Metal and non–metal dynamics and distribution in soil profiles across selected pans in the Ramsar declared subtropical within a national protected area

ABSTRACTThe study investigated the spatial distributions of selected metals, semi–metals and non–metals within a floodplain pan ecosystem in the Ramsar declared Makuleke Wetlands within the Makuleke Contractual National Park, in the northern Kruger National Park (South Africa), along varying soil depths (0–120 cm) at 20 cm intervals. The study identified significant differences in metal concentrations (i.e. Ca, Mn, Fe) and non–metals (i.e. C, S) across sediment depths. Metal and non–metal concentrations in surface sediments (0–40 cm) were generally high. Compared with the sediment quality guidelines, all measured metals were within the ‘no effect’ level across different sites and depths, except for one site (i.e. Mambvumbvanyi pan). In contrast, enrichment factors showed that K, Ca and Mg were enriched in sediments across all the floodplain pans and depths. Principal component and cluster analyses indicated that various metals originated from different sources. Although a high concentration of metals was found in the topsoil, no potential detrimental effects on the aquatic systems could be observed. Based on the findings, this study provides a baseline overview of sediment metal pollution that can inform effective management of these floodplain wetlands systems.KEYWORDS: Floodplain pansRamsar wetlandsmetalssediment profilesgeo-accumulation indexenrichment factor AcknowledgementsWe are grateful to South African National Parks (SANParks) Scientific Services for research permits (SS287), as well as to Mr Aubrey Maluleke the Park Coordinator of Makuleke Contractual National Park for allowing us to conduct research on the Makuleke concession area.Disclosure statementNo potential conflict of interest was reported by the author(s).Data availability statementAll the data collected during this research is presented in the manuscript.Credit authorship contribution statementLFM: Conceptualisation, Investigation, Data curation, Formal analysis, Writing – original draft, review & editing. LM: Investigation, Data curation, Supervision, Writing – review & editing. RJW: Supervision, Conceptualisation, Resources, Writing – original draft, review & editing. FD: Conceptualisation, Investigation, Resources, Data curation, Writing – original draft, review & editing. CK: Investigation, Writing – review & editing. ER: Permits, Data curation, Investigation, Writing – review & editing. TD: Conceptualisation, Investigation, Resources, Data curation, Formal analysis, Supervision, Writing – original draft, review & editing.Additional informationFundingWe greatly acknowledge the financial support of the University of Venda Niche [Grant UID: FSEA/21/GGES/02] and NRF Thuthuka [Grant UID: 138206]. Linton Munyai acknowledge funding from the National Research Foundation Postgraduate Bursary [UID: 129098]. Chad Keates and Ryan Wasserman acknowledge the South African Institute for Aquatic Biodiveristy (SAIAB) for logistical support.Notes on contributorsLinton F. MunyaiMr. Linton F. Munyai is currently working as a Lecturer in Environmental Sciences at the School of Biology and Environmental Sciences, Faculty of Agriculture, University of Mpumalanga, South Africa. Presently, he is a registered PhD student at the University of Venda. His research mostly focuses on aquatic biodiversity, trophic and foodweb dynamics, water quality and remote sensing.Lutendo MugwediDr. Lutendo Mugwedi is a Senior Lecturer in the Department of Geography and Environmental Sciences at the University of Venda, South Africa. Lutendo's research interests are ecosystem restoration, biodiversity conservation, ecosystem services assessment, freshwater ecology, invasive alien plants ecology and management, and conservation agriculture. Lutendo is also a board chairman of the Vhembe Biosphere Reserve (VBR), where he is involved in conservation and sustainable socio-economic development initiatives in the VBR.Ryan J. WassermanProf. Ryan J. Wasserman interests lie in shallow water ecosystems ecology and restoration, with emphasis on arid and semi-arid regions. Climate change, biological invasion and pollution threats are central to his research on these systems. To date, much of his work has assessed how biodiversity loss associated with these threats, compromises ecosystem functioning and services.Farai DondofemaMr. Farai Dondofema is a Chief Technician at the Department of Geography and Environmental Sciences Faculty of Science, Engineering and Agriculture, University of Venda, South Africa. His research focuses on ecosystem modelling, water resources management GIS and remote sensing. His research interest is in Alien Invasive Plant Species' responses to climate change.Eddie RiddellDr. Eddie Riddell is currently the Regional Co-ordinator within the Limpopo Watercourse Commission (LIMCOM) having recently served as the freshwater ecosystem manager in South African National Parks (SANParks). Dr Riddell's focus through both research and technical approaches is to acheive adaptive management for sustainable river basin management and ecosystem outcomes - Dr Riddell is also an Honorary Research Associate at the Centre for Water Resources Research, University of KwaZulu-Natal, South Africa.Chad KeatesDr. Chad Keates is herpetologist and evolutionary biologist currently employed as the General manager and Head Scientist for Hankuzi Explorations, a conservation non-proft company dedicated to the exploration of Africa's most remote wild spaces. In his short career as an academic, he has amassed a healthy publication record with a wide range of co-authors from across the globe (16 peer-reviewed papers, two book chapters, 10+ conference presentations). He is also a Honorary Research Fellow at the South African Institute for Aquatic Biodiversity, having completed his PhD on snake systematics and evolutionary structuring in 2021. While much of his work is herpetological-based, he has co-authored many professional outputs, with scientists from a variety of other disciplines. He is also regularly called upon for expeditionary work and has worked throughout much of sub-Saharan Africa, with groups such as the Okavango Wilderness Project (National Geographic) in Angola and with Hankuzi Explorations in Zambia.Tatenda DaluDr. Tatenda Dalu is a Senior Lecturer in Water Management at the University of Mpumalanga, South Africa, an Iso Lomso and TWAS Young Affiliate Fellow and Honorary Research Associate at the South African Institute for Aquatic Biodiversity.