Urmia University
Abstract: (295 Views)
Abstract
Ciprofloxacin, one of the fluoroquinolone antibiotics, accumulates as a pollutant in the soil environment and is uptake by plants due to the widespread use in human and veterinary medicine and its long half-life.
Therefore, this study investigated the effect of a type of organic material called leonardite on ciprofloxacin adsorption. This was considered as a method to reduce the mobility of this pollutant in the soil environment and its uptake by plants. For this purpose, an experiment was carried out with a concentration of ciprofloxacin (0.8 mmol L-1) at different levels of leonardite (0, 2 and 5%) in a calcareous soil. Leek (Allium Iranicum) was then grown in a factorial experiment based on a completely randomized design with the treatment of leonardite (0, 2 and, 5 %) and ciprofloxacin (0 and 2 mmol L-1) in three replications. The plants were harvested 42 days after planting and the concentration of CIP in the plants were determined using high performance liquid chromatography (HPLC). The results showed that application of leonardite increased the ciprofloxacin adsorption in the soil. So that the adsorption amount (qe) of ciprofloxacin reached from 5102 to 5756 mg kg-1 with the use of 5% leonardite. In addition, the distribution coefficient (Kd) of ciprofloxacin in the presence of 5% leonardite increased 5 times compared to the control, which indicates the immobilization of ciprofloxacin due to its strong adsorption by leonardite. The uptake of ciprofloxacin by leek plants was significantly reduced through the use of leonardite, and it decreased from 4.5 µg g-1 to 3.2 and 1.7 µg g-1, respectively, in the presence of 2% and 5% leonardite compared to the control. In general, it seems that leonardite usage can be effective to stabilize ciprofloxacin in polluted soil and to reduce its entry into crops, especially vegetables.
Keywords: Adsorbent, Distribution coefficient, Pollutant, Soil
Background and Objective: Antibiotics are used in treating a wide spectrum of diseases, and are widely employed to promote animal growth (Cycon et al., 2019). As many of those pharmaceuticals are only partially absorbed by the digestive system, a considerable fraction is excreted in its original active form or only partially metabolized. Therefore, the use of animal excrement in agriculture represents one of the principal routes of insertion of antibiotics into the environment. Within that context, plants, principally those of agricultural interest, will be exposed to those compounds when present in the soil (Rocha et al., 2021).
Methods: An agricultural soil (0–20 cm deep) was collected from a farm in Urmia University, and air-dried. After removal of large pieces of plant materials by screening through a 2 mm sieve, the soil was mixed well and stored at 4 °C until use. Pot test had two treatments with leonardite (0, 2 and 5%), and ciprofloxacin (0 and 2 mmol L-1) in three replicates. Into each pot seeds of leek (Allium Iranicum) were sown at a depth of 0.5 cm. During the test period, the treated pots were placed at a temperature of 25 °C and the soil water moisture was maintained everyday by adding appropriate amount of water. The plants were harvested at the 42th day and ciprofloxacin concentration was measured using HPLC (Liu et al., 2009).
Results: The results showed that the application of leonardite increased adsorption of ciprofloxacin in the calcareous soil, and decreased concentration of ciprofloxacin in leek plants. Therefore, leonardite application is a good choice for controlling ciprofloxacin in the soil environment and preventing its entry into crops, especially vegetables.
Conclusions: The solution to reduce pollution caused by ciprofloxacin is to use efficient and low-cost adsorbents such as leonardite. It will be necessary, however, to consider the co-occurrence of antibiotics in existing environmental matrices (instead of focusing on only a single contaminant).
References:
1. Cycon, M., Mrozik, A., Piotrowska-Seget, Z., 2019. Antibiotics in the Soil Environment-Degradation and Their Impact on Microbial Activity and Diversity. Front. Microbial. 338, 1-45.
2. Rocha, D.C., Rocha, C.S., Tavares, D.S., Calado, S.L.M., Gomes, M.P., 2021. Veterinary antibiotics and plant physiology: An overview. Sci. Total Environ. 767, 144902.
3. Liu, F., Ying, G., Tao, R., Zhao, J., Yang, J., Zhao, L., 2009. Effects of Six Selected Antibiotics on Plant Growth and Soil Microbial and Enzymatic Activities. Environ. Pollut. 157(5), 1636-42.
Type of Study:
Research |
Subject:
Soil health association with soil-plant interactions Received: 2024/10/13 | Accepted: 2025/01/4