Contaminants in kai – Te Arawa rohe
The reports describes:
1. The methods of sampling & analyses used based upon questionnaires completed by iwi members.
2. Results for bioaccumulative contaminants, e.g. DDTs, PCBs, heavy metals, arsenic.
3. A discussion of the significance of these results to respective Iwi.
4. Recommendations for future research.
Questionnaires were used to survey Te Arawa iwi members about their past and present consumption rates of traditional kai species. Hair samples were also collected from Te Arawa participants to assess possible exposure to mercury, a highly accumulative contaminant. Fish and/or shellfish (including longfin or shortfin eel, rainbow or brown trout, koura, pipi, mussel, flounder and kakahi) and watercress samples were gathered from multiple important harvesting sites in the different regions, and tested to assess their bioaccumulative contaminant levels. Aquatic sediments, which are known to concentrate contaminants on organic material, were sampled from these locations as well.
Analytical data for fish, shellfish and sediment samples was collected for a range of organochlorine compounds, including DDT (historically used as a pesticide), chlordane (a pesticide) and dieldrin (an insecticide), arsenic (As),and heavy metals e.g. cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni) and zinc (Zn). Eel and/or trout fillets were also analysed for selected polychlorinated biphenyls (PCBs). Watercress was analysed for heavy metals and arsenic only.
Highest total DDT (ΣDDT) concentrations in Te Arawa rohe were detected in trout from the Upper Puarenga Stream site whereas the concentrations of ΣDDT were generally much lower in eels. Mercury concentrations in Te Arawa Rohe were generally highest in trout tissue, with the highest concentrations found at the Upper Puarenga Stream. Arsenic, cadmium and nickel concentrations were highest in pipis and mussels collected from the Maketu site and copper concentrations were higher in koura than any other species, with the highest concentrations ranging in Lake Rotokakahi and in Lake Okareka in Te Arawa rohe. The average concentration of mercury in the hair samples of Te Arawa iwi was three times higher than the study reference group and twice that of New Zealander’s who consume 1-4 meals of fish per month. The low number of Te Arawa responders in this study meant it was not possible to analyse potential links with consumption of wild kai.
The ANZECC interim sediment quality guideline (ISQG) low values in Te Arawa rohe were exceeded for arsenic and mercury at 55 percent of sites sampled and for cadmium at 10 percent of the sites. The ANZECC ISQG high guideline value for arsenic was exceeded at 15 percent of sites and at 25 percent of sites for mercury. Based on the ratio of sediment to tissue metal concentrations, bioaccumulation “hotspots” were identified at Maketu (for shellfish), the Lower Kaituna site (for whitebait) and the Ohau Channel (for smelt).
This health risk assessment using local iwi data on meal size and weekly consumption showed that mercury and arsenic were the primary contaminants of concern for Te Arawa iwi. The risk assessment indicated that there may be an increased risk to members of the Te Arawa iwi from long-term consumption of trout, pipi, mussel and watercress. Current consumption rates for eel are also close to exceeding safe levels. If kai was mostly gathered at the more contaminated sites then a significant risk exists when eating trout, eel and pipi.
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Citation proposal
Chris Hickey (NIWA) - Michael Stewart (Streamline Environmental Ltd) - Ngaire Phillips (Streamline Environmental Ltd). . https://dc.niwa.co.nz:/niwa_dc/srv/api/records/da042e8f-4b21-78a2-e867-76c20de5b59f |
Simple
- Date ( Creation )
- 2015-06-15T00:15:00
- Date ( Revision )
- 2015-06-15T00:15:00
- Purpose
- The aim of this study was to quantify the risk to Te Arawa iwi members by consuming wild kai gathered from their respective rohe (or regions), e.g. Te Arawa (Rotorua)
- Credit
- Authors: Ngaire Phillips, Mike Stewart, Greg Olsen, Chris Hickey – NIWA Hamilton, Gail Tipa – Tipa & Associates. The research was funded by the Health Research Council of New Zealand, Contract HRC/207. We thank the Te Arawa Lakes Trust, especially Hera Smith, Willy Emery and Roku Mihinui for their efforts in garnering enthusiasm and participation, disseminating knowledge about the project, and for their general support. We also thank Eddie Bowman, Joe Butterworth and Ian Kusabs for sample collection. Organic contaminant data for organochlorine pesticides and PCBs was generated by NIWA. Heavy metals data were generated by Hill Laboraotries.
- Status
- Completed
Author
NIWA
Point of contact
Author
Streamline Environmental Ltd
Author
Streamline Environmental Ltd
Point of contact
- Spatial representation type
- Vector
- Topic category
-
- Biota
- Environment
- Health
- Description
- Rotorua lakes region and Maketu
N
S
E
W
- TimePeriod
- 2009-09-01T00:00:002011-08-16T00:00:00
-
- Te Arawa Iwi, Rotorua, biota, bioaccummulative contaminants, sediment contaminants, organochlorine pesticides, DDT, arsenic, mercury, heavy metals, risk assessment
- NIWA Project Codes
-
- HRC08201
- Use limitation
- Only a small number of people completed the kai consumption questionnaire and only a low number of larger species (i.e., eel and trout) were collected from some sites, therefore, caution must be taken when applying consumption limits on a site by site basis. It should also be noted that only a small amount of the total arsenic detected in the kai samples is likely to be toxic. While our calculations of risk take this into account, without further study we cannot know this amount exactly. Therefore, the risk calculations where arsenic is the main contaminant of concern should be viewed with caution.
- Other constraints
- Data held by Te Arawa Lakes Trust.
- Use limitation
- Data may be obtained from Te Arawa Lakes Trust or point of contact (see above).
- Classification
- Restricted
- Language
- English
mdb:MD_Metadata
- Metadata identifier
- da042e8f-4b21-78a2-e867-76c20de5b59f
- Language
- English
- Character encoding
- UTF8
Custodian
NIWA National Institute of Water and Atmospheric Research
301 Evans Bay Parade
Hataitai
Wellington
6021
New Zealand
- Resource scope
- Dataset
- Date info ( Creation )
- 2015-06-18T08:30:21
- Title
- ISO 19115-3
Overviews
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Views
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Associated resources
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NIWA - Metadata Catalogue