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- Are tolerance processes limiting the responses of Hediste diversicolor to cadmium exposure? A multimarker approachPublication . Pedro, Carmen A.; Bruno, Catarina S.; Sarly, Monique S.; Meireles, Gabriela; Moutinho, Ariana; Novais, Sara C.; Marques, João C.; Gonçalves, Sílvia C.Cadmium (Cd) is considered a priority hazardous substance under the European Community Directive 2013/39 due to its ecotoxicity. The ragworm Hediste diversicolor (O.F. Müller, 1776), a common species in estuaries and coastal lagoons, plays an important ecological role in these ecosystems and is a suitable bioindicator of environmental chemical contamination. In this study, H. diversicolor was chosen as an ecotoxicological model with the aim of evaluating the responses to Cd contamination, considering a multi-biomarker approach (mortality, biometry, behaviour, Cd bioaccumulation, oxidative stress and damage, and energy metabolism). Also, the hypothesis of different tolerances resulting in different responses was evaluated, by collecting worms from three systems distinctly impacted by metal contamination (Mondego estuary, Óbidos Lagoon and Sado estuary – Portugal). Animals were exposed under laboratory conditions to cadmium (10, 50 and 100 μg/L), for 10 days. Significant differences were observed in responses amongst worms originating from the different sites. Organisms from the less impacted systems revealed greater effects on mortality, biomass decrease and burrowing behaviour, as well as higher bioaccumulation potential, after exposure to Cd. Biochemical and behaviour impairments were observed as a consequence of Cd exposure, although not in a concentration-dependant manner. The results obtained in this study reinforce the importance of integrating endpoint responses, at the individual and subindividual levels, to assess potential changes induced by pollutants in the physiological status and fitness of H. diversicolor and help to predict what their ecological consequences might be.
- Is the plant Bolboschoenus maritimus an adequate biomonitor for trace metal contamination in saltmarshes? A field study from the Óbidos lagoon (Portugal)Publication . Santos, Márcia S.S.; Pedro, Carmen A.; Ferreira, Susana M. F.; Gonçalves, Sílvia C.Monitoring the negative impacts of trace metals is crucial to assess the health and stability of ecosystems. In salt marshes, halophyte plants were reported as possible bioaccumulators of these elements. The aim of this work was to explore the bioaccumulation potential of Bolboschoenus maritimus as a tool for monitoring the presence of metals in coastal environments. Bolboschoenus maritimus were collected from a brackish water lagoon, and the presence of the trace metals lead, cadmium, and nickel were seasonally evaluated in distinct parts of the plants, and in water and sediment samples. Lead was the trace metal with the highest concentration detected in water and sediments of the sampling site. The highest lead concentrations in B. maritimus were recorded in the spring season. The transport index indicated an accumulation of lead in the leaves of around 70% in the spring of 2009. Cadmium in leaves in spring and summer of 2009 reached values above 5 mg Cd. kg−1. Nickel was not detected in most samples collected. Bolboschoenus maritimus was considered an adequate biomonitor for lead and cadmium, since it bioaccumulates both metals with seasonally distinct results, as the bioaccumulation factor results indicated.
- Monitoring metal pollution on coastal lagoons using Cerastoderma edule: a report from a moderately impacted system in Western Portugal: Óbidos LagoonPublication . Veiga, Kelly; Pedro, Carmen A.; Ferreira, Susana M. F.; Gonçalves, Sílvia C.The main goal of this monitoring program was to evaluate the contamination in the intertidal environment of Óbidos Lagoon by the metals Cd, Pb, and Ni on water, sediments, and on biological samples, using the bivalve Cerastoderma edule (common name: cockle) as a biomonitor. Since C. edule is an edible mollusc, the risk of their consumption by humans from this lagoon was also evaluated. The study was performed in a restricted area of the lagoon—the MLstation—where human activities, such as shellfish harvesting, intersect with the natural processes occurring in this system. The results obtained revealed that the water samples were polluted with Cd and Pb with concentrations (0.00025 mg l−1 and 0.0072 mg l−1) above the maximum legislated on the Directive 2008/105/EC, while for Ni, this occurred only on one of the seasons sampled (summer 2010: 0.029 mg l−1). The sediments were not contaminated with Cd and Ni, and the contamination detected for the metal Pb, allowed the classification of this station as an unpolluted site ([Pbmin] = 7.477 mg.kg−1 and [Pbmax] = 19.875mg.kg−1). On biological samples, comparing the results of metal contaminations with the values of the maximum levels fixed by European Commission Regulation (EC) No 1881/2006 and USFDA, all the results were below the legal value. Therefore, during the period of study, the consumption of this bivalve by humans was safe. Also, BAF and CF calculations suggest that C. edule can be used as a biomonitor to determine the source of the contaminations. This study supported the use of C. edule as a biomonitor to assess the contamination by the metals Pb and Ni at the Óbidos Lagoon and allowed to predict the potential transfer of metals to higher trophic levels with potential impacts on the natural and human communities.
