Macroalgae in biomonitoring of metal pollution in the Bay of Bengal coastal waters of Cox's Bazar and surrounding areas

Assessment of nutraceutical value, physicochemical, and anti-inflammatory profile of Odonthalia floccose and Odonthalia dentata

The nutraceutical value, and physicochemical profile as well as anti-inflammatory activity potential of Odonthalia floccose and Odonthalia dentata (red macroalgae) dry biomass were investigated in this study. Proximate composition study results revealed that the dry biomass of O. floccose and O. dentae were found to be as ash: 9.11 & 8.7 g 100 g-1, moisture: 8.24 & 8.1 g 100 g-1, total fat: 6.9 & 7.2 g 100 g-1, protein: 24.52 & 25.6 g 100 g-1, and total carbohydrate/polysaccharides: 53.84 & 48.85 g 100 g-1 of dry weight biomass respectively. Both algae biomass contain considerable quantity of minerals (Fe, Cu, Mg, and Zn). Furthermore, the major saturated fatty acids (6.24 & 5.82 g FAME 100 g-1 of total fat of O. floccose and O. dentate) (ΣFAs) present in the test algae were stearic acid, palmitic acid, and margaric acids. O. floccose and O. dentata also contain remarkable protein composition profile that compiled with considerable quantity of essential and non-essential amino acids. The vitamins such as vitamin A, B1, B2, B3, B6, B9, C, and E of O. floccose and O. dentate biomass were also identified at sufficient quantity level. The swelling capacity (SWC), water holding capacity (WHC), and oil holding capacity (OHC) properties of O. floccose and O. dentate at various temperature conditions (25 and 37 ᵒC) were found to be 8.11 & 7.02 mL g-1 and 8.95 & 7.55 mL g-1, 5.1 & 4.87 and 4.8 & 4.1 mL g-1, as well as 2.11 & 1.81 and 1.96 & 1.89 mL g-1 respectively. Among these two marine red macroalgae samples, the O. dentate showed better anti-inflammatory activity than O. floccose at 150 μg mL-1 dosage. Thus, this O. floccose and O. dentate biomass can be considerable as nutritional supplement and pharmaceutical product development related research.

Chemical analysis of marine microdebris pollution in macroalgae from the coastal areas of Argentina

Marine microdebris (MDs, <5 mm) and mesodebris (MesDs, 5-25 mm), consist of various components, including microplastics (MPs), antifouling or anticorrosive paint particles (APPs), and metallic particles (Mmps), among others. The accumulation of these anthropogenic particles in macroalgae could have significant implications within coastal ecosystems because of the role of macroalgae as primary producers and their subsequent transfer within the trophic chain. Therefore, the objectives of this study were to determine the abundance of MDs and MesDs pollution in different species of macroalgae (P. morrowii, C. rubrum, Ulva spp., and B. minima) and in surface waters from the Southwest Atlantic coast of Argentina to evaluate the ecological damage. MDs and MesDs were chemically characterized using μ-FTIR and SEM/EDX to identify, and assess their environmental impact based on their composition and degree of pollution by MPs, calculating the Polymer Hazard Index (PHI). The prevalence of MDs was higher in foliose species, followed by filamentous and tubular ones, ranging from 0 to 1.22 items/g w.w. for MPs and 0 to 0.85 items/g w.w. for APPs. It was found that macroalgae accumulate a higher proportion of high-density polymers like PAN and PES, as well as APPs based on alkyd, PMMA, and PE resins, whereas a predominance of CE was observed in surrounding waters. Potentially toxic elements, such as Cr, Cu, and Ti, were detected in APPs and MPs, along with the presence of epiplastic communities on the surface of APPs. According to PHI, the presence of high hazard score polymers, such as PAN and PA, increased the overall risk of MP pollution in macroalgae compared to surrounding waters. This study provided a baseline for MDs and MesDs abundance in macroalgae as well as understanding the environmental impact of this debris and their bioaccumulation in the primary link of the coastal trophic chain.

Metal and metalloid bioaccumulation in dried red seaweed Hypnea musciformis and health risk assessment for consumers

