Systematic literature review of heavy metal contamination of the Nigerian environment from e-waste management: Associated health and carcinogenic risk assessment

E-waste -the aftermath of large amount of electrical and electronic equipment ferried into Africa from which Nigeria receives a significant chunk, is composed of components known to be hazardous to health. Composition of series of heavy metals (HMs) in e-waste is traceable to many health conditions including cancer which is hitherto incompletely understood. This study harmonizes primary data on HMs from e-waste in different Nigerian environmental media including the air, soil, surface dust, water and plant. We estimated the possible health implications, single and aggregative soil and water pollution indices both in adult and children categories, carcinogenic and non-carcinogenic risks secondary to HM exposure and mapped out the possible mechanism of carcinogenesis. Analysis showed that soil, water, surface dust and plant matrices in Nigerian environment are variedly but considerably contaminated with combination of HMs. The significantly high values of the hazard quotient and hazard index of both water and surface dust matrices are indicative of adverse health effect of the non-carcinogenic risk. The highest HQ is generated by Pb and Cr through dermal exposure to soil and surface dust with mean values of 1718.48, 1146.14, 1362.10 and 1794.61 respectively among Nigerian children followed by the oral exposure. This pattern of observation is similar to that obtained for adult category. HI due to Pb and Cr in soil constitutes the highest HI (2.05E+03 and 1.18E+03 respectively) followed by surface dust. However, this study precipitates the observation that children are more at health risk than adults in contaminated environment. Carcinogenic risk also follows the same pattern of expression in the Nigerian environment. We conclude that exposure to e-waste poses significant carcinogenic and non-carcinogenic health risks and the induction of toxicity may be mediated via DNA damage, oxidative stress and inflammatory/immune cells dysfunction in Nigerian environment.

Association between exposure to heavy metals in atmospheric particulate matter and sleep quality: A nationwide data linkage study

BACKGROUND

Recent studies have demonstrated that long-term exposure to particulate matter (PM) is associated with poor sleep quality. However, no studies have linked PM constituents, particularly heavy metals, to sleep quality.

OBJECTIVE

This study investigated the association between exposure to heavy metals in PM and sleep quality.

METHODS

We obtained nationwide data from the Korean Community Health Survey conducted in 2018 among adults aged 19-80 years. Sleep quality was evaluated using Pittsburgh Sleep Quality Index (PSQI). Poor sleep quality was defined as PSQI ≥5. One-year and three-month average concentrations of heavy metals (lead, manganese, cadmium, and aluminum) in PM with diameter ≤10 μm were obtained from nationwide air quality monitoring data and linked to the survey data based on individual district-level residential addresses. Logistic regression analyses were performed after adjusting for age, gender, education level, marital status, smoking status, alcohol consumption, history of hypertension, and history of diabetes mellitus.

RESULTS

Of 32,050 participants, 17,082 (53.3%) reported poor sleep quality. Increases in log-transformed one-year average lead (odds ratio, 1.14; 95% confidence interval, 1.08-1.20), manganese (1.31; 1.25-1.37), cadmium (1.03; 1.00-1.05), and aluminum concentrations (1.17; 1.10-1.25) were associated with poor sleep quality. Increases in log-transformed three-month average manganese (odds ratio, 1.13; 95% confidence interval, 1.09-1.17) and aluminum concentrations (1.28; 1.21-1.35) were associated with poor sleep quality.

CONCLUSION

We showed for the first time that exposure to airborne lead, manganese, cadmium, and aluminum were associated with poor sleep quality. This study may be limited by self-reported sleep quality and district-level exposure data.

