Plant litter as a heavy metal migration strategy following application of sewage sludge to subtropical forest soils
Xian, Lihua (South China Agricultural University. College of Forestry & Landscape Architecture)
Fang, Jianbo (Ministry of Ecology and Environment of the People's Republic of China. Eco-Environmental Monitoring and Research Center)
Lu, Dehao (South China Agricultural University. College of Forestry & Landscape Architecture)
Yang, Yuantong (South China Agricultural University. College of Forestry & Landscape Architecture)
Feng, Jiayi (Guangdong Eco-Engineering Polytechnic)
Wu, Daoming (South China Agricultural University. College of Forestry & Landscape Architecture)
Peñuelas, Josep (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Zeng, Shucai (South China Agricultural University. College of Forestry & Landscape Architecture)

Data:	2024
Resum:	The environmental risks of migration of heavy metals (HMs) following applications of sewage sludge (SS) to forest soils are garnering increased attention. Plant litter at the forest floor may modify HM migration pathways through impacts on soil aggregates and water/soil erosion; however, HM migration responses to plant litter are poorly understood. The aim of this study was to determine the effects of plant litter cover on HMs migration, and water and soil erosion following the application of SS to subtropical forest soils. Effects of addition of SS along and SS plus plant litter at 0. 75 or 1. 5 kg m-2 on the migration of cadmium, chromium, copper, nickel, lead, and zinc in surface runoff, soil interflow, and sediments were quantified across nine simulated rainfall events in a laboratory experiment and following natural intense rain events in a field experiment. Addition of SS elevated HM concentrations in surface runoff by 38. 7 to 98. 5 %, in soil interflow by 48. 3 to 312. 5 %, and in sediment by 28. 5 to 149. 4 %, and increased the production of sediment aggregates <0. 05 mm that led to greater cumulative migrations of HMs in surface runoff and sediment; sediment accounted for 89. 5 % of HM migrations. Addition of plant litter reduced cumulative migration of HMs by 87. 1-97. 27 %; however, the higher rate of plant litter led to a decrease in surface runoff and sediment yield, and an increase in soil interflow. Addition of plant litter shifted the main pathway of HM migration from sediment to surface runoff and soil interflow. The potential ecological HM risk index was "low" for each treatment. We found consistency in HM concentrations and migrations via surface runoff between the field and laboratory experiments. Overall, the addition of plant litter with SS mitigated soil erosion and reduced total migration of HMs, resulting in a 88. 7-97. 3 % decrease in the ecological risk index of the six HMs. We conclude that the addition of plant litter may provide a management strategy for the mitigation of HM risks to environmental safety for the disposal of SS in subtropical forest systems.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	Sewage sludge ; Plant litter ; Forest soil ; Heavy metal ; Migration pathway ; Ecological risk
Publicat a:	Science of the total environment, Vol. 948 (October 2024) , art. 174820, ISSN 1879-1026

DOI: 10.1016/j.scitotenv.2024.174820

Disponible a partir de: 2026-10-30 Postprint

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