Kidney, liver and bone cadmium content in the western sandpiper in relation to migration

A remote-controlled portable workstation for highly sensitive and real-time chemiluminescent detection of cadmium

The prevention of pollution requires real-time monitoring of cadmium (Cd2+) concentration in the food, as it has a dramatic impact on poultry and can pose a threat to human health. Here, we fabricate a portable workstation integrating a microfluidic chip that facilitates real-time monitoring of Cd2+ levels in real samples by utilizing the Luminol-KMnO4 chemiluminescence (CL) system. Interestingly, Cd2+ can significantly enhance the CL signal, resulting in sensitive detection of Cd2+ in the range of 0-0.18 mg/L with the limit of detection (LOD) of 0.207 μg/L. Furthermore, a remote-controlled unit is integrated into the portable workstation to form a remote-controlled portable workstation (RCPW) performing automated point-of-care testing (POCT) of Cd2+. The as-prepared strategy allows remote control of RCPW to avoid long-distance transportation of samples to achieve real-time target monitoring. Consequently, this system furnishes RCPW for monitoring Cd2+ levels in real samples, thereby holding potential for applications in preventing food pollution.

Potentially toxic elements in different tissues of great cormorant (Phalacrocorax carbo) at a wetland area

Concentrations of 4 potentially toxic elements (As, Cd, Hg, Pb) were investigated in the feather, liver, kidney, and bone of great cormorants (Phalacrocorax carbo). The tissue samples were taken at the Central Tisza - Jászság Nature Conservation Area in Hungary. They were analysed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The goal of the investigation was to analyse the metal burden of the above-mentioned elements in the various tissues of these wild birds and to provide important information for monitoring the environmental pollution.Amongst the examined potentially toxic elements no statistical gender difference was observed, so the data were not separated based on them during the statistical analysis. The concentration of mercury was the highest in the feather, followed by the liver, kidney, and bone. The lead was detected in the feather with the highest level followed by the kidney, liver, and bone. The cadmium was determined in all investigated tissues with the next descending order: kidney > bone > liver > feather. Highest arsenic concentration was measured in the feather, followed by liver, kidney, and bone with the same concentration.The detected concentrations of the investigated potentially toxic elements in different tissues of great cormorants (feathers, liver, kidney, bone) means that the living area of this birds is not highly contaminated to induce health problems or toxic signs, or even other undesirable effect in the animals.

Transition metals in angiogenesis - A narrative review

The aim of this paper is to offer a narrative review of the literature regarding the influence of transition metals on angiogenesis, excluding lanthanides and actinides. To our knowledge there are not any reviews up to date offering such a summary, which inclined us to write this paper. Angiogenesis describes the process of blood vessel formation, which is an essential requirement for human growth and development. When the complex interplay between pro- and antiangiogenic mediators falls out of balance, angiogenesis can quickly become harmful. As it is so fundamental, both its inhibition and enhancement take part in various diseases, making it a target for therapeutic treatments. Current methods come with limitations, therefore, novel agents are constantly being researched, with metal agents offering promising results. Various transition metals have already been investigated in-depth, with studies indicating both pro- and antiangiogenic properties, respectively. The transition metals are being applied in various formulations, such as nanoparticles, complexes, or scaffold materials. Albeit the increasing attention this field is receiving, there remain many unanswered questions, mostly regarding the molecular mechanisms behind the observed effects. Notably, approximately half of all the transition metals have not yet been investigated regarding potential angiogenic effects. Considering the promising results which have already been established, it should be of great interest to begin investigating the remaining elements whilst also further analyzing the established effects.

