Recovery of Smelter-Impacted Peat and Sphagnum Moss: a Microbial Perspective

Peatlands store approximately one-half of terrestrial soil carbon and one-tenth of non-glacial freshwater. Some of these important ecosystems are located near heavy metal emitting smelters. To improve the understanding of smelter impacts and potential recovery after initial pollution controls in the 1970s (roughly 50 years of potential recovery), we sampled peatlands along a distance gradient of 134 km from a smelter in Sudbury, Ontario, Canada, an area with over a century of nickel (Ni) and copper (Cu) mining activity. This work is aimed at evaluating potential shifts in bacterial and archaeal community structures in Sphagnum moss and its underlying peat within smelter-impacted poor fens. In peat, total Ni and Cu concentrations were higher (0.062-0.067 and 0.110-0.208 mg/g, respectively) at sites close to the smelter and exponentially dropped with distance from the smelter. This exponential decrease in Ni concentrations was also observed in Sphagnum. 16S rDNA amplicon sequencing showed that peat and Sphagnum moss host distinct microbiomes with peat accommodating a more diverse community structure. The microbiomes of Sphagnum were dominated by Proteobacteria (62.5%), followed by Acidobacteria (11.9%), with no observable trends with distance from the smelter. Dominance of Acidobacteria (32.4%) and Proteobacteria (29.6%) in peat was reported across all sites. No drift in taxonomy was seen across the distance gradient or from the reference sites, suggesting a potential microbiome recovery toward that of the reference peatlands microbiomes after decades of pollution controls. These results advance the understanding of peat and Sphagnum moss microbiomes, as well as depict the sensitivities and the resilience of peatland ecosystems.

Multiorgan MRI findings after hospitalisation with COVID-19 in the UK (C-MORE): a prospective, multicentre, observational cohort study

INTRODUCTION

The multiorgan impact of moderate to severe coronavirus infections in the post-acute phase is still poorly understood. We aimed to evaluate the excess burden of multiorgan abnormalities after hospitalisation with COVID-19, evaluate their determinants, and explore associations with patient-related outcome measures.

METHODS

In a prospective, UK-wide, multicentre MRI follow-up study (C-MORE), adults (aged ≥18 years) discharged from hospital following COVID-19 who were included in Tier 2 of the Post-hospitalisation COVID-19 study (PHOSP-COVID) and contemporary controls with no evidence of previous COVID-19 (SARS-CoV-2 nucleocapsid antibody negative) underwent multiorgan MRI (lungs, heart, brain, liver, and kidneys) with quantitative and qualitative assessment of images and clinical adjudication when relevant. Individuals with end-stage renal failure or contraindications to MRI were excluded. Participants also underwent detailed recording of symptoms, and physiological and biochemical tests. The primary outcome was the excess burden of multiorgan abnormalities (two or more organs) relative to controls, with further adjustments for potential confounders. The C-MORE study is ongoing and is registered with ClinicalTrials.gov, NCT04510025.

FINDINGS

Of 2710 participants in Tier 2 of PHOSP-COVID, 531 were recruited across 13 UK-wide C-MORE sites. After exclusions, 259 C-MORE patients (mean age 57 years [SD 12]; 158 [61%] male and 101 [39%] female) who were discharged from hospital with PCR-confirmed or clinically diagnosed COVID-19 between March 1, 2020, and Nov 1, 2021, and 52 non-COVID-19 controls from the community (mean age 49 years [SD 14]; 30 [58%] male and 22 [42%] female) were included in the analysis. Patients were assessed at a median of 5·0 months (IQR 4·2-6·3) after hospital discharge. Compared with non-COVID-19 controls, patients were older, living with more obesity, and had more comorbidities. Multiorgan abnormalities on MRI were more frequent in patients than in controls (157 [61%] of 259 vs 14 [27%] of 52; p<0·0001) and independently associated with COVID-19 status (odds ratio [OR] 2·9 [95% CI 1·5-5·8]; padjusted=0·0023) after adjusting for relevant confounders. Compared with controls, patients were more likely to have MRI evidence of lung abnormalities (p=0·0001; parenchymal abnormalities), brain abnormalities (p<0·0001; more white matter hyperintensities and regional brain volume reduction), and kidney abnormalities (p=0·014; lower medullary T1 and loss of corticomedullary differentiation), whereas cardiac and liver MRI abnormalities were similar between patients and controls. Patients with multiorgan abnormalities were older (difference in mean age 7 years [95% CI 4-10]; mean age of 59·8 years [SD 11·7] with multiorgan abnormalities vs mean age of 52·8 years [11·9] without multiorgan abnormalities; p<0·0001), more likely to have three or more comorbidities (OR 2·47 [1·32-4·82]; padjusted=0·0059), and more likely to have a more severe acute infection (acute CRP >5mg/L, OR 3·55 [1·23-11·88]; padjusted=0·025) than those without multiorgan abnormalities. Presence of lung MRI abnormalities was associated with a two-fold higher risk of chest tightness, and multiorgan MRI abnormalities were associated with severe and very severe persistent physical and mental health impairment (PHOSP-COVID symptom clusters) after hospitalisation.

