Aotearoa/New Zealand faces major clean-up of Rio Tinto smelter

Published by MAC on 2021-04-07
Source: RNZ

Rio Tinto-controlled New Zealand Aluminium Smelters (NZAS) denied any material had been buried.

Toxic waste buried at Tiwai Point aluminium smelter, former staff say

Phil Pennington

https://www.rnz.co.nz/news/national/439872/toxic-waste-buried-at-tiwai-point-aluminium-smelter-former-staff-say

6 April 2021

Investigators are looking into claims highly toxic waste has been buried in unmapped sites at Tiwai Point aluminium smelter.

This includes spent cell liner (SCL) waste that contains cyanide and toxic fluoride, and is banned from being buried untreated in both the US and Australia.

The warning last October from the compliance section of the regional council Environment Southland is in documents released to RNZ under the OIA.

"Former staff of the smelter report burying of spent cell linings or contaminated material in various parts of the Tiwai site," said the report into "key matters" for cleaning up the huge site next to conservation land once the smelter shuts in 2024.

Waste burial reportedly went on "particularly prior" to the Resource Management Act's enactment in 1991, by which stage tens of thousands of tonnes of hazardous waste had already been produced.

The report followed this with a warning: "It is likely that a number of unmapped or unconsented contaminated sites exist as a result of these uncontrolled activities."

The government has said it is "blind" on contamination at Tiwai, and abruptly called off talks with Rio Tinto last month, until the company gives it more information.

The Rio Tinto-controlled New Zealand Aluminium Smelters (NZAS) company is also reportedly not sure what it will find underground, though its pollutant discharges have been consented, at least since the 1990s.

NZAS and the government have parallel investigations going on to uncover what is there.

The smelter company denied any material had been buried.

"We are unaware of any material being buried at NZAS, in unmapped or unconsented sites," chief executive and general manager Stew Hamilton said in a statement.

"The detailed closure study, currently underway, will examine the site footprint including management of all waste products. This compliments existing monitoring to inform closure and remediation options."

RNZ asked Environment Southland what it is doing to ascertain if the reports of buried, unmapped waste are true.

The regional council told RNZ in a statement it had discussed historic dumping with NZAS, without saying what that had revealed.

It had monitored the site "in accordance with its consents for many years", said its chief executive Rob Phillips.

It was now increasing monitoring as part of the government-ordered investigation.

This included beginning the monitoring of groundwater under the SCL storage shed.

NZAS already monitored this and the council had asked for its sampling results, Phillips said.

The council expected to get a report back within a month from consulting environmental engineers Aurecon, and that might lead to even more monitoring, Phillips said.

It would share information publicly where it could, for instance, about the Tiwai groundwater management zone.

'Structurally weakened'

The documents also show that engineers recently discovered that sheds containing masses of toxic SCL waste are "structurally weakened".

This has put a halt "for a few months" to monitoring groundwater around the sheds for contaminants, a December 2020 council report said.

The floor of the first shed built in 1992 cracked almost from the word go. Contaminants have from then till now leaked into barrier membranes in the special foundations, as RNZ reported from previous OIA releases. Four sheds hold in total 75,000 tonnes of the waste, the company has said.

The council's October report noted the area around the SCL storage pad "has a legacy of poor management and may have residual groundwater contamination of fluoride from the failure of the storage system in the 1990s".

The regional council has consistently praised the smelter's cooperation on environmental issues over the years.

But now its report lists two issues of "high concern": The SCL storage pad that it notes is "susceptible to coastal erosion"; and the leachate from the landfill getting into groundwater and Foveaux Strait.

"Some groundwater monitoring bores on the south side of the landfill show some high levels of contamination for a number of contaminants including several nitrogen species and fluoride, and minor levels of heavy metals and polycyclic aromatic hydrocarbons," it said.

The smelter company said it operated in compliance with all standards set under its resource consents as monitored by Environment Southland and "conducts a range of monitoring, often in excess of those required". It said it provided reports to Environment Southland every quarter.

Hamilton said the smelter had operated at Tiwai Point for 50 years and during that time environmental monitoring regimes had evolved.

