moanataiari project

Moanataiari Project Residents and stakeholders meeting - PowerPoint PPT Presentation

Moanataiari Project Residents and stakeholders meeting Format of the evening - History of the subdivision (TCDC) - Soil testing and results (WRC) - Public health (DHB) - What next (TCDC) - Question time -

  1. Moanataiari Project Residents and stakeholders meeting

  2. 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

  3. 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.

  4. 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

  5. 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

  6. Sampling locations (28, 3 depths at each)

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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.

  12. Preliminary Arsenic Results Insert PDP plan with As results

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

  14. 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)

  15. 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

  16. 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

  17. 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)

  18. 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

  19. Arsenic in soil What are the potential health issues?

  20. 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

  21. 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

  22. 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

  23. 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

  24. What diseases are linked to arsenic? • Short term: • Poisoning from high dose consumed over a short time • Unlikely from eating soil

  25. 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

  26. 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 .

  27. 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

  28. 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)

  29. 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

  30. 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

  31. Question and Answers

  32. 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

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