Environmental Scientists, Montgomery Watson Harza, conducted the investigations of Lyn Christie Place. A comprehensive report has been produced by them, including recommendations for the Council to take certain actions.

Please find attached a copy of the executive summary of Montgomery Watson Harza’s report. A full copy of this report can be obtained from the Property Unit of Christchurch City Council (Civic Offices, Tuam St).

Montgomery Watson Harza have stated in their report to the Council that:

1. Settling of floors exists in some units. However, structurally, the buildings are satisfactory from a health and safety perspective.

2. Very low(trace) levels of methane gas is detectable in some places below the ground and in some units. There is no concern about health and safety due to this.

3. Soil samples identified elevated levels of polycyclic aromatic hydrocarbons (PAHs) and heavy metals that exceed the relevant guidelines.

4. Shallow groundwater flow direction underneath the site is variable. Water quality testing identified elevated levels of arsenic, ammonia, manganese, iron and boron, when compared to New Zealand drinking water standards.

(Please note that the groundwater system beneath Lyn Christie Place is stratified into several aquifers separated by clay layers. Drinking water is not drawn from shallow groundwater (less than 15m). Water supplied to Christchurch households comes from deeper, protected aquifers. In the Linwood/Wainoni area the shallowest public water supply aquifer is approximately 130m below the ground surface).

Montgomery Watson Harza have reported (p35) that "the concentrations detected in the groundwater below Lyn Christie Place do not pose a risk to human health given that the local supply is derived from the city’s reticulated drinking water system, which originates from deeper bores" and (p28) that "the offsite movement of groundwater does not provide a significant risk to human health or environment above that of comparable urban, shallow groundwater in this part of the city ".

Recommendations provided by Montgomery Watson Harza, ratified by Environment Canterbury and Crown Public Health, to remediate the issues identified at Lyn Christie, are listed below. The Council’s decision relating to each recommendation follows in italics.

Recommendation: Raise the floor of each unit to restrict damage from settling, by injecting resins.

• (The Council will trial the injection of resins underneath the floors to restrict damage from settling)

Recommendation: Undertake a further one-off test for Landfill Gas (LFG) before the end of this year (p22).

• (The Council will undertake a further one-off test for LFG within this timeframe)

Recommendation: Removal and replacement of designated areas of soil, in order to minimise tenants’ exposure to contaminants (p15).

• (The Council will remove all soil in garden areas to a minimum depth of 500mm, and replace it with clean material. Tenants will be compensated for loss of vegetables currently growing).
• (The Council will install an irrigation system for the grass lawn area in order to maintain healthy grass cover).

Recommendation: Develop a specific Remedial Action Plan / Site Management Plan for the property and housing complex (p16).

• (The Council will develop a comprehensive Remedial Action Plan and Site Management Plan for Lyn Christie Place and the land upon which it is built. Procedures included in the plans will ensure the health and safety of the tenants and workers at Lyn Christie Place throughout remediation process and afterwards).

The Council is strongly committed to providing our tenants with a healthy and safe environment in which to live, and to providing current and accurate information about the issues as we become informed ourselves.

We have carefully carried out the investigations of the Lyn Christie Place, and worked in close consultation with Crown Public Health and Environment Canterbury to identify the issues and work towards appropriate solutions.

Dr Mel Brieseman, Medical Officer of Crown Public Health, has made the following statement regarding Lyn Christie Place:

"I have considered the matters raised in the ‘Lyn Christie Place Site Investigation’ report to the Christchurch City Council produced by Montgomery Watson Harza and discussed the issues with those involved. I feel that the issues involved are well covered and that if the recommendations made in the report are implemented the site will not constitute a risk to human health".

Helen Davies, Senior Contaminated Sites Officer of Environment Canterbury, has made the following statement regarding Lyn Christie Place:

"I have been kept informed of the investigative work conducted at Lyn Christie Place. The assessment of results, and the discussions held with involved parties about future work indicate that environmental concerns are being addressed in a responsible way".

What will happen next?

• Housing Officer John MacDonald will visit each tenant to establish the quantity of vegetables to be removed, so that compensation can be arranged.
• Replacement of garden soil will begin in the next fortnight. The Council aims to have all garden areas remediated early in 2002.

Any questions regarding this statement should be directed to the following

Tenants enquiries: John MacDonald , Housing Officer, on 379 1660 extension 8519, or on his mobile phone (025) 372 077.