Biomolecular insights into the inhibition of heavy metals on reductive dechlorination of 2,4,6-trichlorophenol in Pseudomonas sp. CP-1

Influences of heavy metal exposure to the organohalide respiration process and the related molecular mechanism remain poorly understood. In this study, a non-obligate organohalide respiring bacterium, Pseudomonas sp. strain CP-1, was isolated and its molecular response to the five types of commonly existed heavy metal ions were thoroughly investigated. All types of heavy metal ions posed inhibitory effects on 2,4,6-trichlorophenol dechlorination activity and cell growth with the varied degree. Exposure to Cu (II) showed the most serious inhibitive effects on dechlorination even at the lowest concentration of 0.05 mg/L, while the inhibition by As (V) was the least with the removal kinetic constant k decreased to 0.05 under 50 mg/L. Further, multi-omics analysis found compared with Cu (II), As (V) exposure led to the insignificant downregulation of a variety of biosynthesis processes, which would be one possible account for the less inhibited activity. More importantly, the inhibited mechanisms on the organohalide respiration catabolism of strain CP-1 were firstly revealed. Cu (II) stress severely downregulated NADH generation during TCA cycle and electron donation of organohalide respiration process, which might decrease the reducing power required for organohalide respiration. While both Cu (II) and As (Ⅴ) inhibited substrate level phosphorylation during TCA cycle, as well as electron transfer and ATP generation during organohalide respiration. Meanwhile, CprA-2 was confirmed as the responsible reductive dehalogenase in charge of 2,4,6-TCP dechlorination, and transcriptional and proteomic studies confirmed the directly inhibited gene transcription and expression of CprA-2. The in-depth reveal of inhibitory effects and mechanism gave theoretical supports for alleviating heavy metal inhibition on organohalide respiration activity in groundwater co-contaminated with organohalides and heavy metals.

Susceptibility of Hyphantria cunea larvae to Beauveria bassiana under Cd Stress: An integrated study of innate immunity and energy metabolism

Biological control is widely used for integrated pest management. However, there are many abiotic factors that can affect the biocontrol efficiency. In this study, we investigated the susceptibility of Hyphantria cunea larvae to Beauveria bassiana under Cd stress, and the corresponding mechanism was analyzed around innate immunity and energy metabolism. The results showed that mortality of H. cunea larvae treated with Cd and B. bassiana was significantly higher than those treated with B. bassiana alone, and the combined lethal effect exhibited a synergistic effect. Compared with the single fungal treatment group, the total hemocyte count in the combined Cd and fungal treatment group decreased significantly, accompanied by a decrease in phagocytosis, encapsulation, and melanization activity. The expression levels of three phagocytosis-related genes, one encapsulation-promoting gene, and one melanization-regulating gene were significantly lower in the combined treatment group than those in the single fungal treatment group. Furthermore, pathogen recognition ability, signal transduction level, and immune effector expression level were weaker in the combined treatment group than those in the single fungal treatment group. The expression levels of 14 key metabolites and 7 key regulatory genes in glycolysis and tricarboxylic acid cycle pathways were significantly lower in the combined treatment group than those in the single fungal treatment group. Taken together, the weakness of innate immunity and energy metabolism in response to pathogen infection resulted in an increased susceptibility of H. cunea larvae to B. bassiana under Cd pre-exposure. Microbial insecticide is a preferred strategy for pest control in heavy metal-polluted areas. AVAILABILITY OF DATA AND MATERIAL: All the data that support the findings of this study are available in the manuscript.

Integrated multiphase ecological risk assessment of heavy metals for migratory water birds in wetland ecosystem: A case study of Dongzhangwu Wetland, China

