[Show abstract][Hide abstract] ABSTRACT: The main goal of this research was to test the effectiveness of Scrobicularia plana to reflect environmental mercury concentrations, with the aim to propose it as a suitable, sentinel mercury biomonitor.
Significant differences in mercury concentrations were observed between small and larger sized individuals in the most contaminated sampling sites, suggesting progressive mercury accumulation with size. Larger size classes did not significantly differ, however, indicating that organisms attain an equilibrium state between the mercury assimilation and excretion rates. Therefore, the average concentration of individuals larger than 2 cm shell length is indicative of the local contaminant bioavailability.
The diet emerges as the source of contaminant incorporation in this species, which reflects sediment and suspended particulate matter (SPM) contamination regardless of the degree of environmental contamination.
Such consistent bioaccumulation behavior, its widespread distribution, abundance, ease of collection, taxonomic identification and resistance to contamination, emphasize the usefulness of S. plana as a cosmopolitan biomonitor of mercury contamination in temperate estuarine systems.
[Show abstract][Hide abstract] ABSTRACT: The main goal of this study was to assess both mercury (Hg) accumulation and organs' specific oxidative stress responses of gills, liver and kidney of Dicentrarchus labrax with emphasis on seasonality. Fish were collected in cold and warm periods in three stations: reference, moderated and highly contaminated sites. Our results showed that seasonal factors slightly influenced Hg accumulation between year periods (cold and warm) and strongly affected organs' response basal levels. In contrast, seasonality seemed not to influence oxidative stress responses, since similar response patterns were obtained for both year periods, and moderate degree of antioxidant responses was obtained. Moreover, the oxidative stress profile may be attributed to Hg contamination degree, which showed organ-specific response and accumulation patterns. Hence, gills showed to be able to adapt to Hg contamination, and in opposition, kidney and liver demonstrated some vulnerability to Hg toxicity. The critical Hg concentrations indicated specific threshold limits for each organ. Overall, seasonality should be taken into account in monitoring programmes, helping to characterize the individuals' reference values of response and thus to discriminate between the effects induced by natural causes or by contamination.
Environmental Science and Pollution Research 05/2014; · 2.76 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract: The main purpose of this study was to evaluate
the mercury (Hg) bioaccumulation in the Egyptian
mongoose (Herpestes ichneumon), a terrestrial predator
species with an essential role in the Iberian ecosystems
food chain. Differences between males and females and
the effect of age in mercury body burdens were studied,
as well as the geographical distribution of mercury in
tissues of the studied species. Total mercury (T-Hg) was
determined in muscle, liver, lungs, heart, spleen, kidneys,
blood, brain, fat and pelage of the Egyptian mongoose
from 14 locations, encompassing the distribution
range of the element in the species. In order to study
differences between ages, males and females, 20 individuals
from one sampling location were analysed. Total
mercury concentrations ranged between 0.01 and
13 μg g−1 (dry weight (dw)) and followed the order
from the least to the most contaminated: fat<brain<
<blood. Differences between males and females were
only significant for muscle and pelage mercury levels,
suggesting uptake rates and metabolic processes to be
similar between genders.Despite a similar accumulation
pattern with age between males and females, differences
between ages were significant only for females, as a
result of a higher range of male mercury body burdens.
Organic mercury (O-Hg) was analysed in muscle and
liver, and its percentage ranged from 83 to 96 %,
reflecting the high trophic level of the species. None of
the observed mercury levels reached the lethal or toxic
values established for terrestrial predators (20 to
100 μg g−1 wet weight), suggesting that despite its
predatory position in terrestrial food webs, the risk of
mercury associated toxicity is low.
