Iron(II) concentrations in fresh groundwater in Dutch aquifers range from absent up to 50 mg/l. Evaluation of extensive chemical data sets learned that the maximum logarithmic concentration of iron(II) in aquifers, between ± 6.5 < pH < ± 8, is a linear function of pH, governed by Siderite. It is a broad relation due to oversaturation with respect to Siderite and to variation in alkalinity. Iron(II) is continuously supplied to groundwater by reduction of hydrous ferric oxides (HFO), until becoming saturated with respect to Siderite, and from then on, HFO reduction and Siderite precipitation occur simultaneously. In Dutch aquifers, the electron supply rate (equivalent to the organic matter oxidation rate) apparently exceeds the HFO electron uptake rate (equivalent to the HFO reduction rate) and the excess supply is taken up by sulfate (equivalent to the sulfate reduction rate): HFO reduction, sulfate reduction and FeS precipitation occurring simultaneously, where the presence of Siderite prevents a dip in the iron(II) concentration. After sulfate becomes exhausted, the excess electron supply is transferred to methane production: HFO reduction and methane production occurring simultaneously. This evaluation also demonstrated that the organic matter oxidation rate and the HFO reduction rate decrease over time. The results of this study are also relevant for the behavior of As and of Co, Ni and Zn in groundwater, as HFO, Pyrite and Siderite may contain variable contents of these elements.

荷兰含水层新鲜地下水中的铁（II）浓度范围从不存在到最高50 mg / l。对大量化学数据集的评估表明，含水层中铁（II）的最大对数浓度在±6.5 <pH <±8之间，是pH的线性函数，受Siderite控制。由于相对于菱铁矿的过饱和和碱度的变化，这是一个广泛的关系。通过还原含水三氧化二铁（HFO）将铁（II）连续供应到地下水中，直到菱铁矿饱和为止，此后HFO还原和菱铁矿沉淀同时发生。在荷兰的含水层中 电子供应速率（相当于有机物氧化速率）显然超过了HFO电子吸收速率（相当于HFO还原速率），多余的供应量被硫酸盐吸收（相当于硫酸盐还原速率）：HFO还原，硫酸盐还原和FeS沉淀同时发生，其中菱铁矿的存在可防止铁（II）浓度下降。硫酸盐耗尽后，多余的电子供应转移到甲烷生产中：HFO还原和甲烷生产同时发生。该评价还表明有机物氧化速率和HFO还原速率随时间降低。这项研究的结果也与地下水中As和Co，Ni和Zn作为HFO的行为有关，