Activation of Atg5-dependent placental lipophagy ameliorates cadmium-induced fetal growth restriction

Cadmium (Cd), an environmental contaminant, can result in placental non-selective autophagy activation and fetal growth restriction (FGR). However, the role of placental lipophagy, a selective autophagy, in Cd-induced FGR is unclear. This work uses case-control study, animal experiments and cultures of primary human placental trophoblast cells to explore the role of placental lipophagy in Cd-induced FGR. We found association of placental lipophagy and all-cause FGR. Meanwhile, pregnancy Cd exposure induced FGR and placental lipophgay. Inhibition of placental lipophagy by pharmacological and genetic means (Atg5^-/- mice) exacerbated Cd-caused FGR. Inversely, activating of placental lipophagy relieved Cd-stimulated FGR. Subsequently, we found that activation of Atg5-dependent lipophagy degrades lipid droplets to produce free cholesterol, and promotes placental progesterone (P4) synthesis. Gestational P4 supplementation significantly reversed Cd-induced FGR. Altogether, activation of Atg5-dependent placental lipophagy ameliorates Cd-induced FGR.

Review of contaminant levels and effects in shorebirds: Knowledge gaps and conservation priorities

Environmental pollution has emerged as a major threat to bird populations. Many shorebird populations are declining, although contamination has been documented in some shorebirds, evidence of negative impacts is sparse and this important topic remains understudied. To guide future research and develop effective conservation strategies, we carried out a comprehensive review of environmental pollutants and their consequences on shorebirds. In total, we found 93 relevant articles which examined pollutant contamination in ~37% (79 of 215) of all shorebird species, mostly from the Charadriidae and Scolopacidae families. Studies were geographically biased: the majority were conducted in American flyways, while only 1 was found from Australasia and few were conducted in Asian flyways. The main geographic gap for research includes East Africa, South Asia and Siberian Arctic. The most well-documented pollutants included mercury (Hg, 37 studies), cadmium (33), and lead (Pb, 28); less well studied pollutants were barium (1), calcium (1), strontium (1), dicofols (1), and other newly emerging contaminants, such as plastic debris/microplastics (4) and antibiotics resistance (2). Several pollutants have caused considerable concerns in shorebirds, including embryotoxicity caused by PCBs at non-optimum temperature (laboratory experiments); reduced reproduction performance linked to maternal Hg and paternal Pb (field evidence); and reduced refueling and flight performance related to oil contamination (both field and laboratory evidence). Our results confirm that an in-depth understanding of the local, regional and global factors that influence population trends of shorebirds in light of increasing pollution threats is essential for accurate and effective management and conservation strategies.

Gestational cadmium exposure impairs placental angiogenesis via activating GC/GR signaling

Gestational exposure to environmental Cd caused placental angiogenesis impairment and fetal growth restriction (FGR). However, its mechanism remained unclear. This study was to investigate the effects of Cd exposure during pregnancy on placental angiogenesis and its mechanism. Pregnant mice were exposed to CdCl2 (4.5 mg/kg) on gestational day (GD) 8 with or without melatonin (MT) (5.0 mg/kg), an anti-endoplasmic reticulum stress agent, from GD7 to GD15. Human primary placental trophoblasts and JEG-3 cells were stimulated using CdCl2 (20 μM) after MT (1 mM) preprocessing. We firstly found MT treatment obviously mitigated environmental Cd-induced placental angiogenesis disorder and reduction of the VEGF-A level. Mechanistically, MT reversed environmental Cd-downregulated the protein expression of VEGF-A via inhibiting glucocorticoid receptor (GR) activation. Notably, our data showed MT treatment antagonized Cd-activated GC/GR signaling via blocking PERK signaling and thereby upregulated VEGF-A and 11β-HSD2 protein expression. Based upon the population case-control study, the levels of VEGF-A and 11β-HSD2 protein in small-for-gestational-age placentae were significantly reduced when compared to appropriate-for-gestational-age placentae. Overall, environmental Cd exposure during gestation impaired placental angiogenesis via PERK-regulated GC/GR signaling in placental trophoblasts. Our findings will provide a basis for prevention and treatment of placental impairments and fetal growth restriction caused by environment toxicants in future.

Colorimetric cadmium ion detection in aqueous solutions by newly synthesized Schiff bases

Two newly synthesized Schiff bases DMCA and DMBA were used for selective detection of Cd²⁺ over a wide range of other metal ions in acetonitrile (ACN)/ Tris-HCl buffer (10 mM, pH 7.32, v/v 2:1). The sensors can detect Cd²⁺ ions by colour changes from colourless to orange for DMBA and yellow to reddish for DMCA. Response of the probes towards metal ions was investigated by using UV-vis spectroscopy. The complex stoichiometry between the sensors, DMBA and DMCA, and Cd²⁺ was found to be 2:1 and the binding constants were calculated to be 2.65 ×10¹² M^-2 and 4.95 ×10¹² M^-2, respectively. The absorbance-based detection limits of DMBA and DMCA were calculated as 0.438 μM and 0.102 μM, respectively. The sensors were also successfully applied to real samples.

