INTERPRETING THE RESULTS OF SOIL TESTS FOR （解释土壤测试的结果）.pdf

INTERPRETING THE RESULTS OF SOIL TESTS FOR HEAVY METALS Vern Grubinger and Don Ross, University of Vermont Agricultural soils normally contain low background levels of heavy metals. Contamination from industrial activities or byproducts can increase the natural levels of heavy metals in soil, creating a health hazard to people, livestock and plants. Fertilizers and other soil amendments also add small amounts of heavy metals to the soil, which can build up over time with repeated applications. The actua l toxicity of a heavy metal will be affected by soil texture, organic matter, and pH. The health effects of exposure to heavy metals depend on the amount and duration of exposure, i.e. the volume of contaminated soil or food consumed over time. It is not clear exactly what levels of heavy metals in soil are safe or unsafe, so the following information is provided only to help you understand your test results and the relative level of risk they represent. In soils with elevated heavy metal levels, which may pose higher levels of risk, you should consider whether remedial actions are appropriate, or whether crops should be grown at all. UVM Heavy Metals Soil Test The test provided by UVM is only a screen for heavy metals and does not measure the actual total metal content of the soil. This low-cost test uses a weak acid to extract heavy metals. The amount of metal extracted is roughly proportional to the total amount present. Maximum levels for heavy metals in soils established by regulatory agencies are based on total heavy metal content (see below) and require a more involved and expensive test. If your UVM test results indicate an elevated level of heavy metal(s), well above the median levels in Table 1 you should consider submitting another sample for a total heavy metal analysis. Table 1 shows the aggregated results of thousands of UVM heavy metal soil tests from across many soil types and mana