New Zealand map Davis Ogilvie – Engineering, Surveying and Planning

Environmental Science

Our Environmental Team is primarily focused on the investigation and management of contaminated land. Our services can be provided as part of a multi-disciplinary project involving planning, surveying and engineering; or as a stand-alone service for any project requiring contaminated land expertise.

As required by the NESCS legislation our contaminated land investigation and management works are led / undertaken by our Suitably Qualified and Experienced Practitioners (SQEP). Our lead consultant is a Certified Environmental Practitioner – Site Contamination Specialist (CEnvP – SC).

Please contact our experienced environmental scientist below for further information.

Our contaminated land services include:

  • Identification of potentially contaminated land
  • Consenting and planning advice, including discharge consents from contaminated sites
  • Preliminary Site Investigations (PSI)
  • Detailed Site Investigations (DSI)
  • Remedial Action Plans and/or Site Management Plans
  • Remedial Works
  • Site Validation Reports
  • Monitoring and Management Plans

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Detailed Site Investigation (DSI)

A DSI involves intrusive techniques to collect field data and soil samples for analytical testing to determine concentrations of contaminants of concern. A DSI is needed if a PSI indicates a HAIL activity is more likely than not to have occurred and may present a risk.

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A DSI is effectively a PSI with the addition of sampling. In addition to the PSI scope of works:
• Collection of soil samples. Depending on the proposed activity or reason for the DSI and results of the desk study (PSI), the samples will be collected on a random, targeted or combined random and targeted basis from the areas of the site identified being potentially effected by identified HAIL activities
• Analysis of samples for identified contaminants of concern typically including heavy metals, asbestos, and at least one of a variety of potential organic compound contaminant groups such as organochlorine pesticides (OCPs) or polycyclic aromatic hydrocarbons (PAHs).
• Preparation of an investigation report that includes comparison of soil analytical data with relevant Soil Contaminant Standards (SCS) and comment on NESCS compliance and soil management requirements.

• We own and operate a field X-Ray Fluorescence Analyser (XRF) that enables real time analysis of soil samples for heavy metals in the field. Use of this instrument enables:
o Collection of more data than typical site investigations, resulting in a higher degree of confidence in investigation conclusions
o Real time screening enables onsite preliminary advice regarding likely contamination management requirements.
o Quality control on XRF data is undertaken by laboratory analysis
• The NESCS is soil contamination and human health risk focused, and accordingly DSIs are typically focused on these contamination scenarios. However other contaminant phases may be present (for example groundwater, vapour/landfill gas, surface water) that may present a risk to human health and/or contamination may be present that presents a risk to the environment. We are able to assess and advise on alternative receptors and/or contaminant phases on a site specific basis as and if required.

Preliminary Site Investigation (PSI)

The main objectives of a PSI are to gather information about a piece of land to determine whether it may potentially be contaminated, to assess the suitability of the land for its current or intended use, and/or to design a Detailed Site Investigation (DSI), if a DSI is required.

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A PSI comprises of
• A desk top study including (but not limited to) a review of the Council property file and Land Use Registers, available historic aerial photographs and any other existing reports on the site
• A site walkover inspection to identify potential HAIL activities and/or visual indicators of potential soil contamination
• Preparation of a report detailing the investigation methodology and findings.

Depending on the proposed activity (for example a subdivision) we will recommend progression to a Detailed Site Investigation prior to completion of the PSI if HAIL activities that may result in a risk to human health are identified.

Environmental FAQs

Why you need a Contaminated Land Specialist

The introduction of the Resource Management (National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health) Regulations 2011 (NESCS) changed the way contaminated land in New Zealand is managed. The NESCS applies to any site where an activity on the Hazardous Activities or Industries List (HAIL) “has or is more likely than not to have, occurred”, and covers a number of activities onsite including:
• Change of land use, for example from production (farm) land to residential use
• Subdivisions
• Soil Disturbance and Soil Removal

Undertaking the above activities on sites where a HAIL activity has been identified, or is suspected, requires investigation of the site and potentially an application for contaminated land related consents and / or contamination management works.

As required by the NESCS legislation our contaminated land investigation and management works are led / undertaken by our Suitably Qualified and Experienced Practitioners (SQEP). Our lead consultant is a Certified Environmental Practitioner – Site Contamination Specialist (CEnvP – SC).

What we need from you for the contaminated land investigation

We need to know what changes are proposed to your site and if possible, the required scope of works. If you have any information on HAIL or potential HAIL activities this would be useful.

My site is on the regional council listed land use register (LLUR), what does this mean? 

This means your site has been identified as having (verified) or ‘more likely than not having’ (unverified) an activity on the HAIL list that may have resulted in ground contamination.  This means the requirements of the NESCS legislation may apply to activities on the site.

What is a “SQEP”? 

A ‘Suitably Qualified and Experienced Practitioner’, is required under the NESCS legislation to certify contaminated land reports (PSI, DSI, Remediation Action Plans etc).  Our lead consultant is a SQEP and a Certified Environmental Practitioner Site Contamination Specialist (CEnvP – SC) with with over 25 years’ experience across a wide range of industries, contaminant types and contaminant mediums (soil, groundwater, sediment and vapour).

Can Davis Ogilvie manage asbestos? 

Our contaminated land team has significant experience in the investigation, remediation and management of asbestos contamination of soils and are qualified to do so.  We are not qualified asbestos removalists and so do not undertake building assessments,  demolition surveys or directly supervise building demolition works.

How is an investigation undertaken? 

Preliminary site inspections typically involve a desk study plus a site visit and inspection.  Ideally interview of site owners and on site personnel would also occur during the desk study or site inspection phases.  If collection of samples is needed it is usually undertaken using manual sampling techniques with trowels or hand augers.  Machine excavation of test pits and/or machine boreholes may be needed depending on the size of the site, ground conditions and investigation goals.

What type of contaminants are likely to be present?  

This is entirely dependent on the type of HAIL activity.  However, experience across many hundred sites indicates the most common contaminants encountered are heavy metals (for example arsenic and lead), petroleum hydrocarbons, polycyclic aromatic hydrocarbons, organochlorine pesticides and asbestos.

Am I, my family or workers at risk? 

This depends on the type of contamination that’s present, concentrations present, site use and potential exposure.  Ideally potential risks would be identified by undertaking investigations.  However, dependent on the available information, we are happy to talk through the likely risks and possible management options with you, with no obligation or initial consultation charges.  You can click on the below link to arrange a 30-minute session with our expert.


Warren Sharp

Senior Environmental Geologist
027 700 7603