Green silver nanoparticles as a multifunctional sensor for toxic Cd(ii) ions

Silver nanoparticles (AgNPs) were synthesized using Allium sativum (AS) extract. The AgNP-AS was able to detect Cd(ii) ions with various techniques such as optical, fluorescence and electrochemical sensing. The limit of detection was found to be 0.277 μM. Silver nanoparticles were able to quantify Cd(ii) ions from environmental samples. The antibacterial activity of AgNP-AS was explored towards waterborne bacteria.

Bipyridine hydrogel for selective and visible detection and absorption of Cd(2+)

Herein, we report for the first time the use of bipyridine-based hydrogel for selective and visible detection and absorption of Cd(2+). At low concentrations, hydrogelator 1 was applied for selective detection of Cd(2+) in vitro and in living cells with high sensitivity. In the absence of metal ions, 1 is nonfluorescent at 470 nm. Upon addition of metal ions, 1 selectively coordinates to Cd(2+), causing an 86-fold increase of fluorescence intensity at 470 nm via the chelation enhanced fluorescence (CHEF) effect, as revealed by first-principles simulations. At 1.5 wt% and pH 5.5, 1 self-assembles into nanofibers to form hydrogel Gel I. Since Cd(2+) could actively participate in the hydrogelation and promote the self-assembly, we also successfully applied Gel I for visible detection and absorption of Cd(2+). With these excellent properties, Gel I is expected to be explored as one type of versatile biomaterial for not only environmental monitoring but also for pollution treatment in the near future.

Trace elements in Pacific Dunlin (Calidris alpina pacifica): patterns of accumulation and concentrations in kidneys and feathers

Trace element concentrations were measured in Pacific Dunlin (Calidris alpina pacifica) to identify factors that influence accumulation and to assess toxicity risks. We report concentrations of cadmium, copper, and zinc in kidneys as well as copper, lead, mercury, selenium and zinc in feathers. Relationships between element concentrations and Dunlin age, sex, bill length, habitat preference, trophic level, and sample group were investigated with regression analyses. Stable isotope ratios of carbon and nitrogen in Dunlin muscle tissue were used to determine habitat preference and trophic level, respectively. Cadmium concentrations in kidneys were significantly related to habitat preference: [Cd] in estuarine foragers >[Cd] in terrestrial foragers. Cadmium accumulation was age-dependent as concentrations increased significantly within 10 months of hatch dates but not afterward. Concentrations of cadmium and zinc in kidneys as well as lead and mercury in feathers were below those known to cause deleterious effects in birds. In contrast, selenium concentrations in feathers (range: 2.1-14.0 µg/g) were often at levels associated with toxicity risks (>5 µg/g). Toxicity thresholds are not available for copper in kidneys or copper and zinc in feathers; however, measured concentrations of these elements were within documented ranges for sandpipers. Future studies should assess potential impacts of selenium on embryonic development in Dunlin and other sandpipers. Risk assessments would yield more conclusive results for all elements if impacts under ecologically relevant stresses (e.g. development in the wild, migration, predation) were better understood.

Adsorptions of Cd(ii) and methylene blue from aqueous solution by silica hybrid hollow spheres

Silica hybrid hollow spheres prepared via one step method can be used as adsorbents for Cd(ii) and methylene blue.

