This report describes the summer 2014 (Baseline 3) marine benthic monitoring, conducted in late January/early February, and presents a brief description of the benthic invertebrate communities, habitats, sediment types, and sediment contaminant concentrations found at each site. All samples collected were surface samples from either intertidal or subtidal locations. Sampling was conducted at 10 subtidal and 10 intertidal monitoring sites in Porirua Harbour, to quantify and describe benthic communities, sediment characteristics and sediment contaminant levels. Specifically, at the subtidal sites, eight 10 cm diam. x 15 cm deep cores were collected using divers, for macroinvertebrate identification and enumeration and three composite core samples were collected for sediment contaminant and grain size analysis. The surface sediment (0-3 cm) was removed from 5 or 6 smaller cores (7 cm diameter) and these fractions were pooled to produce a composite core sample for contaminant and grain size analysis. One core (13 cm diameter x 15 cm deep) was collected from each intertidal site at low tide from within one 5 m x 5 m grid to determine community composition. A 0.25 m² quadrat was also photographed adjacent to each macroinvertebrate core for later assessment of epifaunal invertebrate community and macroalgal cover. Three samples of surface sediment (0-2 cm) were collected from each site for sediment contaminant and grain size analyses. Three composite samples were prepared, by combining samples from grids A, B, C, D, E (sample 1), from grids F, G, H, I, J (Sample 2), and from grids K, L, M, N, O (Sample 3). All sediment contaminant samples were collected using clean HDPE plastic trowels and trays. Samples were sealed in double zip-lock bags and stored on ice until shipped to the laboratory for processing.

The Greater Wellington Regional Council (GWRC) engaged NIWA to prepare and process estuarine sediment samples collected from Porirua Harbour in late 2010 and manage the analyses of both organic and metal contaminants for comparison with ANZECC sediment quality guidelines. Metal contaminants were analysed by Hill Laboratories and reported elsewhere. NIWA provided analytical data for organochlorine pesticides (OCs), polycyclic aromatic hydrocarbons (PAHs) and particle size distributions (0-300 μm). This report describes methodology and presents results [including quality assurance (QA) data] for the analyses of OCs, PAHs and particle size distributions for estuarine sediment samples collected from Porirua Harbour in 2010.

This report describes the winter 2013 (Baseline 2) marine benthic monitoring, conducted in early July, and presents a brief description of the benthic invertebrate communities, habitats, sediment types, and sediment contaminant concentrations found at each site. All samples collected were surface samples from either intertidal or subtidal locations. Sampling was conducted at 10 subtidal and 10 intertidal monitoring sites in Porirua Harbour, to quantify and describe benthic communities, sediment characteristics and sediment contaminant levels. Specifically, at the subtidal sites, eight 10 cm diam. x 15 cm deep cores were collected using divers, for macroinvertebrate identification and enumeration and three composite core samples were collected for sediment contaminant and grain size analysis. The surface sediment (0-3 cm) was removed from 5 or 6 smaller cores (7 cm diameter) and these fractions were pooled to produce a composite core sample for contaminant and grain size analysis. One core (13 cm diameter x 15 cm deep) was collected from each intertidal site at low tide from within one 5 m x 5 m grid to determine community composition. A 0.25 m² quadrat was also photographed adjacent to each macroinvertebrate core for later assessment of epifaunal invertebrate community and macroalgal cover. Three samples of surface sediment (0-2 cm) were collected from each site for sediment contaminant and grain size analyses. Three composite samples were prepared, by combining samples from grids A, B, C, D, E (sample 1), from grids F, G, H, I, J (Sample 2), and from grids K, L, M, N, O (Sample 3). All sediment contaminant samples were collected using clean HDPE plastic trowels and trays. Samples were sealed in double zip-lock bags and stored on ice until shipped to the laboratory for processing.

This report briefly describes methodology and presents results for the analyses of contaminants and particle size distributions for catchpit sediment samples. TPH, TOC and heavy metal results were produced by Hill Laboratories. PAH and chemical marker compound results were produced by NIWA.

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.

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.

This report briefly describes methodology and presents results [including quality assurance (QA) data] for the analyses of Wellington Harbour marine sediments for sediment contaminants. Results reported for total organic carbon (TOC), total petroleum hydrocarbons (TPH), organochlorine pesticides, Polycyclic aromatic hydrocarbons (PAH), PAH chemical markers, heavy metals and sediment particle size distributions. TPH, TOC and heavy metal results were produced by Hill Laboratories. Organochlorine pesticides, PAH and PAH chemical marker compound results were produced by NIWA.