals and long-term vision that will drive remedial efforts. The concepts of technical impracticability, clean-up to the extent practicable and clean-up to the extent necessary are described. These may be invoked in response to encountering technical and other factors limiting the success of remediation and preventing the desired end points being reached.

A summary of the nature and behaviour of LNAPL petroleum hydrocarbons in various subsurface settings is presented. This includes a general classification of subsurface environments and outlines the important differences in LNAPL behaviour in these settings. Descriptions of the major soil and aquifer systems of interest in Australia are also provided.

In terms of remediation technology selection, emphasis is placed on the process of identifying the risks and concerns associated with the presence of the LNAPL, defining remediation objectives to ameliorate these and establishing the remediation end points that will ensure these objectives are met. As part of this selection process, there is discussion of how specific risks may be addressed, particularly where they relate to individual constituents or classes of constituents of the LNAPL. Key to this is an understanding of how LNAPL mass reduction reduces specific risks or ameliorates particular concerns.

The report provides an extensive examination of the technologies available for LNAPL remediation. The most common in situ remediation technologies are examined along with approaches for the containment of LNAPL. These technologies are grouped as those based on: free-LNAPL recovery; volatilisation and biodegradation; engineered bioremediation; chemical flushing; in situ chemical oxidation; thermal methods and containment. Key factors in the selection of remediation technologies are identified as: the physical setting; remediation objectives and end points; and impacts of the remediation. These factors are imbedded in the steps presented for selecting a remediation technology for a particular site.

Process descriptions of 20 individual remediation technologies are provided, including how they relate to the key selection factors. To aid the preliminary screening of remediation strategies, tables of generalised effectiveness are presented. Effectiveness is rated in given settings, applicability to concerns, assessment of their impacts and other implementation factors. Such rankings and assessments are multi-dimensional in nature. Those given in the report are general in nature. However, how rankings and assessments will vary dependent on specific remediation objectives is emphasised. Also, the rankings and assessments are indicative and based on what is known of the underlying principles of the remediation technologies. The large number of permutations and lack of well-documented, published case studies on remediation effectiveness prevent greater use of field evidence in general rankings.

Stipulation and measurement of performance indicators are seen as fundamental for assessing candidate LNAPL remediation technologies. Performance indicators are also crucial in evaluating the implementation of particular remediation schemes. Ultimately, performance indicators are also used to decide when remediation should cease. A range of performance indicators applicable to the remediation technologies evaluated here are suggested for use. Also, underlying metrics (e.g. mass of LNAPL removed) are presented on which the performance indicators may be based.

Published Australian case studies were reviewed in an attempt to extract experience and guidance on LNAPL remediation performance in settings of particular significance in Australia. This review revealed a dearth of published case studies. Those readily available covered few of the possible remediation technologies and had a sparse coverage of the possible settings. Particular gaps were encountered in reporting of chemical flushing, in situ chemical oxidation and thermal methods. Surprisingly, some of the free product recovery techniques were also poorly reported. In relation to geological settings, gaps were evident in the experience reported for dual porosity materials and fractured rocks.

Full-scale implementation of an LNAPL remediation strategy is commonly preceded by some form of pilot-scale testing of candidate technologies. Here, the process of pilot testing is discussed in terms of how maximum benefit and appropriately representative results may be achieved. The report discusses appropriate performance indicators and metrics, variability, duration and end points of testing as well as the characterisation required for up-scaling and extrapolation. 

 

- Read Less

CRC CARE Technical Report 17: The Australian experience - A comparative analysis of the effects of contamination and its remediation on individuals and communities at two Australian sites

The potential environmental health risks to people living in proximity to contaminated sites garners legitimate interest by the surrounding communities in how the contamination and subsequent remediation and reuse of the land is managed by government and public agencies, and industry and commercial stakeholders.

+ Read More

The potential environmental health risks to people living in proximity to contaminated sites garners legitimate interest by the surrounding communities in how the contamination and subsequent remediation and reuse of the land is managed by government and public agencies, and industry and commercial stakeholders.

Significantly, studies exploring community perceptions and attitudes to land contamination and the related remediation within the Australian context are extremely limited. This project is designed to address this research gap in response to the need expressed by regulators, site managers and other practitioners in the industry to better understand how Australian communities perceive and experience contaminated land and its remediation.

