The bioavailability of chemical elements is poorly related to the chemical composition of soils and plant growth media containing a mineral or any type of adsorbed phase. The chemical potential (pi for element, i,) is an intensity parameter (I), and the sorbed amount in equilibrium with the soil solution is a measure of the quantity (Q). These parameters for each element (essential or toxic) should be measured in the presence of other elements at or near the desired intensity. This test method is the only method that generates these results simultaneously for several elements. The computer software allows these values to be related to the total sorbed quantities of the different elements. For many substrates, it has been found that the theory for the method holds to the degree that vegetation has been established on many non-soil substrates and soil-water-food chain problems have been evaluated by this test method. This test method has been used on many sites in Pennsylvania and other locations to monitor the effect of sewage sludge applications on land as a source of essential elements for plants with no harmful effects on the food chain. It has also been used to evaluate synthetic soils produced from fly-ash alone or as a component of coal refuse for the establishment of vegetation on mine spoils, coal refuse piles, and abandoned mine lands.

The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D 3740 are generally considered capable of competent and objective testing/sampling/inspection and the like. Users of this standard are cautioned that compliance with Practice D 3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D 3740 provides a means of evaluating some of those factors.

1.1 This test method covers the determination of quantity (Q) and intensity (I) results for several elements in soils, spoils, fly-ash, and other soil substitutes to ascertain their suitability for the growth of vegetation and possible adverse effects of metals on the food chain.

1.2 The values stated in SI units are to be regarded as the standard.

1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.