INTERPRETATION

After hospitalisation for COVID-19, people are at risk of multiorgan abnormalities in the medium term. Our findings emphasise the need for proactive multidisciplinary care pathways, with the potential for imaging to guide surveillance frequency and therapeutic stratification.

FUNDING

UK Research and Innovation and National Institute for Health Research.

The impact of severe pollution from smelter emissions on carbon and metal accumulation in peatlands in Ontario, Canada

Peatlands are unique habitats that function as a carbon (C) sink and an archive of atmospheric metal deposition. Sphagnum mosses are key components of peatlands but can be adversely impacted by air pollution potentially affecting rates of C and metal accumulation in peat. In this study we evaluate how the loss of Sphagnum in peatlands close to a copper (Cu) and nickel (Ni) smelter in Sudbury, Ontario affected C accumulation and metal profiles. The depth of accumulated peat formed during the 100+ year period of smelter activities also increased with distance from the smelter. Concurrently, peat bulk density decreased with distance from the smelter, which resulted in relatively similar average rates of apparent C accumulation (32-46 g/m²/yr). These rates are within the range of published values despite the historically high pollution loadings. Surface peat close to the smelters was greatly enriched in Cu and Ni, and Cu profiles in dated peat cores generally coincide with known pollution histories much better than Ni that increased well before the beginning of smelter activities likely a result of post-deposition mobility in peat cores.

Distribution of metals and radionuclides in the lichens Cladonia rangiferina and C. mitis from the past uranium mining region of Elliot Lake, Ontario, Canada

The present study was performed in the Elliot Lake area (Ontario, Canada), a site of uranium mining and milling for nearly 40 years between 1950's and 1990's. Although mining activities ceased in the mid-1990's, the site hosts several tailings management areas (TMAs) which are under ongoing rehabilitation and monitoring. Several surveys using lichens as a biomonitoring tool were completed in the 1980s and the 1990s to assess the levels of contaminants. The present survey aimed to re-visit the historical surveys, and to determine the current status of environmental recovery of the area. Our survey consisted of sampling two lichen species, Cladonia rangiferina and C. mitis, in an area covering up to 50 km from the former mining operation and the TMAs. The results reported in this work indicated that the levels of metals and radionuclides, diagnostic of mining operations, have decreased over time: particularly, the U, Th and Pb levels in both lichen species dropped by about two orders of magnitude by the 2020's compared to the 1980's. Likewise, the Cs-137 levels in both lichen species reflect present day global background. The study provides a new set of present-day regional baseline elemental concentrations for other metals that are associated with mining (Cd, As, Ti, Cs). Finally, there were weak but statistically significant differences in the levels of some elements (U, Th, Cd) between the two lichens, suggesting these two species might have different capture mechanisms or retention abilities.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

A review on the use of lichens as a biomonitoring tool for environmental radioactivity

Lichens have been widely used as a biomonitoring tool to record the distribution and concentration of airborne radioactivity and pollutants such as metals. There are limitations, however: although pollutants can be preserved in lichen tissues for long periods of time, not all radioactive and inert elements behave similarly. The chemical species of elements at the source, once captured, and the mode of storage within lichens play a role in this biomonitoring tool. Lichens are a symbiotic association of an algal or cyanobacterial partner (photobiont) with a fungal host (mycobiont). Lichens grow independently of the host substrates, including rocks, soils, trees and human-made structures. Lacking a root system, lichen nutrient or contaminant uptake is mostly through direct atmospheric inputs, mainly as wet and dry deposition. As lichens grow in a large variety of environments and are resilient in harsh climates, they are adapted to capture and retain nutrients from airborne sources. The context of this review partially relates to future deployment of small modular reactors (SMRs) and mining in remote areas of Canada. SMRs have been identified as a future source of energy (electricity and heat) for remote off-grid mines, potentially replacing diesel fuel generation facilities. For licensing purposes, SMR deployment and mine development requires capabilities to monitor background contaminants (natural radioactivity and metals) before, during and after deployment, including for decommissioning and removal. Key aspects reviewed herein include: (1) how lichens have been used in the past to monitor radioactivity; (2) radiocontaminants capture and storage in lichens; (3) longevity of radiocontaminant storage in lichen tissues; and (4) limitations of lichens use for monitoring radiocontaminants and selected metals.

