Ribeiro D C, Martins G, Nogueira R, Cruz J V, Brito A G
Institute for Biotechnology and Bioengineering, Centre for Biological Engineering--University of Minho, DEB, Campus de Gualtar 4700-057 Braga, Portugal.
Chemosphere. 2008 Jan;70(7):1256-63. doi: 10.1016/j.chemosphere.2007.07.064. Epub 2007 Sep 14.
The phosphorus distribution in volcanic sediments of three lakes that are under different anthropogenic pressures in São Miguel island (Azores - Portugal) was evaluated using a sequential extraction scheme. The P-fractionation scheme employs sequential extractions of sediment with NH4Cl, bicarbonate-dithionite (BD), NaOH (at room temperature), HCl and NaOH (at 85 degrees C) to obtain five P-fractions. The P-fractionation shows that in lakes with higher trophic status (Lake Furnas and Lake Sete Cidades), the NaOH extracted P is the dominant fraction, that contribute with more than 50% to total sedimentary phosphorus. The rank order of P-fractionation for these two lakes was NaOH>NaOH (85 degrees C)>HCl>BD>NH4Cl for Furnas lake and NaOH>HCl>NaOH (85 degrees C)>NH4Cl>BD for Sete Cidades lake. On the other hand, the trend of P contribution in the oligotrophic lake Fogo shows that the most inert P pools have the higher concentrations, with more than 50% of the P contribution from the last extraction step with NaOH at 85 degrees C. For this lake, the rank order of P-fractionation was NH4Cl>BD>NaOH>HCl>NaOH (85 degrees C). The Phosphorus Maximum Solubilization Potential (P-MSP) was also calculated and the results show that for the more bio-available P-fractions (first and second extraction step), the P-MSP values for Furnas and Sete Cidades lakes are sensibly higher than the results obtained in Fogo lake, an indication of the non-point diffuse load discharged in the first ones.
采用连续提取法评估了亚速尔群岛（葡萄牙）圣米格尔岛上三个受不同人为压力影响的湖泊火山沉积物中的磷分布情况。磷分级方案采用氯化铵、碳酸氢盐-连二亚硫酸盐（BD）、氢氧化钠（室温）、盐酸和氢氧化钠（85℃）对沉积物进行连续提取，以获得五个磷级分。磷分级结果表明，在营养状况较高的湖泊（富尔纳斯湖和七城湖）中，氢氧化钠提取的磷是主要级分，占总沉积物磷的50%以上。这两个湖泊的磷分级顺序为：富尔纳斯湖为氢氧化钠>氢氧化钠（85℃）>盐酸>BD>氯化铵，七城湖为氢氧化钠>盐酸>氢氧化钠（85℃）>氯化铵>BD。另一方面，贫营养的福戈湖的磷贡献趋势表明，最惰性的磷库浓度较高，85℃下用氢氧化钠进行的最后一步提取贡献了50%以上的磷。对于该湖，磷分级顺序为氯化铵>BD>氢氧化钠>盐酸>氢氧化钠（85℃）。还计算了磷最大溶解潜力（P-MSP），结果表明，对于生物可利用性较高的磷级分（第一步和第二步提取），富尔纳斯湖和七城湖的P-MSP值明显高于福戈湖，这表明前两个湖泊存在面源分散负荷。
