Local authorities need more support in addressing the potential risks of land contaminated by lead paint from old residential properties. Use of the Hazardous Activities and Industries List (HAIL) is not enough. Graham Aveyard pieces together the evidence.
Archived records from the New Zealand Official Yearbook provide some baseline statistics to help identify the scale of the problem arising from the legacy of lead-based paints. “In 1945 there were more than 326,000 residential properties constructed with wooden outer walls”, the records state. “By 1966 this had risen to 455,213.”
Whilst the precise number of these properties that are still in existence is unknown, the overwhelming conclusion must be that there is a significant number of them.
This information becomes more relevant when considered with the following statement from the Ministry of Health website about the hazard posed by historic use of lead-based paints. “Until 1965, many paints on the New Zealand market had high lead levels. This was particularly true of pre-1945 paints.”
The case against lead
Lead is not required in the human body. There is no known safe blood lead level, although under the Health Act 1956 a blood lead concentration of 10 µg/dl triggers notification to the Medical Officer of Health. Even that concentration of lead in blood presents a greater likelihood of adverse effect to the individual than for many other contaminants at the soil contaminant standard.
We know young children absorb four to five times as much of any ingested lead as adults from a given source. Childhood exposure coincides with the greatest period of development of the brain – the primary organ to suffer long-term damage from absorption of the metal.
Ingested lead is stored in bone and gradually released over many years. Once lead has entered the body in great quantities, the patient may be affected for much of their early to young adult life. During pregnancy, stored lead is remobilised from the bone due to increased demands for calcium which can then travel across the placenta into the foetus, thus impacting children even before birth.
Pica is the persistent craving and compulsive eating of non-food substances. It is often considered to be an unusual behavioural trait amongst young children. Yet exploration by mouthing and tasting of materials is a normal part of learning for many children around 18 months to three years of age.
As a result, the proportion of children who may have ingested lead-contaminated soils and dust in early life may be more significant than first thought and those children exhibiting pica may be the tip of the iceberg.
The health impact from exposure to lead has been known since Greek and Roman times. Valuable work in removing lead from drinking water pipes has been supported by actions such as the removal of lead additives from petrol, and of lead solder in the canning and plumbing industries.
Toxicity to children from lead paint was identified in Australia in 1897. There was widespread understanding in the 1950s and ’60s that paint was the cause of serious childhood illness. Yet it took until the late 1960s and ’70s for lead to be reduced in content from as much as 50 percent to one percent; and, more recently, a fraction of one percent.
During the early to mid-20th century, maintenance, removal, repair or general deterioration of paint on the old timber property created the potential for contamination of surrounding soils.
As a result, analysis now routinely confirms lead concentrations in the residential soil sufficient to potentially impact human health.
In a 2015 BRANZ House Condition Survey (Study Report SR370), 37 percent of rented properties and 29 percent of privately-owned properties were identified as having deteriorating paint (all property ages and types). The same report shows that rental housing stock also tends to be older than owner-occupied premises.
So, those living in rented property are more likely to be at risk from the presence of high concentrations of lead paint residue in soil. These are often identified as being some of the more vulnerable groups in society.
There are typically between 100 and 200 notifications of blood lead levels exceeding public health criteria in this country every year. The data only provides details of those cases that are notified to the District Health Boards. Children only represent 10 percent of those cases notified which are dominated by occupational exposures.
Symptoms of chronic lead exposure are not specific and are, at times, unnoticeable. The number of childhood cases in the data may therefore be significantly under-reported.
It is difficult to quantify the actual impact on public health, due, in part, to limited data on those affected and the lack of obvious symptoms even in those with blood lead levels above the action level set by public health services in countries like New Zealand, Australia and the United Kingdom.
Occupational exposure of decorators due to paint removal processes dominate the notification records, highlighting the risk of exposure to dust even for adults of working age.
For the purposes of the Resource Management (National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health) Regulations 2011 [NESCS] and Hazardous Activities and Industries List [HAIL] occupational exposure is not a relevant exposure.
But this data does highlight the level of potential harm as well as the difficulty in separating those patients affected by dust from paint removal rather than from the soil.
