Ecological risks of heavy metals on surficial sediment of Nijhum Dweep (Island), an important biodiversity area of Bangladesh

• Published in: Marine pollution bulletin 2022-06, Vol.179, p.113688-113688, Article 113688
• Main Authors: Rahman, Mahfuzur, Saima, Jerin, Rima, Sabrina Akhter, Hossain, Md. Imam Sohel, Das, Delip K., Bakar, Muhammad Abu, Siddique, Mohammad Abdul Momin
• Format: Article
• Language: English
• Subjects: Atomic absorption spectrophotometry; Bay of Bengal; Biodiversity; Biodiversity hot spots; Cadmium; Chromium; Contamination; Copper; Correlation analysis; Grain size; Heavy metals; Iron; Lasers; Lead; Manganese; Metal concentrations; Metal pollution; Metals; Nickel; Particle size; Particle size distribution; Pearson correlation; Pollution load index; Risk analysis; Risk factors; Sediment; Sediment samplers; Sediment samples; Sediments; Size distribution; Spectral analysis; Spectrophotometers; Zinc
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2022.113688

Ten surficial sediment samples (up to a depth of 3 cm) were randomly collected during the pre-monsoon and analyzed for nine heavy metals using an atomic absorption spectrophotometer (AAS) to assess the distribution, contamination levels, and potential sources of heavy metals. The particle size distribution of the sediments was also investigated using a laser particle size analyzer. The mean concentration (mg/kg) of the analyzed metals followed a decreasing order of Fe (4706.24) > Mn (95.20) > Cu (36.97) > Zn (20.65) > Ni (9.26) > Cr (7.20) > Pb (5.63) > Co (5.52) > Cd (0.29). Surficial sediment of the Island was low to moderately contaminated by Cd and, to a laser extent by Cu in terms of enrichment factor (EF), geo-accumulation index (Igeo), and contamination factor. Ecologically, the Nijhum Dweep area was at low to moderate risk, where Cd was the most potential ecological risk factor. The Pearson correlation analysis revealed a significant positive correlation among Cr, Pb, Zn, Mn, Cd, Fe, Co, Ni, and silt particles, whereas a negative correlation with sand particles. No correlation was found with Cu and other metals except clay particles. •Surficial sediment of Nijhum Dweep was low to moderately contaminated by Cd and, to a laser extent by Cu.•Ecologically, the Nijhum Dweep area was at low to moderate risk.•Cd was the most potential ecological risk factor at Nijhum Dweep.•Oil spilling from boats and small-scale metallurgical activities were identified as the local sources of HMs.