A biomonitoring study: 210Po and heavy metals in mussels

The mussel Mytilus galloprovincialis (Crimea, Black Sea) as a source of essential trace elements in human nutrition

Micronutrients, or essential trace elements, are important components in various metabolic processes inherent to the normal functioning of organism. To date, a substantial part of the world population suffers from a lack of micronutrients in the diet. Mussels are an important and cheap source of nutrients, which can be utilized to mitigate the micronutrient deficiency in the world. In the present work, using inductively coupled plasma mass spectrometry, the contents of the micronutrients Cr, Fe, Cu, Zn, Se, I, and Mo were studied for the first time in soft tissues, shell liquor, and byssus of females and males of the mussel Mytilus galloprovincialis as the promising sources of essential elements in the human diet. Fe, Zn, and I were the most abundant micronutrients in the three body parts. Significant sex-related differences in the body parts were detected only for Fe, which was more abundant in byssus of males, and Zn, which exhibited higher levels in shell liquor of females. Significant tissue-related differences were registered in the contents of all the elements under study. M. galloprovincialis meat was characterized as the optimal source of I and Se for covering the daily human needs. Regardless of sex, byssus turned out to be richer in Fe, I, Cu, Cr, and Mo in comparison with soft tissues, which fact allows recommending this body part for the preparation of dietary supplements to compensate for the deficiency of these micronutrients in the human body.

Characteristics of 210Po in Asian overbite clam (Potamocorbula laevis) from the coastal area at Thai Binh province, Vietnam

210Po concentration in the edible muscle tissue and digestive diverticulum organs of Asian overbite clam at the near-shore Thai Binh, Vietnam was analyzed using alpha detectors. The 210Po activity in muscle tissue and digestive diverticulum organs ranged from 5 ± 1 to 178 ± 10 and from 118 ± 7 to 812 ± 12 Bq.kg-1 with the average value of 25 and 324 Bq.kg-1, respectively. Results showed that 210Po activity in the digestive diverticulum was significantly higher than in the muscle tissue. There was a slightly inverse correlation between 210Po activity in muscle tissue, digestive diverticulum, and clam weight and size. The annual committed effective dose was calculated from 210Po due to the consumption of Asian overbite clam for adults in the study area was higher than the guideline value of 0.2 - 1 mSv.y-1.

Mediterranean fanworm, Sabella spallanzanii (Gmelin, 1791), as a potential biomonitor of trace metal pollution in the marine environment

Levels of trace metals (Cd, Cr, Cu, Fe, Ni, Pb, Mn, and Zn) were measured in soft tissues and external tubes of the Mediterranean fanworm, Sabella spallanzanii (Gmelin, 1791), to evaluate its suitability as a biomonitor of metal pollution. Study was conducted in the coastal area of the eastern Adriatic Sea. Polychaetes were collected from two locations, a site located in a local marina and an unpolluted control site. Results indicate that S. spallanzanii has the capacity to accumulate metals in soft tissues as well as in tubes. The levels of most metals were considerably higher in tubes compared to soft tissues, indicating long-term accumulation of metals in tubes. High levels of several metals (Cu, Zn, Cr, Pb and Fe), found in soft tissues and tubes sampled at the marina site, reflect the elevated contaminant levels in the marina, associated with the use of antifouling agents, paints, petrol additives, and ship maintenance activities. Metal concentrations in tissues and tubes generally decreased with size, indicating the influence of growth and metabolic rates on trace metal uptake. Trace metal levels found in S. spallanzanii tissues were comparable to the levels found in Mytilus galloprovincialis, a species commonly used in biomonitoring studies, in areas exposed to similar levels of anthropogenic stressors. According to the results of the present study, S. spallanzanii has been identified as a suitable biomonitor of metal pollution due to its sedentary nature, widespread distribution, abundance and the ability to accumulate high levels of metals within its tissues and tubes.