The company acted immediately to remedy any past non-compliances and will close the smelter in a responsible manner, including removing all spent cell lining from the site, Hamilton said.

"We want to make sure the community is confident in the way we deal with any contamination on the site, how waste will be managed and disposed of and address any environmental concerns about an operation that has been part of the community for 50 years," he said.

"We recognise that over time, community and regulatory expectations evolve, and we will ensure our closure processes and outcomes are transparent and meet the needs of today."

The smelter company reports having landfilled 620,000 cubic metres of waste, including cleanfill, but also carbon and dross that contain toxins, and asbestos and hydrocarbon-tainted soil.

It has stockpiled 180,000 tonnes of much more toxic spent cell liner waste, and has exported 58,000 tonnes of it, it said; however, production figures suggest a further 20,000 tonnes of SCL may have been created than accounted for in these figures, and RNZ has queried this with NZAS.

The smelter was allowed to store up to 250,000 tonnes of SCL waste, the city council told RNZ.

The European Union describes SCL waste as "carbon-based linings and refractories from metallurgical processes containing dangerous substances".

Government looking at stronger laws

The long-term risk is from sea-level rise, with engineers advising the government the sea will breach the smelter landfill within a century, releasing toxic material that will damage the environment and even kill people. The smelter rejects this advice.

A powerless-looking government is now looking at law changes to force polluters to clean up.

"I have asked officials for advice on including a clear hierarchy to attribute liability for contamination in legislation or regulation, either through the current RM [Resource Management] reform process or through separate stand-alone legislation," Environment Minister David Parker said in a statement.

In contrast, Australian states have laws to enforce clean-ups, recently deployed in Victoria to ensure Alcoa pays for what is turning into a decade-long clean-up at the defunct Port Henry smelter.

Clean-up order legislation of this type "does not currently exist in New Zealand", the Environment Ministry told RNZ.

The government provided indemnities in 2003 and 2004 over any remediation NZAS may owe for cleaning up relatively minor amounts of dross.

In Southland, the regional council is leading the investigation though activists have accused it of taking a light hand with the smelter for many years.

Neither Environment Southland nor Invercargill City Council has a register of the amount or types of hazardous substances stored.

As part of the investigations, the company has this year been drilling a huge number of new bores - about 240.

It relies on self-monitoring just eight existing bores to know what is happening under the sprawling landfill.

Though the water flows south/southeast towards Foveaux Strait, five of those bores are on the upstream north or west side, and only three on the downstream side to the south, by the beach.

Annual reports of about 100 pages each to the regional council about environmental monitoring, give "typical" levels across a range of analytes in groundwater, including 1-10 grams per cubic metre (gm3) for fluoride, 1-6gm3 for "total nitrogen ", and 15-40gm3 for sulphate.

But the levels downstream are consistently higher than this, with averages over the decade to 2019 in the two primary southern bores:

• Fluoride - 57gm3 (bore A6) and 77 (bore A24)
• Total nitrogen - 20 and 200
• Sulphate - 780 and 90

Nitrogen in bore A24 was trending down but sulphates up; nitrogen and fluoride in bore A6 were largely steady, but sulphates dipped, then doubled by 2019.

By comparison, water in New Zealand is fluoridated to 0.7-1.0gm3, and the US has standards for naturally occurring fluoride in drinking water of 2-to-4gm3.

High concentrations of fluoride can harm human health.

Typical sulphate levels in fresh water are 20gm3; seawater has 2700gm3.

NZAS' reports on its bores contain commentary that quite often contradicts the measurements in key ways.

For example, the 2019 report said fluoride at one southern bore had stabilised at 50gm3 "for a few years", when in fact it averaged 77.

In 2016, the measurements for two separate bores were exactly the same, as if copied over.

In 2017, fluoride was noted to have had a "slight increase" at bore A24, when in fact it rose almost 40 percent.

By contrast to the landfill bore data, the reports contain no measurements for the bores under the SCL pad or storage sheds.

Instead, each annual report said virtually the same thing - that monitoring showed "similar levels" to the year before, without saying what those levels were.

Other reports RNZ has obtained show that concerns existed in 1990 about SCL leachate getting into water-extraction wells. Since 1995, this leachate has been collected and treated, then discharged into the sea, where the cyanide in it disperses.

