The rate of concentration of faecal coliforms in shellfish under different environmental conditions

As filter-feeding organisms, bivalves present a potential health hazard to consumers due to pathogens which may be present in the marine environment. The effects of temperature and concentration of faecal coliforms (FC) in seawater on the rate of concentration in mussels and oysters were studied in both field and experimental conditions. The rates of FC concentration in bivalves were high at the beginning of the experiments, when the initial concentrations of FC in bivalves were low, and decreased as the concentration in bivalves increased. At low initial concentrations of FC in bivalves, the rate of FC concentration increased with the concentration of FC in seawater and with changes of temperature toward optimum. As the concentration of FC in bivalves increased, the rate of FC concentration decreased more rapidly as the concentration of FC in seawater increased and as the temperature was closer to optimum. Maximum concentrations of FC observed in bivalves (level-off concentrations) were the highest at minimum temperature (at which rates of FC concentration were the lowest), whereas the concentration of FC in seawater had no effect on the level-off concentrations of FC in bivalves.     

Polonium-210 in mussels and its implications for environmental alpha-autoradiography

Alpha-autoradiographic and radiochemical studies of the distributions of transuranic nuclides in the tissues and organs of mussels collected from the vicinity of the British Nuclear Fuels plc reprocessing plant at Sellafield, Cumbria, England, appeared to require assessment also of baseline alpha-activities of natural ²¹⁰ Po levels. Results for the latter were found to be in excess of the anthropogenic activities of Pu and Am isotopes. To ensure that the levels of ²¹⁰ Po in Cumbrian mussels were not artificially enhanced by local discharges and in the absence of published data, mussels from remote British and French coastal sites were also analyzed. General similarities in ²¹⁰Po concentrations (111 to 459 Bq kg⁻¹ dry) found in mussels soft parts suggest that the ²¹⁰Po levels in the Ravenglass mussels (279 Bq kg⁻¹) are natural and largely unsupported by ²¹⁰Pb; however these levels are as much as four times greater than the present day ^239+240Pu concentrations in the same samples. As the transuranic nuclide content of Cumbrian mussels produces a major component of the local critical group radiation exposure from the Sellafield discharges, this finding places in some perspective the significance of the baseline natural radionuclide concentrations in generating total exposure of the public. More specifically, these findings severely limit the usefulness of alpha-autoradiographic studies for transuranic nuclides performed on such samples. Because of the recently lower concentrations of alpha-emitting transuranic nuclides (mainly ²³⁸Pu, ^239+240Pu and ²⁴¹Am) in the Ravenglass environment, natural ²¹⁰Po is now a major contributor to alpha-track distributions in autoradiographic studies.     

Spatio-temporal variability of extreme precipitation characteristics under different climatic conditions in Fars province,Iran

Environment, Development and Sustainability - Spatio-temporal variability of extreme precipitation characteristics (EPCs) were analyzed using clustering techniques to establish homogeneous...     

Evidence of genetic damage in grass gobies and mussels from the Venice lagoon

The presence of genetic damage has been investigated in two native species of the Venice lagoon: the common mussel Mytilus galloprovincialis and the grass goby Zosterisessor ophiocephalus. Two sampling campaigns were performed in summer 1998 and 1999. Aromatic-like DNA adducts were analysed in selected tissues of gobies and mussels by using the 32P-postlabelling assay. In 1999, micronuclei and other nuclear abnormalities were additionally scored on gill cells and haemocytes of individual mussels whereas inorganic (As, Cd, Cr, Hg, Ni, Pb, Sn) as well as organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls and other chlorinated compounds) were measured in the total mussel pulp. Compared to the lagoon inlet area, gobies and mussels from the industrial district (Marghera) showed significant DNA adduct levels and increased frequencies of cytogenetic alterations (evidence of genetic damage was absent or inconsistent in other sites). The substantial levels of aromatic and chlorinated contaminants detected in mussels from Marghera also support the exposure of native organisms to genotoxic agents.     

Experimental studies on the biokinetics of 134Cs and 24Am in mussels (Mytilus galloprovincialis).

