Beavers indicate metal pollution away from industrial centers in northeastern Poland

Comparison of trace elements in tissue of beaver (Castor canadensis) and local vegetation from a rural region of southern Ontario, Canada

Beavers have been analyzed in several studies examining trace elements (TEs) in wildlife; however, most of these studies were undertaken in areas with known environmental pollutants. To understand and quantify natural enrichments of TEs in beaver tissue, samples of kidney, liver, muscle from 28 animals were compared with bark from 40 species of trees and shrubs, from the same, uncontaminated watershed. Pearson correlation and factor analysis show that conservative, lithophile elements such as Al, Ga, Th, and Y, all surrogates for mineral dust particles, explain 61% of the variation in the bark data. In contrast, Cd, Co, Cu, Mn, Mo, Ni, Rb, Se, Sr, and Tl in bark are independent of Al, and therefore most likely occur in non-mineral forms. Comparing tissue concentrations of beaver and bark, the organs are enriched in micronutrients such as Cu, Fe, Mo, Se, and Zn, but also non-essential, benign elements such as Cs and Rb, and potentially toxic elements such as Cd and Tl. Thus, the elements most enriched in beaver organs are those that apparently occur in biological form in the plant tissue. The elements enriched in these animals, relative to bark, appear to offer the most promise for monitoring environmental contamination by TEs using beavers. The majority of TEs of environmental relevance are most abundant in beaver kidney. However, monitoring studies must consider the variation in TE concentrations in beaver tissue, including those due to sex and age. Also, due consideration must be given to background concentrations of TEs in the vegetation composing the diet of the animals. The natural enrichment in the case of elements such as Cd, in beaver tissue relative to bark, is profound. These data establish critical baseline values for TEs in beavers in an unpolluted environment, thereby allowing for their use as model organisms in tracking how heavy metal pollutants may affect wildlife.

Monitoring of metal content in the tissues of wild boar (Sus scrofa) and its food safety aspect

The study was performed on 10 female and 10 male wild boars (Sus scrofa) after shooting during the regular hunting season to investigate the concentration of metals in the muscle and fat tissue. The concentrations of essential and non-essential elements were determined (arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), mercury (Hg), and zinc (Zn)) using inductively coupled plasma optical emission spectrometry. The concentrations of As, Hg, and Cd were below the limit of detection (As, Hg: < 0.5 mg/kg, Cd: < 0.05 mg/kg) in every tissue sample of both sexes. The lead was detected as 0.36 ± 0.16 mg/kg and 0.22 ± 0.06 mg/kg in the muscle of females and males, respectively, showing a significant difference between the sexes (p = 0.0184). The measured concentration of Cr was 0.14 ± 0.08 mg/kg and 0.13 ± 0.06 mg/kg, and that of copper was 1.22 ± 0.14 mg/kg and 1.06 ± 0.16 mg/kg in the muscle of females and males, respectively. The same tendency was observed in the case of copper content of fat tissues (female: 0.13 ± 0.10 mg/kg; male: 0.13 ± 0.04 mg/kg; p = 0.2707). Manganese concentration of muscle was 0.45 ± 0.30 mg/kg (female) and 1.36 ± 0.96 mg/kg (male), and that of fat tissue was 0.32 ± 0.22 mg/kg (female) and 0.74 ± 0.75 mg/kg (male). The Zn was detected as 56.75 ± 7.86 mg/kg and 1.83 ± 0.76 mg/kg in the muscle and fat of females and 52.12 ± 11.51 mg/kg and 1.94 ± 0.57 mg/kg in males, respectively. Based on data, the consumption of fat and muscle tissues of the wild boars tested can be food toxicologically objectionable, mainly due to the lead content, and thus pose a risk to frequent consumers of this type of game meat.