A Commentary on the Use of Bivalve Mollusks in Monitoring Metal Pollution Levels

The objective of this commentary is to promote the use of bivalves as biomonitors, which is a part of the continual efforts of the International Mussel Watch. This commentary is an additional discussion on "Bivalve mollusks in metal pollution studies: From bioaccumulation to biomonitoring" by Zuykov et al., published in Chemosphere 93, 201-208. The present discussion can serve as a platform for further insights to provide new thoughts and novel ideas on how to make better use of bivalves in biomonitoring studies. The certainty of better and more extensive applications of mollusks in environmental monitoring in the future is almost confirmed but more studies are urgently needed. With all the reported studies using bivalves as biomonitors of heavy metal pollution, the effectiveness of using Mussel Watch is beyond any reasonable doubts. The challenge is the development of more accurate methodologies for of heavy metal data interpretation, and the precision of the biomonitoring studies using bivalves as biomonitors, whether in coastal or freshwater ecosystems. Lastly, inclusion of human health risk assessment of heavy metals in commercial bivalves would make the research papers of high public interest.

Analysis of 210Po, 210Bi, and 210Pb in atmospheric and oceanic samples by simultaneously auto-plating 210Po and 210Bi onto a nickel disc

²¹⁰Po and ²¹⁰Pb are commonly measured to study particle cycling and particulate organic carbon export (POC) flux from the upper ocean. ²¹⁰Bi is a potential oceanographic tracer. However, no convenient and rapid analytical method for ²¹⁰Bi has been developed in the marine environment due to its short half-life (5 days). The aims are to study factors influencing the simultaneous auto-plating of ²¹⁰Po and ²¹⁰Bi onto nickel disc and to develop an effective ship-board procedure for the rapid measurement of ²¹⁰Po, ²¹⁰Bi, and ²¹⁰ Pb at sea. The results suggest that the optimal conditions for auto-deposition of ²¹⁰Po and ²¹⁰Bi were achieved by using a 25 mm diameter nickel disc in 60 mL acidic solution (pH = 0.5) for 16 h at 25 ± 1 °C. By adding ²⁰⁹Po and ²⁰⁷Bi as yield tracers to the sediments, recoveries of Po and Bi were >90%. If ²¹⁰Po or ²¹⁰Bi were in equilibrium with ²¹⁰Pb, ²¹⁰Po and ²¹⁰Bi could also be potential proxies for ²¹⁰Pb in sedimentary chronology. The overall recoveries of ²⁰⁹Po and ²⁰⁷Bi were >70% for rainwaters and >60% for seawater samples, respectively, which indicates this analytical procedure is also applicable to marine and atmospheric environments. This method allows the rapid measurement of ²¹⁰Bi on a ship and help to obtain its vertical profile or spatial distribution in the marine environment within 1-2 days.

Determination of trace metals in Mytilus galloprovincialis along the Boka Kotorska Bay, Montenegrin coast

The concentrations of six trace metals, cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb), zinc (Zn) and mercury (Hg) were determined in the soft tissues of the mussel Mytilus galloprovincialis and bottom sediments collected from the coastal area of Boka Kotorska Bay (Montenegrin coast). The mussels and sediment samples were collected at three sites along the Boka Kotorska Bay from the autumn of 2014 to the winter of 2016. The concentrations (mg/kg dw) of these metals in the mussel samples ranged from 1.01 to 2.87 for Cd, 6.08 to 13.2 for Cu, 1.37 to 3.55 for Pb, 85.6 to 241 for Zn, 0.72 to 4.05 for Cr and 0.098 to 0.269 for Hg. The concentrations (mg/kg dw) of these metals in the sediment samples ranged from 0.16 to 0.39 for Cd, 4.32 to 48.2 for Cu, 7.02 to 49.8 for Pb, 22.0 to 158 for Zn, 93.1 to 317 for Cr and 0.035 to 0.497 for Hg. The metal content in the mussel samples and the metal content in the sediment collected from three locations over four different seasons were analyzed using the Pearson correlation coefficient (r) and cluster analysis (CA). A correlation between the metal levels found in the mussel soft tissues with those found in the sediments, for both 2014 and 2015, were established. The metal pollution indexes (MPI) for the sediment and mussels were compared, indicating that the most polluted sediment was at the location Institute of Marine Biology Kotor (IBMK) and the most polluted mussels were sampled from the Zanjice location.