This study measured 22 metal and metalloid concentrations in Hypnea musciformis from the Bakkhali River estuary and Saint Martin's Island, Bangladesh and determined their potential impact on consumption. Student t-tests showed a significant variation in metal concentrations between the two sampling sites (p < 0.05). Mean concentrations of Co (2.49 ± 0.05 mg/kg), Fe (793.29 ± 11.76 mg/kg), Mn (368.72 ± 4.87 mg/kg), Pb (3.82 ± 0.02 mg/kg), V (11.23 ± 0.20 mg/kg) and Zn (16.60 ± 0.28 mg/kg) were higher in samples collected from the Bakkhali River estuary compared to Saint Martin's Island, while mean concentrations of Ca (484.18 ± 4.68 mg/kg), Cd (2.44 ± 0.03 mg/kg), Mg (2112.70 ± 17.80 mg/kg), Mo (1.57 ± 0.06 mg/kg), Sr (2377.57 ± 29.98 mg/kg), and Ti (258.27 ± 4.62 mg/kg) were higher in samples collected from Saint Martin's Island. Eight heavy metals (Pb, Cd, Zn, Cu, Ni, Mn, Cr, Fe) were used to assess potential health risks for adults, but no potential health risk was detected (HQ value>1). This study reveals positive Se-HBV for H. musciformis collected from both sampling sites, indicating no potential risks involved with Hg toxicity.

Impact of natural degradation of the invasive alga Rugulopteryx okamurae on anaerobic digestion: Heavy metal pollution and kinetic performance

This study shows, for the first time, how the natural biodegradation of the Phaeophyceae Rugulopteryx okamurae (R.o.) affects its methane yield, by biochemical methane potential assays, and the methane production kinetics. Additionally, a mechanical (zeolite-assisted milling) and a thermal (120 °C, 45 min) pretreatments were assessed. The highest methane yield was obtained from the mechanically pretreated fresh ashore biomass (219 (15) NLCH4 kgVS-1), which presents the use of zeolite during milling as an economical alternative for heavy metal toxicity reduction. Moreover, no significant differences were observed between the other tests (with the exception of the lowest value obtained for the mechanically pretreated fresh R.o.). Low methane yields were linked to the heavy metal content. However, an increase of 28.5 % and 20.0 % in the k value was found for the untreated fresh R.o. biomass and fresh ashore biomass, respectively, when subjected to thermal pretreatment. Finally, an enhancement of 80.5 % in the maximum methane production rate was obtained for the fresh ashore biomass milled with zeolite compared to the untreated fresh ashore biomass.

Removal of mercury by silica-supported ionic liquids: Efficiency and ecotoxicological assessment

Anthropogenic impacts have affected the coastal environment and contributed to its contamination. Mercury (Hg) is widespread in nature and has been shown to be toxic in even the smallest amounts, negatively affecting not only the marine ecosystem but also the entire trophic chain due to its biomagnification. Mercury ranks third on the Agency for Toxic Substances and Diseases Registry (ATSDR) priority list and it is therefore imperative to develop more effective methods than those currently available to avoid the persistence of this contaminant in aquatic ecosystems. The present study aimed to evaluate the effectiveness of six different silica-supported ionic liquids (SIL) in removing Hg from contaminated saline water, under realistic conditions ([Hg] = 50 µg/L), and to ecotoxicologically evaluate the safety of the SIL-remedied water, using as test model the marine macroalga Ulva lactuca. The results revealed that SIL [Si][C3C1im][SCN] (250 mg/L) was the most effective in removing Hg from solution, with a efficiency up to 99 % in just 6 h, that enable to obtain < 1 µg/L Hg (European guideline in drinking water). U. lactuca exposed to either the SIL and/or the remedied water showed no significant changes in relative growth rate and chlorophyll a and b levels, compared to the control condition. Biomarker analysis (LPO, GSH, GSSG, SOD, GPx, CAT and GRed) also showed no significant changes in the biochemical performance of U. lactuca. Therefore, it could be assumed that water treatment with SIL or its presence in an aqueous environment does not pose toxicity levels that could inhibit the metabolism or cause cell damage to U. lactuca.

Macroalgae for biomonitoring of trace elements in relation to environmental parameters and seasonality in a sub-tropical mangrove estuary

Being a resourceful ecosystem, mangrove estuaries have always been subjected to trace elements (TEs) contamination, and therefore, the biomonitoring approach holds immense potential for surveilling the aquatic environment. To investigate the potentiality of mangrove macroalgae as biomonitors, estuarine water, intertidal-sediment, and macroalgal samples were collected from the Pasur River estuary of Sundarbans mangrove ecosystem, Bangladesh, and afterward studied through Atomic Absorption Spectrometer to quantify the levels of six concerned TEs (Fe, Mn, Zn, Cu, Pb, and Cd). This study utilized the geo-environmental and ecological indices and sediment characterization approaches (sediment quality guidelines-SQGs) for assessing the contamination scenario of the adjacent environment to macroalgae whereas the performance of studied algal groups was evaluated using Bio-contamination factor, Comprehensive bio-concentration index, and Metal accumulation index. Metal occurrence scheme in the water followed the order of Fe > Zn > Mn > Pb > Cd while Fe > Mn > Zn > Cu > Pb > Cd for both sediment and macroalgae. Both Pb and Cd exceeded the guideline limit in estuarine water and the indices approach manifested low to moderate contamination with enrichment from anthropogenic origin of Mn, Zn, and Cu in sediment. Moreover, the SQGs revealed rare biological effects of Cu on an aquatic community. Within algal samples, Chlorophyta contributed the highest biomass production, followed by Phaeophyta and Rhodophyta. Statistical relationship disclosed the influence of environmental variables on TE's accumulation in Chlorophyta. By contrast, hydrochemical's association showed prevalence over the TEs accumulation process for Phaeophyta and Rhodophyta. Bioaccumulation performance analysis revealed that the ability to accumulate TEs in macroalgal groups varied with seasons. Therefore, biomonitoring with macroalgae for the region of interest might require further temporal considerations.

