Evaluation of succulent plants Echeveria elegans as a biomonitor of heavy metals and radionuclides.

This work evaluates the use of Echeveria elegans as a biomonitor of metals and radionuclides, using semi-urban soils as a study area. The study area is exposed to various trace elements of concern for various social groups in nearby localities. The quantification of metals and radionuclides was performed by X-ray fluorescence spectrometry and gamma spectrometry, respectively. Cumulative frequency distribution curves, descriptive statistics, and multivariate analysis were used to estimate the local geochemical baseline and identify geochemical and anthropogenic patterns of metals and radionuclides from topsoil and E. elegans. The evaluation of contaminants and the contribution of possible exposure routes (topsoil and atmospheric deposition) was performed with the enrichment factor (EF) and the relative concentration factor (CFR). The results suggest that the plant does not present significant physical stress due to the environmental conditions to which it was exposed. Likewise, it can bioaccumulate heavy metals from natural and anthropogenic sources. The quantification of radionuclides in the plant is below the detection limits, indicating a low bioavailability and transfer factor. The CFR and EF results showed that the plant accumulates metals from the topsoil and atmospheric deposition. The bioaccumulation mechanism would be related to the functioning of Crassulaceae Acid Metabolism (CAM). In topsoil, the organic acids of the plant would modify the solubility of the metals present in an insoluble form in the soil, acting as ligands and, subsequently, following the transport route of these metabolites. In atmospheric deposition, the metals deposited in the leaves would be incorporated into the plant through the opening of the stomata because of the capture of CO2 (at night, day, or during environmental stress) by the CAM. Overall, the evidence showed that the succulent can be used as a biomonitor of heavy metals. However, additional studies are required to determine its usefulness as a radionuclide biomonitor.

Levels and sources of polycyclic aromatic hydrocarbons (PAHs) near hospitals and schools using leaves and barks of Sambucus nigra and Acacia melanoxylon.

Polycyclic aromatic hydrocarbons (PAHs) are among the most studied organic compounds in urban environments, due to their known threat to human health. This study extends the current knowledge regarding the ability of different vegetative parts of different tree species to accumulate PAHs. Moreover, exposure intensity to PAHs in areas frequented by population susceptible to adverse health effects of air pollution is evaluated. For this, leaves and barks of Sambucus nigra (S. nigra) and Acacia melanoxylon (A. melanoxylon) were collected at urban areas in the Andean city of Quito, at seven points near hospitals and schools. A methodology, previously developed, for the extraction, purification, and quantification of PAHs associated with the leaves and bark of S. nigra was employed and also validated for leaves and bark of A. melanoxylon. The total PAH level varied from 119.65 ng g-1 DW (dry weight) to 1969.98 ng g-1 DW (dry weight) with naphthalene (Naph), fluoranthene (Flt), pyrene (Pyr), chrysene (Chry), and benzo[a]pyrene (BaP) predominating in all samples. The results indicate that the leaves and bark of tree species studied have certain abilities to bio-accumulate PAH according to their molecular weight. The leaves of S. nigra and bark of A. melanoxylon showed the highest ability to accumulate PAHs, mainly those with high and medium molecular weight, respectively. The highest incidence of light molecular weight PAHs was found in the leaves of A. melanoxylon. Furthermore, coal combustion, biomass burning, and vehicle emissions were identified as the main PAHs sources. Concentrations of PAHs associated with tree species suggest an affectation in areas frequented by populations susceptible to air pollution. This fact shows the importance of regulatory scheme to significantly improve the air quality in the city integrating a knowledge-based decision-making.

Lichen biomonitoring to assess spatial variability, potential sources and human health risks of polycyclic aromatic hydrocarbons (PAHs) and airborne metal concentrations in Manchester (UK).

