Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen, 361102, China.
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen, 361102, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China.
Environ Pollut. 2022 Jan 15;293:118577. doi: 10.1016/j.envpol.2021.118577. Epub 2021 Nov 27.
Glomalin-related soil protein (GRSP) has received extensive attention due to its ability to immobilize metals in the environment. However, whether it can enter the food chain through digestion is still unclear. Mangroves occupy the transition zone between the sea and land, have important ecological functions. Mangroves suffer from fragmentation due to human activities and urbanization. A variety of waterfowls inhabit near the mangroves and ingest sediment settled on their food inadvertently or for grit; therefore, they are ideal for revealing GRSP's role in metal enrichment. In this study, we investigated the release of metals from mangrove surface sediments and GRSP through a physiologically based extraction test. The investigated metals (As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in sediments and those bound to GRSP would be mainly released in the gizzard phase. GRSP appeared to be an efficient carrier of Cu, Zn, Pb, and As from sediments to the waterfowls via direct sediment ingestion. For instance, 3.21% and 3.34% of sediment Cu were released in the gizzard and intestinal phases, respectively, meanwhile GRSP-bound Cu contributed 5.04% and 5.42% to this flux. The continuum of GRSP enrichment - complexation of GRSP and metals - biological accessibility of GRSP-bound metals, influenced by both direct and indirect effects from major nutrients (e.g., C, N, P, and S) and metal contents (e.g., Cu, Cd, Ni), controlled the release of GRSP-bound metals during simulated digestion. Overall, this study provides new insights into the potential risk of GRSP acting as a metal delivery vehicle in the food chain.
胶磷矿相关土壤蛋白（GRSP）因其能够固定环境中的金属而受到广泛关注。然而，它是否可以通过消化进入食物链尚不清楚。红树林位于海洋和陆地之间的过渡带，具有重要的生态功能。由于人类活动和城市化，红树林遭受了破碎化。各种水禽栖息在红树林附近，它们会无意中或为了砂囊的摩擦而吞食沉积在食物上的沉积物；因此，它们是揭示 GRSP 在金属富集中的作用的理想选择。在这项研究中，我们通过生理基础提取测试研究了红树林表面沉积物和 GRSP 中金属的释放。沉积物中的研究金属（As、Cd、Co、Cr、Cu、Fe、Mn、Ni、Pb、Zn）和与 GRSP 结合的金属主要在砂囊中释放。GRSP 似乎是通过直接摄取沉积物将 Cu、Zn、Pb 和 As 从沉积物转移到水禽体内的有效载体。例如，3.21%和 3.34%的沉积物 Cu 在砂囊和肠道阶段分别释放，而 GRSP 结合的 Cu 分别对该通量贡献 5.04%和 5.42%。GRSP 富集- GRSP 与金属的络合- GRSP 结合的金属的生物可利用性的连续性，受主要营养物质（如 C、N、P 和 S）和金属含量（如 Cu、Cd、Ni）的直接和间接影响，控制了模拟消化过程中 GRSP 结合的金属的释放。总的来说，这项研究为 GRSP 作为食物链中金属输送载体的潜在风险提供了新的见解。
