On 2 Jan 2014, TV3 ran a story “Landfarming is safe practice – soil scientist“. Here is our response:
The Edmeades landfarming report (Sept 2013), commissioned by Taranaki Regional Council (TRC), gives no evidence that landfarming is safe, for the following reasons:
1) The report was based on a snapshot study, conducted on just two days (4 July, 5 Aug 2013). Only three completed landfarms (ie. not receiving further waste disposal) were included in the study and only two of the three farms were visited on 4 July.
2) The number of samples taken for analyses was too small to provide representative results. For petroleum residue testing, only four soil and four pasture samples were collected from the three studied landfarms. Considering the size of the farms (e.g. Geary is 30 ha) and the variety of wastes they have received (water- and synthetic-based muds, oily wastes), a far greater number of samples would be required for thorough analysis. As a reference, Canadian Guidelines require a minimum of 40 samples (at 2 depths) from each hectare (to form 8 composite samples) for soil characteristic, nutrient and metal testing, and an additional 8 discrete samples from each hectare for BTEX and other hydrocarbon testing.
3) Nine operating landfarms were not included in the study. The report clearly showed that chemical characteristics and petroleum hydrocarbons in the soils of the three studied landfarms often exceeded acceptable limits during disposal (Tables 3a, b, c; Tables 11a, b, c). Yet stock animals have been reported by TRC’s own inspectors to graze on operating (not yet completed) landfarms (TRC 169501, 2006; TRC 830821, 2011; TRC 1141122, 2013). By excluding the operating landfarms, and not examining the associated stock health or chemical residues in animals or food products, the study cannot possibly argue that landfarming is safe for animals or food safety.
4) The report excludes any consideration of environmental effects off-site (e.g. runoff or leaching of contaminants), so cannot argue that landfarms are safe for the environment. At least two operating landfarms are located on potentially sensitive areas; the Boyd’s landfarm being adjacent to the national park (TRC 934866, 2012) and the Greymouth Hawera landfarm adjacent to the Nowell’s Lakes (TRC 322550, 2008, TRC 555713, 2009, TRC 931224, 2011).
Contrary to the Edmeades report, the Pattle Delamore Partners (PDP) Review of Petroleum Waste Land Farming (June 2013), also commissioned by TRC, highlighted a number of issues in the current landfarming practices in Taranaki and offered several important recommendations which TRC seems to ignore. E.g. The PDP report pointed out that both old and new consents for landfarms fail to limit hydrocarbon loading to 20,000 mg/kg TPH (or 2 % by mass) as required in Alberta Directive 050; the problem of small, composite samples; and the eco-toxicity of mud-additives in drilling wastes. It recommended the council to review the applicability of the National Environment Standard (NES) for Assessing and Managing Contaminants in Soil to Protect Human Health to former landfarming sites, and the applicability of the new soil contaminants standards for arsenic and lead, rather than using biosolids guidelines for these heavy metals.
In terms of peer review, neither reports have gone through such an independent critique process. If they have been peer reviewed, there would be a statement in the reports, or they would have been further developed into scientific papers for publication in peer reviewed journals.
For further information, please read CJT’s third submission to the Parliamentary Commission for the Environment (CJT submission, 3 Nov 2013) which compares several international and national guidelines with TRC’s consenting and monitoring of drilling waste disposal, and CJT’s response to the Dec 2013 Radio NZ series on landfarming (CJT website).