Wetland is an important feature of the landscape that provides beneficial services. However, with the ever-increasing heavy metal load, the quality of wetlands is deteriorating. Dongzhangwu Wetland in Hebei, China, was taken as our study site. It provides breeding and foraging grounds to migratory water birds such as Little Egret (Egretta garzetta), Great Egret (Ardea alba), and Grey Heron (Ardea cinerea). The current study aimed to quantify heavy metals exposure hazard and risk to the water migratory birds by employing a non-destructive approach. Oral was considered the main exposure route and used as total exposure to explain multiphase exposure. The concentrations of Cr, Zn, Cu, Pb, As, Ni, Mn, and Cd were investigated in water, soil and food compartments of three different habitat components (Longhe River, Natural Pond and Fish Pond). The results showed: (1) The trend of potential daily dose (PDD) was Mn > Zn > Cr > Pb > Ni > Cu > As > Cd. Hazard quotient (HQ) was Cr > Pb > Cu > Zn > As > Ni > Mn > Cd, making Cr, Pb, Cu, Zn, and As the priority pollutants in all habitats, with Natural Pond eliciting the highest exposure. (2) The cumulative heavy metal exposure, explained by the integrated nemerow risk index, characterized all three habitats for all the birds in the high exposure risk category. (3) The exposure frequency index identified that all the birds are frequently exposed to heavy metals from multiple phases in all three habitats. (4) Little Egret is at the highest pedagogy of exposure from single or multiple heavy metal(s) in all three habitats. A rigorous management plan for identified priority pollutants is required to improve wetland functioning and ecological services. Decision-makers could use the developed tissue residue objectives for protecting Egret species in Dongzhangwu Wetland as benchmarks.

The Effect of Smoking Habits on Blood Cadmium and Lead Levels in Residents Living Near a Mining and Smelting Area in Northwest China: a Cross-Sectional Study

Few studies have focused on environmental cadmium (Cd) and lead (Pb) exposure while exploring the effect of smoking on blood Cd (BCd) and blood Pb (BPb) levels. Moreover, essential trace elements affect the absorption, accumulation, and toxicity of Cd and Pb. To investigate the effect of smoking on BCd and BPb levels under high Cd and Pb exposure and the influence of essential trace elements on the effect, 301 residents living near a mining and smelting area in Northwest China were included in our study. After collecting health information and measuring BCd, BPb, serum iron, magnesium, and total calcium levels, we analyzed the association between smoking and BCd and BPb levels and the influence of the essential trace elements on the association. The results showed that BCd and BPb levels in smokers were significantly higher than those in non-smokers. There was a dose-response association between pack-years and the odds ratios (ORs) of high BCd and BPb levels in all participants compared with non-smokers. Serum iron, magnesium, and calcium had a negative effect on the elevations of the ORs of high BCd and BPb levels. In addition, smoking-related elevations of BCd and BPb levels vary by sex, age, BMI, and age of smoking initiation. Our findings present evidence for the effect of smoking on BCd and BPb levels under high Cd and Pb exposure and may provide guidance for the prevention and control of BCd and BPb elevations in residents living in Cd- and Pb-polluted areas.

Nephrotoxic effect of heavy metals and the role of DNA repair gene among secondary aluminum smelter workers

This study aims to estimate the association between some heavy metals in suspended particulate matter (SPM) and kidney damage among workers at different departments in a secondary aluminum production plant. It also investigates the association between Xeroderma Pigmentosum complementation group D (XPD) gene polymorphisms and worker's susceptibility to kidney dysfunction. It was conducted on 30 workers from the administrative departments and 147 workers from different departments in the production line. Estimation of some heavy metals (Al, Co, Ni, Cu, Pb, and Cd) in suspended particulate matter (SPM) is done. Also, urinary levels of those metals were measured for all workers. Kidney injury molecule 1 (KIM-1), clusterin levels, and XPD protein level were estimated. Genotyping of XPD gene polymorphisms was performed. The measured annual average concentrations of the estimated heavy metals were lower than the permissible limits. Gravity area had the maximum concentration of metals with a higher Al average daily dose and hazardous index > 1. Kidney injury biomarkers (clusterin and KIM-1) were increased significantly (p < 0.05) while XPD protein showed the lowest levels among workers at the gravity and cold rolling areas. XPD Asn/Asp genotype was more dominant among those workers (85.7%). Conclusion: aluminum workers are at risk of kidney disorders due to heavy metal exposure. The individual's susceptibility to the diseases is related to the DNA repair efficiency mechanisms. The defect in XPD protein represents a good indicator of susceptibility to the disease. KIM-1 and clusterin estimation is a predictor biomarker for early-staged kidney diseases.