Decomposing the asymmetric effects of terrorism and FDI on carbon emission: evidence from fragile economies

Terrorism is a universal phenomenon that creates economic, political, social, and environmental problems. The literature infers that little consideration is delivered to the nexus of terrorism and pollution emissions. To the best of the authors' knowledge, this study is a pioneer that investigates the linear/symmetric and non-linear/asymmetric impacts of foreign direct investment and terrorism on the CO₂ emissions for ten fragile economies. For the empirical task, the study collected data for time 1973 to 2019 and employed ARDL and NARDL approaches. The findings demonstrate an asymmetric association between foreign direct investment (FDI), terrorism, and CO₂ emissions. The findings infer that positive changes in FDI and terrorism have a significant positive impact on CO₂ emissions. However, the negative changes in FDI and terrorism significantly impact CO₂ emissions in most economies. Furthermore, the NARDL approach delivers more explanatory and powerful estimates for selected countries in contrast to the ARDL approach. On the basis of these findings, the study delivers some appropriate policies to combat terrorism.

The asymmetric associations between foreign direct investment inflows, terrorism, CO2 emissions, and economic growth: a tale of two shocks

Foreign direct investments can exert ambiguous effects on the environmental quality of the host economies. At the same time, terrorism is a worldwide phenomenon that affects human life, FDI inflows, economic growth, and, most importantly, environmental well-being. Hence, it can be expected that there are relationships between terrorism, foreign direct investment inflows, and carbon dioxide emissions. However, in the previous literature, less attention has been given to explore these nexuses. In addition, the possible non-linearities in data are also mostly ignored in the preceding related studies. Against this backdrop, this paper explores the linear and non-linear influences of terrorism and foreign direct investment inflows on carbon dioxide emissions, controlling for energy consumption and economic growth within the model, on carbon dioxide emissions in the context of ten global economies that are most impacted by terrorism. To this end, we used the data from 1973 to 2016 and deployed the linear and non-linear autoregressive distributed lag methods to scrutinize the environmental impacts of the explanatory variables of concern. The results confirmed the presence of non-linearities in the relationships between terrorism, inflows of foreign direct investments, and carbon dioxide emissions. Furthermore, the findings revealed that the positive shocks to terrorism and foreign direct investment inflows significantly deteriorate the environment with a dominating effect. Unlike the previous studies, this current study validates the pollution haven hypothesis for the sample economies. Energy consumption and economic growth  were also evidenced to exacerbate the carbon dioxide emission levels in all selected countries. Based on these results, we recommend that our sample economies should focus on promoting education, employment, economic stability, and public awareness to eradicate terrorism which, in turn, can mitigate the emissions of carbon dioxide further. In addition, stringent environmental regulations on foreign direct investment inflows are required to reduce the adverse environmental effects of such sources of foreign finance. Furthermore, the international firms should be encouraged to invest in cleaner technologies by offering them tax benefits and other financial incentives.

Temporal trends (1953-2012) of toxic and essential elements in red deer antlers from northeastern Poland

Red deer antlers have a number of advantages that make them a unique material for monitoring trace elements. As antlers are shed and regrown every year, results of toxicological investigations can be applied to a particular region and time. We analyzed the content of four toxic (Pb, Cd, Hg, As) and three essential (Cu, Zn, Fe) trace elements in 254 red deer antler samples spanning between 1953 and 2012. Age of stags did not influence concentrations of analyzed elements in antlers, except for Zn whose level increased with age. The highest concentrations of toxic elements occurred at the beginning of the analyzed period. Levels of Pb, Hg and Zn in antlers decreased over the course of the study. Levels of Cd and As were low and presented a steady trend. Variations in the levels of the analyzed elements in red deer antlers are considered to reflect levels of exposure of animals in their habitat over the sixty-year study period. The range of essential element levels did not indicate any contamination. Environmental conditions in the Mazury Region during the last decades appeared to have improved significantly, as established by declining trends of toxic elements levels in deer antlers.

