Kao Po-Hsu, Huang Cheng-Chieh, Hseu Zeng-Yei
Department of Environmental Science and Engineering, National Pingtung University of Science and Technology, 1 Hseuh-Fu Road, Nei Pu, Pingtung 91201, Taiwan.
Chemosphere. 2006 Jun;64(1):63-70. doi: 10.1016/j.chemosphere.2005.11.039. Epub 2006 Jan 3.
Application of biosolid on land has been widespread in numerous countries for last several decades. This study performed incubation experiments by mixing a neutral loamy soil and biosolid enriched in Cu, Pb and Zn to explore how heavy metal affects soil mineralization and microbial biomass. The experimental results indicated that large nutrient, microorganism and C sources from biosolid were beneficial to microbial respiration. However, compared to the biosolid alone treatment, the supplemented Cu, Pb and Zn in biosolid reduced the mineralized C by roughly 36%. This phenomenon was probably caused by a portion of the Cu, Pb and Zn being complexed with organic matter to prevent decomposition of organic carbon by microorganisms. Equally, soil treated with biosolid increased the quantity of mineralized N by approximately five-fold and accelerated the rate of N mineralization by about one-fold compared to untreated soil. Notably, addition of heavy metals impaired the mineralization process, particularly when Pb reached about 64%. The reduced N mineralization occurred for similar reasons to the microbial respiration. The addition of biosolid in soil considerably increased the amount of mineralizable N; however, the increase was lower in biosolid-treated soil spiked by heavy metals. The addition of heavy metals in the soil-biosolid mixture clearly reduced the microbial biomasses C (MBC) and N (MBN), indicating that the microbial activities had been disrupted by the heavy metals. The microbial biomass C/N ratio had changed initially from 8 to 13 at the end of incubation period, owing to various groups of microbes expressing different mechanisms of metabolism, indicating that the microbial population had changed from bacteria to fungi, which had higher metal tolerance.
在过去几十年中，生物固体在许多国家的土地上得到了广泛应用。本研究通过将中性壤土与富含铜、铅和锌的生物固体混合进行培养实验，以探究重金属如何影响土壤矿化和微生物生物量。实验结果表明，生物固体中的大量养分、微生物和碳源有利于微生物呼吸。然而，与单独使用生物固体处理相比，生物固体中添加的铜、铅和锌使矿化碳减少了约36%。这种现象可能是由于一部分铜、铅和锌与有机物络合，从而阻止了微生物对有机碳的分解。同样，与未处理的土壤相比，用生物固体处理的土壤使矿化氮的量增加了约五倍，并使氮矿化速率加快了约一倍。值得注意的是，重金属的添加损害了矿化过程，尤其是当铅含量达到约64%时。氮矿化减少的原因与微生物呼吸类似。在土壤中添加生物固体显著增加了可矿化氮的量；然而，在添加了重金属的生物固体处理土壤中，增加量较低。在土壤-生物固体混合物中添加重金属明显降低了微生物生物量碳（MBC）和氮（MBN）, 表明微生物活动受到了重金属的干扰。在培养期结束时，微生物生物量碳/氮比最初从8变为13，这是由于不同微生物群体表达不同的代谢机制，表明微生物种群已从细菌转变为具有更高金属耐受性的真菌。