Airborne metals and organic pollutants are linked to severe human health impacts, i.e. affecting the nervous system and being associated with cancer. Airborne metals and polycyclic aromatic hydrocarbons (PAHs) in urban environments are derived from diverse sources, including combustion and industrial and vehicular emissions, posing a threat to air quality and subsequently human health. A lichen biomonitoring approach was used to assess spatial variability of airborne metals and PAHs, identify potential pollution sources and assess human health risks across the City of Manchester (UK). Metal concentrations recorded in lichen samples were highest within the city centre area and along the major road network, and lichen PAH profiles were dominated by 4-ring PAHs (189.82 ng g-1 in Xanthoria parietina), with 5- and 6-ring PAHs also contributing to the overall PAH profile. Cluster analysis and pollution index factor (PIF) calculations for lichen-derived metal concentrations suggested deteriorated air quality being primarily linked to vehicular emissions. Comparably, PAH diagnostic ratios identified vehicular sources as a primary cause of PAH pollution across Manchester. However, local more complex sources (e.g. industrial emissions) were further identified. Human health risk assessment found a "moderate" risk for adults and children by airborne potential harmful element (PHEs) concentrations, whereas PAH exposure in Manchester is potentially linked to 1455 (ILCR = 1.45 × 10-3) cancer cases (in 1,000,000). Findings of this study indicate that an easy-to-use lichen biomonitoring approach can aid to identify hotspots of impaired air quality and potential human health impacts by airborne metals and PAHs across an urban environment, particularly at locations that are not continuously covered by (non-)automated air quality measurement programmes.

Temporal Trends and Suspect Screening of Halogenated Flame Retardants and Their Metabolites in Blubbers of Cetaceans Stranded in Hong Kong Waters during 2013-2020.

Halogenated flame retardants (HFRs) are a large class of chemical additives intended to meet flammability safety requirements, and at present, they are ubiquitous in the environment. Herein, we conducted the target analysis and suspect screening of legacy and novel HFRs and their metabolites in the blubber of finless porpoises (Neophocaena phocaenoides; n = 70) and Indo-Pacific humpback dolphins (Sousa chinensis; n = 35) stranded in Hong Kong, a coastal city in the South China Sea, between 2013 and 2020. The average concentrations of total target HFRs (ΣHFRs) were 6.48 × 103 ± 1.01 × 104 and 1.40 × 104 ± 1.51 × 104 ng/g lipid weight in porpoises and dolphins, respectively. Significant decreasing temporal trends were observed in the concentrations of tetra-/penta-/hexa-bromodiphenyl ethers (tetra-/penta-/hexa-BDEs) in adult porpoises stranded from 2013-2015 to 2016-2020 (p < 0.05), probably because of their phasing out in China. No significant difference was found for the concentrations of decabromodiphenyl ether and hexabromocyclododecane, possibly due to their exemption from the ban in China until 2025 and 2021, respectively. Eight brominated compounds were additionally identified via suspect screening. A positive correlation was found between the concentrations of tetra-BDE and methyl-methoxy-tetra-BDE (Me-MeO-tetra-BDE) (p < 0.05), indicating that the metabolism of tetra-BDE may be a potential source of Me-MeO-tetra-BDE in marine mammals.

Accuracy of atrial fibrillation detection by an insertable cardiac monitor in patients undergoing catheter ablation: Results of the BioVAD study.

BACKGROUND: Insertable cardiac monitors (ICMs) are increasingly used to evaluate the atrial fibrillation (AF) burden after catheter ablation of AF. BioMonitor III (BM3) is an ICM with a long sensing vector, which enhances sensing capabilities. The AF detection algorithm of the BM3 is based on R-R interval variability. OBJECTIVE: To evaluate the performance of the AF detection algorithm of BM3 in patients before and after catheter ablation of AF using simultaneous Holter recordings. METHODS: In this prospective study, we enrolled patients scheduled for catheter ablation of paroxysmal or persistent AF. After BM3 implantation, patients had a 4 days Holter registration before and 3 months after ablation. All true AF episodes ≥2 min on the Holter were annotated and matched with BM3 detected AF detections. RESULTS: Thirty-one patients were enrolled (mean age 60 ± 8, 74% male, 68% paroxysmal AF). Fifty-six Holter registrations were performed in 30 patients. Twelve patients demonstrated at least one true AF episode with a total AF duration of 570 h. The AF burden accuracy of BM3 before catheter ablation was 99.6%, with a duration sensitivity of 98.6% and a duration specificity of 99.9%. The AF burden accuracy of BM3 after catheter ablation was 99.8%, with a duration sensitivity of 90.2% and a duration specificity of 99.9%. Overall, the AF burden detected on the Holter and BM3 demonstrated a high Pearson correlation coefficient of 0.996. CONCLUSION: BM3 accurately detects AF burden in patients before and after catheter ablation of AF.

