Bioindicators of Toxic Metals

Horse Whole Blood Trace Elements from Different Sicily Areas: Biomonitoring of Environmental Risk

Horses are excellent bioindicators for the assessment of environmental pollution. The aim of this study was to evaluate the levels and potential bioaccumulation of 28 mineral elements in 75 horse whole blood samples collected from five pollution-prone areas of Sicily, Italy. A direct mercury analyzer (DMA-80) was used for Hg determination, and an inductively coupled plasma mass spectrometer (ICP-MS) for all other elements. A one-way ANOVA test, followed by Bonferroni's multiple comparison for post hoc comparison, was applied to assess statistically significant differences between mineral elements and the five experimental groups. The levels of mineral elements in hay and concentrate were below the limits set by Regulation No. 744/2012. The mineral content of whole blood samples was slightly influenced by the region of origin of the horse. p values < 0.05 were statistically meaningful. However, the concentrations of mineral elements in horses' whole blood remained within reference ranges. In conclusion, the present study shows that the mineral content does not represent a toxicological risk for the analyzed horses. In addition, the study areas did not appear to show a high mineral element contamination.

Mercury in the feathers of Golden eagle (Aquila chrysaetos) from Western Carpathian, Slovakia

In this study, mercury (Hg) concentrations were detected in feathers of golden eagle (Aquila chrysaetos), a bird that typically inhabits alpine and forest areas. The mercury rates in feathers were compared in two groups of eagles: first, estimated home range (breeding, hunting, etc.) was located only in forest and lowland meadow habitats; second, the home range also included alpine habitats-rocks and meadows. Consequently, mercury concentration based on the feather typology were observed and the mercury levels in feathers were also compared among different Slovak Western Carpathian districts. It was found that there was no significant difference between groups classified by elevation level, which we attribute to the fact that eagle hunting territories are broad, so that alpine-dwelling and forest-dwelling eagles do not only reflect the pollution of the environments they typically inhabit. Non-significant differences were found also within different feather types, which means that the type of feather is not crucial for tracking mercury in eagle feathers. As the measurement of feather appears to be a simple and non-invasive method, the detection of non-significant differences in diverse types of golden eagle feathers provides useful knowledge for the future environment monitoring. The average mercury concentration measured in eagle samples was lower than the mercury concentration causing health complications among birds of prey. Our assumption that due to past mining activity in the Spiš region, the highest concentration in this region would be observed was confirmed.

Human Health Risk Assessment for Exposure to Heavy Metals via Dietary Intake of Rainbow Trout in the Influence Area of a Smelting Facility Located in Peru

Abandoned mining-metallurgical sites can significantly impact the environment and human health by accumulating heavy metals in aquatic ecosystems. The water in the sub-basin near an abandoned smelting facility in the city of La Oroya, Peru, is primarily used for pisciculture. The objective of this study was to assess the risk to human health from exposure to heavy metals via dietary intake of rainbow trout (Oncorhynchus mykiss) in the influence area of a smelting facility located in the central Andean region of Peru. The bioconcentration factor, biosediment accumulation factor, and consumption risks were evaluated using the Monte Carlo method. The results showed that the concentrations of elements (Zn > Pb > Cu > As) in rainbow trout muscle did not exceed the maximum limit (ML). However, the water significantly exceeded the ML for Pb in all sectors and As in the lower and middle parts of the river. The concentration of Pb in sediments also significantly exceeded the ML in the upper and lower parts of the river. Consequently, rainbow trout consumption in the study area presents risks to human health due to the bioaccumulation of heavy metals, with a 1.27% carcinogenic risk in samples from the lower part of the river.

A review on effective soil health bio-indicators for ecosystem restoration and sustainability

Preventing degradation, facilitating restoration, and maintaining soil health is fundamental for achieving ecosystem stability and resilience. A healthy soil ecosystem is supported by favorable components in the soil that promote biological productivity and provide ecosystem services. Bio-indicators of soil health are measurable properties that define the biotic components in soil and could potentially be used as a metric in determining soil functionality over a wide range of ecological conditions. However, it has been a challenge to determine effective bio-indicators of soil health due to its temporal and spatial resolutions at ecosystem levels. The objective of this review is to compile a set of effective bio-indicators for developing a better understanding of ecosystem restoration capabilities. It addresses a set of potential bio-indicators including microbial biomass, respiration, enzymatic activity, molecular gene markers, microbial metabolic substances, and microbial community analysis that have been responsive to a wide range of ecosystem functions in agricultural soils, mine deposited soil, heavy metal contaminated soil, desert soil, radioactive polluted soil, pesticide polluted soil, and wetland soils. The importance of ecosystem restoration in the United Nations Sustainable Development Goals was also discussed. This review identifies key management strategies that can help in ecosystem restoration and maintain ecosystem stability.