The biokinetics of 134Cs and 241Am in mussel species contaminated through water pathway has been studied under laboratory conditions. At equilibrium, the concentration factors for 134Cs and 241Am in small and large mussels were 2.80 and 2.57 and 200 and 150, respectively. The concentration factor of 134Cs in soft parts of the mussels was significantly high than whole body and shell tissue. However, the concentration factors of 241Am in soft parts and shell tissue samples were found to have similar rates. The depuration kinetics of the radionuclides were described by two-component exponential models. The biological half-lives at slow components between small and large mussels did not change significant, and were found to be 46.8-46.5 and 72.2-75.3 days for 134Cs and 241Am. The depuration kinetics of 134Cs and 241Am in soft parts described a single-component exponential model and the biological half-lives were found to be 29.4 and 41.1 days, respectively.     

210Po concentration in Perna perna mussels: looking for radiation effects

Twenty ropes with 400 Perna perna mussels seeds (3 cm shell size) were set-up on floating structures at Cabo Frio Island, Arraial do Cabo, approximately 100 km northeast of Rio de Janeiro city. A rope was taken out on a monthly basis, and the shell sizes of 100 seeds were measured. The haemolymph of 10 male and 10 female individuals was taken, and the same individuals were separated for 210Po/210Pb determination. After one year of monthly sampling, no clear correlation was observed between the 210Po concentration, mussel's age and weight. A mean 210Po concentration of 155 Bq kg(-1) wet weight basis, was obtained, which is comparable with data reported in the literature. The radiation dose did not have any observable effect on the micronuclei frequency and DNA breaks in the mussels. This was probably due to the low dose rate, 0.02 mGy d(-1), in comparison with the suggested potential dose limit of 10 mGy d(-1).     

Body burden of contaminants and biological effects in mussels: an integrated approach

An investigation of contaminants and biological effects in mussels from Halifax Harbour, Nova Scotia, Canada, focused on a 6 km section in the central most industrialized core of the harbour, where a site was previously identified as highly contaminated. The aim of the study was to compare the body burden of mussels in terms of polycyclic aromatic hydrocarbons (PAH), dichlorophenyltrichloroethane (DDT family), coprostanol and elements, relative to biological parameters such as condition indices, sex ratio, survival time in air, and to biochemical indicators of mussels' health analysed in gills, digestive gland and gonad tissues. These markers are total sugar and lipid content of gonads, mitochondrial electron transport activity in digestive gland and gonad tissues, lipid peroxidation in gill, digestive gland and gonad tissues, and heme oxidase activity in the digestive gland. At the north western end of the area, near a major sewage effluent, shorter survival time, higher oxidative stress and metabolism, gonad electron transport activity, levels of coporostanol, PAH, p,p'-dichlorophenyldichlo-roethylene (p,p'-DDE), Ag, Cu, Fe and P were observed. At the opposite south eastern end, longer survival time, higher lipid content, lowest condition indices and concentrations of coprostanol, PAH and p,p'-DDE, but higher concentrations of Sn and Cd, were detected. On-going improvements to sewage treatment in Halifax Harbour, including construction of sewage treatment plants that will discharge into deeper parts of the central harbour, should improve inter-tidal mussels' health in our study area.     

Radionuclides and metals in freshwater mussels of the upper South Alligator River, Australia

During an inspection of the old Rockhole Mine area in Kakadu National Park in 1999, it was found that a small amount of tailings from the former South Alligator uranium (U) mill had been uncovered by wet season rain and road works. Samples of sediment, water and freshwater mussels, Velesunio angasi, were collected from the South Alligator River, near and at the confluence of Rockhole Mine Creek, and adjacent to the exposed tailings. The 228Ra/226Ra activity ratios in sediments and mussel tissue indicate a small influence from the tailings and from Rockhole Mine adit water on 226Ra concentrations. The uptake of 226Ra in mussels does not correlate with other alkaline-earth metals. Mussel U concentrations are higher immediately downstream of Rockhole Mine Creek, but there is no noticeable increase in the immediate vicinity of the tailings area. A hypothetical ingestion of 2 kg of mussels from the sites was used to estimate the committed effective dose for a 10-year-old child resulting in a figure of 0.23 mSv per annum, of this total dose, 69% is attributed to 210Po. Only 0.03 mSv per annum can be directly linked to impacts of the tailings.     

Comparison of different ecological scales with respect to efficiency in assessing ecological conditions in forests of the Southern Ural region

Ecological scales proposed by H. Ellenberg, E. Landolt, and D.N. Tsyganov have been used to evaluate the roles of three ecological factors—elevation above sea level, soil moisture, and soil nitrogen—in determining the composition of forest communities in the Southern Ural region. The results obtained with all these scales are similar, which indicates that any of them can serve the purpose.     

