Using dredged sediments from Lake Taihu as a plant-growing substrate: Focusing on the impact of microcystins

• Published in: Journal of environmental management 2024-11, Vol.370, p.122927, Article 122927
• Main Authors: Cao, Qing, You, Bensheng, Liu, Weijing, Xu, Haibo, Ma, Shuzhan, Wang, Tong
• Format: Article
• Language: English
• Subjects: China; Dredged sediment; Ecological risk; Food quality; Geologic Sediments - chemistry; Human health risk; Lactuca - drug effects; Lactuca - growth & development; Lakes; Microcystins; Microcystins - analysis; Plant Development - drug effects; Plant growth; Soil - chemistry
• ISSN: 0301-4797; 1095-8630; 1095-8630
• DOI: 10.1016/j.jenvman.2024.122927

Using dredged sediment as plant growth substrates is a promising way to deal with large amounts of excavated sediments. However, it is a big challenge to deal with various pollutants in sediments, among which microcystins (MCs) gained limited attention. In this study, sediments collected from Lake Taihu were mixed with agricultural soil at a 1:1 ratio to create various growing substrates for lettuce (Lactuca sativa L. var. ramosa Hort.). Results indicated that fresh weight and leaf area of lettuce increased in some sediment-amended treatments due to additional nutrients, but food quality was negatively affected by sediment amendment as suggested by the soluble sugar and Vitamin C levels. MCs were detected in all lettuce grown in sediment-amended substrates, particularly in treatments with sediments collected during the bloom. The highest MC contents were found in treatment amended with sediments collected from Meiliang Bay in August (88.6 μg kg−1 for MC-LR and 65.6 μg kg−1 for MC-RR). MC accumulation in lettuce and the associated human health risks were significant, especially in treatments with sediments from the bloom period. Ecological risk assessments revealed high RQ values, indicating potential harm to the soil ecosystem. This study underscores the importance of considering MC content in sediments when evaluating their use as growing substrates. The findings contribute to understanding the environmental and health implications of sediment reuse, offering insights for safer agricultural practices and sediment management. [Display omitted] •Highest microcystin content was found in sediment collected in August.•High nutrients in sediment amended soil did not necessarily increase plant growth.•Microcystins are present in all plants growing in sediment amended soil.•High content of microcystin bioaccumulated in lettuce poses a potential human health risk.•Microcystins in the dredged sediments could pose a high risk to the soil ecosystem.