Temporal and spatial biomonitoring of atmospheric heavy metal pollution using moss bags in Xichang.

Heavy metal air pollution poses a serious threat to human health and the environment in Chinese tourist cities. In this study, we investigated the temporal and spatial variations of atmospheric heavy metal pollution using moss bags in Xichang, a tourist destination in Southwest China. The biomonitoring investigation used an indigenous moss (Taxiphyllum taxirameum) transplanted into bags. Moss bags were exposed to 22 sites including industrial, agricultural, urban/residential, tourist, and high-traffic sites, across four different seasons in 2019-2020. The results showed that T. taxirameum was a good biomonitor of air pollution in Xichang. Among the 22 sample points, air pollution was the worst along the G102 motorway. Heavy metal emissions varied in different regions and directions. Temporal changes significantly influenced the heavy metals accumulated in moss bags, with low deposition of most elements observed at nearly all sampling sites in summer. Different seasons and regions were important factors affecting atmospheric heavy metal pollution. Based on the correlation analysis and the positive matric factorization model, the results revealed that heavy metals in moss bags in Xichang were mainly derived from anthropogenic sources and atmospheric deposition. Overall, this research provides an important reference for air pollution monitoring in urban areas.

Impact of device length on electrogram sensing in miniaturized insertable cardiac monitors.

BACKGROUND: Little data exists on electrogram sensing in current generation of miniaturized insertable cardiac monitors (ICMs). OBJECTIVE: To compare the sensing capability of ICM with different vector length: Medtronic Reveal LINQ (~40 mm) vs. Biotronik Biomonitor III (BM-III, ~70 mm). METHODS: De-identified remote monitoring transmissions from n = 40 patients with BM-III were compared with n = 80 gender and body mass index (BMI)-matched patients with Reveal LINQ. Digital measurement of P- and R-wave amplitude from calibrated ICM electrograms was undertaken by 3 investigators independently. Further, we evaluated the impact of BMI and gender on P-wave visibility. RESULTS: Patients in both groups were well matched for gender and BMI (53% male, mean BMI 26.7 kg/m2, both p = NS). Median P- and R-wave amplitude were 97% & 56% larger in the BM-III vs. LINQ [0.065 (IQR 0.039-0.10) vs. 0.033 (IQR 0.022-0.050) mV, p < .0001; & 0.78 (IQR 0.52-1.10) vs. 0.50 (IQR 0.41-0.89) mV, p = .012 respectively). The P/R-wave ratio was 36% greater with the BM-III (p < .001). The 25th percentile of P-wave amplitude for all 120 patients was .026 mV. Logistic regression analysis showed BM-III was more likely than LINQ to have P-wave amplitude ≥.026 mV (OR 7.47, 95%CI 1.965-29.42, p = .003), and increasing BMI was negatively associated with P-wave amplitude ≥.026 mV (OR 0.84, 95%CI 0.75-0.95, p = .004). However, gender was not significantly associated with P-wave amplitude ≥.026 mV (p = .37). CONCLUSION: The longer ICM sensing vector of BM-III yielded larger overall P- and R- wave amplitude than LINQ. Both longer sensing vector and lower BMI were independently associated with greater P-wave visibility.

Detection of landscape species as a low-cost biomonitoring study: Cr, Mn, and Zn pollution in an urban air quality.

