ICAR- Indian Institute of Soil Science, Nabibagh, Berasia Road, Bhopal, 462038, India.
Ecotoxicology. 2021 May;30(4):719-732. doi: 10.1007/s10646-021-02398-2. Epub 2021 Apr 1.
TiO nano particles (NPs) are one of the most produced nanoparticles in the world which are increasingly being released in to the soil. Soils are exposed to various level of concentration of TiO NPs, which has raised concern over the adverse influence on soil microbial community, in turn on ecosystem functions. Although, increasing number of studies on ecotoxicological effect of TiO NPs are coming up recently, however, a common conscience has yet to be reached regarding the impact of TiO NPs on soil microbial community and processes. Moreover, very few studies have targeted soil enzymes which are being considered as sensitive indicator of soil health. Therefore, the present study has been carried out to estimate the ecotoxicological effect of various doses of TiO NPs (5, 10, 20, 40, 80, 100 mg kg soil) on different soil enzymes and microbial community structure. Results revealed that soil enzyme activities and microbial biomass had a uniform trend where the value increased up to the dose of 20 mg TiO NPs kg soil and there onwards reduced drastically up to 100 mg TiO NPs kg soil dose. On the contrary, soil respiration and metabolic quotient kept increasing up to 100 mg TiO NPs kg soil dose indicating sub-lethal stress on microbial community. Nevertheless, the structure of microbial community had slightly different trend where the biomass of total phospho lipid fatty acid (PLFA), Gram positive, Gram negative bacteria, fungi, actinomyctetes and anaerobes were found to be increased up to dose of 80 mg TiO NPs kg soil, but, significantly declined at 100 mg TiO NPs kg soil dose. Furthermore, temperature effect on TiO NPs toxicity had exhibited a less negative impact at 40 °C rather than at 25 °C. In addition alteration index (AI3), an integrated indicator of C, N, P cycling of soils as well as a well-documented indicator of soil pollution, has been found to be regulated by soil respiration, clay content, anaerobe and eukaryote for AI3-Acid Phos. and by fungi to bacteria ratio, soil respiration, microbial biomass and Gram positive bacteria for AI3-Alk. Phos. Overall, the study provided valuable information regarding ecotoxicological impact of environmentally relevant concentrations of TiO NPs in clay loam soils as well as improved our perception regarding the impact of NPs on soil functioning.
TiO 纳米颗粒（NPs）是世界上产量最大的纳米颗粒之一，越来越多地被释放到土壤中。土壤暴露于各种浓度的 TiO NPs 中，这引起了人们对其对土壤微生物群落的不良影响的关注，进而对生态系统功能产生影响。尽管最近越来越多的研究关注 TiO NPs 的生态毒理学效应，但对于 TiO NPs 对土壤微生物群落和过程的影响，尚未达成共识。此外，很少有研究针对被认为是土壤健康敏感指标的土壤酶。因此，本研究旨在评估不同剂量（5、10、20、40、80、100mgkg 土壤）的 TiO NPs 对不同土壤酶和微生物群落结构的生态毒理学效应。结果表明，土壤酶活性和微生物生物量呈一致趋势，在 20mgTiO NPskg 土壤剂量下增加，然后在 100mgTiO NPskg 土壤剂量下急剧减少。相反，土壤呼吸和代谢商一直增加到 100mgTiO NPskg 土壤剂量，表明微生物群落受到亚致死胁迫。然而，微生物群落的结构呈现出略微不同的趋势，总磷脂脂肪酸（PLFA）、革兰氏阳性菌、革兰氏阴性菌、真菌、放线菌和厌氧菌的生物量在 80mgTiO NPskg 土壤剂量下增加，但在 100mgTiO NPskg 土壤剂量下显著下降。此外，温度对 TiO NPs 毒性的影响在 40°C 时表现出的负面影响较小，而在 25°C 时较大。此外，作为土壤碳、氮、磷循环的综合指标以及土壤污染的良好指标的调整指数（AI3），已被发现受土壤呼吸、粘粒含量、厌氧菌和真核生物的调节（AI3-酸性磷酸）以及真菌与细菌的比例、土壤呼吸、微生物生物量和革兰氏阳性菌（AI3-碱性磷酸）调节。总的来说，该研究提供了有关环境相关浓度的 TiO NPs 在粘壤土中生态毒理学影响的有价值的信息，并提高了我们对 NPs 对土壤功能的影响的认识。
