Assessment of public health risk from the remediation of the former Fruitgrowers

Chemical Company site, Mapua:challenges and lessons learned

Wasteminz Conference October 2010

Dr Jill SherwoodNelson Marlborough DHB Public Health Service

Outline of Presentation

Background and context of the investigation

What we found

Conclusions

Challenges

Lessons learned

Background

Site activities Pesticides factory,

mineral processing plant, private landfill

1932 – 1988 Site left “orphaned” Historic

contamination Environmental and

public health risk assessed in 1990s

Remediation planned

Location of Mapua Site

Protected disclosure

Mapua Site remediation commenced 2004Concerns raised about remediation process 2006Agencies involved in investigation

Parliamentary Commissioner for the Environment, Ministry of Health, Department of Labour

Public Health Service involvement Requested to undertake investigation for MoH

Public Health Brief

Investigate the possibility of risk to public health

Risk of exposure to any emissions and discharges

Risk to health of the population From the start of the remediation

Approach

Information gathering Identify possible hazards Resource consent conditions for protection of public

health and review of monitoring results Community concerns

Risk assessment of hazards of concern Chemicals included in the total hazard index other hazards if health impact appeared possible

Hazards

In the soil or groundwater Testing prior to remediation Baseline sampling early in the remediation Unexpected finds during the remediation

Resulting from the remediation process By-products formed in soil dryer By-products formed in MCD reactor

Other Dust Noise and/or vibration Odour

Exposure Potential

Summary as how hazards might leave the Site Stack emissions

Fugitive emissions

Groundwater discharges

Site activities during remediation (early 2007)

Treated “fines”

Issues re Exposure Information

Monitoring not all contaminants of concern monitored PM10 not monitored PUF filters not suitable to measure TSP Tahi Street monitoring station location No background monitoring station

Modelling OCPs – poor correlation Dioxins – uncertainty due to assumptions in

model

Conclusions

Risk if Site left unremediated OCP exposure - soil and marine environment

OCPs reduced to acceptable levels in soilPublic health risk resulting from remediation

Low – negligible for a few chemicals during remediation Low and manageable for a few chemicals post

remediation Unknown for a few chemicals – expert advice

recommended on further environmental/biological testing

Noise and vibration – nuisance/irritation

Public Health Risk During Remediation

Contaminant Exposure Health RiskPM10 (Likely) numerous (Likely) low-medium

Ammonia (Likely) low (Likely) very low

Dioxins(period of concern Nov 04-March 06)

Probable Unknown

PCBs (non-dioxin like) Possible Unknown

Benzene Possible Unknown

OCPs, arsenic Low (north and west of Site)

Possible (south of Site)

NegligibleUnknown

OCPs groundwater Drinking water – UnlikelyIrrigation - Possible

NegligibleUnknown

OCPs shellfish Unlikely (notices in place) Negligible(notices in place)

Public Health Risk Post Remediation

Contaminant Exposure Health Risk

Ammonia in soil on Site Unlikely Site tests show very low levels

OCPs in soil on Site Possible for DDX (await testing)

Uncertain (await testing)

OCPs groundwater Drinking water – UnlikelyIrrigation - Possible

NegligibleUnknown

OCPs shellfish Unlikely if advisory notices in place

Negligible if notices in place

Challenges

Complexity of the science

Missing historical data

Lack of / poor quality monitoring data

Incomplete temperature records for dryer

Community concern - keeping them informed

Range of agencies involved in investigation

Lessons learned for future similar projects

Have flexible approach – recognise may need to adaptShould have Peer Review Panel to oversee project with appropriate range of skills for the projectMedical Officer of Health or representative should be on panelBe aware of potential and risk from fugitive emissions when remediation site is in residential areaRobust Proof of Performance testing under normal operating and site conditionsA statutory review condition in all consents that includes:

“Reviewing monitoring requirements”

Acknowledgements

• My colleagues at Nelson Marlborough DHB Public Health Service: Dr Ed Kiddle and Geoff Cameron

• Dr Deborah Read, Ministry of Health