Urban air pollution in cities, among the world's most critical problems, has escalated to such an extent that it threatens human health in many urban centers and causes the death of millions every year. Trace metals are significant among the components of air pollution. Trace metals can endure long without undergoing biodegradation and bioaccumulation in living organisms. Moreover, their concentration in the air increases gradually. Therefore, monitoring metal concentration is extremely important for reliable indicators of environmental pollution. Biomonitoring is an effective method for describing metal concentrations in urban areas. Chromium, manganese, and zinc, selected within the present study, have various adverse effects on plants in high concentrations. Their identification is highly critical for monitoring the pollution level in their regions. This study aimed to determine the Cr, Mn, and Zn concentration changes according to organ, and age in Elaeagnus angustifolia L., Platanus orientalis L., Koelreuteria paniculata Laxm, Ailanthus altissima (Mill.) Swingle, and Cedrus atlantica (Endl.) Manetti ex Carr is 30 years old. The accumulation of metals in the outer bark can be found as follows Zn > Mn > Cr in all species, although Ailanthus altissima (Mill.) Swingle and Platanus orientalis L. can be suitable for biomonitoring tools because concentrations change significantly depending on the airborne metal.

Highly contaminated river otters (Lontra canadensis) are effective biomonitors of environmental pollutant exposure.

River otters (Lontra canadensis) are apex predators that bioaccumulate contaminants via their diet, potentially serving as biomonitors of watershed health. They reside throughout the Green-Duwamish River, WA (USA), a watershed encompassing an extreme urbanization gradient, including a US Superfund site slated for a 17-year remediation. The objectives of this study were to document baseline contaminant levels in river otters, assess otters' utility as top trophic-level biomonitors of contaminant exposure, and evaluate the potential for health impacts on this species. We measured a suite of contaminants of concern, lipid content, nitrogen stable isotopes (δ15N), and microsatellite DNA markers in 69 otter scat samples collected from twelve sites. Landcover characteristics were used to group sampling sites into industrial (Superfund site), suburban, and rural development zones. Concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ether flame-retardants (PBDEs), dichlorodiphenyl-trichloroethane and its metabolites (DDTs), and polycyclic aromatic hydrocarbons (PAHs) increased significantly with increasing urbanization, and were best predicted by models that included development zone, suggesting that river otters are effective biomonitors, as defined in this study. Diet also played an important role, with lipid content, δ15N or both included in all best models. We recommend river otter scat be included in evaluating restoration efforts in this Superfund site, and as a potentially useful monitoring tool wherever otters are found. We also report ΣPCB and ΣPAH exposures among the highest published for wild river otters, with almost 70% of samples in the Superfund site exceeding established levels of concern.

Evaluation of homing pigeon feather tissue as a biomonitor of environmental metal concentrations in China.

Biomonitoring provides direct evidence of the bioavailability and accumulation of toxic elements in the environment, and homing pigeons have been proposed as a biomonitor of atmospheric pollution. We evaluated metal concentrations in homing pigeon feather tissue as a biomonitoring tool. We measured cadmium, lead, and mercury concentrations in feathers collected from 5-6-yo homing pigeons from Guangzhou, Beijing, and Harbin, China during 2011, and feathers of 1, 5, and 10-yo homing pigeons collected from Guangzhou, Beijing, and Harbin, China during 2015-16. We compared metal concentrations in feathers between sexes and among ages and evaluated spatio-temporal differences. Correlations between feather metal concentrations and previously evaluated kidney and liver metal concentrations are reported. There were no significant differences in feather metal concentrations between male and female pigeons or among 1, 5, and 10-yo pigeons. Cadmium, lead, and mercury concentrations in feathers of 1-yo pigeons were significantly correlated with concentrations in liver and kidney tissues, although the correlations were not consistent. Spatio-temporal differences in feather metal concentrations suggest the usefulness of feathers in identifying areas of concern and remedial effectiveness. Homing pigeon feather metal concentrations appear to be useful as a screening biomonitoring tool.

Physiological, Biochemical and Defense System Responses of Roadside Vegetation to Auto-Exhaust Pollution.

This study determined the effects of traffic pollutants on plants (Nerium oleander and Ricinus communis) growing along Faisalabad to Okara (R-1) and Okara to Lahore (R-2) roads in Pakistan. The photosynthetic pigments, photosynthetic rate, transpiration rate and total soluble proteins of roadside vegetation were significantly lower than control plants (50 m away from road). The average decrease in photosynthetic rate of Nerium oleander and Ricinus communis was 33.90% and 27.94% along R-1 and 41.85% and 32.409% along R-2 road, respectively. The decreased photosynthesis in roadside flora resulted in higher water use efficiency and substomatal CO2 concentration. However, higher antioxidant activity and free amino acid contents were noted in roadside plants that might be due to their defensive response to traffic pollutants. N. oleander was more affected by traffic pollutants and R. communis showed more resistance. Thus, N. oleander could be used for biomonitoring and R. communis for phytoremediation of vehicular pollution.

