Information provided by Napier City Council about the testing that led to the hard cordon at Awatoto indicates a number of concerning contaminants at the site.
“The Awatoto industrial area houses a range of different industries, therefore there are a wide range of chemical and biological materials held in the area. These materials may have been disturbed and mixed and contaminated flood water and silt in the area as floodwater moved through the area,” a report from council titled, Preliminary information on Awatoto Industrial Zone, says.
Preliminary testing was done at nine sites around the Awatoto industrial area on 21 February, the results of which show a large variation in the concentration of different contaminants. According to council scientists, results indicate an incomplete mixing from multiple sources of contamination.
BayBuzz is awaiting confirmation of the exact contaminants tested for and their concentrations, as well as up to date testing results, as testing has been ongoing.
Here’s what we know.
There were extremely elevated levels of different forms of nitrogen and sulphur in some samples and the levels of ammonia nitrogen are of most concern.
“When samples had extremely elevated nitrogen, the bulk of that nitrogen was in ammonium form. Ammonia at the observed levels would be extremely toxic to aquatic life and may pose human health risks. Phosphorus was often elevated above natural levels,” the brief council report states.
Faecal contamination was found at all nine testing sites and pathogens were at concentrations
indicating that contact with the water should be avoided as it could cause severe human health issues.
Metal levels, including arsenic and lead, were not of notable concern in any sample and there were no notably concerning levels of pesticides or volatile organic compounds in any sample.
Asbestos was not detected in any of the silt samples. Poly-aromatic Hydrocarbons were detected in the silt samples, indicating that there may have been oil and petrol spills in the area.
It’s important to note that testing has been more or less continuous since then, and air testing has also just commenced, so the information in this initial report will be superceded.
“A larger programme of sampling, run by independent experts, is currently being undertaken to better understand contaminants throughout the entire Awatoto area. This will provide a more comprehensive picture and inform decisions around clean up and silt disposal,” the report says.
NIWA aquatic chemist Jennifer Gadd said the ammonia could come from the Ravensdown site or from the wastewater treatment plant, and potentially some of the other industrial sites.
“Ammonia is a gas, but it gets dissolved in water, and it’s very toxic to aquatic animals – it basically suffocates them. For example, tests with New Zealand freshwater mussels show you only need a few milligrams per litre (12-15 mg/L) to kill 50% of them when exposed for 48 hours.
“Ammonia can be responsible for irritating eyes and lungs – its smelly though so you might know it’s there depending on the amount.”
Elevated phosphorous was to be expected in flood waters, especially those that might have contacted wastewater or fertiliser stockpile’s and stormwater systems, she said.
The fact that metals, pesticides and volatile organic compounds were not at concerning levels was “good news”.
“I would be most worried about these floating around. Whilst ammonia will break down over time, metals do not break down (being elements) and some pesticides can be long-lived too,” Gadd said.
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I notice vehicles are being sprayed down on leaving this area
And immediately after cyclone, it was reported ‘they’ (?) began pumping it into the nearby river. Where is it being removed to now?
Why is the area limited to Awatoto when the water washed over Brookfields and sat there for days. Pumping liquid into the public golf course area was seen as well through cordened area