Concentration and partitioning of metals in intertidal biofilms: implications for metal bioavailability to shorebirds

We compared zinc, copper and cadmium concentrations and the operationally defined geochemical partitioning of the three metals in sediments enriched with biofilm versus sediments without obvious biofilm present (reference) sampled from five locations within the Fraser River Delta, British Columbia, Canada. Two-way ANOVA's with site and biofilm (enriched or reference) as the two factors were applied to determine if metal concentrations or the partitioning of the metal was dependent on the two factors. Sediment enriched in biofilm contained greater amounts of aqua regia extracted zinc and copper and tended to have greater amounts of reducible cadmium as compared to reference sediments. By contrast, reference sediments had greater concentrations of easily reducible copper suggesting differences in speciation between the two sediment types. Greater concentrations of reducible cadmium within biofilm may provide a route of contaminant exposure to shorebirds whose diet is dependent on biofilm.

Twin applications of highly selective Cu2+ fluorescent chemosensor and cytotoxicity of 2-(2-phenylhydrazono)-1H-indene-1,3(2H)-dione and 2-(2-(4-methoxyphenyl)hydrazono)-1H-indene-1,3(2H)-dione: molecular docking and DFT studies

Turn on chemosensor for paramagnetic Cu²⁺ have been developed based on indene 1,3-dione. Their ability to inhibit KB cell, molecular docking and DFT studies also carried out.

The retention of cadmium and selenium influence in fowl and chickens of F1 generation

The retention of cadmium and selenium influence on Cd retention in the muscle, liver and kidneys of hens, chickens and in eggs was studied. Cadmium (Cd) as cadmium chloride (CdCl(2)) and selenium (Se) as sodium selenite (Na(2)SeO(3)) were added to feed at dosages: group 0-control, group 1-20 mg/kg Cd, group 2-30 mg/kg Cd + 4 mg/kg Se. The birds were exposed to Cd for 8 weeks. Cadmium level in hens and cocks was found highest in the kidneys, followed by the liver and muscle. Se supplementation resulted in Cd increase in the muscle tissue and in the reduction of Cd content in the liver and in significant decrease in the kidneys (p < 0.05). A higher Cd level in the yolk and lower in the white was noted in both experimental groups. Nonsignificant increase of Cd in eggs was noted in experimental groups with Se supplementation. Level of cadmium in organs of 7-day-old chicks hatched from Cd-treated hens in both experimental groups was low but the tendency to accumulate preferentially the Cd in the liver and kidneys was recorded. Supplementation of selenium in hens and cocks was not reflected in the decrease of Cd in these two organs of F(1) chickens but was reflected in increase in the muscle. In spite of relatively high Cd levels in the organs of layers no layer-egg-chickens transfer was observed. It was confirm that kidneys and liver are organs more attacked by dietary cadmium than muscle. Supplementation of low dose of Se resulted in decrease of cadmium deposition in analyzed organs.

Environmental contaminants in Canadian shorebirds

Canadian shorebirds are exposed to environmental contaminants throughout their annual cycle. Contaminant exposure among species varies with diet, foraging behaviour and migration patterns. We sampled twelve species of shorebirds from four locations across Canada to assess their exposure to PCBs, organochlorine pesticides, as well as four trace elements (Hg, Se, Cd, As). SigmaPCB and SigmaDDT followed by SigmaCHL were most frequently found above trace level in the shorebird carcasses. In general, the plover species (American golden, semipalmated, black-bellied) appear to be the most contaminated with organochlorines, whereas Hudsonian and marbled godwits appear to be the least contaminated. Among adult birds, the greater and lesser yellowlegs had the highest hepatic Hg concentrations (2.4-2.7 microg g(-1) dw), whereas American golden plovers as well as Hudsonian and marbled godwits contained relatively low levels of Hg (<1 microg g(-1) dw). Renal Se concentrations varied from 3.2 to 16.7 microg g(-1) dw and exhibited little interspecific or seasonal variation. Renal Cd levels in adult birds were highest in Hudsonian godwits from Quill Lakes (43 microg g(-1) dw) and Cape Churchill (12 microg g(-1) dw), and lowest (0.8-1.5 microg g(-1) dw) in greater and lesser yellowlegs from Cape Churchill and Bay of Fundy. Renal As concentrations varied from 0.06 microg g(-1) dw in golden plovers from Cape Churchill to 4.6 and 5.1 microg g(-1) dw in dunlin samples from the Pacific coast. There is no evidence that contaminants were adversely affecting the shorebirds sampled from the Canadian locations in this study.