DNA barcoding of marine macroalgae as bioindicators of heavy metal pollution

Metal pollution in the marine coastal environment is an important topical issue. In this study, the water quality in five locations along the Alexandria coast (Eastern Harbor, El-Tabia pumping station, El Mex Bay, Sidi Bishir, and Abu Talat) was assessed by measuring physicochemical parameters from water samples. Depending on the morphological classification of macroalgae, the collected morphotypes were related to Ulva fasciata, Ulva compressa, Corallina officinalis, Corallina elongata, and Petrocladia capillaceae. Corallina officinalis and Corallina elongata demonstrated a high capacity for Cd, Pb, and Ni accumulation, and the highest values of Fe, Cu, and Mn were reported in Ulva fasciata and Ulva compressa. Two standard markers were applied, and results showed that the morphological classification matched the molecular data. Moreover, the analysis of algae can only reflect the accumulation of metals. The conclusion is that Ulva compressa and Corallina officinalis are potentially suitable indicators of localized short-term heavy metal pollution.

The Biological Monitoring as a Source of Information on Environmental Pollution with Heavy Metals

The influence of environmental pollution on living organisms has been known for a long time, but it was not until the second half of the twentieth century that methodical studies on the influence of anthropopressure on changes in ecosystems began. Living organisms began to be used as biological indicators of environmental pollution. Cyclical and quantitative studies of pollutant concentrations in bioaccumulators have become the basis of modern biological monitoring (biomonitoring) of environmental pollution. Biomonitoring studies are carried out with the passive method (passive biomonitoring), in which living organisms occurring in their natural environment are analysed, and with active methods (active biomonitoring), in which, for example, plants living in the environment with low pollution are transferred and displayed in more polluted ecosystems e.g. heavy metals. The analysis of trace elements, including heavy metals accumulated in algae, mosses and lichens used in biological monitoring provides a lot of information on, among others concentration and origin of pollutants and the directions of their spread. Biomonitoring is used to assess the level of contamination of selected ecosystems, as well as the impact of individual emitters on the environment. An important element in determining the concentrations of trace elements in biological material used in biomonitoring is the proper planning of the experiment, taking into account, among others: methods of collecting or exposing samples, selection of analytical methods and methods of evaluation and interpretation of results. The aim of the presented long-term research, conducted by the Research Team of the Institute of Biology of the University of Opole, was to show that analytical techniques using biota samples can provide reliable data on the past, present and future state of the environment. However, it should be remembered that in order for the results of biomonitoring studies to be reliable and comparable, the applied research methodologies should be consistent and repeatable. In the presented research, Palmaria palmata and Spirogyra sp. algae, Pleurozium schreberi mosses, Hypogymnia physodes and bark of deciduous trees were used. In samples of biological material by the method of atomic absorption spectrometry, the concentrations of heavy metals, including Ni, Cu, Zn, Cd and Pb, were determined. On the basis of the conducted research, it was unequivocally stated that the biomonitoring methods are a good complement to the classic methods of environmental quality assessment. The analysis of the elements accumulated in the biological material provides us with information about the quality of the examined ecosystems, the introduced pollutants and their potential sources. This information allows for the introduction of effective measures to improve the quality of the environment.

Trace elements in the detoxifying and accumulating body parts of Mytilus galloprovincialis Lamark, 1819 (Crimea, Black Sea): human health risks and effect of the sampling site location

The mussel M. galloprovincialis is one of the most popular species in world's mariculture and environment pollution bioindicators. Although this mollusk was in a focus of numerous publications, the detoxifying and accumulating role of some of its body parts was insufficiently studied. The goals of the present work were as follows: (a) to study the distribution of potentially toxic elements (Cr, Co, Ni, Cu, Zn, As, Cd, Hg, Pb) in soft tissues, byssus, and shell liquor of this bivalve as a function of sampling location in the Black Sea near the southwestern coast of Crimea and (b) to assess human health risks from consuming soft tissues of mussels cultivated on a mollusk farm. Multivariate analysis showed significant differences in the overall distribution of the elements among the body parts and sampling sites under consideration. The trace element contents in soft tissues of M. galloprovincialis decreased in the following order: Zn > Cu > As > Ni > Pb > Cd > Cr > Co > Hg. The noncarcinogenic hazard index from the cultivated mussel consumption was found to be well below one and the carcinogenic risk index was found within the tolerable limits, which indicate the safety of consuming these mussels for humans. Byssus of M. galloprovincialis was characterized as a perfect indicator of marine environment pollution with Ni, Cu, Pb, Сo, and Cr. For the first time, the concentrations of trace elements were determined in the shell liquor and the function of byssus and shell liquor as the systems of trace element excretion from soft tissues was demonstrated.

