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Soil and Water Contamination

Soil / Contamination


Benbow Environmental has extensive experience in undertaking assessments to determine the extent and nature of potential, or known existing site contamination and its potential risk to human health and/or the environment.  An assessment is typically needed to satisfy a requirement of a Development Application (DA)  or to determine potential environmental liabilities, prior to purchasing a site.  Our services include:


Preliminary Site Investigation (PSI previously termed Phase I)

A desktop study is undertaken of all available documentation and information regarding a site’s history to determine whether contamination is likely to exist at the site. A site visit and inspection is also undertaken to verify site conditions, such as its layout, fitness of the hardstand and stormwater channels.


The information is assessed and presented in the report that will provide a statement regarding the site’s contamination status and/or recommendations as to whether further investigation is warranted such as a Detailed Site Investigation (DSI). If further investigation is recommended, the PSI would dictate the direction of the DSI regarding what soil contaminants are likely, whether groundwater is potentially impacted or the potential presence of soil vapour.


Detailed Site Investigation (DSI previously termed Phase II)

A DSI is undertaken when it is known or is highly likely that contamination has occurred onsite either from historical or recent activities. Typically, a PSI has identified the contaminants of concern requiring investigation.  A DSI is a comprehensive investigation for specific or broad site contaminates in soils and/or water involving chemical testing of samples taken from the site’s media. Groundwater is usually included in a DSI but may not be required if contaminants identified in the PSI are highly unlikely to impact the site’s groundwater.


Laboratory results obtained from sampling are used to define the nature and extent of site contaminants. This information is then used to assess whether an unacceptable risk to human health or to the environment exists as a result of the proposed land use. If a risk exists, the DSI will provide recommendations on what remedial action is required to make the site fit for its intended future use.


Limited Site Investigation

This is where contamination is known or expected within a localised or small area, often due to improper storage procedures or an incident such as a spill (diesel etc.), or of poor demolition practises such as asbestos containing material found on surface soils after the removal of an old structure. Typically, this investigation being limited in size or scope is a cost-effective way to determine the risk to the site from an incident and can allow targeted remediation to follow if required, such as removing impacted soils or employing known and effective remediation techniques to treat soils or groundwater onsite.


Remedial Action Plans (RAP)

A RAP is required when soil and or groundwater contamination, as identified in the DSI, requires treatment. Contaminated media is either removed, or treated onsite to reduce contaminants to levels where they no longer pose a risk to either human or environmental health for the site’s proposed future use.  Benbow Environmental can develop a RAP to ensure that site contamination is adequately cleaned prior to development.  We have extensive experience particularly involving sites contaminated with asbestos, petroleum hydrocarbons and unknown waste materials utilising methods such as bioremediation, microbes, barrier methods, soil amelioration, capping and removal of contaminated media.


Validation Report

Once a site has been remediated, Benbow Environmental can assist in undertaking sampling and analysis to verify the site has been adequately cleaned to a standard that presents no further health risks.


Waste Classification & Management

Benbow Environmental offers services to the building and manufacturing industries. NSW legislation requires any excavated soil material that is to be removed from a site, must be assigned a waste classification before leaving the site. Additionally, where it is known that a site contains or potentially contains contaminated waste material (such as soil or sand stockpiles), or generates toxic or contaminated waste as a byproduct of production processes (such as foundries), Benbow Environmental can sample, analyse and classify all wastes in accordance with relevant State agencies’ guidelines and legislation.


Site Management Plans

Benbow Environmental can assist with the on-going management of contaminated sites, including legislative requirements, performing monitoring tasks such as sampling surface water, groundwater or soil gas monitoring wells.


Acid Sulfate Soils (ASS)

Acid Sulfate Soils are naturally formed soils containing iron sulfides that become toxic when exposed to air.  They are commonly found in estuarine environments and low-lying coastal floodplains. Many coastal urban homes and businesses have been built on ASS. Such soils do not pose a risk if left undisturbed. However, excavation of ASS may be necessary when installing underground infrastructure such as piping or cabling, or building footing or even for a swimming pool.  


Benbow Environmental provide the following services in relation to ASS,


  • Initial screening assessment to identify the likely presence of ASS;

  • Soil sampling and analysis;

  • ASS Management Plans (typically required by Councils when proposed site work is likely to encounter ASS); and

  • Application of relevant legislated guidelines.

Water Contamination


Benbow Environmental can also undertake sampling for various water environments including for ongoing monitoring purposes. These include:

  • Stormwater sampling and analysis. - Some EPA Environment Protection Licences requires facilities to know the expected level of contaminants in their site’s stormwater before it is discharged off site. Sampling for this must occur during certain wet weather events, requiring flexibility on behalf of the sampler to be able arrive onsite within a timeframe compliant with EPA guidelines. Benbow Environment can work with facilities to be able to sample during wet weather events during or outside of typically business hours without a facility incurring exorbitant costs.

  • Surface water sampling and analysis from streams, lakes or ponds. – Benbow Environmental is experienced in collecting representative samples from water bodies and adheres to EPA guidelines and Australian Standards;

  • Sampling groundwater (g/w) monitoring wells. - Benbow Environmental is experienced in sampling g/w for a variety of contaminants from either deep or shallow aquifers. Typically this is performed during a DSI, however, management of some sites (such as historical landfills) require ongoing monitoring for leachate in g/w. Benbow Environmental is experienced in sampling and the analysis of potential g/w contaminants.

  • Installation of groundwater monitoring wells. Typically, we use contractors whom we have an established trusted relationship. We are onsite during all fieldwork and work with our contractors during the installation procedure to ensure wells are not only installed correctly for site specific needs but at the location and depth required to capture contamination in the g/w.

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