Land Use Change and Mangrove Restoration Modulate Heavy Metal Accumulation in Tropical Coastal Sediments: A Nearly Decade-Long Study from Hainan, China

Tingting Si, Penghua Qiu (), Lei Li, Wenqian Zhou, Chuanzhao Chen, Qidong Shi, Meihuijuan Jiang and Yanli Yang
Additional contact information
Tingting Si: College of Life Sciences, Hainan Normal University, Haikou 571158, China
Penghua Qiu: College of Geography and Environmental Sciences, Hainan Normal University, Haikou 571158, China
Lei Li: College of Life Sciences, Hainan Normal University, Haikou 571158, China
Wenqian Zhou: College of Geography and Environmental Sciences, Hainan Normal University, Haikou 571158, China
Chuanzhao Chen: Hainan Guoyuan Institute of Land and Mineral Survey Planning & Design Co., Ltd., Haikou 570203, China
Qidong Shi: College of Geography and Environmental Sciences, Hainan Normal University, Haikou 571158, China
Meihuijuan Jiang: College of Geography and Environmental Sciences, Hainan Normal University, Haikou 571158, China
Yanli Yang: College of Geography and Environmental Sciences, Hainan Normal University, Haikou 571158, China

Land, 2025, vol. 14, issue 6, 1-18

Abstract: Mangrove forests, vital coastal ecosystems that provide critical biodiversity habitats and carbon sequestration services, face increasing heavy metal pollution that threatens their ecological functions through bioaccumulation and toxicity to marine organisms. However, existing studies lack dynamic insights into temporal and spatial variations of heavy metals in mangrove sediments. This study systematically analyzed two mangrove reserves in Hainan Island, China (Hainan Dongzhaigang National Nature Reserve [DZG] and Hainan Qinglan Provincial Nature Reserve [QL]), by collecting sediment samples in 2014 and 2022, analyzing metals (Cr, Cu, Zn, As, Cd, and Pb) via ICP-MS, and applying the geo-accumulation index, potential ecological risk index, Markov transition matrix, and statistical analyses. Results showed that DZG exhibited rising Cu and Zn levels but declining Cr, As, Cd, and Pb, with Cd showing the most significant decrease (66.83%). In contrast, QL saw only a 42.7% reduction in Cd, while other heavy metals increased. Spatial heterogeneity linked higher concentrations to anthropogenic hotspots, DZG’s southeast (industrial/aquaculture inputs), and QL’s northwest (urban/industrial discharges). Although ecological risks were generally low, Cd in QL reached a moderate risk level (E Cd = 46.44, 40 ≤ E i < 80). The large-scale pond-to-mangrove conversion significantly increased vegetation cover, which enhanced sedimentation rates and exerted a “dilution effect” on sediment heavy metals. These findings underscore anthropogenic activities as the dominant driver of heavy metal contamination. We recommend (1) stringent wastewater control near QL, (2) enhanced shipping regulation, and (3) the establishment of mangrove buffers in heavy metal accumulation zones to improve ecological status.

Keywords: mangroves sediment; heavy metals; spatiotemporal variations; ecological risk; land use change (search for similar items in EconPapers)
JEL-codes: Q15 Q2 Q24 Q28 Q5 R14 R52 (search for similar items in EconPapers)
Date: 2025
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/2073-445X/14/6/1259/pdf (application/pdf)
https://www.mdpi.com/2073-445X/14/6/1259/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jlands:v:14:y:2025:i:6:p:1259-:d:1677239

Access Statistics for this article

Land is currently edited by Ms. Carol Ma

More articles in Land from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().