Association of paternal cadmium and other heavy metal exposure to birth outcomes using propensity score matching

BACKGROUND

Human exposure to cadmium has various effects on health, especially on male reproductive organs. Although it is widely known that prenatal maternal cadmium exposure can affect birth outcomes, the effect of paternal exposure to cadmium remains unclear.

OBJECTIVES

This study aimed to evaluate the effect of paternal cadmium exposure on fetal growth by considering maternal cadmium exposure and exposure to other heavy metals, namely mercury and lead.

METHODS

The Mothers and Children's Environmental Health (MOCEH) study is a prospective birth cohort study in Korea. Overall, 1313 families (father-mother-child triple) without child abnormalities and who completed paternal whole blood cadmium assessments were included in this study. Families were divided into two subgroups based on the blood sampling periods, namely early and late pregnancy. Subjects were selected as follows: one family triple with a high level of paternal cadmium and two triples with low levels of paternal cadmium, using the method of propensity score matching. And linear regression analyses were performed.

RESULTS

The group with high paternal cadmium exposure (80% or more; 1.93 μg/L) had lower birth weight infants compared to the group with low cadmium concentrations (β(se) = -0.21(0.10); p-value = 0.0283). After stratification by infant sex, prenatal paternal cadmium exposure significantly reduced the birth weight of females in subgroups of different sampling times, namely early pregnancy (β(se) = -0.52 (0.22); p-value = 0.0170) and late pregnancy (β(se) = -0.43 (0.18); p-value = 0.0160). Finally, after performing propensity score matching in the early pregnancy measurement group, it was found that the prenatal exposure of father to cadmium significantly reduced birth weight in females (β(se) = -0.72(0.25); p-value = 0.0047).

CONCLUSION

This study assessed the effect of paternal cadmium exposure on birth outcomes in family units consisting of a father, mother, and child. Prenatal paternal cadmium exposure negatively affected birth weight, especially that of female, considering covariates and other heavy metals exposure, namely mercury and lead.

Multi-leveled insights into the response of the eelgrass Zostera marina L to Cu than Cd exposure

Seagrass beds are recognized as critical and among the most vulnerable habitats on the planet; seagrass colonize the coastal waters where heavy metal pollution is a serious problem. In this study, the toxic effects of copper and cadmium in the eelgrass Zostera marina L. were observed at the individual, subcellular, physiologically biochemical, and molecular levels. Both Cu and Cd stress significantly inhibited the growth and the maximal quantum yield of photosystem II (Fv/Fm); and high temperature increased the degree of heavy metal damage, while low temperatures inhibited damage. The half-effect concentration (EC₅₀) of eelgrass was 28.9 μM for Cu and 2246.8 μM for Cd, indicating Cu was much more toxic to eelgrass than Cd. The effect of Cu and Cd on photosynthesis was synergistic. After 14 days of enrichment, the concentration of Cu in leaves and roots of Z. marina was 48 and 37 times higher than that in leaf sheath, and 14 and 11 times higher than that in rhizome; and the order of Cd concentration in the organs was root > leaf > rhizome > sheath. Heavy metal uptake mainly occurred in the organelles, and Cd enrichment also occurred to a certain extent in the cytoplasm. Transcriptome results showed that a number of photosynthesis-related KEGG enrichment pathways and GO terms were significantly down-regulated under Cd stress, suggesting that the photosynthetic system of eelgrass was severely damaged at the transcriptome level, which was consistent with the significant inhibition of Fv/Fm and leaf yellowing. Under Cu stress, the genes related to glutathione metabolic pathway were significantly up-regulated, together with the increased autioxidant enzyme activity of GSH-PX. In addition, the results of recovery experiment indicated that the damage caused by short-term Cd and Cu stress under EC₅₀ was reversible. These results provide heavy metal toxic effects at multiple levels and information relating to the heavy metal resistance strategies evolved by Z. marina to absorb and isolate heavy metals, and highlight the phytoremediation potential of this species especially for Cd.