Water Air and Soil Pollution 01/2014; 225(6):1-11. · 1.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Although mercury bio-amplifies through the food chain and accumulates in top predators, mercury concentrations in tissues of the wandering albatross are greater than in any other vertebrate, including closely related species. In order to explore the alternative explanations for this pattern, we measured total mercury concentrations in feathers, plasma and blood cells of wandering albatrosses of known age, sex and breeding status sampled at South Georgia. Mercury concentrations were low in feathers and blood components of chicks, and higher in the feathers of young pre-breeders than in feathers or blood of older pre-breeders and breeding adults. There was no effect of sex on mercury concentrations in the feathers of pre-breeders or breeding adults, whereas levels were significantly higher in blood cells of breeding females than males. The high feather mercury concentrations of young pre-breeders compared with older birds suggest an increase in moult frequency as birds approach maturity.
[Show abstract][Hide abstract] ABSTRACT: Trace element levels in fish are of particular interest, owing the potential risk to human health. In accordance, juveniles of Dicentrarchus labrax and of Liza aurata were sampled and arsenic, cadmium, chromium, selenium and zinc were determined in the muscle. The levels of trace elements in muscle demonstrated to be similar for both species and sites, with the exception of selenium levels at reference, which seemed to be higher in D. labrax. Moreover, apart from arsenic levels in muscle, all elements were in conformity with the existent regulatory guidelines for fish consumption. The dietary intake of each element was also calculated, with arsenic and selenium showing intakes above the recommended dietary allowances. Nevertheless, no arsenic speciation was carried out and thus no accurate risk evaluation could be established. Additionally, selenium levels never exceeded the dietary allowances more than five times, which are considered safe.
[Show abstract][Hide abstract] ABSTRACT: The Mondego estuary is a mainly polyhaline estuary in central Portugal in which eutrophication increased during the last decades of the 20th century. In 1998 the system hydrology was changed, aiming to reverse the eutrophication process. A long environmental monitoring database showed that the mean concentrations of dissolved inorganic phosphorus (DIP) increased by 50%, due to the increase in winter concentrations, i.e., in periods characterized by lower temperature and lower salinity. Given existing background knowledge, especially on the system hydrodynamics, phosphorus dynamics and phosphorus speciation in the estuary, we framed the hypothesis that the significant increase of DIP could be related to different sorption capacities of the sediments. The results highlighted two scenarios: i) Before 1998 the nutrient-rich freshwater input from the upstream cultivated lands entered the system through the area with the highest PO4–P adsorption capacity (Q∗ = 657 μg P g−1 wwt), thus the PO4–P availability in the water column was mostly dependent on the mineralization processes, which is in agreement with previous findings; ii) After 1998, the water residence time diminished from moderate (weeks) to short (days). This change coincided with a diversion of the water to an area with a much lower PO4–P adsorption capacity (Q∗ = 410 μg P g−1 wwt), which represented a decrease in 7.3% of the system adsorption capacity. This means that sediments were not able to adsorb much of the PO4–P and a higher equilibrium concentration occurred in the water column. The sorption study proved to be a valuable tool in testing our hypothesis and provided essential information on the mobility of PO4–P from soils/sediments to the water column.
[Show abstract][Hide abstract] ABSTRACT: Soil quality in urban areas is affected by anthropogenic activities, posing a risk to human health and ecosystems. Since the pseudo-total concentrations of potentially toxic elements may not reflect their potential risks, the study of element mobility is very important on a risk assessment basis. This study aims at characterising the distribution and major sources of 34 elements in two Portuguese urban areas (Lisbon and Viseu), with different geological characteristics, industrial and urban development processes. Furthermore, the potential availability of As, Co, Cr, Cu, Ni, Pb and Zn was assessed, by measuring the fraction easily mobilised. Lisbon is enriched in elements of geogenic and anthropogenic origin, whereas in the smaller city, the high levels observed are mainly related to a geogenic origin. Background values can be more relevant than the dimension of the city, even when anthropogenic components may be present, and this parameter should be considered when comparing results from different cities. Regarding the potential available fraction, a high variability of results was observed for elements and for sampling sites with an influence of the soil's general characteristics. Elements showing very high concentrations due to geological reasons presented, in general, a low mobility and it was not dependent on the degree of contamination. For elements with major anthropogenic origin, only Zn was dependent on the pseudo-total content. Yet, the highest available fractions of some elements, both with major geogenic and anthropogenic origin, were observed in specific contaminated samples. Therefore, a site-specific evaluation in urban soils is important due to the high spatial variability and heterogeneity.
