McMurtrie, S. (2019, July). Food safety of fish & shellfish in Ōtautahi Christchurch: 2019 survey. EOS Ecology.

Funded by Environment Canterbury (ECan) in 2019, this report contributed to the “Food Safe to Eat” component of the “Healthy Estuary and Rivers of the City” programme established by ECan, Christchurch City Council (CCC), and the Avon-Heathcote Estuary Ihutai Trust. When in high concentrations, heavy metals and metalloids can be harmful to human health. Man-made chemicals such as polychlorinated biphenyls (PCBs), alongside pathogens from faecal material, indicated by high E. coli levels can also have serious human health effects. The purpose of this report was therefore to measure the levels of some heavy metals, polychlorinated biphenyls, and E. coli found in commonly gathered fish and shellfish within the Avon-Heathcote estuary and rivers.

Overall, the report found that metal concentrations in fish and shellfish gathered from the Ihutai estuary were below 2015 FSANZ limits and therefore considered safe for consumption in relation to heavy metal contamination, however, lead levels in yelloweye mullet approached food safety limits in several samples. The report also found that PCB levels were below detection limits of 0.04mg/kg in all samples. E. coli levels in shellfish collected from the Causeway and Southshore sites were at safe levels for consumption based on ANZFSC standards, however, many samples near the Christchurch Wastewater Treatment plant were not. The report stressed that high E. coli levels can signal the presence of pathogens from faecal material, therefore, more regular E. coli testing should occur around the estuary.