Assessment of metal concentrations in indigenous and caged mussels (Mytilus galloprovincialis) on entire Turkish coastline

This survey was conducted to determine metal concentrations in the biomonitor organism Mytilus galloprovincialis collected from all coasts of Turkey. Naturally-occurring mussels were gathered along the coast of the Black Sea, Sea of Marmara, Bosphorus and Aegean Sea, while a 6-month transplantation session was implemented on the Levantine Sea coast where M. galloprovincialis does not adapt naturally. Mussels collected from the Izmir area were employed for transplantation to five locations along the Levantine Sea coast of Turkey. Concentrations of Ag, Al, As, Cd, Co, Cr, Cu, Fe, K, Mn, Ni, Pb, Sn, V, and Zn were measured using ICP-MS (Inductively Coupled Plasma-Mass Spectrometry). Results showed that concentrations of some essential elements (Co, Fe, K, Mn, Zn) generally fell within the range of acceptable global values. However, at some sampling sites the metal concentrations were found at higher levels compared to the world average and recommended limits. For instance, very high Ag and Cu concentrations were observed in mussel caged at Yumurtalık. Elevated As, Ni, Pb, and V concentrations were observed at the Tirebolu, Ereğli, Eskihisar, and Tekirdağ locations, respectively. Taking into account all measured metals, it can be inferred that Yumurtalık is the most metal-contaminated locality. The results highlighted metal-specific pollution at coastal areas in each sea cover Turkey. In spite of the high metal levels estimated daily intakes (EDI) of the measured elements were well below through very low mussel consumption by Turkish public.

Spatial and seasonal distribution of trace metal concentrations in mussel (Mytilus galloprovincialis) and sediment of Bosphorus and Golden Horn

The Golden Horn Estuary and Bosphorus Strait are two major marine environments of metropolitan Istanbul which have been exposed to intensive industrial discharges for more than 50 years. In the present study, concentrations of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb) and zinc (Zn) were measured in mussel tissue and sediment samples by using inductively coupled plasma-atomic emission spectroscopy to assess the current status of metal pollution in the Golden Horn and Bosphorus Strait. Ranges of Cd, Cr, Cu, Pb and Zn concentrations in soft parts of the mussels were BDL-2.59; BDL-7.35; 3.96-20.90; BDL-10.0; and 124.8-293.2 μg g(-1) dry weight (dw), respectively, while the ranges of Cd, Cr, Cu, Pb and Zn in <63 μm sediment fractions were BDL, 19.5-300.3, 16.9-724.7, 10.5-260.9, and 39.3-793.1 μg g(-1) dw, respectively. Ranges of Cd, Cr, Cu, Pb and Zn in >63 μm sediment fractions were BDL, 4.73-52.81, 3.45-481.87, 3.13-174.67 and 10.7-241.2 μg g(-1) dw, respectively. Trace metal concentrations found in sediment of the Golden Horn were 5-10 times higher than average literature values obtained in Mediterranean marine environment, whereas those of the Bosphorus Strait were consistent with or slightly higher than average literature values.

Bioaccumulation of 210Po and 210Pb in cephalopods collected from Kudankulam (Southeastern coast of Gulf of Mannar, India) and assessment of dose in human beings

Activities of (210)Po and (210)Pb in various tissues of two common species of cephalopod molluscs (cuttlefishes) of Kudankulam coast were studied. Of all the tissues, (210)Po and (210)Pb were found accumulated more in the digestive gland, shell gland and intestine. Urotheuthis duvauceli accumulated more (210)Po and (210)Pb in certain organs when compared with Sepiella inermis. The activity ratio of (210)Po/(210)Pb fell within the range of 0.6-29.3 in the organs. The biological concentration factor for the organs ranged from 1.2×10(3) to 2×10(5) for (210)Po and 3.6×10(2) to 7.6×10(4) for (210)Pb. A significant variation in the accumulation of (210)Po and (210)Pb was noted between species, organs and seasons (p < 0.05). The whole-body internal dose rate due to (210)Po was 1.24 and 0.83 µGy h(-1) and it was 2×10(-3) and 3×10(-3) µGy h(-1) due to (210)Pb for both the species. The effective dose in humans due to (210)Po intake ranged from 96.3 to 376.6 µSv y(-1) and that of (210)Pb ranged from 35.2 to 105.7 µSv y(-1), respectively. The data generated will act as a reference database for these organisms of this coast in which a nuclear power station is under construction.

