The increased desire to develop inner city areas while at the same time protecting the countryside has stimulated the demand for the redevelopment of old industrial ‘Brown Field’ sites. These sites may be grossly contaminated with residues left by their previous owners which typically include used solvents, petrochemical products such as gasoline, naphtha, gas oil/diesel, lubricating oil and synthetic lubricants, detergents and surfactants. SGS M-Scan has extensive experience of characterising and speciating products in soil and groundwater.
Gas Chromatography with Flame Ionisation Detection (GC-FID) is used as a first screening technique particularly where complex mixtures of these products are present.
Contaminants can be extracted from soil, ground water or collected as free product floating on top of ground water. Under certain circumstances this technique can go beyond merely identifying the products present being also able to age the diesel input into the soil. Age dating of diesel input can be to within ± 2 years with 95% accuracy – please contact SGS M-Scan for more details.
The source of a gasoline input can also be investigated. SGS M-Scan has developed techniques for branding petrol which can be used to identify the source of a contamination. Similarly, the ‘fingerprinting’ of spilled oil can be used to assess the likely source.
For more complex industrial inputs Gas Chromatography with Mass Spectrometry Detection (GC-MS) must be used. This technique has the advantage of an extensive library of data which can be drawn on to assist in the identification of unknowns but it is also used on some of the commoner contaminants e.g. Polycyclic Aromatic Hydrocarbons (PAHs) and Perchlorinated Biphenyls (PCBs).
Where inorganic as well as organic compounds are thought to be contributing to a contamination, SGS M-Scan uses approved sub contractor laboratories for the identification of inorganic compounds by ICP-OES, ICP-MS and ion chromatography.
SGS M-Scan is at the forefront of developing new techniques to enhance the sensitivity of detection of environmental contaminants. Recently, the carcinogen Perfluorooctane Sulfonic Acid (PFOS) was found in drinking water in several European countries and North America. SGS M-Scan first developed a technique for analysing this compound in 1997, since then more sensitive techniques have been developed as remediation of the sources has reduced the concentrations detected in the environment.