The permitted level of cyanide discharge into the sea at Tiwai (20gm3) is four times higher than India's limit on cyanide in smelter leachate.

Reports also showed NZAS had used patchy ways of measuring or recording such things as saltwater intrusion.

Long, complicated clean-up

The regional council documents show the smelter's plans at the point in late 2020 when it expected to shut the smelter in August 2021 (a date pushed back to December 2024 under a deal with power supplier Meridian).

It had been planning for a "make-safe" phase of five months.

Only after this were "detailed plans for the future of the site" to be drawn up.

These included "final site investigations as well as marketing the site for sale (approximately a year)".

"Once the final land use and the state of the site's environmental legacy is determined, a plan for decommission will be made. At this stage there is no final closure plan," the report said.

The Port Henry smelter clean-up in Victoria shows what could be ahead at Tiwai: It is long and highly complicated - but because of much tougher laws there than here, there is a lot more public information that must be made available.

At Port Henry in December 2014 the groundwater was found to be so polluted it was "detrimental to any beneficial use".

Victoria is toughening its clean-up powers still further, this July, under what its Environment Protection Authority calls the "biggest change in 50 years to Victoria's environment protection laws".

Rio Tinto co-founded the aluminium stewardship initiative (ASI) in 2012 and was the first to be ASI certified, including for its Tiwai Pt smelter.

The certification said it "provides proof of responsible production, responsible sourcing and material stewardship".

About half of SCL waste worldwide is estimated to be landfilled.

However, international guidelines say this is the least preferable disposal method, and that it should be treated first. The US has banned its untreated burial since 1998, and it only goes into landfills that are double-lined and have two levels of leachate collection, plus leak detection.

Even treated, it is still classified as a hazardous waste due to its caustic nature.

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Report details consequences of landfill of toxic waste at Tiwai Point

Phil Pennington

https://www.rnz.co.nz/news/national/438550/report-details-consequences-of-landfill-of-toxic-waste-at-tiwai-point

17 March 2021

"Catastrophic" consequences of "extensive, irreversible" environmental damage and even loss of life is being forecast from sea level rise breaching a giant landfill including toxic waste at Tiwai Point aluminium smelter in Southland.

The smelter company rejects the findings, but engineers' reports to Treasury say it is "almost certain" the sea will swamp a landfill that contains 250 Olympic-size pools of waste.

That report is looking a century ahead but Rio Tinto plans to leave the smelter in less than four years, and talks on how to clean up the site foundered this month, with the government protesting lack of transparency by the company.

In the reports, a risk assessment on coastal inundation said there were no "existing controls" to deal with it.

"Sea level rise of 1m combined with erosion generating storm surge events will cause an inland movement of the coastline by 100 metres within 100 years, eroding landfill

'berms' and releasing contaminants, causing extensive irreversible environmental damage and health impacts, with the potential to cause fatalities," the report by consultants Aurecon said.

Before that happened, seawater would intrude underground with similar impacts including "potential health impacts to humans with the potential to cause loss of life".

Environment Minister David Parker told RNZ they were serious issues.

But he remained "blind" on the extent of the contamination, despite the 170 pages of reports released to RNZ under the OIA; these went to Parker and Treasury last September-October, and a second tranche of as-yet unreleased advice went to them last November.

"I really don't know how contaminated the site is. I do need to know," Parker said.

The company pushed back, saying it had not see the Treasury reports until RNZ sent them through on Tuesday.

New Zealand Aluminium Smelters chief executive Stew Hamilton said in a statement: "We are very concerned by what we believe are inaccurate assertions and conclusions made by this desktop study".

Their preliminary modelling showed "no impact" from sea level rise on the landfill "within the next 100-200 years", he said.

Parker said the reports did not say "we've got immediate sea level rise around the corner, it says that we've got a future problem".

The edge of the 19ha landfill southwest of the main smelter is within 100m of the beach, with Bluff just across the channel.

The regional council, Environment Southland, said it took sea level rise into account when it issued a 20-year landfill consent in 2003.