Monitoring of Cr, Cu, Pb, V and Zn in polluted soils by laser induced breakdown spectroscopy (LIBS)

Laser Induced Breakdown Spectroscopy (LIBS) is a fast and multi-elemental analytical technique particularly suitable for the qualitative and quantitative analysis of heavy metals in solid samples, including environmental ones. Although LIBS is often recognised in the literature as a well-established analytical technique, results about quantitative analysis of elements in chemically complex matrices such as soils are quite contrasting. In this work, soil samples of various origins have been analyzed by LIBS and data compared to those obtained by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The emission intensities of one selected line for each of the five analytes (i.e., Cr, Cu, Pb, V, and Zn) were normalized to the background signal, and plotted as a function of the concentration values previously determined by ICP-OES. Data showed a good linearity for all calibration lines drawn, and the correlation between ICP-OES and LIBS was confirmed by the satisfactory agreement obtained between the corresponding values. Consequently, LIBS method can be used at least for metal monitoring in soils. In this respect, a simple method for the estimation of the soil pollution degree by heavy metals, based on the determination of an anthropogenic index, was proposed and determined for Cr and Zn.

(210)Po and (210)Pb in the tissues of the deep-sea hydrothermal vent mussel Bathymodiolus azoricus from the Menez Gwen field (Mid-Atlantic Ridge)

The hydrothermal deep-sea vent fauna is naturally exposed to a highly specific environment enriched in potentially toxic species such as sulfides, metals and natural radionuclides due to the convective seawater circulation inside the oceanic crust and its interaction with basaltic or ultramafic host rocks. However, data on radionuclides in biota from such environment are very limited. An investigation was carried out on tissue partitioning of (210)Po and (210)Pb, two natural radionuclides within the (238)U decay chain, in Bathymodiolus azoricus specimens from the Mid-Atlantic Ridge (Menez Gwen field). These two elements showed different distributions with high (210)Pb levels in gills and high (210)Po levels in both gills and especially in the remaining parts of the body tissue (including the digestive gland). Various factors that may explain such partitioning are discussed. However, (210)Po levels encountered in B. azoricus were not exceptionally high, leading to weighted internal dose rate in the range 3 to 4 μGy h⁻¹. These levels are slightly higher than levels characterizing coastal mussels (~1 μGy h⁻¹).

Mussels as a bio-indicator of the environmental quality of the coastal water of the Boka Kotorska bay (Montenegro)

The Mediterranean blue mussel Mytilus galloprovincialis was used as a pollution level indicator in the Boka Kotorska Bay of the southeastern Adriatic on the Montenegrin coast. The ever-increasing urbanization and industrialization, combined with a poor sewage system, an increase in both marine and inland traffic, as well as insufficient water circulation in the Bay itself have resulted in some level of pollution. Since heavy metals are extremely toxic and do not easily undergo biodecomposition, the results of this study supply valuable information concerning the metal pollution of the marine environment in Boka Kotorska Bay. The concentrations of the investigated metals and nonmetals accumulated in the mussels were determined during the fall of 2007 using Atomic Absorption Spectroscopy (AAS) for Cr, Mn, Co, Ni, Cu, Cd, Hg, Pb, Sn and V, and Energy Dispersive X-ray Fluorescence (ED-XRF) to determine the concentrations of Fe, Zn, Si, P, S, Cl, K and Ca. ED-XRF was also used to determine the levels of non-metals and elements present in high concentrations. Comparing the data from this study in relation to data from other regions for Mytilus galloprovincialis, the mussel sampled from the Boka Kotorska Bay showed a moderate level of pollution.