| Autor: |
Lima, Daniel Jadson Noronha, Menezes, Rosemberg F., Araújo, Fabiana Oliveira |
| Předmět: |
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| Zdroj: |
Journal of Soils & Sediments: Protection, Risk Assessment, & Remediation; Mar2022, Vol. 22 Issue 3, p982-993, 12p |
| Abstrakt: |
Purpose: We quantified the phosphorus (P) fractions and oxide content in the sediment of eight tropical semiarid reservoirs to assess how water-level decreases affect the potential P internal loading. Methods: Chemical fractionation analyses were carried out to determine the P fractions in the reservoirs' sediment, and their chemical composition was evaluated via X-ray fluorescence. Linear regressions were performed to evaluate how changes in the oxide content in the reservoirs' sediment and percentage of the maximum volume stored (%MVS) affected the P fractions. Results: About 35 to 46% of the content of the sediment load of the total phosphorus (TP) was associated with potentially mobile P forms (NaOH-P and BD-P). The chemical composition of the sediments indicated a strong presence of Al2O3 and Fe2O3. The regressions showed that the lower the proportions of Al2O3 content, the lower was both P mobile (Total-P and BD-P) and non-mobile forms (HCl-P and Res-P) in the reservoirs sediment, whereas the proportions of Fe2O3 content were positively related to NaOH-P and Res-P. Moreover, the proportions of SiO2 and CaO content in the sediment were respectively negatively related to NaOH-P and positively related to HCl-P. The decrease in the %MVS in the reservoirs favored both the accumulation of non-mobile forms of P (HCl-P and Res-P) and CaO in the sediments, whereas an opposite pattern was observed for Al2O3. Conclusion: The high P load in the sediments, associated with potentially mobile forms and low water level, indicates that an internal loading mechanism may be present in the environments observed. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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