Moanataiari Project Residents and stakeholders meeting - - PowerPoint PPT Presentation

Moanataiari Project

Residents and stakeholders meeting

www.tcdc.govt.nz/moanataiari

Format of the evening

• History of the subdivision (TCDC)
• Soil testing and results (WRC)
• Public health (DHB)
• What next (TCDC)
• Question time
• Break-away time with experts
• Register to allow soil testing

www.tcdc.govt.nz/moanataiari

The history

1800s: The reclamation formed progressively over 100 years through the use of mine tailings, rocks and dredging from the port. 1960s: There was a cap of clay and weathered rock placed on top of the reclamation from the hills surrounding the site. This capping was completed under controlled conditions in the mid to late 1960s.

www.tcdc.govt.nz/moanataiari

Background

• 2006 - WRC learns of Moanataiari reclamation
• 2007 – Limited testing of soil at Moanataiari

School shows no issues but further testing planned

• WRC investigates one high priority site a year
• 2011 – Moanataiari soil sampling and testing

Sampling overview

• Pattle Delamore Partners (PDP Ltd) contracted to

undertake sampling and reporting

• Main sampling undertaken 26-28 October 2011
• 28 sample locations
• Predominately from roadside verges, avoiding

underground services and access to individual residential properties

• Samples collected from surface down to 1.5 metre depth
• Sent to laboratory for chemical analysis

Sampling locations (28, 3 depths at each)

Testing

• Heavy metals
• Occur naturally – but can some can be at high

concentrations in mine workings

• All samples tested for antimony, arsenic, cadmium,

copper, chromium, lead, mercury and zinc

• Selected samples tested for wider suite of 32 trace

elements to ensure nothing was missed

• Petroleum hydrocarbons where sampling showed

the possibility of problems

Results and final field-work

• Final results reported back from laboratories last

week (Friday pm)

• Final field testing (X-ray fluorescence) undertaken

last week (15 Nov)

• Data for 80 additional locations
• Not a certified technique, but helps to fill the gaps

Results – arsenic at surface

• National Soil Contaminant Standard (SCS)* for

arsenic in residential soils:

• 20 mg/kg (parts per million)
• Applies to surface soil samples
• Exceeded at all 28 locations
• Degree of exceedance from marginal to

substantial

* Source: Resource Management (National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health) Regulations 2011

Results – arsenic at surface

• Highest concentrations: Kuranui Road and east
• Two highest surface results: 320 and 350 mg/kg
• 16 and 17.5 times higher than the Soil Contaminant

Standard

Results – arsenic at depth

• Arsenic concentrations increase with depth
• Two highest deep results: 1020 and 4700 mg/kg
• 51 and 235 times higher than the Soil Contaminant Standard
• However in this case the Soil Contaminant

Standard may not directly apply

• Its main relevance relates to the possibility that this material

may be brought to the surface through excavation.

Preliminary Arsenic Results

Insert PDP plan with As results

National Soil Contaminant Standard (SCS) = 20 mg/kg Human health, residential land use 10% produce consumption

Results – arsenic at depth

• Findings confirm
• Presence of mine tailings material at depth
• The partial effectiveness of the cap
• (Without the cap, surface concentrations would be much

higher)

Inferences

• Results for verge samples indicate potential

issues for residential properties

• Presence of arsenic at the surface will depend on

the soil mixing history

• Each property may need to be sampled

individually

• Unknown mixing history
• Variability between surface sites means we can not infer

results for one property based on results from another

Other contaminants – heavy metals

• Potential issues with other metals at a few

locations

• Thallium
• Lead
• Antimony
• These issues will be fixed by addressing the

arsenic issue

Other contaminants - hydrocarbons

• Total petroleum hydrocarbons (TPH) – tested for

at 11 locations – and not an issue

• Polycyclic aromatic hydrocarbons (PAHs) – tested

for at one location where TPH detected – not an issue (meets Soil Contaminant Standard)

Applying for funding

• MfE has fund available under its CSRF
• Ministry funds up to 50%
• Two-staged funding:
• First stage for property-specific investigation
• Second stage for remedial work where required

Arsenic in soil

What are the potential health issues?

Who is at risk?

• Only serious immediate risk is for very

young children who repeatedly eat soil

• Risk much lower for everyone else
• Simple things will reduce any further

exposure

What is known about arsenic in soil?

• Affects millions globally
• Most have it in water AND soil
• Risk lower in Moanataiari – Thames

water supply unaffected

Reducing arsenic exposure

• Children should not eat or play in soil –

anywhere

• Hand washing, shoes
• Do not eat your home grown fruit and

vegetables for now

• If you still choose to do this
• Scrub to remove dirt
• Peel to remove layer with most arsenic

Soil management

• Well established lawns with no bare patches
• Protect high traffic areas from becoming

muddy or dusty

• matting, wood chips, re sow grass
• Dampen dusty areas in dry weather

What diseases are linked to arsenic?

• Short term:
• Poisoning from high dose consumed over a

short time

• Unlikely from eating soil

Diseases linked to longer term exposure

• All are also common in communities without

arsenic exposure

• Strongest long term exposure links are:
• Cardiovascular disease (heart and arteries)
• Skin cancer
• Bladder cancer
• Other factors probably more important
• Genetic differences, sun exposure etc

Can body arsenic levels be measured?

• Urine levels can be measured
• Results meaningful only if one off exposure
• Cannot easily differentiate between harmful

and harmless forms of arsenic

• Measures exposure in last few days only
• No easy way of removing arsenic from body
• Most goes away naturally over time.

Put this in context …

• As time goes by new risks emerge e.g.

asbestos, lead in petrol

• ALL diseases have many contributing

factors

• Cannot undo earlier exposure
• Reduce future exposure
• Be aware of small increase in risk
• Priority is protecting the young – keep their

exposure low

www.tcdc.govt.nz/moanataiari

What happens next

Finalising results and report

• Not all results have been analysed
• Full draft report from soil sampling is

due from the contractor PDP (earliest Friday 25/11)

www.tcdc.govt.nz/moanataiari

What happens next

• Manage community health and implement

MoH advice

• Council is checking public land and helping

the ‘schools ‘

• Seek funding from the MfE's CSRF to

begin testing all private property

www.tcdc.govt.nz/moanataiari

What happens next

• Seek property owners permission to test
• After the testing we will make contact again

with the results and the various options available to address

• Establish a multi-agency project and

governance group

• Community forums at the primary school –

start next week

www.tcdc.govt.nz/moanataiari

Question and Answers

www.tcdc.govt.nz/moanataiari

Housekeeping

• Stay in contact, register with us so we can

keep you informed by post or email

• Permission to test on private property form
• Experts available to take your questions at

the back of the hall