Accumulation of (137)Cs in Brazilian soils and its transfer to plants under different climatic conditions

The spatial distribution and behaviour of the global fallout (137)Cs in the tropical, subtropical and equatorial soil-plant systems were investigated at several upland sites in Brazil selected according to their climate characteristics, and to the agricultural importance. To determine the (137)Cs deposition density, undisturbed soil profiles were taken from 23 environments situated between the latitudes of 02 degrees N and 30 degrees S. Sampling sites located along to the equator exhibited (137)Cs deposition densities with an average value of 219Bqm(-2). Extremely low deposition densities of 1.3Bqm(-2) were found in the Amazon region. In contrast, the southern part of Brazil, located between latitudes of 20 degrees S and 34 degrees S, exhibited considerably higher deposition densities ranging from 140Bqm(-2) to 1620Bqm(-2). To examine the (137)Cs soil-to-plant transfer in the Brazilian agricultural products, 29 mainly tropical plant species, and corresponding soil samples were collected at 43 sampling locations in nine federal states of Brazil. Values of the (137)Cs concentration factor plant/soil exhibited a large range from 0.020 (beans) to 6.2 (cassava). Samples of some plant species originated from different collecting areas showed different concentration factors. The (137)Cs content of some plants collected was not measurable due to a very low (137)Cs concentration level found in the upper layers of the incremental soils. Globally, the soil-to-plant transfer of (137)Cs can be described by a logarithmic normal distribution with a geometric mean of 0.3 and a geometric standard deviation of 3.9.     

Effects of different deposition models on the calculated dose conversion factors from 222Rn progeny

Regional lung deposition for radon progeny (size range, 1 nm to 1000 nm, monodispersed) has been determined employing Gormley-Kennedy, Ingham, Cohen-Asgharian and Yu-Cohen expressions (which describe diffusion deposition), together with Gurman and Cheng formulae for impaction and sedimentation, respectively. The deposition values have been compared with those obtained by using the algebraic expressions recommended by ICRP66. The behavior of the deposition curves for breathing rates of 0.45, 0.78 and 1.2 m3 h(-1) are similar, with a broad maximum in the range (1-100) nm. In the particle size range (1-100) nm, where the thermodynamic efficiency predominates, there are large differences among the five approaches, with ICRP values lying somewhat in the middle. Dose Conversion Factors nearly follow the regional deposition trends, Cohen-Asgharian and Ingham, close to the highest values, Yu-Cohen the lowest and ICRP, again, somewhat in the middle.     

Introduction to and experimental conditions during the first year of the GMR chronic inhalation studies of diesel exhaust

A chronic exposure study was initiated to determine the effects of diesel exhaust on the health of experimental animals. For this purpose, test atmospheres of clean air (control) or freshly diluted diesel exhaust at concentrations of 250, 750, and 1500 μg/m³ were supplied to four 12.6 m³ inhalation chambers which housed rats and guinea pigs. Diesel aerosol size and concentration, as well as chamber temperature and relative humidity, were continually monitored and controlled to maintain the exposure dose levels and an environment of 22±2°C and 50%±20% relative humidity. The concentrations of CO and NO_x were found to be 5.8±1.0 mg/m³ and 7.9±1.0 mg/m³ above ambient in the chamber containing 1500 μg/m³ of particulate. Animals were supplied from the chambers, on a random basis, for both intramural and extramural studies throughout the exposure period. The experiment ran uninterrupted for over twelve months with mean diesel particle mass concentrations within 2% of the target values.     

The influence of benzo(a)pyrene on the growth of wheat and corn

Corn seeds responded to soaking in aqueous solutions of benzo(a)pyrene with increased root growth. Growth stimulation decreased from 14% to 0 with increasing concentrations (0.0005–0.02 ppm), and with increasing soaking times (6 and 12 hr). Shoot growth and dry weights of shoots were not affected. Wheat did not respond as distinctly as corn to similar treatments. A decrease in the growth of shoots and roots with increasing BaP concentrations was not statistically significant.     