Environmental Monitoring and Assessment 02/2012; · 1.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Food chain models are essential tools to assess risks of soil contamination in view of product quality including fodder crops and animal products. Here we link soil to plant transfer (SPT) models for potentially toxic elements (PTEs) including As, Ba, Cd, Co, Cu, Hg, Ni, Pb, Sb, U and Zn with models describing accumulation in animal organs. Current EU standards for food products and acceptable daily intake levels (ADI) for humans were used as critical limits. The combined model is used to assess the impact of soil contamination on animal health, product quality and human health using data from 100 arable fields. Results indicate that 42 existing arable fields near industrial and mining sites are unsuitable for animal grazing in view of food safety due to elevated intake of Cd, Cu, Hg and Pb by cows and sheep. At 10 sites daily intake levels of As by cows exceeded threshold concentrations regarding the quality of animal products. The food chain model also was used inversely to derive soil threshold concentrations in view of EU fodder standards. Calculated threshold levels in soil for As, Cd, Cu, Pb, Hg and Zn appear to be in line with those proposed or used in other EU countries. As such the approach applied here can form a conceptual basis for a more harmonized risk assessment strategy regarding the protection of animal and human health.
Environment international 02/2012; 39(1):27-37. · 6.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This chapter introduces the plant family Brassicaceae (Cruciferae or mustard family) and also summarizes significant roles of some representative plant species from this family for metals and metalloids phytoremediation. Brassicaceae family is one of the largest dicot families of flowering (angiospermic) plant kingdom which comprises 10–19 tribes with a total of 338–360 genera and nearly 3,709 species. The Brassicaceae are easily recognized by having unique flowers [with four petals, forming a cross or sometimes reduced or lacking; six stamens, the outer two being shorter than the inner four (however, sometimes only two or four stamens are present) and capsule (having two valves capsule with a septum dividing it into two chambers)]. The plant family Brassicaceae includes several plant species of great scientific, economic and agronomic importance including model species (Arabidopsis and Brassica), developing model generic systems (Boechera, Brassica, and Cardamine), as well as many widely cultivated species. The well-known model plants from the family Brassicaceae viz., Arabidopsis (Arabidopsis thaliana) and Brassica species have revolutionized our knowledge in almost every field of modern plant biology. In addition, several representatives of the family Brassicaceae are equally playing significant roles for achieving environmental sustainability.
The Plant Family Brassicaceae: Contribution Towards Phytoremediation, 1st 01/2012: chapter 1: pages 1-33; Springer Dordrecht, The Netherlands.., ISBN: 978-94-007-3912-3
[Show abstract][Hide abstract] ABSTRACT: With the advent of the Industrial Revolution , the biosphere has been continuously polluted with a myriad of contaminants that urgently need global attention. In this perspective, most of the genera of the plant family Brassicaceae (Crucifereae or the mustard family) are significant parts of the plants- and associated microbes-based strategies adopted for the cleanup of varied contaminants from environmental compartments. Important genera such as Alyssum, Arabidopsis, Brassica and Thlaspi from Brassicaceae which, besides acting as attractive genetic models, well-represent the metal hyperaccumulation among approximately 0.2% of all angiosperms and thus, play a key role in the phytoremediation technology. This book i) provides an exhaustive evaluation of the current status of contaminants (metals/metalloids)-addition to varied environmental compartments and its consequences, ii) offers comprehensive and state-of-the-art information on the significance of the plants from the family Brassicaceae in solving environmental pollution issues, iii) examines the physiological, biochemical and molecular-genetic strategies adopted by the plants from Brassicaceae for the remediation of and tolerance to varied environmental contaminants, and iv) supplies a broad reference to the field of environmental science and related disciplines. As a pioneer work on the subject and significant addition to the Environmental Pollution book series, the current volume promises to be a useful asset for researchers, students, other academics and policy makers involved in sustainable remediation of varied environmental compartments.