Total Mercury and Fatty Acids in Selected Fish Species on the Polish Market: A Risk to Human Health

The muscles of lake trout (Salvelinus namaycush Walbaum, 1792), crucian carp (Carassius carassius Linnaeus, 1758), flounder (Platichthys flesus Linnaeus, 1758), gilthead seabream (Sparus aurata Linnaeus, 1758), mackerel (Scomber scombrus Linnaeus, 1758) and tench (Tinca tinca Linnaeus, 1758) were examined. The total mercury (THg) was processed using the Milestone DMA-80 and the fatty acids were analyzed using the 7890A Agilent Technologies chromatograph. The THg content in analyzed fish ranged from 0.024 (lake trout) to 0.092 mg/kg wet weight (gilthead seabream). The muscles of fish examined had lower amounts of SFAs, and n-3 and n-6 PUFAs than MUFAs. The ratio of n-3/n-6 was higher in muscles of mackerel than other fish (p < 0.05). Due to the fact that both the THQ and HI are below 1, the tested fish are safe for the consumer from a nutritional point of view. Similarly, fatty acid indices indicate the safe consumption of selected fish species, and the daily consumption of the recommended dose of EPA + DHA (250 mg/day) and the concentration of mercury in fish calculations showed a hazard quotient for the benefit−risk ratio HQEFA below 1, suggesting that the intake of EPA + DHA poses no evident risk to human health. The ratio was calculated for a person weighing 60 kg. Therefore, it is important to monitor the fish, not only bought in the store, but also caught in various aquatic environments.

Mercury-Induced Oxidative Stress Response in Benthic Foraminifera: An In Vivo Experiment on Amphistegina lessonii

The evaluation of the effects of pollution (e.g., Hg pollution) is a difficult task and relies mostly on biomonitoring based on bioindicators. The application of biomarkers may represent a complementary or alternative approach in environmental biomonitoring. Mercury is known to pose a significant health hazard due to its ability to cross cellular membranes, bioaccumulate, and biomagnify. In the present research, the effects of short-term (i.e., 24 h) Hg exposure in the symbiont-bearing benthic foraminiferal species Amphistegina lessonii are evaluated using several biomarkers (i.e., proteins and enzymes). Mercury leads to significant changes in the biochemistry of cells. Its effects are mainly associated with oxidative stress (i.e., production of reactive oxygen species: ROS), depletion of glutathione (GSH), and alteration of protein synthesis. Specifically, our findings reveal that exposure to Hg leads to the consumption of GSH by GPx and GST for the scavenging of ROS and the activation of antioxidant-related enzymes, including SOD and GSH-enzymes (GST, GSR, GPx, and Se-GPx), that are directly related to a defense mechanism against ROS. The Hg exposure also activates the MAPK (e.g., p-p38) and HSP (e.g., HSP 70) pathways. The observed biochemical alterations associated with Hg exposure may represent effective and reliable proxies (i.e., biomarkers) for the evaluation of stress in A. lessonii and lead to a possible application for the detection of early warning signs of environmental stress in biomonitoring.

Differential Zn and Mn sensitivity of microalgae species from genera Bracteacoccus and Lobosphaera

One of the most common pollutants in natural ecosystems is heavy metals. Algae are sensitive to the action of heavy metals. This allows to use algae to assess the toxicity of heavy metals, bioindication, and during phycoremediation. This study examines the effect of different Zn and Mn concentrations (1.0, 5.0, 25.0, 50.0, 500.0, 1000.0 mg L^-1) on green algae Bracteacoccus minor and Lobosphaera incisa in a chronic bioassay. The results of this study showed that the toxic effect of Zn and Mn on B. minor and L. incisa begins to manifest itself at the lowest of the studied metal concentrations-1 mg L^-1. The critical concentration of Zn, which leads to the complete death of B. minor and L. incisa, is 50.0 and 500.0 mg L^-1, and Mn is 1000.0 mg L^-1 and 500.0 mg L^-1, respectively. It was found that principal component (PC) 1 accounts for 60.47% of the total variance and reflects changes associated with low concentrations of heavy metals (up to 5.0 mg L^-1). PC2 accounts for 27.95% of the total variance. PC2 is mostly associated with high concentrations of ions of heavy metals. Thus, the effect of Zn and Mn concentrations up to 5 mg L^-1and above 50 mg L^-1on B. minor and L. incisa has a different character. At the same time, the response of the studied algae species to the action of Zn and Mn has individual differences. In general, B. minor is more resistant to Mn, while L. incisa is more resistant to Zn.