Sentinel species for biomonitoring and biosurveillance of environmental heavy metals in Nigeria

Nigeria receives copious annual precipitation to nourish its forests and agriculture, it has an extensive river drainage system, and it possesses valuable mineral deposits that stimulate both commercial and artisan mining activities. The combination of these features complicates Nigeria's efforts to produce adequate amounts of healthy foods to support its population. Toxic heavy metals like lead, cadmium, and mercury, and toxic metalloids such as arsenic, are also present in its mineral deposits and they migrate gradually into the soil and water of Nigeria by natural means. However, mining activities can liberate higher levels of toxic metals, which adversely affect Nigerian ecosystems and its food chains. Thus, environmental pollution due to anthropogenic activities is a major public health concern in Nigeria. This review covers the importance of native Nigerian and African wild and cultivated plants along with livestock and wild animals as sentinel species to evaluate heavy metals as environmental stressors and the use of sentinel species for food safety monitoring and for predicting potential risks to human health.

A geochemical perspective on the natural abundance of trace elements in beaver (Castor canadensis) from a rural region of southern Ontario, Canada

Chalcophile (Ag, Cd, Co, Cu, Mo, Ni, Pb, Se, Tl, Zn) and lithophile (Al, Ba, Ce, Cr, Cs, Fe, La, Li, Mn, Nd, Rb, Sr, V, Y) trace elements (TEs) were determined in kidney, liver and muscle of beaver (Castor canadensis) from a rural watershed in southern Ontario, Canada. To estimate the relative bioavailability of TEs in the landscape, they were also determined in the dissolved (<0.45 μm) fraction of water from the river where the animals were harvested. Concentration ratios (tissue/water) always showed the greatest enrichments for Cd (kidney, 1.1 × 10⁷; liver, 2.4 × 10⁶; muscle, 7.2 × 10⁵), most likely due to the metal binding properties of metallothioneins. Despite its potential toxicity, Tl also showed considerable enrichment: kidney, 4.2 × 10⁴; liver 1.2 × 10⁴; muscle 1.5 × 10⁴. Enrichments of Cs and Rb exceeded those of Tl in all three tissues, suggesting that the chemical similarity of their ionic species (Cs⁺, Rb⁺, Tl⁺) to K⁺ may be the key to their uptake. Lithophile elements of limited solubility in natural waters (Al, Ce, La, Nd) show moderate enrichments, despite the lack of physiological role. The smallest enrichments were found for Sr and Ba, the two TEs which are most abundant in the river. Of the TEs considered essential for animal nutrition, V was the least enriched in tissue relative to water (liver 19×, kidney, 33× and muscle 28×). Despite the lack of physiological function and absence of any known sources of contamination, Al, Ag, Cd, Ce, Cs, La, Pb, Rb, and Tl, are all enriched in beaver tissue, relative to water, by at least three orders of magnitude, due to natural processes. The widespread abundance of beaver in Canada combined with the growing need to manage their numbers in populated regions offer a unique opportunity for monitoring environmental quality in the riparian zone.

Fatty acid composition, cholesterol content and lipid oxidation indices of intramuscular fat from skeletal muscles of beaver (Castor fiber L.)

The lipid characteristics of the intramuscular fat (IMF) from skeletal muscles of different beaver carcass parts (the loin, hind leg and shoulder) were characterised in detail for the first time. The shoulder muscles had higher (P < 0.05) proportion of n-3 polyunsaturated fatty acids (PUFA) than the loin muscles, which had higher percentages of saturated fatty acids (SFA), odd-chain fatty acids (OCFA) and sum of conjugated linoleic acids (ΣCLA). Moreover, the shoulder muscles were found to contain higher fat, cholesterol and total fatty acids (FA) concentrations, as well had a beneficial fatty acid profile, especially in terms of the absolute content of PUFA and some nutritional FA indices (thrombogenic index and SFA/PUFA), as well as FA ratios (n-6/n-3 and PUFA/SFA). No differences (P > 0.05) in lipid oxidation parameters (FFA, PV and TBARS) were observed between muscles from different carcass parts. Irrespective of muscle location, the predominant class of FA in IMF of beaver was PUFA (averaging 49.39%), followed by SFA (27.81%) and MUFA cis (15.96%). Linoleic acid (LA, 18:2 n-6) was the most abundant FA in all muscles (>34% of total FA). Minor percentages of unusual FA (OCFA, trans FA and branched-chain FA), which are more typical for ruminants than monogastric animals, were also detected (3.46%, 1.92% and 1.22%, respectively).

