Department of Biology and Environmental Science, Linnaeus University, Norrakajplan 6, 39231 Kalmar, Sweden.
Department of Biology and Environmental Science, Linnaeus University, Norrakajplan 6, 39231 Kalmar, Sweden.
Sci Total Environ. 2022 Nov 10;846:157463. doi: 10.1016/j.scitotenv.2022.157463. Epub 2022 Jul 19.
Dredging of sediments is conducted worldwide to maintain harbours and water bodies. As a result, large amounts of materials generated require proper management and could have useful applications in a circular economy context. The current use of peat as organic material in cultivating plants requires urgent replacement by more sustainable alternatives. In this context, using nutrient-rich sediments generated by dredging could be an attractive option. However, due to contaminants in dredged sediments, more investigations are required. The present study investigated the potential to employ dredged material as a plant-growing substrate to cultivate lettuce (Lactuca sativa). The study employed compost and dredged sediments from Malmfjärden Bay, Sweden, with low and high nutritional content (LN and HN, respectively), with and without polymer (PO) used for dewatering. The tests were carried out under controlled conditions in a greenhouse, and the studied substrates were (% vol): (1) 100 % sediment (100S); (2) 50 % sediment +50 % compost (50S-50C); (3) 70 % sediment +30 % compost (70S-30C); (4) 50 % polymer sediment +50 % compost (50S-50C); and (5) 100 % compost (100C). Fertilisers were added to 50S-50C and 70S-30C during the experiment. Lettuces with the highest weight were harvested from substrates 100C, 50S-50C and 50S-50C. However, the lettuces only reached a weight of 18.57 ± 4.67 g. The results showed that a main limitation of the growth was probably a lack of aeration of the sediments during sampling and development of the experiment. The low aeration possibly caused a lack of available forms of N in the substrates, hindering the growth. Lettuces harvested from substrates containing sediments presented Cd concentrations slightly overpassing the Swedish thresholds, and the health risk index was marginally exceeding 1. Hence, sediments need to be pre-treated before using them to cultivate edible crops, or they could be employed to cultivate ornamental or bioenergy plants.
疏浚沉积物在全球范围内进行，以维护港口和水体。因此，产生的大量材料需要妥善管理，并可以在循环经济背景下得到有用的应用。目前，泥炭作为有机物质用于种植植物的用途迫切需要用更可持续的替代品来替代。在这种情况下，利用疏浚产生的富营养沉积物可能是一个有吸引力的选择。然而，由于疏浚沉积物中的污染物，需要进行更多的调查。本研究调查了将疏浚材料用作种植生菜（Lactuca sativa）的植物生长基质的潜力。该研究使用了来自瑞典马尔默法尔登湾的低营养和高营养含量的堆肥和疏浚沉积物（分别为 LN 和 HN），以及用于脱水的聚合物（PO）。测试是在温室控制条件下进行的，研究的基质为（%体积）：（1）100%沉积物（100S）；（2）50%沉积物+50%堆肥（50S-50C）；（3）70%沉积物+30%堆肥（70S-30C）；（4）50%聚合物沉积物+50%堆肥（50S-50C）；和（5）100%堆肥（100C）。在实验过程中，向 50S-50C 和 70S-30C 添加了肥料。生菜的重量最高是从 100C、50S-50C 和 50S-50C 基质中收获的。然而，生菜的重量仅达到 18.57±4.67g。结果表明，生长的主要限制可能是在采样和实验发展过程中沉积物的通气不足。低通气可能导致基质中可用的 N 形式缺乏，从而阻碍了生长。从含有沉积物的基质中收获的生菜的 Cd 浓度略高于瑞典的阈值，健康风险指数略高于 1。因此，在使用它们种植食用作物之前，需要对沉积物进行预处理，或者可以将它们用于种植观赏或生物能源植物。
