Contaminated Land Report
Soil and water analysis
Planning permissions and property conveyancing now require the analysis of soils for heavy metals and arsenic contaminants from mining waste. Crofty Consultancy carries out contaminated land surveys for numerous clients and all types of sites, from greenfield and live industrial to disused brownfield sites. We offer water contamination surveys and landfill gas surveys. We can undertake urgent testing - please enquire for prices.
Crofty Consultancy’s own on-site geochemical laboratory can provide a prompt and trustworthy analysis and detailed report for an average domestic site within 7* working days. Our laboratory team is headed by Clifford Rice, our Chief GeoChemist with over 20 years experience of assaying and geochemistry in the Southwest mining industry.
*Assumes test is for normal mineral suite of selected inorganic contaminants as accepted by Kerrier District Council and other authorities.
Prices vary according to the number of samples taken and the contaminants being tested for. The sampling procedures and documentation comply with the latest British Standards, such as BS 10175:2001.
As all builders in Cornwall are now aware, many building sites require special Sulphate Resistant Concrete to be used for footings, to resist the degradation of the concrete by the action of sulphate in the soil. We offer an unbeatable turnaround time for this analysis at very competitive rates. All testing is carried out to BS 1377:Part 3:1990 by our own experienced chemists.
Footings excavation and construction
Concrete footings or foundations are at risk of deterioration from chemical attack, typically due to acidic solutions or solutions of sulphate salts. This risk increases in areas of past mining activity, such as Cornwall and West Devon, where mineral concentrations in the soil present a higher risk.
An example is when rainwater absorbs carbon dioxide from the atmosphere, forming weak carbonic acid. This in turn can result in the in-situ decomposition of sulphides in the soil (concentrated by mining waste) producing sulphates. These sulphates then react with cement within concrete, causing gradual degradation and eventual failure of the concrete. Mundic Block problems associated with old buildings are the result of a similar process.
Areas of ground with high sulphate levels require the use of sulphate-resisting concrete for footings. This obviously increases the cost of construction, which can be as much as £12 per cubic metre more than normal concrete.
Acidic water increases the likelihood and strength of the attack and so pH testing needs to be carried out in conjunction with any chemical analysis for sulphate. Samples are taken either from trial pits or footing trenches, dependant on the stage of the development. Sample collection and interpretation is carried out by several companies in the South West.
Crofty Consultancy use our own geochemical laboratory for analysis of soil for sulphate, as well as other mineral assemblages, such as inorganic elements and heavy metals.
Due to the nature of construction works, any delays to works are most unwelcome. The Consultancy provides a fast and accurate turn-around for sulphate samples. This means that the need for sulphate-resistant concrete can be determined by the laboratory within 5 working days, dependant on the size of the site (sometimes quicker, enquire for details). All tests are carried out to BS1377.
New standards for contaminated land
Keeping up with newly issued Government guidelines and standards can be time consuming and expensive, but Crofty Consultancy have always prided themselves in understanding and using the latest procedures and methods for their consultancy work.
There is now a new British Standard for the investigation of potentially contaminated sites, BS 10175:2001, which came into force on 1st January 2001.
Consultants dealing with contaminated sites in the Southwest can now discard the 1988 DD175, which is withdrawn. Historically Consultants have used DD175 and the ICRCL (Interdepartmental Committee for the Redevelopment of Contaminated Land) guidelines to assess sites for possible contamination and make recommendations. The new standard is a Code of Practice for investigating suspect sites and has information and methodologies which have been extensively updated since 1988. More specific guidance would still be welcomed by the industry, especially in relation to areas with high local background levels of potentially harmful contaminants.
The standard is designed for use by people who already have some understanding of the risk-based approach to sites and site investigations. The relevant guidance and recommendations within this new standard can be selected to ensure that the objectives of an investigation are achieved.
To accompany the new standard, the DETR and the EA are working on a Handbook of Model Procedures for the Management of Contaminated Land, although no publication date has been set for this handbook.
Crofty Consultancy are also frequently working to the National House Building Council or NHBC standards, where new building work is taking place in areas of suspected contamination. Amongst their routine Contaminated Land Investigation works on new building sites, recent works have included mine waste tips (Kerrier), retail parks (B&Q Camborne) and fuel storage depots (Restormel).
PBET testing
High Levels of arsenic and/or nickel contamination?
A laboratory test now available from Wheal Jane Services could be the answer.
Until recently, accepted laboratory testing methods have identified “total” arsenic in soils, however only the “available” fraction is a danger to health and this is often a small percentage of the total arsenic detected.
A new test, developed by the British Geological Survey, which can identify “available” arsenic, has the potential to re-classify some sites currently designated contaminated land as un-contaminated.
The Physiologically Based Extraction Test (PBET) recreates in a laboratory environment the digestive tract of a 2 to 3 year old child, considered the most “at risk” group.
The test is already becoming widely accepted by many, including Local Authorities, particularly in areas where arsenic is a common soil contaminant such as Cornwall and the other mining areas of the South West.
Crofty Consultancy, the first mining consultancy in Cornwall to achieve ISO9001 quality assurance registration, is now able to provide this cost effective test in as little as 5 days through its associated laboratory facility at Wheal Jane.
For more information on site surveys and PBET testing please contact us.
SBET testing
This is similar to the SBET test and is specific to lead.
Ground gas testing
Gas surveys identify any risk of toxic gas emission from landfill and other legacy activities.
