Distribution characteristics of heavy metals and nutrient elements in inter-tidal surface sediments of Yellow River estuary
Bibliographic record
Abstract
In May,2010,surface sediment samples were collected from the high,middle and low inter-tidal zones along five sections in the Yellow River Estuary,and analysis were carried out on their physico-chemical properties as well as the distribution characteristics of heavy metals and nutrient elements across the area.Through adopting the index number techniques of single factor and Hakanson ecological risk and referring the sediment quality standards of Environment and Energy Department in the province of Ontario,Canada,quality status of these sediments were evaluated.Results showed that concentrations of most heavy metals and nutrient elements exhibited a higher tendency in the northern bank than the southern bank,except Cu and Pb;Concentrations of heavy metals and nutrient elements showed no significant differences among high,middle and low tidal flats except Hg,and hence no prominent vertical characteristics of a mature tidal flat were exhibited.The concentration of Pb was higher than the maximum value of surface sediment in Bohai Sea,making it the most important pollution factor in the research area;The concentration of Hg of low tidal flat at two stations near estuary severely exceeded the class Ⅰ standard of GB 18668-2002,namely,1.7 and 1.8 times of it respectively and possessed a certain potential ecological risk.TN and TOC were in the range of safety level,while TP at 20% stations exceeded the lowest safety level and possessed security risk to some extent.Compared with other tidal flats,the concentrations of Zn,Cd,Hg and As in sediments of the study area were at a relatively low level,those of Cu and Pb were at a moderate level;concentrations of TOC and TP were equivalent to those in the intertidal zone of Yangtze River;while that of TN was relatively low.The results of this study would supply some basic data for the ecological protection,environmental management and pollution controlling in Yellow River Delta.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".