Microbial biomass and activity dynamics in restored lands in a metal contaminated region

Soil microbial communities are important for biogeochemical processes, along with the cycling of nutrients in an ecosystem. Their enzymatic activities are key indicators of their responses to stress. The objective of this research was to assess the effect of land reclamation on microbial biomass and activities in soils impacted by metal contamination. Phospholipid fatty acid analysis (PLFA) (PLFA) results revealed a significant increase in total microbial biomass, fungi, actinomycetes, and bacteria when limed soils were compared to unlimed samples. This change in microbial biomass was associated with a significant increase of pH. The overall level of the β-glucosidase (BG), cellobiohydrolase (CBH), and aryl sulfatase (AS) activities was significantly higher in the dolomitic limestone treated soils than in the untreated samples. However, the activity of glycine aminopeptidase (GAP) was significantly lower in the limed soil than in unlimed samples used as reference. No significant differences (P ≥ 0.05) were observed between the two types of lands (limed vs unlimed) for other enzymes tested, which includes β-N-acetylglucosaminidase (NAGase), acid phosphatase (AP), alkaline phosphatase (ALP), leucine aminopeptidase (LAP), and peroxidase (PER). The levels of enzymatic responses also varied among sites. Overall, this study revealed for the first time the effects of liming on soil microbial activities in recently reclaimed sites damaged by metals.

Blended municipal compost and biosolids materials for mine reclamation: Long-term field studies to explore metal mobility, soil fertility and microbial communities

Application of stable soil amendments is often the key to successful phytostabilization and rehabilitation of mine tailings, and microbial guilds are primary drivers of many geochemical processes promoted by these amendments. Field studies were set up at a tailings management area near Sudbury, Ontario to examine performance of blends of lime stabilized municipal biosolids and compost at nine different rates over thick (1 m) municipal compost covers planted with agricultural crops. Based on biogeochemical variability of the substrates four and ten years after application of the initial compost cover, the experimental plots could be classified into three categories: "Low" rate (0-100 t ha^-1 biosolids), "Medium" rate (200-800 t ha^-1), and "High" rate (1600-3200 t ha^-1) treatments. The addition of biosolids materials to the thick compost cover at rates higher than 100 t ha^-1 significantly reduced C:N ratio of the substrates, available phosphorus, and some of the nutrient cations, while notably increasing inorganic carbon and the potential solubility of Ni and Cu. This suggests that increasing biosolids application rates may not equivalently ameliorate soil quality and geochemical stability. Correspondingly, microbial communities were altered by biosolids additions, further intensifying the negative impacts of biosolids on long-term efficiency of the initial compost cover. Abundance of cellulose, hemicellulose, and lignocellulose decomposers (as key drivers of mineralization and humification) was significantly reduced by "Medium" and "High" rate treatments. Most DNA sequences with high affinity to denitrifiers were detected in "High" rate treatments where geochemical conditions were optimal for higher microbial denitrification activities. These findings have implications for improving the long-term efficiency of reclamation and environmental management programs in mine tailings of northern temperate climates.

Changes in ambient air quality and atmospheric composition and reactivity in the South East of the UK as a result of the COVID-19 lockdown

The COVID-19 pandemic forced governments around the world to impose restrictions on daily life to prevent the spread of the virus. This resulted in unprecedented reductions in anthropogenic activity, and reduced emissions of certain air pollutants, namely oxides of nitrogen. The UK 'lockdown' was enforced on 23/03/2020, which led to restrictions on movement, social interaction, and 'non-essential' businesses and services. This study employed an ensemble of measurement and modelling techniques to investigate changes in air quality, atmospheric composition and boundary layer reactivity in the South East of the UK post-lockdown. The techniques employed included in-situ gas- and particle-phase monitoring within central and local authority air quality monitoring networks, remote sensing by long path Differential Optical Absorption Spectroscopy and Sentinel-5P's TROPOMI, and detailed 0-D chemical box modelling. Findings showed that de-trended NO₂ concentrations decreased by an average of 14-38% when compared to the mean of the same period over the preceding 5-years. We found that de-trended particulate matter concentrations had been influenced by interregional pollution episodes, and de-trended ozone concentrations had increased across most sites, by up to 15%, such that total O_x levels were roughly preserved. 0-D chemical box model simulations showed the observed increases in ozone concentrations during lockdown under the hydrocarbon-limited ozone production regime, where total NO_x decreased proportionally greater than total non-methane hydrocarbons, which led to an increase in total hydroxyl, peroxy and organic peroxy radicals. These findings suggest a more complex scenario in terms of changes in air quality owing to the COVID-19 lockdown than originally reported and provide a window into the future to illustrate potential outcomes of policy interventions seeking large-scale NO_x emissions reductions without due consideration of other reactive trace species.

