Abstract:

Dimethyl phthalate (DMP), a kind of toxic organic compound ubiquitous in the environment, has been listed as an environmental pollutant for priority control by the Ministry of Environmental Protection of China (MEP). The purpose of this study is to explore impacts of DMP contamination (0-40 mg•kg^-1) on microflora, functional groups and diversity of soil microbes in black soil. Results show that the populations of bacteria and actinomyces in the black soil were inhibited by DMP contamination and the impact was positively related to concentration of the pollutant. However, the amount of fungi in the soil was promoted and the effect increased with rising DMP concentration. Functional bacteria, like nitrogen fixing bacteria, ammonia oxidizing bacteria, nitrite-oxidizing bacteria, organic phosphorus-dissolving bacteria and inorganic phosphorus-dissolving bacteria, were all inhibited by DMP contamination, but iron bacteria were promoted by DMP contamination. DMP contamination decreased richness and Shannon-Wiener index of the soil microbes in the black soil and the negative impacts lasted for more than 25 d, in the treatments with concentration of the pollutant being 10, 20 and 40 mg•kg^-1. All the findings indicate that DMP in the range of 5-40 mg•kg^-1 in concentration may affect structure of the soil microflora and populations of functional groups and biodiversity of the flora, and hence functions of the black soil ecosystem.

Key words: dimethyl phthalate, black soil, microflora, functional bacteria, biodiversity