Uranium in sediments, mussels (Mytilus sp.) and seawater of the Krka river estuary

The response of an aquatic environment to the decrease of phosphate discharges from a technologically improved transhipment terminal, situated at the Croatian Adriatic coast in the port of Sibenik, has been assessed based on uranium activity and concentration in sediment, seawater and mussels Mytilus sp. The highest 238U activities (485+/-16Bqkg(-1) dry weight) were found in the sediment sample collected from the sampling site closest to the terminal. The maximum concentrations in the sediment samples are above the natural ranges and clearly indicate the harbour activities' influence. The 238U/226Ra activity ratios in sediment samples demonstrate the decreasing trend of phosphate ore input. Mussel samples showed levels of 238U activities in the range from 12.1+/-2.9 to 19.4+/-7.2 Bqkg(-1) dry weight, thus being slightly higher than in normally consumed mussels. Only the seawater, taken just above the bottom sediment at the sampling site closest to the terminal, shows a slightly higher uranium concentration (3.1+/-0.2 microgL(-1)) when compared to the samples taken in upper seawater layers (2.1+/-0.2 microgL(-1)) but is in the range of the concentration level of uranium in natural seawater. Since the transhipment terminal in the port of Sibenik was modernised in 1988, discharge of phosphate ore into the seawater was drastically reduced and, consequently, uranium concentration levels in seawater have decreased. However, enhanced uranium activity levels are still found in deeper sediment layer samples and in mussel.     

Metal and metallothionein level in the heat-treated cytosol of gills of transplanted mussels Mytilus galloprovincialis Lmk

A stock of mussels Mytilus galloprovincialis was transplanted over 1 year to four sites in a semi-enclosed bay in Croatia which is under the influence of various sources of pollution. The positive correlation of metal (Cd, Zn, Cu, Mn, Fe) and metallothionein (MT) tissue contents based on the analysis of heat-treated cytosol of gills with shell mass, as an indicator of mussel age, indicated to accumulation of metals, as well as the increase of MTs with mussel age. The principal component analysis (PCA) revealed that 74% of total variance of obtained results could be explained through two principal components. The first principal component was highly correlated with MT, Cd and Zn indices (metal or MT content/shell mass), and the second one with Cu, Mn, and Fe indices, as well as the gill index. High correlation of MTs with Zn and Cd is consistent with their affinity for binding to MTs.     

Factors affecting 210Po and 210Pb activity concentrations in mussels and implications for environmental bio-monitoring programmes

The activity of ²¹⁰Po and ²¹⁰Pb was determined in mussels of the same size (3.5-4.0 cm shell length) sampled monthly over a 17-month period at the Atlantic coast of Portugal. Average radionuclide concentration values in mussels were 759 ± 277 Bq kg⁻¹ for ²¹⁰Po (range 460-1470 Bq kg⁻¹ dry weight), and 45 ± 19 Bq kg⁻¹ for ²¹⁰Pb (range 23-96 Bq kg⁻¹ dry weight). Environmental parameters and mussel biometric parameters were monitored during the same period. Although there was no seasonal variation of radionuclide concentrations in sea water during the study period, the concentration of radionuclide activity in mussels varied seasonally displaying peaks of high concentrations in winter and low concentrations in summer. Analysis of radionuclide data in relation to the physiological Condition Index of mussels revealed that ²¹⁰Po and ²¹⁰Pb activities in the mussel (average activity per individual) remained nearly constant during the investigation period, while mussel body weight fluctuated due to fat storage/expenditure in the soft tissues. Similar variation of radionuclide concentrations was observed in mussels transplanted from the sea coast into the Tejo Estuary. However, under estuarine environmental conditions and with higher food availability throughout the year, transplanted mussel Condition Index was higher than in coastal mussels and average radionuclide concentrations were 210 ± 75 Bq kg⁻¹ (dry weight) for ²¹⁰Po and 10 ± 4 Bq kg⁻¹ (dry weight) for ²¹⁰Pb, therefore lower than in coastal mussels with similar shell length. It is concluded that the apparent seasonal fluctuation and inter-site difference of radionuclide concentrations were mostly caused by mussel body weight fluctuation and not by radionuclide body burden fluctuation. This interpretation can be extended to the apparent seasonal fluctuation in concentrations of lipophilic and lipophobic contaminants in mussels, and provides an explanation for occasional high concentrations of ²¹⁰Po and man-made contaminants measured in mussels far from pollution sources.     