Effectiveness of naturally occurring Aphis gossypii on tomato plants as a bio-indicator for heavy metals in Riyadh and Hafar Al-Batin, Saudi Arabia

Although certain pollutants can be biologically degraded by microorganisms, rendering their impact short-term, others can not be impaired, such that their effect persists. The present study evaluates the effectiveness of using a field-collected aphid, Aphis gossypii, as a bio-indicator for heavy metals in tomato farms in Riyadh and Hafar Al-Batin, Saudi Arabia. Heavy metals were selected (Cd, Cu, Zn, and Pb) and measured for comparative screening in field-collected plants, soil, and aphids using inductively coupled plasma-mass spectrometry (ICP-MS). Field-collected aphids from both studied regions were identified as Aphis gossypii. In Riyadh, there was no significant difference observed for Cd, Cu, and Zn for all experimental samples, while, Pb was showed differences among samples especially tomato leaves None of the studied samples in Hafar Al-Batin were showed statistically significant differences in Cd, in reverse to significant differences in the other heavy metals. Comparing concentrations of selected heavy metals between the two studied regions was showed that neither region showed a significant difference in heavy metals except for Cu. This study demonstrates that tomato leaf samples showed the highest concentrations of most studied heavy metals, followed by soil, then aphids. Aphids were utilized as a bio-indicator of heavy metals in the studied regions.

A bibliometric analysis: what do we know about metals(loids) accumulation in wild birds?

Metals and metalloids pollution is an important worldwide problem due to the social and ecological effects and therefore has been the subject of many disciplines and the adverse impacts have been documented. In this study, content analysis and trends of studies focused on heavy metal accumulation in birds were presented. For this purpose, a bibliometric network analysis of the studies that use the concepts of "pollution," "heavy metal," and "birds" together in the abstract, keywords, and titles of the papers was carried out. The purpose of choosing this research method was summarizing the relation between birds and environmental pollution in an understandable manner to determine metals(loids) pollution, which become an important environmental problem. Bibliometric data consisting of approximately 971 papers were evaluated with VOSviewer program using the network analysis method to answer the research questions. The results revealed that birds act as bioindicators in the determination of environmental pollution and that the contaminant metals deposited in the various tissues of birds provide preliminary information about environmental pollution. The most of bird studies emphasized that the metal accumulation was mostly in the liver, kidneys, and feathers and the accumulation caused serious problems in most of the vital activities of the birds. The USA is in the leading country in birds-heavy metal studies followed by Spain, Canada, and China. In addition, the mercury (Hg) was the most extensively studied heavy metal in these studies.

Sources and Metal Pollution of Sediments from a Coastal Area of the Central Western Adriatic Sea (Southern Marche Region, Italy)

Sediments represent a critical compartment of marine coastal ecosystems due to the toxic and long-lasting effects of the contaminants buried therein. Here, we investigated the properties of surficial sediments in front of the Southern Marche Region coast (Central Adriatic Sea, Italy). The grain size of the surficial sediments was determined by X-ray sedigraphy. TN and OC contents were determined by elemental analysis. The concentrations of Al, Fe, Mg, K, S, Ca, Ti, P, Na, Mn, Mg, Li, As, Ba, Ga, Pb, Sr, and Zn were determined by ICP-OES to evaluate their spatial patterns and temporal trends. A Q-mode Factor Analyses was applied and resulted in the identification of three compositional facies (Padanic, Coastal, and Residual) characterized by common biogeochemical, mineralogical, sedimentological properties, transport pathway, and source. Some pollution indicators, such as the enrichment factor, the geoaccumulation index, and the pollution load index were calculated to assess the deviation from the natural background levels. The results showed a pollution by As and Ba due to the human activities in the 20th century. Furthermore, a general decreasing of Al, Ti, P, Co, Cr, Cu, Ga, Ni, Pb, Sc, V, and Y concentrations from the background levels suggested a change in the sedimentation processes during the last decades.