Heavy metals and metalloids in edible seaweeds of Saint Martin's Island, Bay of Bengal, and their potential health risks

The present study aimed to assess the levels of heavy metals and metalloids present in six seaweeds and their potential impact on consumption. The highest concentration of 11 metals, i.e., Be (0.47 mg/kg), Co (4.34 mg/kg), Cr (23.46 mg/kg), Cu (11.96 mg/kg), Fe (2290.26 mg/kg), Li (11.55 mg/kg), Ni (13.75 mg/kg), Pb (6.67 mg/kg), Ti (736.62 mg/kg), Tl (0.14 mg/kg), and V (33.09 mg/kg) were observed in Enteromorpha intestinalis (green seaweeds). Besides, the highest concentration of Ca (1071.09 mg/kg), Cd (5.81 mg/kg), Mn (1003.41 mg/kg), Sr (2838.86 mg/kg), and Zn (41.95 mg/kg) were found in Padina tetrastromatica (brown seaweeds). Eight metals (Pb, Cd, Zn, Cu, Ni, Mn, Cr, Fe) have been used to assess the potential health risk for adults, but no potential health risk was detected (HQ value > 1). The HI value of E. intestinalis and P. tetrastromatica were >1, implying that these two seaweeds are not safe for human consumption as there is a carcinogenic health risk for adults.

Investigation of Global Trends of Pollutants in Marine Ecosystems around Barrang Caddi Island, Spermonde Archipelago Cluster: An Ecological Approach

High-quality marine ecosystems are free from global trending pollutants’ (GTP) contaminants. Accuracy and caution are needed during the exploitation of marine resources during marine tourism to prevent future ecological hazards that cause chain effects on aquatic ecosystems and humans. This article identifies exposure to GTP: microplastic (MP); polycyclic aromatic hydrocarbons (PAH); pesticide residue (PR); heavy metal (HM); and medical waste (MW), in marine ecosystems in the marine tourism area (MTA) area and Barrang Caddi Island (BCI) waters. A combination of qualitative and quantitative analysis methods were used with analytical instruments and mathematical formulas. The search results show the average total abundance of MPs in seawater (5.47 units/m³) and fish samples (7.03 units/m³), as well as in the sediment and sponge samples (8.18 units/m³) and (8.32 units/m³). Based on an analysis of the polymer structure, it was identified that the dominant light group was MPs: polyethylene (PE); polypropylene (PP); polystyrene (PS); followed by polyamide-nylon (PA); and polycarbonate (PC). Several PAH pollutants were identified in the samples. In particular, naphthalene (NL) types were the most common pollutants in all of the samples, followed by pyrene (PN), and azulene (AZ). Pb⁺² and Cu⁺² pollutants around BCI were successfully calculated, showing average concentrations in seawater of 0.164 ± 0.0002 mg/L and 0.293 ± 0.0007 mg/L, respectively, while in fish, the concentrations were 1.811 ± 0.0002 µg/g and 4.372 ± 0.0003 µg/g, respectively. Based on these findings, the BCI area is not recommended as a marine tourism destination.

Seagrass and green macroalgae Halimeda as biomonitoring tools for metal contamination in Chuuk, Micronesia: Pollution assessment and bioaccumulation

In this study, we evaluated metal accumulation in different species and tissues of seagrasses and green macroalgae Halimeda and assessed metal pollution levels in Chuuk, Micronesia. In seagrass, the concentrations of Ni, Cu, Zn, Cd, Pb, and Hg were higher in leaves than in roots, whereas Cr and As concentrations were higher in roots. Halimeda had higher concentrations of Ni than of the other metals, and the mean Ni concentration was approximately 2.1 times higher in Halimeda than in seagrass leaves. The concentrations of Cr, As, Cu, Pb, and Hg in Halimeda were similar to those in seagrasses, whereas the Zn and Cd concentrations in Halimeda were very low. Significant correlations in metal concentrations between sediment and both seagrasses and Halimeda were observed for Cr, Ni, Cu, Zn, and Pb. This study suggests that seagrasses and Halimeda are useful indicators for monitoring metal pollution in coastal environments.