Comparing bulk extraction methods for chemically available polycyclic aromatic hydrocarbons with bioaccumulation in worms
Bibliographic record
Abstract
Environmental context. Determining the bioavailability of organic contaminants in sediments is a critical step in assessing the ecological risks of contamination in aquatic ecosystems. Standardised sediment bioaccumulation tests using benthic organisms are often performed to determine the relative bioavailability of sediment contamination. Unfortunately biological methods are time consuming, expensive and organisms are often difficult to maintain in good health in a laboratory exposure system. Contradictory results have been reported in the last decade and factors that affect the behaviour of extractants need to be examined for a large range of sediments. A study was conducted to determine the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in sediment using worms and to compare the uptake by the biological samplers with mild solid/liquid extractions when exposed to unspiked low and highly contaminated marine and freshwater sediments. Abstract. The purpose of this study is to evaluate different techniques for assessing the availability of polycyclic aromatic hydrocarbons (PAHs) in contaminated sediments. This goal was achieved by comparing results from 28-day uptake experiments by Nereis virens and Lumbriculus variegatus with PAHs extracted by three non-exhaustive extraction methods using: n-Butanol (BuOH, 100%), an aqueous solution of hydroxypropyl-ß-cyclodextrin (HPCD) and a surfactant solution of Brij700 (B700). Our results highlight the importance of considering both the PAH level in sediments and the molecular size of PAHs when attempting to predict their bioaccumulation in a biological sampler like worms using a solid/liquid extraction method. The surfactant B700 solution was quite successful to predict PAH bioaccumulation when exposed to unspiked highly contaminated sediments (25–5700 µg g–1). When low contaminated sediments (0.06–11 µg g–1) were used, HPCD and BuOH were better extractants for estimating bioaccumulation whereas B700 appeared to be too mild an extractant for most samples. Our results illustrate the interest and difficulties in finding an adequate chemical predictor for PAH bioavailabilty, particularly because PAH concentrations and sequestration processes play a determining role in the quality of results. Because B700 is not expansive and extraction solutions are easy to prepare, an extraction procedure involving this surfactant is proposed as a reliable predictor for aged highly contaminated sediments.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".