Great-tailed Grackles (Quiscalus mexicanus) as Biomonitors of Atmospheric Heavy Metal Pollution in Urban Areas of Monterrey, Mexico.

Heavy metals exposure has been linked to severe health problems. In Mexico, the Monterrey metropolitan area (MMA) is considered one of the most polluted industrial regions. Because birds have been used successfully as environmental biomonitors, the levels of lead, cadmium, and arsenic in feathers of Great-tailed grackles (Quiscalus mexicanus) from two sites within and one site outside the MMA were determined. One hundred birds were captured, samples were analyzed by atomic absorption spectrometry. Ciudad Universitaria had the highest mean values of lead and cadmium, 11.91 ppm d.w. and 1.66 ppm d.w., respectively. This was at least, 10- and 8-times higher than the two other sample sites. We believe that using Great-tailed grackles as bioindicators in conjunction with air pollutants sampling from meteorological stations in Monterrey City could help in making decisions when applying environmental remediation measures as well as in the selection of places for housing, school and work among others.

BioMonitor 2 in-office setting insertion safety and feasibility evaluation with device functionality assessment: results from the prospective cohort BioInsight study.

BACKGROUND: Insertable cardiac monitors are utilized for the diagnosis of arrhythmias and traditionally have been inserted within hospitals. Recent code updates allow for reimbursement of office-based insertions; however, there is limited information regarding the resources and processes required to support in-office insertions. We sought to determine the safety and feasibility of in-office insertion of the BioMonitor 2 and better understand in-office procedures, including patient selection, pre-insertion protocols, resource availability, and staff support. METHODS: Patients meeting an indication for a rhythm monitor were prospectively enrolled into this single-arm, non-randomized trial. All patients underwent insertion in an office setting. Two follow-up visits at days 7 and 90 were required. Information on adverse events, device performance, office site preparations, and resource utilization were collected. RESULTS: Eighty-two patients were enrolled at six sites. Insertion was successful in all 77 patients with an attempt. Oral anticoagulation was stopped in 20.8% of patients and continued through insertion in 23.4%, while prophylactic antibiotics were infrequently utilized (37.7% of study participants). On average, the procedure required a surgeon plus two support staff and 35 min in an office room to complete the 8.4 min insertion procedure. The mean R-wave amplitude was 0.77 mV at insertion and 0.67 mV at 90-days with low noise burden (2.7%). There were no procedure related complications. Two adverse events were reported (event rate 2.7% [95% CI 0.3, 9.5%]). CONCLUSIONS: In-office insertion of the BioMonitor 2 is safe and feasible. Devices performed well with high R-wave amplitudes and low noise burden. These results further support shifting cardiac monitor insertions to office-based locations. TRIAL REGISTRATION: clinicaltrials.gov, NCT02756338. Registered 29 April 2016.

Relating trophic ecology and Hg species contamination in a resident opportunistic seabird of the Bay of Biscay.

Methylmercury (MeHg) is the most bioavailable and toxic form of the globally distributed pollutant Hg. Organisms of higher trophic levels living in aquatic ecosystems have potentially higher concentrations of MeHg. In this work, we analysed both MeHg and inorganic Mercury (Hg(II)) concentrations from dorsal feathers of chicks from ten colonies of Yellow-legged Gull (Larus michahellis) in the south-eastern part of the Bay of Biscay. Overall, we detected a high mean MeHg concentration that, however, differed among colonies. Additionally, based on stable isotopes analysis (δ13C and δ15N) and conducting General Linear Mixed Models, we found that chicks which were mostly/mainly fed with prey of marine origin had higher levels of MeHg. We propose Yellow-legged Gull as a reliable biomonitor for Hg species, as it is easy for sampling and in compliance with the Minamata convention on Mercury.

