Environmental

In most cases yes. For any subdivision Council will require a site history check, or Preliminary Site Investigation (PSI). This is to establish if there is a risk from historical or current activities that might (have) cause(d) soil contamination. A Detailed Site Investigation (DSI) involving soil samples is required if the PSI identified potential contamination, or if the site has been flagged for known HAIL¹ activities. Residential subdivisions often require the removal of topsoil. Savvy developers will require a pre-purchase investigation to inform possible soil disposal options.

¹ Regional councils maintain a database of sites with known activities listed on the Hazardous Activities and Industries List (HAIL)

In many cases yes. Straightforward PSI and DSI investigations are usually offered for a fixed price. Call us further to discuss your plans.

For standard investigations we offer fixed fees so there are no surprises.

The NES-CS applies to land with known or potential HAIL activities AND an activity like subdivision, a change in land use (e.g., from farming to residential), soil disturbance or removal or replacing a fuel storage system. A PSI is usually required to establish if HAIL activities occur on the land or have occurred in the past.

Environmental investigations are typically staged as follows:

1. A desktop study of the site’s history and walkover (called a Preliminary Site Investigation, or PSI)
2. Soil sampling and analysis (called a Detailed Site Investigation, or DSI)
3. Recommendations for remediating or managing contamination if required (called a Remedial Action Plan, or RAP)
4. Long-term site management (e.g., if contaminated soil has been contained on site)

If contamination is found, you may need to develop a remediation or management plan to deal with it. This could involve removing contaminated soil, capping the site, or treating the contamination on-site. The goal is to reduce risks to human health and comply with environmental regulation.

The NES-CS (National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health) is designed to protect human health from contaminants in soil. Different soil contaminant standards apply for different land uses like residential, recreational and commercial. The NES-CS and associated Contaminated Land Management Guidelines set out requirements for investigating contamination and provide guidance on managing contaminated land to protect people living or working on the site.

An environmental investigation under the NES-CS is important because it makes sure that e.g., garden soil in a residential development is not contaminated with asbestos, lead or other contaminants. Contaminated soil is usually removed from the land prior to the development of the subdivision. Most soil cannot be disposed of as cleanfill, i.e., soil disposal costs including transport and gate fees at a managed landfill are usually unexpected and very expensive!

By doing a thorough investigation prior to buying the land will avoid expensive surprises. This step ensures that the developer can make informed decisions before committing to subdivide or develop a site.

There are hundreds of contaminants associated with the 51 activities listed on the HAIL. The most common contaminants in residential developments are arsenic, lead and asbestos. Sometimes there are other heavy metals like chromium, and mercury. Heavy metals usually accumulate in topsoil from removing lead-based paint from weatherboard-clad houses and fences, or historical lead-arsenate applications to market garden areas that have become residential decades ago. Lead-arsenate was the most common insecticide in the early 1900s that was later replaced by organochlorine pesticides (DDT and the like). The trouble with heavy metals in soil is that they don’t decay, so lead-arsenate that has been applied around 100 years ago is still in the soil today. Asbestos also remains in soil indefinitely, and the half-life of DDT in New Zealand is 5-15 years, i.e., some 6% of a DDT application in the 1970s may still be in the soil today.

The turnaround for a PSI is usually three weeks but can be faster if required. Detailed Site Investigations take 1-2 weeks longer including soil laboratory times which are usually one week.

You can check with your regional council, as they maintain a contaminated land register with records of sites that have been used for hazardous activities. These records are ‘work in progress’, i.e., an unregistered site does not guarantee that the land is not contaminated.