Two case study sites were selected, both in New South Wales, Australia – the Botany Area (BA), consisting of the Botany Industrial Park and adjoining Southlands site, and the North Lake Macquarie Area (NLMA), consisting of the adjoining industrial sites of Pasminco Metal Sulphide Ltd and Incitec Pivot Cockle Creek. Both study sites have been exposed to a range of toxins from over a century of industrial activity, with the resulting contamination extending beyond the industrial property boundaries into the surrounding residential areas.

A mixed method research approach was adopted to generate primary empirical data on community perceptions of contaminated land and its remediation.  Methods included media content analysis, stakeholder analysis, community surveys, interviews and focus groups. The quantitative outcomes of the telephone surveys conducted are the key focus of this report, supplemented by the results of other qualitative research.

Similarities were found between the experiences and perceptions of the residents in the two case study sites, and those held by other research communities, both in Australia and internationally.

Five themes were identified for exploration in the project, and the following key findings emerged:

1. Levels of concern and interest. The survey showed a clear tendency for people to be concerned about the contamination in their local area, and an interest in keeping up to date with relevant information and with the progress of the remediation process. This was most prevalent in those over 35 years and lowest in those below 35 years of age. Interestingly, while respondents with children living in the household in the BA were more interested in keeping up to date with relevant information than those without children, this trend in interest was true for those without children living in the household in the NLMA. This may be a finding worthy of further research.

2. Risk communication, trust and confidence. While survey respondents from both sites had received their information from a variety of sources, the most frequently reported sources of information were the local media and the remediators, and to a lesser extent the local councils.

A major finding was that the levels of trust were the lowest for those sources from where the majority of information is being received; thus the information was treated as less trustworthy. The information sources that were rated most trustworthy, by respondents from both areas, were more ‘localised’ sources, i.e. community and environmental groups as well as local councils. This finding suggests that there is significant room for improvement in the practice of risk communication. In particular, making better use of sources deemed to be trustworthy, and also improving the trustworthiness of sources that are most readily accessed by residents.

The respondents also voiced concern about the value of information they were receiving, with the (perceived) poor quality and slim quantity appearing to amplify levels of distrust.

3.      Impacts on routines and lifescape. Focus group participants detailed the anxieties about health, distrust and a loss of control the impact of the contamination caused. While some participants indicated these losses were also felt as a result of the remediation, they also suggested they were often ameliorated as a result of the remediation.
 
The impact was felt most significantly within the home and affected the sense of security and safety they associated with their home. In the NLMA this largely involved increased cleaning routines to protect children from lead exposure, while in the BA changes were focused on the restriction on groundwater use.

The research highlighted:

  • how perceptions of the local area and the environment can become a source of concern, anxiety, stress and distrust, and
  • how trust in and reliance on personal experiences, or ‘tangible evidence’, was more highly valued by the communities than the expert, information-based evidence. 

4.      Stigma. A large proportion of residents from both sites believed that other people’s perception of their area was neither better nor worse off as a result of the contamination. A few respondents did however feel that other people’s perceptions were negatively affected by the contamination. There was a distinct difference in how residents felt the media portrayed the contamination between the two sites.
 
5.      Community capacity. An encouraging finding in this theme was the respondents’ strong sense that the community had been able to influence the remediation process. This suggests that proactive efforts from site managers to involve the community are likely to be well received, if presented as a genuine opportunity for involvement.
 
The majority of survey respondents felt that the contamination and remediation had no or little impact on community relationships. The remainder of respondents were split between those who felt it had brought people together and those who believed that it had been divisive. This highlights the importance of considering potential social polarisation. Moreover, focus needs to be given to those forces in the community that generate consensus – the shared acceptance generated through trusted community structures can play a key role, not only in the remediation process, but also with rebuilding levels of individual and community agency.
 
While approximately half of the survey respondents in both areas had discussed the contamination with their neighbours, far fewer had engaged in more active forms of community or individual action. By providing alternative and possibly more accessible opportunities for engagement may be another way for site managers and government agencies to improve affected residents’ level of satisfaction with the contamination management and remediation processes.

The themes explored in this research project, and the findings presented, provide a useful starting point for future research. The results warrant consideration by those charged with the regulation and management of contaminated sites in Australia, contributing to a deeper understanding of community perceptions, which in turn has the potential to inform the development of more effective community engagement practices across this industry.

 

- Read Less

Purchase with PayPal

When you click the Buy Now button you will be taken to PayPal to complete this transaction.

Title
Price
Total
Apply Code
The coupon code you entered was invalid.
×