Does dilute nitric acid improve the removal of exogenous heavy metals from feathers? A comparative study towards the optimization of the cleaning procedure of feather samples prior to metal analysis.

Feather analysis has been widely used as a biomonitoring tool to assess metal contamination in birds, as their sampling is a non-destructive and ethically preferable technique. However, for feathers to be useful as a biomonitor of heavy metals, exogenous contamination has to be efficiently removed. Although much effort has been put into this, no washing procedure has yet proven able to ensure the total removal of the surface-associated metals. The purpose of this study was to propose an efficient washing procedure of feather samples prior to metal analysis, on the basis of comparison of various washing schemes designed according to previous analytical trials, and of the verification of the efficacy of the optimal scheme in cleaning intentionally contaminated feathers. Our investigation showed that dilute nitric acid alone or in combination with a detergent (Extran) or acetone under mild agitation of the samples performed better that any other cleaning scheme applied. Thus, a multi-step procedure including the sequential use of all three reagents was tested against feather samples contaminated by adsorbed or particulate metal species. The procedure was able to completely eliminate the external metal loads in all cases except for the partial removal of severe contamination with adsorbed Cd.

Trace elements baseline levels in Usnea antarctica from Clearwater Mesa, James Ross Island, Antarctica.

Clearwater Mesa is a pristine area located SE of Croft Bay in James Ross Island, at the northeast of the Antarctic Peninsula. The closest anthropic construction is the summer Mendel station located 25 km to the NE. Clearwater is a remote basalt volcanic mesa, (64° 01' S, 57° 42' W) located at ~ 250 m a.s.l., with around 50 small shallow lakes, a well-developed lichens flora and scarce fauna. The mesa offers a good opportunity to use lichens, like Usnea antarctica, as a biomonitor species. The aim of this study was to determine the baseline levels of trace elements in Usnea antarctica and their relationships with geographical parameters and climatological aspects, to use them as reference levels in futures studies. Usnea antarctica was collected in 23 sites in two transects: perpendicular and parallel to the shore. We found high contents of the elements associated with long-distance transport like Sm, La, Sc, Fe, Co, Hg, and Ca. The elements linked to the marine biogenic cycle as Sr, Rb, Cs, K, Na, Sb, As, Se, and Br were less significant. The distance to the sea was the factor that related the element contents. Hg, Se, As, and Br content in Usnea antarctica increased from the inland towards the sea coast.

Changes in heavy metal accumulation in some edible landscape plants depending on traffic density.

Food scarcity is one of global issues that our world faces today. A significant portion of the world's population has no access to adequate food, and it is stated that approximately 830 million people suffer from chronic famine. This predicament is estimated to grow even further. Many attempts have been made to solve the food problem. Some examples are using new resources which have not been used for dietary purposes up to this point, planting new areas to produce food products, and increasing the potential harvest per an area unit. One of the solution proposals, which has come up recently within this scope, is the term of "edible landscaping", which means the use of edible plants in the landscaping works, and thus maximizing the potential for food security. However, edible landscaping poses a considerable risk. Heavy metal accumulation in plants grown in urban centers can reach to high levels, and consuming these plants will allow these heavy metals a direct access into the human body and wreak havoc to the public health. But since this subject has not been sufficiently studied yet, the extent of such a risk is not accurately determined yet. This study aims to determine the changes of Ni, Co and Mn concentrations depending on traffic density in the leaves, branches, barks and fruits of cherry, plum, mulberry and apple trees growing in areas with dense traffic, low-density traffic and no-traffic zones in Kastamonu province. The results showed that the concentrations of Ni and Co elements increased in many organelles depending on traffic density, and that the heavy metal concentrations in fruits could be very high. This situation indicates that fruit and vegetables grown in industrial zones and urban centers, where heavy metal pollution may be high, can be harmful to the public health if consumed as crops.

Magnetic biomonitoring of atmospheric dust using tree leaves of Ficus benjamina in Querétaro (México).

