Samples of oysters from multiple sites in the Manukau Harbour and transplanted mussels from multiple sites in Auckland estuaries and Waitemata Harbour were analysed for %lipid, organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Analytical data for oysters and mussels were presented along with analytical procedures, methods and a quality assurance summary. The report includes lipid-normalised data sets of selected contaminants for comparison with earlier data sets.

Samples of oysters from multiple sites in the Manukau Harbour and transplanted mussels from multiple sites in Auckland estuaries and Waitemata Harbour were analysed for %lipid, organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Analytical data for oysters and mussels were presented along with analytical procedures, methods and a quality assurance summary. The report includes lipid-normalised data sets of selected contaminants for comparison with earlier data sets.

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.

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 Arowhenua iwi members about their past and present consumption rates of traditional kai species. Fish and/or shellfish (including longfin or shortfin eel, brown trout, koura, pipi, mussel and flounder) and watercress samples were gathered from multiple important harvesting sites in the different regions, and tested to assess their bioaccumulative contaminant levels. Hair samples were also collected from Arowhenua participants to assess possible exposure to mercury, a highly accumulative contaminant. 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. High total DDT (ΣDDT) concentrations were recorded in eel fillet from Winchester, Ohapi Creek and Doncaster in Arowhenua rohe. The concentrations of ΣDDT in trout and flounder were generally much lower than for eels. Other organochlorine pesticides were either below the limits of detection, or measured in much lower concentrations than any of the DDT congeners. Polychlorinated biphenyls (PCBs) were analysed in eels from Arowhenua rohe. The most elevated levels of PCBs were found at Doncaster and Winchester. The concentrations of mercury were generally highest in eel fillet whereas arsenic was only present in flounder and trout. The average concentration of mercury in the Arowhenua hair samples was similar to levels found in the study reference group. The low number of Arowhenua responders in this study meant we couldn’t analyse potential links with consumption of wild kai. The results show that if kai was gathered randomly across all sites throughout the Arowhenua rohe, then there is no significant risk to members of Arowhenua from eating eels, trout, flounder or watercress. If kai was mostly gathered at the more contaminated sites then a significant risk exists when eating eel. A number of potential “hotspots” (i.e., area of increased risk) were identified for Arowhenua rohe. From the risk assessment, consumption of eel from Doncaster, Ohapi Creek or Winchester should be less than once per month. Furthermore, consumption should also be limited for eel harvested from Waihi River, Temuka, Opihi River upstream and below Pleasant Point to 1- 4 meals/month. With respect to trout, a degree of caution should be exercised when consuming individuals from Opihi River mouth, Temuka or Orari Ohapi. Flounder from Washdyke Lagoon and Orari Ohapi also represent a risk, with allowable consumption limits of 1-4 meals/month. Watercress consumption risk was highest when harvested from the Opihi River (below Pleasant Point site), with consumption limits of 2.7 meals/month.

Samples of oysters from multiple sites in the Manukau Harbour and transplanted mussels from multiple sites in Auckland estuaries and Waitemata Harbour were analysed for %lipid, organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Analytical data for oysters and mussels were presented along with analytical procedures, methods and a quality assurance summary. The report includes lipid-normalised data sets of selected contaminants for comparison with earlier data sets.

Samples of oysters from multiple sites in the Manukau Harbour and transplanted mussels from multiple sites in Auckland estuaries and Waitemata Harbour were analysed for %lipid, organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Analytical data for oysters and mussels were presented along with analytical procedures, methods and a quality assurance summary. The report includes lipid-normalised data sets of selected contaminants for comparison with earlier data sets.

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.