1st edited by Anjum NA, Ahmad I, Pereira ME, Duarte AC, Umar S, Khan NA, 01/2012; Springer (Science + Business Media), Dordrecht, The Netherlands., ISBN: 978-9400739123
[Show abstract][Hide abstract] ABSTRACT: The urinary levels of catecholamines (adrenaline (AD), noradrenaline (NA), and dopamine (DA)) and their metabo- lites (L-3,4-dihydroxyphenylalanine (L-DOPA), and 3,4-dihy- droxyphenylacetic acid (DOPAC)), as indicators of physiological stress, were assessed in 40 patients with Down syndrome (DS). The analysis was performed by an optical fiber (OF) bioanalyzer; which was constituted by two main components: a miniaturized chromatographic system and a detection system based on an OF coated with an enzymatic matrix. In this study some working conditions such as, number offibers in the miniaturized chromato- graphic column, number of dips for sensitive coating deposition, temperature and time of cure of the sensitive matrix, were opti- mized in order to achieve higher analytical performance. After tested for calibration the bioanalyzer was applied to urine samples analysis of catecholamines and their metabolites, comparing the results with those obtained by both, a classical analytical method, namely high performance liquid chromatography coupled to an electrochemical detector (HPLC-ED), and an OF biosensor based on a sensitive cladding of laccase (LacOF biosensor). The results of catecholamines in patients with DS revealed that 15% and 22.5% of the analyzed subjects showed DA and AD concentrations, re- spectively, above the pathological levels. In the determinations of NA, the 40 samples showed concentration values below the normal levels, while in the determination of catecholamines metabolites
[Show abstract][Hide abstract] ABSTRACT: Toxic metals (TMs) and metalloids are natural components of environments, but elevated toxic levels and high persistence of TMs and metalloids in major compartments of the biosphere has posed various uncompromising and fatal effects on flora and fauna, and thus, has threatened the stability of the ecosystems as well. In addition, with the rapid increase in anthropological practices, a large number of TMs and metalloids ions are being added to the natural environment disrupting the ecosystem. A plethora of plant species have been identified so far to have potential for the remediation of TMs and metalloids-contaminated sites. Although, a large number of natural metal hyperaccumulator plant species from 34 different plant families including Asteraceace, Brassicaceae, Caryophyllaceae, Poaceae, Violaceae and Fabaceae has evolved the ability to take up, tolerate and accumulate exceptionally high concentrations of metals and metalloids present in the soil (and water) and, more importantly, in their aboveground biomass without visible toxicity symptoms but with 87 species classified as metal hyperaccumulators, the family Brassicaceae best represents amongst these metal-hyperaccumulator families. Of these 87 different metal-hyperaccumulator plant species in the family Brassicaceae, plant species in particular model metal hyperaccumutaor plant species Alyssum, Thlaspi and Arabidopsis have been studied extensively for their ability to hyperaccumulate, remove, destroy, degrade, sequester, transform, assimilate, metabolize or detoxify majority of TMs and metalloids in varied environmental compartments. Additionally, significant technological advancements in varied scientific fields have now deciphered important physiological and molecular mechanisms of TMs- and metalloids-remediation processes/intricacies in metal hyper accumulating plant species. Based on the plethora of recent published reports the current chapter critically discusses important strategies adopted by Alyssum, Arabidopsis and Thlaspi for TMs- and metalloids-hyperaccumulation/remediation and tolerance.