Whether the exposure occurs during removal, or at some time later from contamination of the soil, the impact on health resulting from lead absorption remains significant. Yet the regulatory mechanisms are quite different.
There are examples of childhood impacts from lead exposure. But without an evidence base to link these with exposure to soil it isn’t clear whether this is a soil contamination or a health and safety issue.
Tackling lead with HAIL
The primary intervention in relation to contaminated land management in this country is through application of the NESCS under the Resource Management Act. However, the consistency of approach in relation to residential lead exposure can be variable, not least due to this source of contaminant not being included in the Hazardous Activities and Industries List [HAIL].
Although the option to use a ‘safety net’ provision seems to exist within HAIL, land potentially contaminated by flaking, removed or deteriorating paint from old buildings seems never to have been intended to be captured by the overall NES process.
The primary focus of development of the HAIL was to ensure the identification of significant commercial or industrial processes where use of hazardous substances could lead to the risk of contamination such as ‘petrochemical industries’, ‘mining industries’, ‘chemical manufacture’ and ‘pesticide manufacture’, and their ‘bulk storage or use’.
The 2010 discussion document on the implementation of NESCS estimated that councils “have identified approximately 20,000 potentially affected sites”. This figure is now known to be an under-estimate; a more realistic figure would be in the order of 100,000.
If we reflect on the potential numbers of old wooden properties still in the housing stock that are ‘more likely than not’ contaminated, we may easily add 250,000 sites by the inclusion of these properties onto a catchall section of the HAIL. This seems to lead to a case of the ‘exceptions’ dominating the rule.
Whether the move would be considered justifiable or not, the predictable public outrage resulting from such inclusion should not be underestimated and up until now has resulted in the decision being firmly placed into the ‘too hard’ basket.
Problems with HAIL for TAs
Whether such affected land is, or isn’t, HAIL may be to some extent academic. The real concern is much more straightforward and rather more pragmatic. New Zealand has 1.84 million residential properties, being subject to around 25,000 consents from district councils per year.
The Resource Management Act (as given effect by the NES) does not affect existing uses of land and is only triggered when soil disturbance (above Permitted Activity levels), subdivision or change of use is proposed. It therefore provides an ineffective tool to react to a perceived health risk which, if confirmed, demands a far shorter-term outcome. Some sites may wait tens of years to be remediated, others possibly never.
One of the three stated priorities for introducing the NES was to “develop a nationally consistent method for deriving and applying soil contaminant levels, protective of human health, that trigger a defined management action.”
However, one criticism of the implementation of the NES, particularly referencing lead paint in soil, is that there is still inconsistent interpretation and application of NES, HAIL and consenting requirements. This is, at least due in part, to the absence of guidance in relation to lead paint residues which leave consenting authorities with the difficult question of how to address the potential hazard and having few other obvious means to manage potential risks to occupants of
the land.
The authorities deserve more support than this from central government, both to determine the magnitude of the risk, but also a transparent methodology to resolve the legacy left on land from past uses of a human health and environmental contaminant.
Conclusion
Many professionals who specialise in contaminated land believe we have a problem with residential lead exposure, particularly for younger children. From the notification data it is not entirely clear that this level of risk or actual harm is present. However, there is plenty of anecdotal evidence of cases of blood lead being increased after exposure to lead in soil or removed paint, so there is no denying that the risk
is real.
If used, the NESCS process for determining the likely presence of hazard shows no difference in the level of risk to occupants of
lead-affected sites as those activities already on the HAIL. In fact, as a nation the numbers of potentially affected sites would suggest this issue is of greater priority than many other activities already included.
But, as discussed above, HAIL isn’t the complete answer. The lack of ability to drive remediation means other options need to come forward, particularly working in partnership with health professionals.
In the meantime, we still do not know how much our children are being affected by the legacy of the paints that once were widely used and considered acceptable. But we do now understand that legacy could pose a risk to our
nation’s children.
- Graham Aveyard is a member of the WasteMINZ residential lead working group.
Graham.Aveyard@ecan.govt.nz
This article was first published in the June 2019 issue of NZ Local Government Magazine.