Can red deer antlers be used as an indicator of environmental and edible tissues' trace element contamination?

Venison is an attractive product for consumers concerned with healthy lifestyle; however, it can contain high levels of toxic elements, and therefore, it is a possible source of hazardous contaminants in human diet. Antlers are suitable bioindicators of environmental metal contamination, and herein, we assessed the ability of trace element levels in antlers to indicate levels in edible soft tissues. We determined the concentrations of lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As), copper (Cu), zinc (Zn), and iron (Fe) in the liver, kidney, muscle, and antlers of 14 free-ranging red deer (Cervus elaphus) from northeastern Poland using atomic absorption spectrometry. We found the highest concentrations of Pb (0.321 ± 0.165 mg/kg), As (0.045 ± 0.074 mg/kg), Zn (105.31 ± 16.33 mg/kg), and Fe (220.92 ± 117.18 mg/kg) in antlers; of Cd (4.974 ± 1.90 mg/kg) and Hg (0.048 ± 0.102 mg/kg) in kidney; and of Cu (7.29 ± 7.02 mg/kg) in the liver. A positive relationship between concentrations in antlers and muscle was found only for Cu (p = 0.001), and it therefore appears that red deer antlers cannot be used as an index for element concentrations in soft tissues. While our results confirm that the Mazury region is little polluted, consumption of red deer offal from this area should be limited according to extant legal limits set for livestock consumption.

Asymmetrical positive assortative mating induced by developmental lead (Pb2+) exposure in a model system, Drosophila melanogaster

Anthropogenic pollutants have the potential to disrupt reproductive strategies. Little is known about how lead (Pb²⁺) exposure disrupts individual-level responses in reproductive behaviors, which are important for fitness. Drosophila melanogaster was used as a model system to determine the effects of: 1) developmental lead exposure on pre-mating reproductive behaviors (i.e., mate preference), and 2) lead exposure and mating preferences on fitness in the F₀ parental generation and F₁ un-exposed offspring. Wild-type strains of D. melanogaster were reared from egg stage to adulthood in control or leaded medium (250 μM PbAc) and tested for differences in: mate preference, male song performance, sex pheromone expression, fecundity, mortality, and body weight. F₀ leaded females preferentially mated with leaded males (i.e., asymmetrical positive assortative mating) in 2-choice tests. This positive assortative mating was mediated by the females (and not the males) and was dependent upon context and developmental exposure to Pb. Neither the courtship song nor the sex pheromone profile expressed by control and leaded males mediated the positive assortative mating in leaded females. Leaded females did not incur a fitness cost in terms of reduced fecundity, increased mortality, or decreased body weight by mating with leaded males. These results suggest that sublethal exposure to lead during development can alter mate preferences in adults, but not fitness measures once lead exposure has been removed. We suggest that changes in mate preference may induce fitness costs, as well as long-term population and multi-generational implications, if pollution is persistent in the environment.

Variations of selected trace element contents in two layers of red deer antlers

Introduction: Hard antlers of deer are unique bioindicators of environmental metal pollutions, but sampling methods presented in the literature are inconsistent. Due to the specific growth pattern of antlers and their histological structure, sampling methods described in the literature were reviewed, the suitability of using mixed samples of both antler layers as element bioindicators was assessed, and the codified method of antler sampling used for bioindication was described. Material and Methods: Lead, cadmium, mercury, arsenic, copper, zinc, and iron in trabecular and cortical parts of hard antlers of red deer (Cervus elaphus) were determined using different methods of atomic absorption spectrometry (depending on the element). Results: Mean mercury content in trabecular bone (0.010 ±0.018 mg/kg) was 5 times higher than in cortical bone (0.002 ±0.003 mg/kg). Mean iron concentration was approximately 15 times higher in trabecular (239.83 ±130.15 mg/kg) than in cortical bone (16.17 ±16.44 mg/kg). Concentrations of other analysed elements did not differ statistically between antler layers. Conclusion: In mixed antler samples, concentrations of mercury and iron depend on the particular antler layer contents. This therefore warrants caution when comparing results across studies and specification of the sampling methodology of antlers is highly recommended.