Rhizobioaugmentation of Casuarina glauca with N-fixing actinobacteria Frankia decreases enzymatic activities in wastewater irrigated soil: effects of Frankia on C. glauca growth

The use of wastewater for irrigation in agroforestry is cost-effective for water management. It is well established that rhizospheric microorganisms such as N₂-fixing bacteria are able to modulate rhizobioaugmention and to boost phyoremediation process. To date, no study has been conducted to evaluate biological effects of rhizobioaugmentation in Casuarina glauca trees induced by their symbiont N-fixing actinobacteria of the genus Frankia. The objective of the present study was to evaluate the main effects of rhizobioaugmentation on the biological activity in the C. glauca's rhizosphere and on C. glauca growth in soils irrigated with industrial wastewater. Two Frankia strains (BMG5.22 and BMG5.23) were used in a single or dual inoculations of C. glauca seedlings irrigated with industrial wastewater. Soil enzymes activity related to carbon, phosphorus, sulfur and nitrogen cycling were measured. Results revealed that the BMG5.22 Frankia strain increases significantly the size (dry weight) of C. glauca shoots and roots while dual inoculation increased significantly the root length. Surprisingly, β-glucosidase (BG), cellobiohydrolase (CBH), β-N-acetylglucosaminidase (NAGase), aryl sulfatase (AS), acid phosphatase (AP), alkaline phosphatase (AlP), glycine aminopeptidase (GAP), leucine aminopeptidase (LAP), and peroxidase (PER) activity in the rhizosphere decreased significantly in soils treated with the two strains of symbionts. This suggests no positive correlations between enzymatic activity and C. glauca growth.

Blended pulp mill, forest humus and mine residual material Technosols for mine reclamation: A growth-chamber study to explore the role of physiochemical properties of substrates and microbial inoculation on plant growth

A growth chamber trial was conducted to investigate the effects of blends of pulp and paper mill residuals and forest humus on soil properties, microbial communities and germination rate and biomass production of annual ryegrass (Lolium multiflorum) in both acid-producing and neutral to mildly alkaline mine tailings in a mine reclamation context. The organic residual amendments improved the nutritional status of the tailings substrates, and increased pH in acid-generating tailings, leading to higher germination rates and improved plant growth. A trace addition (<0.02% of sludge by dry weight) of natural forest floor material as a microbial inoculum to the sludge could increase plant biomass up to four-fold. The effects of sludge application on bioavailability of metals were variable, with the concentration of soluble copper (Cu) and nickel (Ni) increasing in some of the substrates following organic amendments. Addition of paper mill residuals to mine tailings modified the microbial communities observed in the oligotrophic tailings with the majority of DNA sequences in the sludge amended substrates being found to be closely related to heterotrophic bacterial species rather than the chemolithotrophic communities that dominate tailings environments.

Demographics, management and survival of patients with malignant pleural mesothelioma in the National Lung Cancer Audit in England and Wales

INTRODUCTION AND METHODS

Malignant pleural mesothelioma (MPM) is an uncommon cancer with poor survival. We have used data collected for the UK National Lung Cancer Audit to assess current practice and to highlight regional variation in the management of mesothelioma patients, as well as to describe survival patterns in subgroups.

RESULTS

Our data on 8740 cases seen in hospitals in England and Wales is the largest cohort of MPM in the literature and represents approximately 80% of the total incident cases. 83% are male and median age is 73 years. Performance status is recorded in 81% and of these approximately 70% are PS 0-2. Stage is poorly recorded and unreliable in this dataset. The patient pathway is similar to lung cancer with approximately one-fifth having a non-elective referral to secondary care. A histo-cytological diagnosis is made in 87% and varies across organisations. Only 67% have anti-cancer treatment, and this also varies across organisations, but there has been an annual increase in the proportion receiving chemotherapy. Overall median survival was 9.5 months, with a 1YS of 41.4% and 3YS of 12.0%, but was strongly linked to performance status and histological subtype. Median survival also varied by cancer network from 209 days to 349 days, but appeared to increase from of 9.2 months in 2008 to 10.5 months in 2012.

