PRELIMINARY INVESTIGATION OF THE CHEMICAL COMPOSITION OF BALLAST WATER AND TANK SEDIMENTS OF SELECTED SHIPS WITHIN THE LAGOS HARBOUR, NIGERIA
Notice bibliographique
Résumé
Ballast water is important for safe and efficient operation of vessels, helping to maintain stability during voyage in seas and docking in harbours. However, ballast water can pose considerable environmental challenges because they are often laden with polluted sediments and invasive species. The Lagos Harbour, which houses in the largest port in West Africa, receives about five thousand vessels annually which discharge ballast water and tank sediments into the water with the potential to cause environmental pollution. In the Nigerian context there is high potential for pollution due to weak regulations, poor enforcement and limited research of this kind in order to understand their composition, fate and impacts. This study aims at characterizing the chemical composition (Heavy metals- Arsenic, Cadmium, Chromium, Copper, Lead & Zinc, as well as carbon and nitrogen content) of the ballast water and the tank sediments because of their positive correlation with the survival of invasive species in the ballast water and tank sediments. Water samples were collected from four ships (2 cargos and 2 tankers) within the Lagos Harbour; surface (1-5 cm) sediment samples were scooped from ship tanks using a specialized grab for sampling ballast sediments. The sediments were transferred in specialized sample containers (cool boxes) to the University of Portsmouth in United Kingdom for analysis. Total metal concentrations were analysed using X-ray fluorescence (XRF). They were subjected to two acid digestions: Aqua regia (AR) and 1 M hydrochloric acid (1 M HCl) following the procedures set out by the Canadian National Water Research Institute (NWRI) and the United States Environment Protection Agency (US-EPA Method 3050B). Total carbon and nitrogen contents were determined using an in-line Yanaco MT-5 CHN analyser. The results obtained were compared with established guidelines and subjected to correlation and Principal Component Analysis (PCA). The findings indicated high concentrations of Nickel, Lead, and Zinc in the sediments with values of 59.6 mg/kg, 33.75 mg/kg and 43,145.7 mg/kg respectively which exceeded NOAA and CSQGs permissible standards. Tanker vessels contained relatively higher concentrations of the pollutants than cargo vessels. The findings from this study provide useful baseline data which will guide a more intensive investigation of the chemical composition of ballast water and tank sediments for effective comparison with what is obtainable elsewhere in the world. The maritime industry needs to pay close attention to ballast as a potential source of marine pollution particularly in developing countries like Nigeria where there is limited regulation for management of coastal areas with respect to shipping activities. The IMO needs to direct further effort at investigating the non-biological components of ballast water and sediments in order to protect valuable biodiversity. Keywords: Coastal Pollution, Ballast Water Management, Ships, Analytical Techniques
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 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 tête enseignante, 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 ».