This report presents results from a study of coastal processes and hazards on a section of the South Canterbury coastline, at Waimate Creek just south of Wainono Lagoon, where Fonterra Ltd have proposed an ocean outfall for effluent disposal related to planned expansion of their milk processing plant at Studholme. The overall aim study was to assess the effects of the outfall installation and operation on the local shore morphology and position, in the context of existing shoreline movement trends and as complicated by future sea-level rise and climate change effects. Scope: (a) a literature review, (b) assessment of existing shoreline management along the project shore, (c) an updated analysis of shoreline stability, (d) field inspections of the proposed outfall site at Waimate Creek and of the Clandeboye outfall that was installed north of Timaru in 2005, (e) assessment of sea flooding by wave overtopping and storm surge and assessment of Tsunami hazard on the project and (f) assessment of effects on the project shore of predicted rises in sea-level and changes in wave-climate. The assessment of project effects included: (a) advice/recommendations on outfall design and construction issues relating to coastal process (b) assessment of project effects on shore processes, stability, and flooding hazard during and post construction, and (c) mitigation and monitoring recommendations during and post construction.

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.