Trace metal concentrations are higher in cartilage than in bones of scaup and pochard wintering in Poland

Bones and cartilage of two species of diving ducks: the scaup Aythya marila (n=24) and the pochard A. ferina (n=24) were studied. Scaup is protected in Poland where it spends only the winter, while pochard is a game bird, abundant and breeding in Poland. In winter, the two species form large flocks off the southern coast of the Baltic, particularly in the Szczecin Lagoon where they were collected for this study. The bones and cartilage (trachea) were assayed for concentrations (dry weight-based) of three essential metals: iron (Fe), copper (Cu), and zinc (Zn); concentrations of the two toxic metals: lead (Pb) and cadmium (Cd) were assayed as well. These hard tissues of the two species showed the following order of metal concentrations Zn>Fe>Pb>Cu>Cd. In scaup and pochard bones, the respective geometric mean concentrations of Zn, Fe, Pb, Cu, and Cd were 94.4 and 102.0; 20.2 and 24.7; 6.2 and 9.6; 0.19 and 0.26; 0.114 and 0.162 mg/kg. The levels of all the metals in cartilage (Zn 149.1 and 165.8; Fe 58.4 and 116.3; Pb 10.6 and 14.9; Cu 1.41 and 3.31; Cd 0.144 and 0.175 mg/kg, respectively) were higher than in the bones of A. marila and A. ferina. However, statistically significant differences were found in respect to the essential metals only (Zn, Fe, Cu). The inter-species comparisons showed the two species to differ in their cartilage concentrations of Fe, Cu, Zn, and Cd and in their bone concentrations of Pb and Cd. In each case, the pochard exhibited higher concentrations of metals. This study showed distinct differences between trace element accumulation by two heavily mineralised avian body parts: leg bones (tarsometatarsus) and cartilage (trachea). The results are in agreement with data reported by other workers who analysed trace metals in cartilaginous and bone components of the femoral head in homoiotherm vertebrates, including humans. Therefore it is important that intra- and inter-species comparisons of hard biological components be based on corresponding body parts, and that relevant biochemical and ecotoxicological research be pursued.

Heavy metal dispersion, persistance, and bioccumulation around an ancient copper mine situated in Anglesey, UK

The vicinity of an ancient abandoned copper mine located on the Isle of Anglesey was assessed for the dispersion of copper, zinc, lead, and cadmium into the surrounding environment. Extraction of soil, lichens, cattle feces, and Calluna vulgaris L. (ling) tissue, using aqua regia, was carried out and together with water samples, these were analyzed using flame atomic absorption spectroscopy. Atmospheric dispersion and dilution was plotted from the workings to the coast and the resultant dilution ascertained. Evidence of bioaccumulation by plants and animals is presented and partitioning within plants highlighted. The results suggest that atmospheric dispersion has ceased but residual metal concentrations in the soil remain persistent and could present health hazards to animals and humans in the past and in the future.

Evidence for sexual partitioning of foraging mode in Western Sandpipers (Calidris mauri) during migration

Migrating Western Sandpipers, Calidris mauri (Cabanis, 1857), observed feeding at an intertidal stopover site on the Fraser River delta, British Columbia, shifted their foraging mode from surface-pecking to probing over a 3-week period in April and May. We tested possible mechanisms to account for the field observations. Using control and shorebird exclusion plots over a 3-month period bracketing the migration, we determined that neither seasonal nor shorebird-induced changes in the relative availability of epifaunal compared with infaunal prey accounted for the decline in the prevalence of epifaunal feeding behaviour. However, strong peaks in both epi- and in-faunal prey densities coincided with the migration period, suggesting that migratory timing may be linked with the productivity schedule of major stopover sites. Males, which precede females in the migration and have relatively shorter bills, were observed to engage in epifaunal feeding more frequently than females. Thus, while foraging behaviour of the Western Sandpiper at a population level appears "plastic", the feeding repertoire of individuals is more specialized and results in sexual partitioning of prey resources. The implications of our findings for differential distribution patterns over the nonbreeding range and sex-related differences in contaminant profiles are discussed.