Impacts of Bioaccumulative Contaminants in the Te Waihora Catchment on Mahinga Kai Gatherers: Data Report and Risk Assessment.
A kai consumption survey was completed by 34 whānau members in 2013 which provided the underpinning knowledge required to understand the spatial dimensions of whānau interactions with mahinga kai sites and species in the Te Waihora catchment. Selected mahinga kai species were sampled from Te Waihora catchment in November 2013, including longfin and shortfin eel (tuna), brown trout, wai kākahi (freshwater mussels), swan eggs and watercress, along with other important taonga species such as raupō (bullrush). In addition, the surficial sediment that is in contact with lower trophic species, from which bioaccumulation up the food chain occurs, were also sampled at the same time to provide information on potential source “hotspots” of contamination. Bioaccumulative contaminants, including heavy metals (e.g., mercury, arsenic) and organochlorine contaminants (e.g., DDT, PCB, dieldrin), were measured in the samples collected. The contaminant concentrations in mahinga kai species were then compared with national and international studies and the levels in commercially produced applicable foods.Sediment heavy metal concentrations were all below Australian and New Zealand Environment Conservation Council (ANZECC) Low Interim Sediment Quality Guidelines (low-ISQG).Total organic carbon normalised ΣDDT concentrations in sediments from Taumutu Lagoon, Halswell River and the Kaituna River were above ANZECC low-ISQG, suggesting that these are potential organochlorine “hotspots” in Te Waihora catchment. ΣDDT concentrations were similar in Te Waihora eels when compared to international studies, while ΣPCB concentrations were orders of magnitude less.
This study highlights two valid, but differing, approaches to assessment of risk. While the US EPA-based risk assessment illustrated a small but increased risk in consumption of most mahinga kai species from Te Waihora catchment - no FSANZ regulatory limits were exceeded. It is important to note that although based on sound scientific principles, the setting of FSANZ regulatory limits is not as scientifically transparent as the US EPA risk assessment procedure. Comparisons between regulatory limits and consumption limits suggest that New Zealand regulatory bodies use a less conservative risk profile than the US EPA risk assessment when setting their maximum limits.
This report is concerned with contaminants that are a long-term (chronic) risk to human health. As such, the contaminants analysed in this risk assessment are environmentally persistent, have a tendency to bioaccumulate in biota and are known (or suspected) to be toxic to humans.
This study has significantly increased understanding of risks associate with consumption of kai from Te Waihora. It presents the results of a preliminary human health risk assessment that is based on relatively few samples collected across a large variety of mahinga kai species and a broad spatial area.
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Citation proposal
Greg Olsen (NIWA) - Mandy Home (NIWA) - Chris Hickey (NIWA) - Michael Stewart (Streamline Environmental Ltd). . https://dc.niwa.co.nz:/niwa_dc/srv/api/records/d585ffdb-d5aa-2d66-dbfd-14a4dadd4fd2 |
Simple
- Date ( Creation )
- 2015-06-12T02:01:00
- Date ( Revision )
- 2015-06-12T02:01:00
- Purpose
- One of the overarching goals of the Whakaora Te Waihora Joint Cultural and Ecological Restoration Plan (WTW) is to restore mahinga kai, so that whānau will be able to gather where they want to, using the methods they are accustomed to. In 2012 the WTW identified three key research questions relating to mahinga kai that are addressed in this report: 1. Are mahinga kai safe to eat from the lake and the specified catchments in WTW? 2. What standards are available to use as a test for mahinga kai health? 3. What water quality/quantity/pollution standards need to be met to enable whānau to continue to exercise the full extent of their customary rights - i.e., taking mahinga kai whenever they require.
- Credit
- Authors: Erica Williams, Chris Hickey, Greg Olsen, Mandy Home, Michael Stewart, Gail Tipa. Whakaora Te Waihora is a cultural and ecological restoration programme led by Te Waihora Management Board, Te Rūnanga o Ngāi Tahu and Environment Canterbury with funding provided by the Ministry for the Environment. We thank Te Waihora Management Board and ngā rūnanga whānau for guidance in this project. Heavy metals results were produced by Hill Laboratories. Organic contaminant data for organochlorine pesticides and PCBs were generated by NIWA.
- Status
- Completed
Point of contact
Author
NIWA
Author
NIWA
Author
NIWA
Author
Streamline Environmental Ltd
- Spatial representation type
- Vector
- Topic category
-
- Health
- Description
- Canterbury Region-Lake Ellesmere/Te Waihora
N
S
E
W
- TimePeriod
- 2013-11-05T00:00:002014-11-18T00:00:00
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- Te Waihora, Lake Ellesmere, Bioaccumlative contaminants, PCBs, organochlorine pesticides, DDT, heavy metals, risk assessment, sediment contaminants, Mahinga Kai, Wild food, tuna, eel, trout, flounder
- NIWA Project Codes
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- ENC13513
- Use limitation
- Funding for the study was provided by the Ministry for the Environment and produced in consultation with Te Waihora Management Board, Te Rūnanga o Ngāi Tahu and Environment Canterbury. Contact Erica Williams (email details above) in the first instance.
- Use limitation
- Contact Erica Williams for access to report/data.
- Classification
- Restricted
- Language
- English
mdb:MD_Metadata
- Metadata identifier
- d585ffdb-d5aa-2d66-dbfd-14a4dadd4fd2
- 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 )
- 2015-06-15T14:51:40
- Title
- ISO 19115-3
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Access to the portal
Read here the full details and access to the data.
Associated resources
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NIWA - Metadata Catalogue