Universidad Andina Simón Bolívar, Área de Salud, Toledo N22-80, P.O. Box 17-12-569, Quito, Ecuador.
Certop, CNRS UMR 5044, Université Toulouse J. Jaurès, Toulouse, France.
Environ Sci Pollut Res Int. 2019 Jul;26(20):20052-20063. doi: 10.1007/s11356-018-3010-2. Epub 2018 Aug 25.
At the global scale, urban agriculture is increasingly developing in cities due to demographic growth and sustainable food concerns. But, urban soils are frequently polluted with metals. In urban gardens, organic matter is also commonly added both to valorize organic household waste and to promote biophysicochemical fertility. As earthworms promote the decomposition and the recycling of soil organic matter, they can also influence the biogeochemical cycle of metals in urban polluted soils. In order to produce safe vegetables in urban areas, it is crucial to highlight the mechanisms involved in complex soil-earthworm-plant ecosystems. An experiment was set up to examine these relationships using lettuce cultivated in controlled conditions with RHIZOtest® devices. Thanks to the RHIZOtest® devices, metal transfer and bioaccessibility were for the first time compared for urban polluted soil without (1-urban soil polluted with Pb, Cd, Cu, and Zn: essential or toxic metals currently found in environment, SNB) and with bioturbation (2-this metal-polluted soil subjected to earthworm bioturbation, SB) and earthworm casts (3-earthworm casts produced in this polluted soil and naturally enriched in organic matter and microorganisms, T). Metal concentration, phytoavailability, and human gastric bioaccessibility were determined in the different samples. Results showed that earthworm bioturbation increased the phytoavailability of all the metals. For the experimental condition SB, the phytoavailability of metals was increased up to 75% compared to SNB. In addition, surprisingly, metal phytoavailability was always superior in SB compared to earthworm casts (T). Moreover, earthworms led to an increase in Zn gastric bioaccessibility up to 10% in the soils in the same way as for phytoavailability, meaning Zn bioaccessibility in SB > T > SNB, whereas it remained unchanged in the lettuces. These data are important to promote sustainable agriculture activities in urban areas; actually, databases concerning different experimental conditions are needed to develop decision support tools.
在全球范围内，由于人口增长和对可持续食品的关注，城市农业在城市中日益发展。但是，城市土壤经常受到金属污染。在城市花园中，有机物通常也被添加到其中，以利用有机家庭废物并促进生物物理化学肥力。由于蚯蚓促进土壤有机物的分解和再循环，它们还可以影响城市污染土壤中金属的生物地球化学循环。为了在城市地区生产安全的蔬菜，必须强调复杂的土壤-蚯蚓-植物生态系统中涉及的机制。进行了一项实验，使用 RHIZOtest®设备在受控条件下种植生菜来研究这些关系。借助 RHIZOtest®设备，首次比较了没有（1-受 Pb、Cd、Cu 和 Zn 污染的城市土壤，这些金属是当前环境中发现的必需或有毒金属，SNB）和有生物扰动（2-这种受金属污染的土壤受蚯蚓生物扰动，SB）和蚯蚓粪（3-在这种污染土壤中产生的蚯蚓粪，自然富含有机物和微生物，T）的城市污染土壤的金属迁移和生物可利用性。在不同的样本中测定了金属浓度、植物可利用性和人体胃生物可利用性。结果表明，蚯蚓生物扰动增加了所有金属的植物可利用性。对于实验条件 SB，与 SNB 相比，金属的植物可利用性增加了 75%。此外，令人惊讶的是，与蚯蚓粪（T）相比，金属的植物可利用性在 SB 中总是更高。此外，蚯蚓导致土壤中 Zn 的胃生物可利用性增加了 10%，与植物可利用性相同，这意味着 Zn 生物可利用性在 SB> T> SNB，而在生菜中保持不变。这些数据对于促进城市地区的可持续农业活动非常重要；实际上，需要有关不同实验条件的数据库来开发决策支持工具。
