Investigation of Lithium Application and Effect of Organic Matter on Soil Health

The extensive use of lithium (Li) ion-based batteries has increased the contamination of soil and water systems due to widespread dispersal of Li products in the environment. In the current study, the influence of Li application on soil fertility and leachate was observed. Three soil samples were collected and five treatments of Li (0, 50, 100, 150 and 200 mg/L) were applied. After three months of Li treatment, leachate was collected and soil samples were subjected to physical and chemical analyses. The results showed that the mean values of soil pH were increased slightly after Li application while electrical conductivity (EC) ranged from 1.2 to 5.1 mu S/cm, indicating that soil was slightly saline in nature. The sodium was observed to be greater than the recommended values (0.3-0.7 mg/kg) in Li-amended soil while calcium and magnesium values decreased in soils compared to untreated soil. Mean values of phosphorus and potassium were greater before Li application and reduced considerably after Li application. Leachate analysis showed that all the parameters differed significantly except those of zinc and iron. The EC of leachate samples ranged from 2286-7188 mu S/cm, which shows strong salinity. The sodium adsorption ratio (SAR) ranged from 1-11, which indicates that it falls into the marginal soil category. Lithium concentration in leachate samples ranged from 0-95 mg/L, which was significantly higher than the acceptable value for lithium (2.5 mg/L) in leachate. A soil sample (3) with an additional 10% organic matter showed that after Li application, the loss of nutrients in leachate was less as compared to the other two samples, demonstrating that organic matter improved soil conditions and suppressed the negative effects of Li on soil. Our results could raise concerns about risks in situations where food and fodder crops are associated with Li-contaminated waste disposal.