Possible influence of lipid content on levels of organochlorine compounds in mussels from Galicia coast (Northwestern, Spain). Spatial and temporal distribution patterns

Influence of lipid content of mussel on levels of organochlorine compounds (polychlorinated biphenyls [PCBs] and OC pesticides) has been studied. Mussel samples coming from three sites in Galicia coast (Northwestern, Spain), Moa?a and Cangas C from Ría de Vigo and Barallobre from Ría de Ferrol, collected monthly in the period from November 2000 to October 2001, have been analysed. Organochlorine compounds, PCBs (IUPAC nos. 31, 28, 52, 101, 118, 153, 105, 138, 156 and 180) and OC pesticides (pp'-DDE, op'-DDT, pp'-DDT, aldrin, isodrin and endrin) have been extracted by means of Soxhlet and determined by using gas chromatography (electron capture detector [ECD]) and gas chromatography-mass spectrometry. Statistical analysis has been performed using the SPSS statistical package. Few compounds were correlated with lipid content (Pearson product-moment correlation); for samples coming from Barallobre, only the individual PCBs 31, 28, 52 (tri- and tetrachlorinated biphenyls) and 180 (heptachlorinated biphenyl) presented a significant correlation; for Moa?a samples, two cyclodiene pesticides, endrin and isodrin, presented a slight significant correlation with lipid content. From these results, it is deduced that the normalization of the concentration of organochlorine compounds to the lipid content is not necessary, in this way, avoiding possible error sources associated to the analytical determination of the lipid contentor reproductive status of mussel. Multivariate techniques (PCA) have been employed in order to study spatial and temporal distribution patterns of organochlorine compounds. The great differences found in studied samples are mainly related to spatial distribution: separations between estuarine bays (samples coming from Ría de Vigo and Ría de Ferrol) and between rural and urban zones (samples coming from Moa?a and Cangas C and samples from Barallobre, respectively).     

Cesium accumulation by aquatic organisms at different trophic levels following an experimental release into a small reservoir

The rates of accumulation and subsequent loss of stable cesium (¹³³Cs) by organisms at different trophic levels within plankton-based and periphyton-based food chains were measured following the addition of ¹³³Cs into a small reservoir near Aiken, South Carolina, USA. An uptake parameter u (L kg⁻¹ d⁻¹ dry mass) and a loss rate parameter k (d⁻¹) were estimated for each organism using time-series measurements of ¹³³Cs concentrations in water and biota, and these parameters were used to estimate maximum concentrations, times to maximum concentrations, and concentration ratios (C_r). The maximum ¹³³Cs concentrations for plankton, periphyton, the insect larva Chaoborus punctipennis, which feeds on plankton, and the snail Helisoma trivolvis, which feeds on periphyton, occurred within the first 14 days following the addition, whereas the maximum concentrations for the fish species Lepomis macrochirus and Micropterus salmoides occurred after 170 days. The C_r based on dry mass for plankton and C. punctipennis were 1220 L kg⁻¹ and 5570 L kg⁻¹, respectively, and were less than the C_r of 8630 L kg⁻¹ for periphyton and 47,700 L kg⁻¹ for H. trivolvis. Although the C_r differed between plankton-based and periphyton-based food chains, they displayed similar levels of biomagnification. Biomagnification was also indicated for fish where the C_r for the mostly nonpiscivorous L. macrochirus of 22,600 L kg⁻¹ was three times less than that for mostly piscivorous M. salmoides of 71,500 L kg⁻¹. Although the C_r for M. salmoides was greater than those for periphyton and H. trivolvis, the maximum ¹³³Cs concentrations for periphyton and H. trivolvis were greater than that for M. salmoides.     

Molecular biomarkers of energy metabolism in mussels under anthropogenic pollution of Peter the Great Bay, the Sea of Japan

The functional state of the indicator species, the Gray mussel Crenomytilus grayanus (Bivalvia), has been analyzed in five areas of Peter the Great Bay exposed to anthropogenic pollution. The following indices of the state of mussels have been used: molecular biomarkers of energy metabolism—Na⁺,K⁺-ATPase, Mg²⁺-ATPase, and total ATPase activity—as well as the level of lipid peroxidation (LPO) and glutathione concentration in the hepatopancreas, gills, and gonads of mussels. The activity of ATPases, LPO level, and glutathione concentration significantly change in mussels from polluted areas relative to those in mussels from a conventionally unpolluted area (a bay in the Far Eastern State Marine Reserve). The molecular biomarkers used in the study provide reliable information on animal metabolism in impact areas. With consideration of the data obtained, it is concluded that the state of mussels in polluted areas is impaired.