Heavy metals in ecosystems affect human health through the web chain. Castellon Province is home to the largest ceramic production hub in Spain, with 94% of the country's total production. Agricultural soils in the vicinity of the ceramic hub were reported to contain potentially toxic elements (Pb, Cr, Ni and Cd) in 2008 and have since been subject to repeated amendment with biosolids (sewage sludge). The sample sites were revisited in 2019, and the chemical distribution of these metals reassessed. The distribution of heavy chemical forms was analysed using a sequential extraction protocol that fractionates these four heavy metals into five phases. The incorporation of biosolids for the past 10 years has changed the chemistry of the soil, leading to increased levels of some hazardous elements. The carbonate-sorbed, residual and reducible phases were dominant. From the point of view of compliance with regulations, levels of Cd remained elevated and have increased over the 10-year period.

中文翻译：

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西班牙东北部陶瓷生产区用生物固体（污水污泥）修正的农业土壤金属污染：10年重采样期

生态系统中的重金属通过网络链影响人类健康。卡斯特利翁省拥有西班牙最大的陶瓷生产中心，占该国总产量的94％。据报道，2008年陶瓷中心附近的农业土壤含有潜在的有毒元素（Pb，Cr，Ni和Cd），此后一直反复使用生物固体（污水污泥）进行修正。在2019年对样本站点进行了重新评估，并对这些金属的化学分布进行了重新评估。使用顺序提取方案分析了重化学形式的分布，该方案将这四种重金属分为五个阶段。在过去的十年中，生物固体的掺入改变了土壤的化学性质，导致某些有害元素的含量增加。被碳酸盐吸收的 残留相和可还原相占主导地位。从遵守法规的角度来看，镉的含量在十年中一直保持着上升的趋势，并且一直在上升。