Examinando por Materia "BIOLOGIA"
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- Artículo de Publicación PeriódicaApplying the monitoring breakdown structure model to trace metal content in edible biomonitors: an eight-year survey in the Beagle Channel (southern Patagonia)(2020-02) Conti, Marcelo Enrique; Tudino, Mabel Beatriz; Finoia, Maria Grazia; Simone, Cristina; Stripeikis, Jorge"The purpose of this paper is to investigate the trace metal content in edible biomonitors (i.e., mollusks) in the Beagle Channel (southern Patagonia) and to assess the human health risks associated with their consumption. Rationale: The monitoring breakdown structure (MBS) conceptual model was applied to four sampling campaigns (2005 → 2012) that collected 729 samples of Mytilus chilensis and Nacella magellanica. The composition of trace elements (Cd, Cr, Cu, Ni, Pb and Zn) in the mollusks was determined using graphite furnace (GFAAS) or flame atomic absorption spectrometry (FAAS). We compared the mean obtained values with the maximum levels (MLs) of each element established by international organizations. Then, based on semi-structured interviews, we calculated the estimated daily intake (EDI) of local residents and compared it with safety reference doses, i.e., the provisional tolerable daily intake (PTDI), provisional maximum tolerable daily intake (PMTDI), and tolerable daily intake (TDI), as well as the benchmark dose level lower confidence limit for Pb (BMDL01, a reference point (RP)/point of departure (POD). Moreover, to obtain information about the potential health risks of ingesting heavy metals (HMs) through mollusk consumption, we evaluated the target hazard quotient (THQ) and the hazard index (HI). Findings: For Cd and Pb, 65% and 40% of bivalves exceeded the MLs established by the Mercado Común del Sur (Mercosur), respectively. Except for Cd in N. magellanica (i.e., 1.20 μg/kg/bw/day), EDI values were clearly lower than the safety reference doses. For Cr, Cu, Ni, Pb and Zn, mussels were safe for consumption and did not raise concerns for public health. Likewise, THQ values were well below one for most of the studied metals, indicating that the exposed human population is assumed to be safe. Occasional high consumers of mollusks from the most contaminated sites may be at some health risk. Originality: The food production system and the environment are complex systems; this is crucial to understand when we consider ecosystems as a food source (i.e., marine ecosystems). Here we consider edible biomonitors, that are organisms that can have a dual function. They are food, and at the same time, if properly calibrated, they can act as indicators of environmental quality. This study is the first to investigate relevant essential and non-essential trace metal content in two edible mollusks from the Beagle Channel in a long-term survey (2005 → 2012). The information variety was high; approximately thirteen thousand determinations were conducted to support the risk assessment for mollusk consumption. Other aspects connected with the health risks and the uncertainty factors related to the presence of essential and non-essential minerals in edible mollusks as well as the use of the MBS are also discussed."
