We thank Mr Devey for his recent commentary Conclusions on city pollution questioned dated 16th February 2017. His opinion piece was in response to the Newcastle Herald’s coverage of our recent research on the city of Newcastle titled Geochemical sources, forms and phases of soil contamination in an urban industrial city, published in Science of the Total Environment.
In considering and responding to Mr Devey’s comments it was unclear if he has read the research article upon which the news story was based. Our article provides the ‘quantitative evidence’ that Mr Devey calls for in relation to our work. A minor factual correction is that our study analysed 170 soils not 150 as stated in Mr Devey’s opinion piece.
Below we provide brief clarification based on Mr Devey’s several criticisms and comments in relation to the Newcastle Herald story.
Copper, chromium and zinc are not heavy metals and are essential micronutrients.
In the original study we use the phrase ‘metal(loid)s’, rather than heavy metals, with respect to the contaminants of interest.
Mr Devey notes that just because soil contaminant values exceed guidelines this does not necessary mean they are unsafe. We not only concur with that viewpoint but we specifically address this issue in our study.
Our study results were benchmarked against the soil contaminant values listed in the Australian National Environment Protection (Assessment of Site Contamination) Measure 1999 (NEPM), which was amended in 2013. The NEPM contains soil Health investigation (HIL) levels (HIL) for different land use types which:
…are scientifically based, generic assessment criteria designed to be used in the first stage (Tier 1 or ‘screening’) of an assessment of potential risks to human health from chronic exposure to contaminants.
(NEPM 2013, Schedule B1, section 2.2, page 4)
The NEPM advises that where soils exceed the relevant HIL soil concentrations:
The nature of the response should be determined on a site-specific basis and be proportional to the potential risk posed to human health and/or the environment.
(NEPM 2013, Schedule B1, section 3.2.2, page 20)
We are cognisant that the NEPM recommends that further assessment of the potential risk of harm including potential exposure pathways and risk/hazard modelling should be undertaken where contaminants exceed those advised in the NEPM. We assessed soils using the internationally accepted protocol, US EPA method for lead bio-accessibility.
The study results were benchmarked against the international literature relating to exposure thresholds and the consequent potential health impacts arising from exposure to soil metal(loid)s in Newcastle city.
The approach we undertook including the conclusions drawn were subject to blind peer review. This resulted in the approval and publication of the article.
We were aware of Mr Devey’s 1995 Newcastle soil study of lead concentrations in public places, which were broadly similar to those identified in our article. Our study was different to Devey’s 1995 study in that it examined previously unstudied private space soils. Our approach provided access to soils in the highest exposure environment—the backyards of homes where children play. Importantly, our study results revealed multiple soil metal(loid) exceedances of residential HILs and not just lead as was examined in Mr Devey’s 1995 study.
Mr Devey raises concerns that:
There appears to be no mention of leaded fuel exhaust being a source of lead dust in the Macquarie study.
The brief news report of our article did not cover the fact that this had been considered in our study:
Leaded petrol and paint are also potential contributors to Pb in the surface soils of the urban environment.
Harvey et al. (2017, section 3.2, page 6)
Regardless of technical semantics, our study used comprehensive geochemical and analytical methods that demonstrated unequivocally that in the city of Newcastle:
· smelter emissions and waste have contributed to soil contamination
· a significant hazard persists in easily accessible surface soils from multiple environmental contaminants.
Mr Devey concludes his commentary by recommending that:
Residents may be advised to seek blood-lead level testing before concluding that their property is contaminated.
Our study noted that:
…bio-accessible Pb concentrations indicate a potential burden of disease associated with Newcastle's soil Pb concentrations, which could be better quantified with a childhood blood Pb survey in Newcastle city linked to participant's home soil and dust-metal analysis.
Harvey et al. (2017, section 3.4, page 8)
However, human health screening is a matter for the Hunter New England Public Health Unit who noted recently that they do not recommend routine testing of children for environmental pollutants. Rather, they suggest that blood lead testing be used under specific circumstances including where children:
· present with symptoms suggestive of lead poisoning
· have a history of pica (eating soil)
· have developmental or behavioural issues that predispose children to elevated exposure through contact or ingestion of bare soil in which past industrial activity or lead paint use cannot be excluded
· have been exposed to renovation activities resulting in scraping, sanding or burning of lead-based paint (typically paint applied prior to 1970).
The Hunter New England approach addresses situations where children have already been exposed. Our research work related to contamination focuses on prevention and to that end, we recommend that homeowners consider having their soils and household paint tested to determine the extent of domestic lead exposure hazards. Akin to our recent VegeSafe study of contamination in Sydney household soils, we contend that it is critical that homeowners have relevant information about actual or potential contamination in their home environments. Such knowledge means that when homes are bought, sold or rented it occurs with informed consent, supported by contemporary evidence-based research.
Where environmental concerns are identified via testing, homeowners can then undertake informed and targeted remedial actions. Blood lead screening on the advice of a medical professional would only be recommended if there is a likelihood or a suggestion that exposure has occurred.
Original research article:
Harvey et al. 2017. Available at: http://www.sciencedirect.com/science/article/pii/S0048969717300530 (PDF copies available from email@example.com).
Environmental testing and information
Paint testing kits are available from major hardware stores
Soil screening is available via VegeSafe (https://research.science.mq.edu.au/vegesafe/advice-on-soil/) or at cost via an accredited laboratory (https://www.nata.com.au/nata/)
Lead safety advice is available the NSW EPA: http://www.epa.nsw.gov.au/pesticides/lead-safety.htm
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