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Detecting heavy metal contamination in soils

Design, investigation and development of a system for the fast and cost-effective detection of soil pollution.

The aim of the project is to design, investigate and develop devices for the detection of heavy metals in soil. A new method will provide fast, cost-effective in-situ checking of soil pollution without the need to prepare samples chemically. PROBLEM Growing contamination of surface and subsurface soil with heavy metals is one of the most important problems of our civilization. Areas near industrial plants, roads and military installations are exposed to contamination by toxic substances, for instance by heavy metals. Current methods for the quantitative analysis of heavy metals in soil are expensive and time consuming. Therefore, fast and cost-effective in-situ devices for the detection of soil contamination that enable several elements to be determined simultaneously are needed. SOLUTION Laser Induced Breakdown Spectroscopy (LIBS) is the method to solve this problem. LIBS system provides fast in-situ analysis of heavy metal contents in soils. The system uses optical fibre sensors and can be deployed in a stand-alone system to analyse surficial soil samples or grab samples. Surficial soil can be analyzed in-situ using backpack or car-mounted systems. HOW IT WORKS The LIBS-based system for soil pollution detection consists of a high-energy laser and a spectrometer. The pulse of laser radiation reaches an investigated sample. The energy of laser radiation is absorbed in the material of the sample. This causes the plasma to be created. The high-temperature plasma emits photons. The wavelength of plasma radiation depends on the energy difference between higher and lower energy levels of excited elements. The plasma emission spectrum is detected and registered by an optical fibre spectrometer. The elemental composition of the sample material is computed by analysis of wavelength and intensities of the emission lines that depend on the type and amount of material. LIBS instrumentation can be quite compact and it requires only optical access to the investigated material, thus it enables non-contact checking to be conducted. Using LIBS technology, it is possible to determine the concentration and location of elemental species rapidly. It is an effective method for quantitative analysis of soil contamination. LIBS could be used for detection of numerous elements: lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn), chromium (Cr), iron (Fe), manganese (Mn), arsenic (As), silver (Ag), nickel (Ni), mercury (Hg), magnesium (Mg), titanium (Ti) and silicon (Si). ADVANTAGES Advantages of the LIBS system for subsurface heavy metals detection are as follows: * In-situ analysis of location and concentration of heavy metals in soils; * Measurements carried out during soil penetration; * Fast analysis that takes a few minutes; * Low cost of the detection process; * Minimal interference to the environment. Keywords: contamination, heavy metals, soil.
Acronym: 
ANENVIR
Project ID: 
3 072
Start date: 
19-03-2003
Project Duration: 
34months
Project costs: 
950 000.00€
Technological Area: 
Laser Technology
Market Area: 

Raising the productivity and competitiveness of European businesses through technology. Boosting national economies on the international market, and strengthening the basis for sustainable prosperity and employment.