PRELIMINARY INVESTIGATION OF THE CHEMICAL COMPOSITION OF BALLAST WATER AND TANK SEDIMENTS OF SELECTED SHIPS WITHIN THE LAGOS HARBOUR, NIGERIA
Bibliographic record
Abstract
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
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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| 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) | 0.000 | 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 teacher head, 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".