The Plant Family Brassicaceae: Contribution Towards Phytoremediation, 1st 01/2012: chapter 4: pages 99-137; Springer Dordrecht, The Netherlands.., ISBN: 978-94-007-3912-3
[Show abstract][Hide abstract] ABSTRACT: The aim of this research was to compare mercury (Hg) accumulation (total and organic) and tissue distribution in two marine fish species with contrasting feeding tactics. Thus, juvenile specimens of European sea bass and Golden grey mullet were surveyed in an estuary historically affected by Hg discharges. Total Hg was preferentially accumulated in intestine, muscle, and liver, whereas gills and brain presented the lowest Hg levels observed in both species. Significant differences between species were only verified for muscle, with D. labrax's levels being greater than L. aurata's. Muscle accounted for >87% of the Hg relative tissue burden, whereas liver did not exceed 11%. Organic Hg accumulation occurred mainly in liver and muscle, with D. labrax evidencing significantly greater loads. Moreover, organic Hg in consumed prey items was also significantly greater in D. labrax. Accumulation of organic Hg in liver, intestine, and muscle seemed to vary as a function of the consumed prey items contamination, suggesting fish feeding strategies as the dominant factor determining metal accumulation. For both fish species, a stable ratio was observed between Hg increments from the reference to the contaminated site, possibly indicating that the organic Hg content of diet may regulate the internal levels of this contaminant. Thus, this ratio might prove to be a useful contamination predictor tool in early life stages of fish.
Archives of Environmental Contamination and Toxicology 12/2011; 63(1):125-36. · 2.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In the present study, the risk to humans by consuming European sea bass (Dicentrarchus labrax), captured at three sites along a Hg contamination gradient, was evaluated by comparing muscle and kidney total Hg (T-Hg) levels with the European regulations for marketed fish. Moreover, T-Hg and organic Hg (O-Hg) levels in muscle were compared with the Provisional Tolerable Weekly Intake (PTWI) and the Reference Dose (RfD). Although T-Hg levels in muscle were below the European value allowable for marketed fish, kidney's levels were higher than the set value, stressing the importance of redefining the concept of edible tissue and which tissues should be considered. Mercury weekly ingestion in the contaminated areas was higher than the PTWI, and O-Hg daily ingestion rates were higher than the RfD in all sampling sites. Thus, populations consuming sea bass from the contaminated sites may be at risk, with particular relevance for children and pregnant women.
[Show abstract][Hide abstract] ABSTRACT: The integration of bioaccumulation and effect biomarkers in fish has been proposed for risk evaluation of aquatic contaminants. However, this approach is still uncommon, namely in the context of mercury contamination. Furthermore, a multi-organ evaluation allows an overall account of the organisms' condition. Having in mind the organs' role on metal toxicokinetics and toxicodynamics, gills, liver and kidney of golden grey mullet (Liza aurata) were selected and mercury accumulation, antioxidant responses and peroxidative damage were assessed. Two critical locations in terms of mercury occurrence were selected from an impacted area of the Ria de Aveiro, Portugal (L1, L2), and compared with a reference area. Although kidney was the organ with the highest mercury load, only gills and liver were able to distinguish mercury accumulation between reference (R) and contaminated stations. Each organ demonstrated different mercury burdens, whereas antioxidant responses followed similar patterns. Liver and kidney showed an adaptive capacity to the intermediate degree of contamination/accumulation (L1) depicted in a catalase activity increase. In contrast, none of the antioxidants was induced under higher contamination/accumulation (L2) in any organ, with the exception of renal GST. The lack of lipid peroxidation increase observed in the three organs denunciates the existence of an efficient antioxidant system. However, the evidences of limitations on antioxidants performance at L2 cannot be overlooked as an indication of mercury-induced toxicity. Having in mind the responses of the three organs, CAT revealed to be the most suitable parameter for identifying mercury exposure in the field. Overall, organ-specific mercury burdens were unable to distinguish the intermediate degree of contamination, while antioxidant responses revealed limitations on signalizing the worst scenario, reinforcing the need to their combined use.
Ecotoxicology and Environmental Safety 08/2011; 74(8):2225-32. · 2.20 Impact Factor