Identifying Heavy Metals in Soil with a Field Spectroradiometer

Soil contamination with heavy metals is a growing problem worldwide. Elevated heavy metal contaminants in soils impact soil quality and can accumulate in the food chain and eventually endanger human health. Standard testing for heavy metals in soil are usually done via chemical analysis that is time consuming and relatively expensive.

NIR field spectroscopy can provide a fast and accurate method for identifying the presence of heavy metals in soil. SPECTRAL EVOLUTION offers a range of field spectroradiometers for soil analysis including the SR-6500, NaturaSpecâ„¢, RS-8800, PSR+ and RS-3500. Measurements can be taken quickly and easily with a contact probe, benchtop probe or fiber optic lens without affecting the sample. Also, there is no sample preparation necessary. A single click and you capture a scan in seconds.

Heavy metals that can be found in soil include zinc, lead, manganese, nickel, chromium and copper. Important absorption features for these metals include:

  • Lead: 440-584nm
  • Zinc: 430-570nm and 590-770nm
  • Manganese: 390-550nm and 580-710nm
  • Nickel: 870-990nm
  • Chromium: 620nm
  • Copper: 820nm

In analyzing heavy metals in soils, first and second derivatives can also supply useful information. DARWin SP Data Acquisition software that runs on all SPECTRAL EVOLUTION instruments provides these derivatives. In addition further analysis of heavy metal content can also be discovered using chemometrics software, such as
Unscrambler from Camo Analytics. Build, optimize and test your model in Camo Analytics Unscrambler. The coefficients from your model are used in the prediction engine built into our DARWin software to identify heavy metals in new samples.

PSR+ used in a soil pit

A contact probe can be used with a Spectral Evolution field spectroradiometer like the PSR+ to take soil measurements in the field.

DARWin first and second derivatives

First and second derivatives are available in our DARWin SP Data Acquisition software that controls our instruments. Derivatives can be helpful in identifying heavy metals in soil analysis.