- Artículo de Publicación PeriódicaManaging complexity of marine ecosystems: from the monitoring breakdown structure (MBS) to the baseline assessment. Trace metal concentrations in biomonitors of the Beagle Channel, Patagonia (2005–2012)(2019-09) Conti, Marcelo Enrique; Tudino, Mabel Beatriz; Finoia, Maria Grazia; Simone, Cristina; Stripeikis, Jorge"In this study we propose a conceptual framework, i.e. the Monitoring Breakdown Structure (MBS) as a tool for the management of marine ecosystems. The conceptual framework thinks through the complexity of marine ecosystems keeping into account the variety (space) and variability (time) dimensions. Consistently with the MBS we have built the control charts of trace metal concentrations of two selected biomonitors in the Beagle Channel (south Patagonia) (case study). Thus, we have tested the aptitude of two species of mollusks as biomonitors of heavy metal (HMs) pollution. The selected species were the limpet Nacella (P) magellanica and the bivalve Mytilus chilensis. Seven hundred eighty-five samples were collected along 170 km of the coastal area of the Beagle Channel (BC), (Tierra del Fuego, Argentina) in seven selected georeferenced locations and four sampling campaigns (2005, 2007, 2011, 2012). Cd, Cr, Cu, Ni, Pb and Zn determinations in seawater and mollusks by atomic absorption spectrometry (AAS) were carried out. The calculation of the respective concentration factors (CFs), i.e. their capacity as strong bioaccumulators, was also conducted. This is of relevance because it aims to use these data as a baseline reference for other geographical areas. Second, we have compared metal bioaccumulation differences among sites and the contamination trend by building, for the first time, the control charts of the baseline metal concentrations in the biomonitors. For these purposes, we applied probabilistic Johnson's method. Furthermore, the control charts (based on four years baseline data) allowed us to test the contamination trend by plotting data from 2012 vs 2011. Our results confirm N. magellanica as an extremely strong accumulator of Cd, and M chilensis strong bioaccumulator of Cd and Zn. Zn was the most abundant metal followed by Cu. Overall, regarding the contamination trend, based on thousands of determinations we observed that the six mean metal levels were quite constant over time. Moreover, metal distribution among sites turned out to be not univocal (no one site is more contaminated than the other sites). Thus, the expected hypothesis of Ushuaia Harbour as being the most contaminated site should be reconsidered. This reinforces the hypothesis of our data as baseline data (except for cadmium), that should be considered in management decisions about future environmental monitoring programs, i.e. preventing/managing marine accidents."
- Artículo de Publicación PeriódicaPerformance of two Patagonian molluscs as trace metal biomonitors: the overlap bioaccumulation index (OBI) as an integrative tool for the management of marine ecosystems(2019-06) Conti, Marcelo Enrique; Tudino, Mabel Beatriz; Grazia Finoia, Maria; Simone, Cristina; Stripeikis, Jorge"In this study, we have investigated Cd, Cr, Cu, Ni, Pb and Zn in the biomonitors Mytilus chilensis and Nacella (P) magellanica sampled along seven selected sampling sites along 170 km of the coastal area of the Beagle Channel (Tierra del Fuego, Argentina) in four sampling campaigns: 2005, 2007, 2011 and 2012. The control charts were built by applying Johnson’s probabilistic method for the first time in this marine area. We determined the metal concentration overlap ranges in the selected biomonitors (as well as medians and distribution), and the overlap bioaccumulation index (OBI) with respect to the lowest (OBI-L1) and the highest (OBI-L) extreme values of the overlap metal concentration ranges. The OBI can be used as an integrative tool in the management of prevailing unpolluted/polluted marine coastal ecosystems. It consents to identify the most suitable organisms for managing several environmental conditions where an ecosystem quality control is needed. The OBI-L1 index can be employed as a preventive signal of alarm when the contamination process is in its early stages. For Cd, Ni, Cu and Cr, Nacella showed high OBI-L values that suggest its use as a biomonitor for mainly polluted marine ecosystems, in particular for Cd. Mytilus showed high Cd values for the OBI-L1 which means that this species is highly sensitive to a very low variation of the Cd levels in seawater. The OBI index enhances the observer’s information variety about the performance of the molluscs as metal biomonitors in marine ecosystems. Eventually, here we propose to conceptualize the wide set of biomonitoring knowledge endowment as an open and evolutionary endowment of information variety supporting the environmental management."
- Artículo de Publicación PeriódicaWhy nestedness in mutualistic networks?(2007) Burgos, Enrique; Ceva, Horacio; Perazzo, Roberto P. J.; Devoto, Mariano; Medan, Diego; Zimmermann, Martín; Delbue, Ana María"We investigate the relationship between the nested organization of mutualistic systems and their robustness against the extinction of species. We establish that a nested pattern of contacts is the best possible one as far as robustness is concerned, but only when the least linked species have the greater probability of becoming extinct. We introduce a coefficient that provides a quantitative measure of the robustness of a mutualistic system."