Potential Toxic Elements (PTEs) Dataset of Surface Sediments in the Sanjiangyuan Region
Description
1. Dataset Title Potential Toxic Elements (PTEs) Dataset of Surface Sediments in the Sanjiangyuan Region 2. Authors & Affiliation Dongdong Chen, Qi Li, Yukun Zhang, Li Zhang, Fuquan He, Quanbang Li, Liang Zhao (Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China) Xin Chen (Xingzhi College, Zhejiang Normal University, Jinhua 321000, China) Zongjian Zhao (Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China) 3. Contact Information Corresponding Author: Liang Zhao E-mail: lzhao@nwipb.cas.cn Affiliation: Northwest Institute of Plateau Biology, Chinese Academy of Sciences Address: Xining 810008, Qinghai Province, China 4. Geographic Coverage 4.1 Study Area Sanjiangyuan Region, located in the hinterland of the Qinghai-Tibet Plateau (31°39′-36°16′ N, 89°24′-102°23′ E), southern Qinghai Province, China. As the source area of the Yellow River, Yangtze River, and Lancang River (Mekong River), it is known as "China's Water Tower". It plays a critical role in the national ecological security barrier. 4.2 Sampling Site Distribution Sampling sites cover the main streams and tributaries of three major river systems, with a total of 48 sampling points (Figure 1 in the associated manuscript): 5. Data Content and Structure The dataset is stored as an Excel file with 4 worksheets, integrating raw concentration data, pollution assessment indices, and source apportionment results. All data are complete (no missing values) and consistent with the analytical results in the associated manuscript. 6. Data Collection and Processing Methods 6.1 Sample Collection Medium: Surface sediments collected via the multi-point mixing method. Preservation: Samples sealed in acid-washed polyethylene bags, stored at 4°C, air-dried, and sieved through a 0.15 mm mesh in the laboratory. 6.2 Laboratory Analysis Instrumentation: Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) for Cr, Ni, Cu, Zn; atomic fluorescence spectrometry for Hg, As, Pb, Cd (compliant with Chinese national standards GB/T 17141—1997, GB/T 22105.1-2008, GB/T 22105.2—2008). Quality Control: Method Detection Limits (MDLs): Hg=0.002 mg kg-1, As=0.01 mg kg-1, Pb=17.50 mg kg-1, Cr=7.500 mg kg-1, Cd=0.050 mg kg-1, Ni=1.750 mg kg-1, Cu=1.500 mg kg-1g, Zn=1.000 mg kg-1; recovery rate: 85%–115%. 6.3 Data Calculation Enrichment Factor (EF): Normalized by Ni (reference element) with background values from Chinese fluvial sediments. Geo-accumulation Index (Igeo): Igeo = log₂(Cₙ/(1.5×Bₙ)), where Cₙ=measured concentration, Bₙ=background value. PMF Model: EPA-PMF 5.0 with 5 factors (Qrobust/Qtrue=60.3, residuals within [-3, 3]). 7. Data Format File Type: Microsoft Excel (.xlsx) Compression: Uncompressed (single file) Encoding: UTF-8 8. Acknowledgment This work was supported by the Chief Scientist Program of Qinghai Province (2024-SF-102).
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Steps to reproduce
1. Data Preparation 1.1 Required Data Files Primary dataset: Potential Toxic Elements (PTEs) Dataset of Aquatic Sediments in the Sanjiangyuan Region.xlsx (4 worksheets) Supplementary materials: Background values of PTEs in Chinese fluvial sediments (Shi et al., 2016), Sediment Quality Guidelines (MacDonald et al., 2000) 1.2 Software & Tools Data processing: Microsoft Excel 2016+, SPSS 24.0+, R 4.0+. Statistical analysis: EPA-PMF 5.0. Visualization: Origin 2020+, ArcGIS 10.8. 2. Step-by-Step Reproduction Procedures 2.1 PTE Concentration Validation Open the PTEs worksheet in Excel/R. Verify basic statistics for 8 PTEs using descriptive statistics in SPSS or summary() function in R. Cross-check spatial patterns: Group data by river system and confirm concentration rankings via one-way ANOVA (p < 0.05). 2.2 Pollution Assessment Replication 2.2.1 Enrichment Factor (EF) Retrieve background values (Shi et al., 2016) and use Ni as the reference element. Calculate EF using the formula: EF=((C_c^i)/(C_ref^i ))sample/((B_c^i)/(B_ref^i ))background (Where C_c^i =measured PTE, C_ref^i = Ni concentration, B_c^i = background PTE concentration, B_ref^i = background Ni concentration) Classify EF results: ≤2 (no enrichment), 2–5 (moderate enrichment), >5 (high enrichment). 2.2.2 Geo-accumulation Index (Igeo) Use the formula (Müller, 1979): I_geo=〖log〗_2 ((C_c^i)/(kB_c^i )) (Where 1.5 = correction factor) Classify Igeo: ≤0 (unpolluted), 0–1 (unpolluted-moderate), >1 (moderate pollution) and validate against the dataset’s Geo-accumulation index worksheet. 2.2.3 SQGs-Based Toxicity Assessment Compare PTE concentrations with ERL/ERM and TEL/PEL thresholds (MacDonald et al., 2000). Calculate the proportion of samples in three risk tiers: <ERL/TEL (minimal risk), ERL-ERM/TEL-PEL (possible adverse effects), >ERM/PEL (frequent adverse effects) and cross-verify with the manuscript’s Table 1. 2.3 Source Apportionment Replication (PMF Model) Prepare input data: Extract PTE concentrations (from PTEs worksheet) and calculate uncertainties using: For C≤MDL: Ui=5/6×MDL For C>MDL: U_ij=√((EF×c)^2+(0.5×MDL)^2 ) (EF = relative standard deviation, MDL = method detection limit provided in the dataset) Run EPA-PMF 5.0: Set factor number range: 3–5 (20 iterations per factor). Select optimal factors (5 factors) based on Qrobust/Qtrue ratio (≈60.3) and residual distribution (within [-3, 3]). Validate factor contributions. 2.4 Spatial Distribution Mapping Extract geographic coordinates (longitude/latitude) and elevation from the PTEs worksheet. Use ArcGIS 10.8 to create point shapefiles and generate spatial distribution maps (e.g., Kriging interpolation) for PTEs. Verify consistency with the manuscript’s Figure 3 (spatial concentration gradients). 3. Quality Control & Validation Checks Ensure all calculated statistics (mean, EF, Igeo) match the dataset’s precomputed values. Confirm PMF model fit. Cross-validate with supplementary literature.
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Funders
- Chief Scientist Program of Qinghai ProvinceGrant ID: 2024-SF-102