CONCLUSION

Our data provide a large scale, detailed assessment of MPM epidemiology, treatment choices and outcomes. Incidence is increasing in line with predictions and uptake of treatments has generally mirrored publication of key MPM treatment trials, in particular increasing use of chemotherapy but low uptake of radical surgery. However, there is significant variation in care patterns and outcomes that may reflect limited expertise in area with low incidence. Initiatives to improve outcomes should include improved recording of clinical stage.

Risk factors and survival outcome for non-elective referral in non-small cell lung cancer patients--analysis based on the National Lung Cancer Audit

INTRODUCTION

Survival after diagnosis of lung cancer is poor and seemingly lower in the UK than other Western countries, due in large part to late presentation with advanced disease precluding curative treatment. Recent research suggests that around one-third of lung cancer patients reach specialist care after emergency presentation and have a worse survival outcome. Confirmation of these data and understanding which patients are affected may allow a targeted approach to improving outcomes.

METHODS

We used data from the UK National Lung Cancer Audit in a multivariate logistic regression model to quantify the association of non-elective referral in non-small cell lung cancer patients with covariates including age, sex, stage, performance status, co-morbidity and socioeconomic status and used the Kaplan-Meier method and Cox proportional hazards model to quantify survival by source of referral.

RESULTS

In an analysis of 133,530 cases of NSCLC who presented 2006-2011, 19% of patients were referred non-electively (following an emergency admission to hospital or following an emergency presentation to A&E). This route of referral was strongly associated with more advanced disease stage (e.g. in Stage IV - OR: 2.34, 95% CI: 2.14-2.57, p<0.001) and worse performance status (e.g. in PS 4 - OR: 7.28, 95% CI: 6.75-7.86, p<0.001), but was also independently associated with worse socioeconomic status, and extremes of age. These patients were more likely to have died within 1 year of diagnosis (hazard ratio of 1.51 (95% CI: 1.49-1.54) after adjustment for key clinical variables.

CONCLUSION

Our data confirm and quantify poorer survival in lung cancer patients who are referred non-electively to specialist care, which is more common in patients with poorer performance status, higher disease stage and less advantaged socioeconomic status. Work to tackle this late presentation should be urgently accelerated, since its realisation holds the promise of improved outcomes and better healthcare resource utilisation.

Field dependence of the relaxation of 79Br in KBr and its use as a temperature calibrant

The longitudinal relaxation time of (79)Br nuclei in KBr is field independent, between 4.7 T and 14.1 T. The results suggest that inconsistencies in the literature are due to differences in the experimental set-ups. The limitations of KBr as temperature calibrant are discussed.

Exploring variations in lung cancer care across the UK--the 'story so far' for the National Lung Cancer Audit

The National Lung Cancer Audit was developed to improve the quality and outcomes of services for patients with lung cancer, knowing that outcomes vary widely across the UK and are poor compared to other western countries. After five years the audit is capturing approximately 100% of the expected number of incident cases across hospitals in England, Wales, Scotland, Northern Ireland and Jersey. Measures of process and outcome have improved over the audit period, such as the histological confirmation rate (64-76%), the proportion of patients discussed in a multidisciplinary team meeting (78-94%), and the proportion of patients having anti-cancer treatment (43-59%), surgical resection (9-14%) and small cell lung cancer chemotherapy (58-66%). These national averages hide wide variations between hospitals providing lung cancer care which cannot be accounted for by differences in casemix. This paper describes the evolution of the audit, and describes the ways in which it may have improved clinical practice.

Comparative soil metal analyses in Sudbury (Ontario, Canada) and Lubumbashi (Katanga, DR-Congo)

DR-Congo is a main world producer of copper (Cu) and cobalt (Co). Several hydrometallurgical plants and smelters also produced zinc, arsenic, and cadmium as by-products. In Sudbury (Canada), the production of nickel, copper and other metals has been maintained at high levels while industrial SO(2) emissions have been reduced by approximately 90% through combination of industrial technological developments and legislated controls. Metal analysis in the present study revealed that the levels of copper and cobalt in soils from mining sites in the Lubumbashi (DR-Congo) were up to 200 fold higher compared to contaminated Sudbury sites and tailings. Zinc content in soil samples from some mining areas in Lubumbashi was at least 70 times higher compared to samples from the Sudbury area. Nickel content in soil samples from Lubumbashi were much lower compared to the Sudbury Region samples. Overall, this study confirms that the African Copper belt region is among the ten most polluted areas in the world.