Considerations for sampling contaminants in agricultural soils.

Area of Science:

• Environmental Science
• Soil Science
• Analytical Chemistry

Background:

• Agricultural soil contaminant analysis is a developing field.
• Traditional soil nutrient sampling protocols may not be suitable for contaminant analysis due to low analyte levels and heterogeneity.
• A robust scientific approach is required to develop reliable contaminant sampling methods.

Purpose of the Study:

• To evaluate the adequacy of existing soil sampling protocols for contaminants.
• To propose a systematic scientific approach for developing new soil sampling protocols for contaminants.
• To ensure the representativeness and defensibility of soil contaminant data.

Main Methods:

• Development of Sample Quality Criteria.
• Characterization of soil material properties, focusing on heterogeneity.
• Application of the Theory of Sampling (TOS) using Sample Quality Criteria and material properties as inputs.
• Determination of sampling protocol specifics (mass, increments, tools) to control error.

Main Results:

• Existing nutrient sampling protocols are insufficient for contaminants.
• A systematic approach integrating Sample Quality Criteria and TOS is essential.
• The TOS provides a framework for designing protocols to reliably estimate contaminant concentrations.

Conclusions:

• A systematic scientific approach, grounded in the Theory of Sampling, is necessary for developing accurate agricultural soil contaminant sampling protocols.
• Implementing these scientifically-based protocols ensures sample representativeness and data equivalency.
• This approach provides a sound technical basis for defensible decision-making to enhance food and feed safety regarding soil contaminants.