Genotoxicity evaluation using micronucleus test in Rattus norvegicus captured in urban ecosystems of Buenos Aires, Argentina

The overall goal of the present study was to evaluate and compare the existence of genotoxic damage in Rattus norvegicus captured in sites with different levels of chemical mixtures along the Matanza-Riachuelo river basin (MRRB). For this, thirty-six wild rats (R. norvegicus) were captured from six different sites in the MRRB. Capture sites were characterized with concentrations of 20 parameters in surface water, including concentrations of metals and its soluble state and physicochemical parameters. To evaluate genotoxic damage in the rats, the bone marrow micronucleus test was performed. For this, the frequency of micronucleated polychromatic erythrocytes (MNPCE) was calculated based on the observation of 2000 polychromatic erythrocytes (PCE) per animal. Also, to detect possible cytotoxic effects, the PCE/TE (total erythrocytes) ratio in 1000 erythrocytes/animal was calculated. The frequency of MNPCE was positively associated with the highest concentration of chrome, lead, copper, biological oxygen demand, and chemical oxygen demand. Also, the decrease on PCE/TE ratio in bone marrow was related with increase of practically all metals and physicochemical parameters in surface water. The results of this study reveal that rats that live in the MRRB were exposed to concentrations of pollutants that can cause genotoxic damage, even though the concentrations of these pollutants are mostly below the safety standards. Therefore, this work highlights the importance of using methods that allow to integrate all environmental parameters in risk assessment, such as sentinel species.

Are soft tissues of urban rats good indicators of exposure to heavy metal pollution? A study conducted in one of the most polluted basins of Buenos Aires, Argentina

The overall goal of this work was to analyze the relationship between the concentration of lead in the kidney, liver, and stomach contents of rats captured in a polluted urban basin and the concentration of this metal in the environment, meteorological factors, and different intrinsic characteristics of the individuals. To this end, we determined the concentration of lead in the kidney, liver, and stomach contents of 133 Norway rats (Rattus norvegicus) captured in the Matanza-Riachuelo River Basin (Buenos Aires, Argentina). This basin is one of the most severe cases of water pollution in Latin America and metals like lead represent the most common chemical pollutants. Rats were trapped in nine sites with different soil and water lead concentrations, between 2014 and 2015. A positive relationship was found between lead concentration in the liver and kidney of R. norvegicus and the environmental concentration of this metal in water and soil. Although the remaining variables analyzed were also related to the lead concentration in soft tissues, they did not affect the association between the lead concentration in soft tissues and that in the environment. The lead concentration in the stomach contents was not related to any of the variables analyzed. Our results constitute the first study in an urban basin with a gradient of environmental lead concentration and suggest that the quantification of lead in the kidney and liver of rats can be used as an indicator of exposure to this metal within a large city.

The impacts of seawater physicochemical parameters and sediment metal contents on trace metal concentrations in mussels-a chemometric approach

The concentrations of Al, Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Ni, Pb, Sr, Zn, and Hg were studied in Mytilus galloprovincialis collected from the coastal area of Montenegro. The impact of seawater temperature, salinity, dissolved oxygen, total organic carbon (TOC), and metal content in sediment samples on the metal contents in mussels collected from three locations in four different seasons was analyzed by a Pearson correlation coefficient (r), principal component analysis (PCA), and cluster analysis (CA). These analyses were used to discriminate groups of samples, elements, and seawater parameters, according to similarity of samples chemical composition in different seasons, as well as the impact of seawater parameters and surface sediment composition on the mussels' element concentrations. Synergistic interactions occurred between seawater TOC, Fe, and Al concentrations in mussels. Compared with other studies, which are usually performed under constant laboratory conditions where mussels undergo only one stress at a time, this study was performed in nature. The analyses showed the importance of considering simultaneously acting environmental parameters that make determining of separate impacts of each factor selected very difficult and complex.

Analysis of lead pollution levels within an urban ecosystem using the cestode Hymenolepis diminuta and its rat hosts as bioindicators

The overall goal of this study was to use the Rattus spp./Hymenolepis diminuta model to assess environmental lead pollution in different landscape units of an urban ecosystem. Rats of the genus Rattus were collected from three shanty towns and three residential neighbourhoods of the city of Buenos Aires. Concentrations of lead in the livers of wild rats and in their parasite H. diminuta were measured using inductively coupled plasma mass spectrometry (ICP-MS). The landscape unit and tissue type had a significant effect on lead concentration, being higher in residential neighbourhoods as well as in H. diminuta tissue. Nevertheless, no significant differences were found for the mean lead concentration in livers between uninfected and infected rats. Since the available information describing heavy-metal pollution within the city of Buenos Aires is scarce, the results of this study allow us to update data about the extent of biologically available lead contamination. Considering that rats and H. diminuta are distributed worldwide, this monitoring system for lead pollution might be applied successfully in other urban ecosystems.