Trace element levels in the muscles of three tern species (Aves: Laridae) from the western Arabian Gulf: environmental assessment and implications for conservation

In the Arabian Gulf (called also Persian Gulf; hereafter 'the Gulf'), Jana and Karan Islands are recognized as one of the most Important Bird Areas in the region. Many migratory breeding seabirds, like the Greater Crested Tern Thalasseus bergii, White-cheeked Tern Sterna repressa and Bridled Tern Onychoprion anaethetus, depend on these islands during the breeding season. However, these aquatic wildlife species are suffering from intensified urban and industrial coastal development and various contamination events including wars and related oil spills. In this study, we used these three piscivorous top predator birds to analyse the levels of 19 trace elements (TEs; i.e. Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Pb, Sr, V and Zn) in 15 muscular tissue samples from Jana and Karan Islands. PERMANOVA analysis showed no difference in contamination profile between sites nor between species probably due to their spatial and ecological proximity and therefore similar levels of exposure to TEs. Comparing these levels with existing literature, our results showed no particular concern for all elements, except for Al (maximum values recorded = 116.5 mu g g-1 d.w.) and, in two samples, Ba (33.67 mu g g-1 d.w.) and Pb (5.6 mu g g-1 d.w.). The results can be considered as an initial step for supplementary evaluations with a larger number of samples and specified time intervals for the collection of specimens. This study provided baseline information on the pollution status of these two ecologically important sites which require a continuous biomonitoring programme

Microplastic pollution: An emerging contaminant in aquaculture

Aquaculture largely contributes to aquatic products and consequential dietary protein for many households. Aquaculture, just like every other food sector, is faced with enormous challenges such as unfavorable climatic events, environmental stressors and contaminants. Microplastics (MP) are emerging contaminants in aquaculture following their perturbing occurrence in cultured fish, fishmeal and aquafeed. Several MPs pathways into aquaculture facilities include wastewater, pipe-borne water, dilapidated aquaculture facilities, fish gears, and aquafeed stuff (fishmeal). Techniques for the digestion, identification and characterization of MPs are critical to understanding their pathways, bioavailability and bioaccumulation patterns in aquaculture species. The impacts of MPs on cultured fish species are identified as impaired growth, oxidative stress, neurotoxicity, reproductive toxicity, immunotoxicity, embryotoxicity, and histopathology. Bioaccumulation of MPs in tissues and biological systems have been evidenced in several cultured fishes. Mitigation efforts cum strategies such as upgrade of wastewater treatment facilities, screening of inlet pond water, screening of aquafeed stuff, regular maintenance and repair of culture facilities, could be effective to eradicate MP contamination in aquaculture. Additionally, regulatory policy on the use of plastics is key to mitigating the impact of MPs and ensure cleaner and sustainable aquaculture

Biochemical composition of Meretrix meretrix in the Bakkhali river Estuary, Cox’s Bazar, Bangladesh

The present study was conducted in the Bakkhali river estuary, Cox’s Bazar, Bangladesh from September 2012 to July 2013. Percentage of protein was the main component of the biochemical composition in the mussels followed by carbohydrate, ash, and lipid. The proximate composition of Meretrix Meretrix revealed that it contained protein (12.184-14.291%), lipid (0.721-0.922%), ash (2.435- 3.201%), moisture (77.0-78.9%) and carbohydrate (4.914-5.907%). The mineral content of the Meretrix Meretrix were Ca (0.601-0.801 mg/g), Fe (0.070-0.099 mg/g) and phosphorus (0.300-0.794 mg/g).</p

Bioaccumulation of trace elements and hydrocarbons in chondrichthyans of the western Arabian Gulf: Environmental and human health risk assessment and implications for conservation

This is a first attempt to assess the levels of trace elements, PAHs, and TPHs in six elasmobranch species (Carcharhinus dussumieri, C. sorrah, Chiloscyllium arabicum, Gymnura poecilura, Sphyrna lewini, S. mokarran) from the Arabian Gulf. The chemical analysis showed that the concentrations of contaminants differed significantly between liver and muscle samples with both pelagic and benthic species and all families. For all species, contaminant concentrations were significantly higher in the liver than in the muscle. While muscle contaminant concentrations differed significantly with respect to species' lifestyles and families, those of liver showed no significant differences between pelagic and benthic species, neither between the four families nor between the si

Assessment of As, Cr, Cd, and Pb in urban surface water from a subtropical river: contamination, sources, and human health risk

This work aimed to determine the level of some toxic elements (As, Cr, Cd, and Pb) in the water of the Rupsha River, Bangladesh, concerning their potential dangers to human exposure. The elemental concentrations (mg/L) were determined using Atomic Absorption Spectrometer and found to decrease in the order of Cr (0.041) > Pb (0.029) > As (0.004) > Cd (0.002). The level of elements in this river water surpasses various international limits, making it unfit for human consumption. Furthermore, the metal pollution index and contamination index indicated that the water was also unsuitable for this purpose. The elements chosen were persuasive to discern the hazard quotient of non-carcinogenic risk. Moreover, total targeted hazard quotient (TTHQ) values were found for adults and children within acceptable limits (TTHQ −6 to 10−4) of the threshold limit. Due to their high-water consumption per unit of body-weight and physiological development, children were found to be more sensitive than adults. Multivariate analyses demonstrated that human activities were the primary origin of toxic elements in river water. According to the findings, urban and industrial effluents should be treated before being released into rivers. Development along the river bank must be carefully controlled to safeguard the river environment. In the end, this will improve the quality of the water and lower the chance that people will be exposed to metals.</p