Evaluation of metals availability in sediments of the Bertioga Channel (Santos Estuarine Complex - SP - Brazil): A tool for chemical pollution monitoring
Notice bibliographique
Résumé
"The Bertioga Channel (SE Brazilian coast) is part of the Santos Estuarine Complex, situated at the Baixada Santista. The Baixada Santista is a very important economic region of Brazil which, due to its intensive economic development, has been experiencing several interventions on its coastal environment. Both the largest harbor, located on the city of Santos, and the Cubatão industrial complex, which presents large chemical, petrochemical and steel industries, are found near the Bertioga Channel. As a conse quence, this socially and environmentally relevant channel is exposed to various sources of pollution that can increase the content of contaminating metals in sediments. For these reasons, the main objective of this study was to an a- lyze the availability of potentially toxic elements (Cd, Cr, Cu, Ni, Pb and Zn) in sediment cores sampled along the Bertioga Channel. In this study, the term availability refers to the possibility of metal remobilization in sediments. By applying the chemical procedure of sequent ial extraction of metals, it was determined the contents of the elements of interest associated with the sediments’ main components, enabling the assessment of the mobile fraction and the behavior of the elements regar d- ing their remobilization. Therefore, this study can serve as a management tool for monitoring chemical pollution in the region. In order to evaluate the chemical contamination in sediments, the elements’ available levels (excepting Ni) were compared to Canadian quality guidelines (ISQG and PE L). Due to the absence of comparative values of Ni for this guide, this element was compared to values described on the CONAMA 454/2012 resolution for dredging material from the Brazilian Ministry of E n- vironment. For the environment risk assessment, the Ri sk Assessment Code - RAC - was employed toward a better unde r- standing of the risk concerning the elements’ remobilization. The maximum available levels, estimated from the sum of all mobile fraction, were 22.06 mg kg - 1 for Cr, 5.57 mg kg - 1 for Cu, 11.53 mg kg - 1 for Ni, 36.43 mg kg - 1 for Pb and 57.53 mg kg - 1or Zn. Cd presented levels below its quantification limit for all samples. It was observed that, excepting Cd, there is potential for the remobilization of all those elements, even though they exist i n very low concentration and are not associated, mainly, to the acid - soluble fraction (considered the most environmentally relevant one due to its mobility level). Changes on local cond i- tions can induce the remobilization of those metals and, thus, allow t hem to become available to the environment. However, even when released possibly they should not be hazardous to the biota as a result of their low contents in the sediments. D e- spite the low concentrations of Cr, Cu, Ni, Pb and Zn and con"
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».