There are limited economic and reliable tools to monitor the effects of airborne particulate matter PM originating from rapid industrialization, urbanization, population growth, and economic development. It is now well established that urban PM contains magnetic particles along with other air pollutants. The velocity and temporal variability of the deposition of such PM on tree leaves are subject to the pollution sources, climate, and local atmospheric conditions. Therefore, these variables have to be taken into account during a biomonitoring. This study presents a magnetic biomonitoring in the city of Querétaro. In the city's metropolitan area, the most abundant and perennial tree species for biomonitoring is Ficus benjamina. For leaves of this species, the number of days needed for collection NDNC was measured, taking into account the meteorological conditions and the time at which they reached the saturation of airborne PM (pollutants). By means of sequential sampling, we identified that the minimum NDNC after a rainfall > 3 mm is 15 days. In such a period, total suspended particle TSP depositions reach its dynamic equilibrium. This behavior can be observed from measurements of specific magnetic susceptibility χ in Ficus benjamina samples and their comparison with TSP depositions collected with traditional Hi-Vol monitoring systems. After the NDNC calculation, a magnetic monitoring was performed with the biomonitor Ficus benjamina to evaluate the air quality at different sites in the metropolitan area every month for a period of 5 months. Values of χ ranged from 0.45 to 18.52 × 10-8m3kg-1. The species Ficus benjamina can be used as a biomonitor in the city of Querétaro only in seasons (winter-spring) with no or low rainfall. The species has the advantage of providing current PM information about a specific period of time.

Determining of risk areas due to exposure to heavy metals in the Toluca Valley using epiphytic mosses as a biomonitor.

The work aim is to identify the risk areas by exposure to Cr, Cu, Pb and Zn in the Metropolitan Zone of Toluca Valley (MZTV) using the mosses Fabriona cilaris and Leskea angustata as a biomonitors, geostatistical interpolation and multi-criteria evaluation by analytical hierarchy process. The results from the estimation of the enrichment factors (EF) showed that Pb is the heavy metal with the highest values, followed by the Zn, Cu and Cr. The EF obtained for all heavy metals show that there is a moderate to high anthropogenic enrichment. The above indicates that in the MZTV there are emission sources that contribute (significantly) in the amount of Cr, Cu, Pb and Zn accumulated in the biomonitor. Combustion processes, vehicle emissions, biomass burning, brick kiln emissions, agricultural and livestock activities, manufacturing industry and re-deposition by the action of the wind, were identified as the main heavy metals sources in the MZTV. Risk maps showed the high and medium risk areas are located in sites with poor urban vegetation coverage and close to highways and industrial parks. Low risk areas are located in sites with high urban vegetation coverage. The method used for identifying risk areas is a rapid and low-cost evaluation tool can allow local government environmental agencies to define public policies on air pollution control.

Background element content in the lichen Pseudevernia furfuracea: a comparative analysis of digestion methods.

In bioaccumulation studies, the interpretation of pollutant contents in the target biomonitor has to be performed by assessing a deviation from an unaltered reference condition. A common strategy consists in the comparison with background element content (BEC) values, often built up by uncritically merging methodologically heterogeneous data. In this respect, the acid digestion of samples was identified as a major step affecting BEC data. Here, the analytical outcomes of two acid mixtures were compared on a set of matched paired samples of the lichen Pseudevernia furfuracea, a widely used biomonitor for which BEC values based on partial digestion were previously provided. The standard reference material BCR 482 (P. furfuracea) was used to validate analytical procedures consisting of either a HF total mineralization or an aqua regia partial one, both associated to ICP-MS multi-element analysis. In particular, the performance of the procedures was evaluated by comparing analytical results of field samples with the accuracy obtained on BCR aliquots (measured-to-expected percentage ratio). The total digestion showed a better performance for Al, As, Ba, Ca, Cd, Cu, Fe, Mn, Ni, Se, Sn, and Zn, whereas the opposite was found for Cr, Co, P, and S. Moreover, new BEC values were provided for P. furfuracea using a consolidated statistical approach, after a total sample digestion with hydrofluoric acid. The multivariate investigation of the background variability of 43 elements in 57 remote Italian sites led to the identification of geographically homogeneous areas for which BEC values are provided for use as reference in biomonitoring applications.