- How do salinity and heavy metal contamination affect Salicornia ramosissima and the Cadmium accumulation capacity?Publication . Pedro, CarmenThe major aim of this study was to evaluate the capacity of Salicornia ramosissima, a halophyte present in Obidos lagoon (Portugal), on Cadmium (Cd) phytoremediation, when submitted to different salinities and Cd concentrations, for a month. Two Cd concentrations were used to evaluate this capacity and, consequently, the toxic effect of Cd on the plant development. The contamination levels were tested in different salinities (0, 5 and 10), taking into consideration the natural conditions that S. ramosissima is subject in its natural environment. The mortality registered in the end of the experiment, as the growth parameters measured (length and weight), did not showed significantly differences between the treatments, which means were not affected for the salinity or Cd concentrations, neither for the interaction of those two stress factors. However, length elongation and the variation of weight, observed in the end of the experiment, may have been induced by the increase of salinity and Cd concentration. A highest Cd accumulation was detected in the roots of S. ramosissima, compared with the aerial portion. The Cd accumulation in roots decreased with the increase of salinity and Cd concentration, even though statistically there were no significant differences between treatments. In all treatments, a biofilm was form, highlighting treatment salinity 0 x 50 μg Cd.l-1, where microorganisms and, eventually, organic matter (from the plant), suspended revealed a higher Cd amount relatively to the water initial Cd concentrations. The dissolved Cd concentration, detected in the final of the experiment, was in accordance with the initial contamination levels used in this study; however an increase was observed for some treatments, possible as a result of decomposition of organic matter and consequent release of Cd to the water. Salicornia ramosissima is a potential candidate for Cd phytoremediation at salinities close to 0, where development is maximum and, consequently, is Cd accumulation capacity. The optimization of phytoremediation processes by S. ramosissima could turn possible the use of this plant in freshwater ecosystems.
- Use of the gonadal tissue of the sea urchin Paracentrotus lividus as a target for environmental contamination by trace metalsPublication . Sarly, Monique S.; Pedro, Carmen A.; Bruno, Catarina S.; Raposo, Andreia; Quadros, Helenita; Pombo, Ana; Gonçalves, Sílvia C.Many environmental monitoring works have been carried out using biomarkers as a tool to identify the effects of oil contamination on marine organisms; however, only a few studies have used sea urchin gonadal tissue for this purpose. Within this context, the present work aimed to understand the impact of an oil spill, proposing the use of sea urchin gonadal tissue as a biomarker for environmental contamination by trace metals in the species Paracentrotus lividus. Biometric analysis, quantification analyses of the elements Cd, Pb, Ni, Fe, Mn, Zn, and Cu, as well as histopathological evaluations were performed in gonads of P. lividus collected from an area affected by hydrocarbons, named as impacted shore (IS) and an area not affected, named reference shore (RS). The results showed that carapace diameter (DC), total wet weight (WW), and Cd concentrations in the gonads were significantly influenced by the interaction between the rocky shores of origin, the months of sampling, and by the sex of the individuals. Moreover, from July until September, the levels of Zn and Cd were significantly lower in male than in female gonads. In July (the month of the oil spill), the indexes of histopathological alterations (IHPA) of membrane dilation were significantly higher in individuals from the IS, compared to the individuals from the RS. In addition, there were significant correlations between biometric variables (wet weight, diameter of carapace, gonadal weight, and gonadosomatic index) and the elements Cd, Cu, Ni, and Mn concentrations. Lastly, a delay in the gametogenic cycle of the sea urchins from IS was also observed. Taken together, these findings suggest that direct exposure to trace metals induces histopathological lesions in P. lividus’ gonads and affects its reproductive cycle.
- The presence of cadmium in the intertidal environments of a moderately impacted coastal lagoon in western Portugal (Óbidos Lagoon)—spatial and seasonal evaluationsPublication . Pedro, Carmen; Santos, Márcia S. S.; Ferreira, Susana; Gonçalves, SílviaA seasonal environmental monitoring program was carried out (winter 2009 to summer 2010) to evaluate the spatial and seasonal cadmium concentrations in the intertidal environments of the Óbidos Lagoon (Portugal). Also, some environmental parameters were monitored at each sampling station. Both the water and the sediment samples were contaminated, although to different degrees. In general, cadmium contamination appears to be mostly focused on the inner areas of the lagoon, namely, in Barrosa’s arm, which receives a small tributary contaminated by agro-industrial activities. Only cadmium concentration in sediment showed to be significantly influenced by seasons. Some environmental parameters presented spatial and temporal heterogeneity which influenced, to some extent, cadmium bioavailability. The results of this study allow a better understanding of the environmental quality of this ecosystem regarding cadmium contamination and may assist in the definition of future coastal management measures specifically targeted to trace metal contamination and pollution monitoring.
- Phytoremediation of cadmium by the facultative halophyte plant Bolboschoenus maritimus (L.) Palla, at different salinitiesPublication . Santos, Márcia S. S.; Pedro, Carmen; Gonçalves, Sílvia; Ferreira, SusanaThe cadmium phytoremediation capacity of the halophyte plant Bolboschoenus maritimus (L.) Palla and the influence of water salinity were assessed in a greenhouse experiment, in order to better understand the bioremediation capacity of this plant. Three concentrations of cadmium (0, 50 and 100 μg l−1) and four salinity conditions (0, 5, 10 and 20) were chosen to evaluate the cadmium accumulation, in order to test these plants as a potential phytoremediation tool in brackish environments. The cadmium content in water and plants (underground organs, stems and leaves) was analysed with graphite furnace atomic absorption spectrometry. All the plants submitted to salinity 20 and in the three cadmium treatments died. The plants’ survival was highest in the lowest salinities, where highest growth and biomasses were also obtained. The plants presented more cadmium content in the rhizomes, followed by stems and even less in leaves. The salt stress of the plants interfered with their cadmium accumulation capacity. The highest cadmium accumulation in the rhizomes occurred at salinity 0, while the salinities 0 and 5 were the most adequate for stems and leaves. The experiment pointed out that B. maritimus represents a good possible intervenient for cadmium bioremediation in freshwater and low salinity brackish water environments, but its use is limited in the habitats of higher salinity. © 2015, Springer-Verlag Berlin Heidelberg.