PICT (Pollution Induced Community Tolerance) to Cu is a useful and sensitive tool to assess the effects of Cu pollution in soils under laboratory conditions. However, in field situations, the absence of reference values, i.e. bacterial community tolerance to Cu baseline from non-polluted soils, make the method uncertain when we want to know if a soil is or is not polluted from a microbiological point of view. In order to shed some light on this topic, the PICT (Pollution Induced Community Tolerance) concept was used to determine the bacterial community tolerance to Cu in uncontaminated soils developed on five different parent materials, using log IC₅₀ as a tolerance index. IC₅₀ was calculated as the amount of Cu that inhibit 50% of bacterial growth (estimated via the leucine incorporation method) in a bacterial suspension extracted from soil. With physico-chemical soil characteristics and type of parent material, a linear multiple regression equation was fitted explaining 80% of the variance in log IC₅₀ values. This equation provides a useful tool to estimate the bacterial community tolerance to Cu baseline in a soil using the general soil characteristics, allowing for the more general use of PICT without the need of reference soils.

对铜的PICT（污染引起的社区耐受）是评估实验室条件下土壤中铜污染影响的有用且敏感的工具。但是，在野外情况下，由于缺乏参考值，即无污染土壤对Cu基线的细菌群落耐受性，因此当我们想从微生物学角度了解土壤是否受到污染时，该方法不确定。为了阐明这一主题，使用PICT（污染诱导的社区耐受性）概念，使用log IC ₅₀作为耐受指数，确定了在五种不同母体材料上发育的未污染土壤中对Cu的细菌群落耐受性。IC ₅₀计算出的铜含量是抑制从土壤中提取的细菌悬浮液中50％细菌生长的铜含量（通过亮氨酸掺入法估算）。根据土壤的理化特性和母体材料的类型，拟合了线性多重回归方程，该方程解释了log IC ₅₀值的80％的方差。该方程式提供了一个有用的工具，可以利用土壤的一般特性估算土壤中细菌对Cu基线的耐受性，从而无需参考土壤即可更广泛地使用PICT。