The landfill is the second of two major threats at Tiwai Point, in addition to the tens of thousands of tonnes of spent cell liner (SCL) waste that is too nasty to be buried and is piled on a concrete pad also within 100m of the beach with the regulating councils' knowledge, as well as being stored in four sheds.

The company is trying to find a buyer for the 181,000 tonnes of SCL.

It confirmed Aurecon's estimate that about 620,000 cubic metres of waste had been buried at the landfill since the smelter started in 1971.

But there were data gaps - the Treasury reports said the company had not provided landfill records prior to 1992, or for 2003-17.

A Treasury report from 2012 said the company was dealing with the waste by covering it over and revegetating the land - but these latest reports suggest the sea would wash that out.

Hamilton rejected that.

"NZAS would not allow conditions to exist which could result in the landfill being breached, and will take all necessary preventative action to ensure that such a scenario could not occur, including management of the landfill and comprehensive monitoring of coastal erosion," he said in a statement.

NZAS had not been consulted and Aurecon had not visited the site, but it and the government team working on the issue was welcome to, he said.

The smelter's landfill management plan runs to many scores of pages.

The landfill has taken 20,000 tonnes of waste or more in some years, of all kinds; not all toxic but dominated by huge amounts of used refractory material, including heavy metals, toxic fluorides and asbestos.

'We've made no decisions' - Parker

Last month, Parker said he was almost "completely blind" about the residual contamination, and soon after the government suspended talks that began last September with mining giant Rio Tinto.

The reports, released under the Official Information Act, list risk mitigation options for breaches by sea level rise across two pages, but they were redacted.

RNZ has appealed to the Ombudsman to have that reversed.

Parker at first said he could not recall what the options were, then said with regard to remediation options that there was "a large range of cost around them, and we don't want to disclose what that range is to Tiwai Point smelter owners in case we get it wrong".

He later said that in general, the landfill options were to "either dig stuff up and take it away, or you cap it" or contain it in cells.

"We've made no decisions as to what is necessary because we don't know the state of the site."

Aurecon did not know either, its reports were based on "estimates", he added.

Parker read out from Aurecon's report a line that was not in the redacted copy RNZ had, that said "the key activity that we consider is likely to be occurring and does not appear to have been authorised is the discharge of contaminants into land and groundwater".

"I still don't know the extent of that," Parker said.

The government is relying on a $300,000 investigation by Environment Southland to shed more light on the issue.

Parker said he trusted the council to do that, though groundwater monitoring that was overseen by the council did not seem to have been "done to the highest of standards".

"I saw in a report a reference to the fact that there has not been groundwater monitoring on the site, which disturbs me, which is one of the reasons why I have asked the regional council to do that [investigation]," Parker said.

The landfill

The council said the landfill existed before the Resource Management Act was introduced.

Environment Southland chief executive Rob Phillips said: "The current landfill consent is due for renewal in 2023 and will be subject to landfill rules under our proposed Southland Water and Land Plan and the RMA".

"Addressing the climate change impacts is part of the investigation process."

Under the NZ Coastal Policy Statement 2010, planners must look at least 100 years ahead.

The council refused to release information to RNZ about what clean up maybe required or interventions needed, saying that would likely prejudice the maintenance of law (including the prevention, investigation and detection of offences).

Past problems at the landfill include dross leachate getting into groundwater when it shouldn't have, according to a 2006 council-smelter report.

The Treasury reports showed the amount of waste being buried rose in 2018 and 2019.

The smelter must also now deal with 22,000 tonnes of dross from Mataura and the elsewhere which is being returned to Tiwai over the next four years.

The Treasury reports also showed that the government knew in October the smelter had stockpiled tens of thousands of tonnes of spent cell liner waste it also has to deal with, and that this had previously leaked cyanide and fluoride into the groundwater and sea for years, probably for three decades from the 1970s.

RNZ revealed that publicly last month.

Aurecon estimated there might be 330,000 tonnes of SCL all up.

But the company told RNZ yesterday that it had exported 58,000 tonnes and the total in storage was 181,000 tonnes.

The Ministry for the Environment has said it did not know if it could hold the smelter company legally liable to clean up.

The Environment Protection Authority told RNZ it had no involvement in contamination issues at Tiwai or any clean up, though it got new RMA enforcement powers last year.