『Abstract
Speciation of particulate phosphorus in soils and aquatic sediments
by sequential extraction techniques is commonly used to address
both fundamental and applied problems. It has been suggested,
however, that sequential extraction techniques can produce misleading
results due to the generation of new solid phases during the extraction
process. In this study, a well-established fractionation technique
introduced by Psenner et al. (1984) for crystalline sediments
was reevaluated in four calcite-rich lake sediments using a set
of additional extraction tests and structural analyses. Extended
tests using a sediment artificially enriched with Al and Ca, regarded
as model sediment, showed a distinct overestimation of Ca-bound
P (HCl-TP) and concomitant underestimation of metal oxide-bound
P (NaOH-SRP). The formation of new solid phases during extraction
was evident by P addition to the alkaline extract, change of volume-to-solid
ratio, and variation of extraction time. Examination of the model
sediment with infrared and X-ray spectroscopy demonstrated that
Ca-bound P was not present before the NaOH step. Apatite structures
were detected by IR spectroscopy in the model sediment after NaOH
extraction. In contrast, in the three natural calcite-rich sediments
with high HCl-TP portions, underestimations of NaOH-SRP were not
detected with the standard protocol. Therefore, a modification
of the Psenner method does not appear necessary for most conditions.
In hardwater lakes, however, especially those restored with al
and Fe salts, a shift from NaOH-SRP to HCl-P cannot be excluded.
Our study provides helpful tools to identify such artifacts and
thus to prevent misinterpretation of fractionation results.』
Acknowledgments
Introduction
Materials and procedures
Sequential phosphorus extraction
Analysis with X-ray and infrared spectroscopy
Sampling sites
Assessment
Extraction tests
Structural analysis
Discussion
Comments and recommendations
References
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| 1M NH4Cl（脱酸素化された） | 0.5 | TP | 孔隙水中のP、表面にゆるく吸着したP（例えば、FeOOHやCaCO3の表面） |
| 0.11M BD（bicarbonate/dithionite） | 1 | TP | 酸化されたFeとMn化合物に主に結合した酸化還元に敏感なP |
| 1M NaOH |
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SRP | OH-イオンに対して交換可能なP〔例えば、AlとFe（オキシ）水酸化物に吸着したP〕および塩基中で可溶な無機P化合物〔FeとAl（水酸化）リン酸塩〕 |
| NRP | ポリリン酸（poly-P）と砕屑物中の有機Pとフミン化合物に結合したPを含む微生物中のP | ||
| 0.5M HCｌ | 16 | TP | Caリン酸塩鉱物および酸に可溶の有機P |
| 残渣P（Residual-P、Res-P） | TP | 溶けにくい（refractory）有機Pおよび抽出できない（nonextractable）鉱物P | |
| NRP＝非反応性リン（nonreactive phosphorus）、SRP＝可溶の反応性リン（soluble reactive phosphorus）、TP＝全リン（total phosphorus） | |||