|
(02-03) Role of fertilizer on As, Cd, and Pb accumulation in California cropland soils. Krage, Natalie*,1, Chang, Andrew1, Page, Albert1, 1 Department of Environmental Sciences, Riverside, CA ABSTRACT- Phosphorus fertilizers and other inorganic soil amendments may contain high levels of potentially harmful elements such as As, Cd and Pb. Long-term repeated uses in crop production may contribute to the increased heavy metal load in agricultural soils around the world. Cropland soils are the starting point of the food chain transfer of potentially toxic trace elements. In this study, the As, Cd and Pb accumulations in soils were determined in the production-scale vegetable fields in six regions of California. Over 600 soil samples were collected and analyzed. To ensure the reliability of the data, strict protocols for field sampling and sample processing were established and, in chemical determinations, QA/QC protocols were followed to ensure the accuracy and precision. The data from each region was evaluated separately and three patterns of trace element accumulation emerged. In the first case, As and Cd of the soils were above the background level and increased in proportion to the P contents of the soil, indicative of accumulations due to the P fertilizers over a long period of time. In the second case, As, Cd and Pb concentrations of the soils were significantly higher than the background levels. However, the concentrations did not increase with P and Zn contents of the soils. Rather, they scattered over wide ranges, indicating that the accumulations were caused by diffused sources and fertilizer was not a major contributor. In the third case, the trace element concentrations scattered over wide ranges and exhibited a rising trend against the increasing concentrations of P and Zn of the soils, indicating that the trace element accumulations were the results of both fertilizer and diffused sources. Key words: Arsenic, Cadmium, Lead, Fertilizer |
