适宜水分和养分提高土壤中磺酸二甲嘧啶降解率

    Suitable moisture and soil nutrient improve degradation of sulfadimidine in soils

    • 摘要: 医疗和养殖过程中抗生素的广泛使用导致了土壤环境中抗生素的污染。为了解进入农田土壤中抗生素的降解规律,该文以养殖业广泛使用的磺胺二甲嘧啶和2种不同养分水平的土壤为试验材料,采用盆栽方法研究了肥料种类(有机肥、NPK肥、N肥、PK肥等)、耕作强度(翻耕、免耕)、水分条件(长期干燥、长期湿润、干湿交替、长期潮湿)及种植作物(种植蔬菜、不种蔬菜)对土壤中磺胺二甲嘧啶降解的影响。结果表明,与不施肥处理比较,施用有机肥、NPK肥、N肥可促进土壤中磺胺二甲嘧啶在土壤中的降解,并以施用有机肥的效果最为明显;但施用PK肥对土壤中磺胺二甲嘧啶的降解影响不明显。翻耕可促进土壤中磺胺二甲嘧啶的降解,干湿交替、长期湿润比长期干燥和长期潮湿土壤环境下更有利于磺胺二甲嘧啶的降解。种植蔬菜比不种蔬菜土壤的磺胺二甲嘧啶的降解率高,根际土壤中磺胺二甲嘧啶的降解高于总体土壤。高养分土壤中磺胺二甲嘧啶的降解一般高于低养分土壤。分析认为,施肥、土壤养分水平、种植蔬菜对土壤中磺胺二甲嘧啶的降解的影响可能主要与这些因素改变了土壤微生物活性有关;翻耕可促进土壤中抗生素的光降解强度。研究认为, 施肥、耕作和水分管理可以在一定程度上加速土壤中磺胺二甲嘧啶的降解。

       

      Abstract: Abstract: Widely application of antibiotics in medicine and animal breeding had resulted in its pollution in soil environment. Antibiotic resistance is an increasing challenge for health care services worldwide. Antibiotics of both human and veterinary origins have been widely detected in various environmental matrices including surface water, groundwater, soils, and sediments. Within a relatively short period of time after the first antimicrobial drugs were introduced, bacteria began exhibiting varying degrees of resistance. The excessive use (and abuse) of antibiotics in agriculture, and in both human and veterinary medicine, has played a critical causative role in the development of antibiotic resistance. Sulfadimidine and its epimers/isomers were most frequently detected, and it enters soils by the use of animal excrements as fertilizers. In order to understand the degradation characteristics of antibiotics in agricultural soils, two soils with different nutrient levels were selected to carry out several pot soil culture experiments for studying the effect of fertilizers (organic manure, NPK, N, PK), tillage intensity (tillage, no tillage), water conditions (drought, udic, drought-udic alternation, wetness) and crop plantation (vegetables, not vegetables) on degradation of sulfadimidine in the soils. The results showed that the application of organic manure, NPK, and N fertilizers could promote the degradation of sulfadimidine in the soils, as compared with no fertilizer treatment. The effect of organic manure application on the degradation of sulfadimidine was the most obvious. However, the effect of PK fertilizer application on the degradation of sulfadimidine was not obvious. Tillage also could promote the degradation of sulfadimidine in the soils. Both udic moisture regimes and drought-udic moisture alternation were more favorable for the degradation of sulfadimidine in the soils than drought and wetness. Plantation of vegetable crop could improve the degradation of sulfadimidine in the soils. The degradation proportion of the antibiotics in the rhizosphere soil was higher than the whole soil. While the degradation proportion of the antibiotics in soil with high nutrient level was generally higher than soil with low soil nutrient level. It was thought that effects of fertilization, soil fertility, crop plantation on the degradation of sulfadimidine in the soils were related to alteration in soil microbial activity caused by those factors. Tillage can promote the degradation of antibiotics in the soils by increasing its photolysis.

       

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