Application of magnetic susceptibility and heavy metal bioaccessibility to assessments of urban sandstorm contamination and health risks: Case studies from Dunhuang and Lanzhou, Northwest China

Direct ingestion of sandstorm particles is an important pathway in human exposure to heavy metals. This study investigated the potential health risks of heavy metals transported in sandstorms from Dunhuang to Lanzhou in northwestern China using environmental magnetic parameters and metal bioaccessibilities in simulated gastric and intestinal tracts. The mean magnetic susceptibility of sandstorms in Lanzhou was 366.86 × 10^-8 m³/kg, which was more than 5-fold higher than that of sandstorms in Dunhuang, indicating that these sandstorms continuously receive heavy metals with high magnetic mineral content along their pathways. Heavy metal concentrations in sandstorms were higher than background values and those in urban topsoil. Enrichment factors and pollution load indices showed that these heavy metals were derived from both natural and anthropogenic sources, with Cu, Zn, Pb, and Cd being strongly influenced by anthropogenic sources. The bioaccessibilities of Cd, Cu, Zn, and Pb in the sandstorms of Lanzhou were very high, ranging from 22.69% (Cu) to 50.86% (Pb) for gastric phase, and 12.07% (Pb)-22.11% (Cd) for interstinal phase, with the significant reduction in χ_lf of the physiologically-based extraction testing (PBET) treated sandstorms. The magnetic minerals are significant correlation with the concentrations of heavy metals in sandstorm and effect the release of heavy metals during human digestion process. The overall ecological risk posed by heavy metals contained in sandstorms was relatively low; however, the risk was moderate to high at individual sites. Ingestion posed the highest carcinogenic and non-carcinogenic risks for both adults and children, with the risk for children being higher.

Metal elements associate with in vitro fertilization (IVF) outcomes in 195 couples

PURPOSE

Environmental factors may affecting reproductive function reduction and embryonic development. Couples who are exposed to heavy metals for a long time may affect the outcome of in vitro fertilization (IVF). To evaluate the effect of elements on IVF outcomes, a total of 195 couples undergoing IVF were included in this study.

METHODS

Elements including V, Cr, Mn, Ni, Cu, Zn, As, Mo, Cd, Ba, Hg, Tl, Pb were measured in serum and follicular fluid (FF) samples of female and semen samples of male by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Multiple linear regression were applied to evaluate the association between metal elements and semen quality parameters and the number of oocytes in MII stage. Poisson regression and the robust variance estimation of the generalized estimation equation were used to evaluate the association between elements and IVF outcomes.

RESULTS

The statistical results showed that Cr had a significant negative correlation with total sperm concentration (TSC) and total motile sperm count (TMC), the correlation coefficients were -0.52 (-0.27∼1.43) and -0.4(-1.24, 0.45), respectively. At the same time, Ba was significantly correlated with TSC and TMC, the correlation coefficients were 0.1(-0.15∼0.34) and 0.12(-0.13, 0.36), respectively. Cr, Ba and Pb in follicular fluid (FF) had a significant positive correlation with the number of oocytes in MII stage. The correlation coefficients were 3.15 (0.79, 5.52), 1.54 (-0.27, 3.36), 12.27 (7.49, 17.04). The Tl level of FF was significantly associated with the high probability of blastocyst formation and high-quality blastocysts (RR: 2.83, 95 % CI: 0.92∼7.95; RR: 3.12, 95 % CI: 0.64, 12.84). The Hg level (RR: 3.98, 95 % CI: 0.78∼14.77) and the Ba level in serum (RR: 12.75 95 % CI: 1.31∼89.71) were significantly correlated with high-quality blastocysts. The levels of Ni, Cu, Mo in seminal plasma of men were significantly correlated with blastocyst formation and high-quality blastocysts (RR values were all greater than 1.5). In addition, the level of Ba was significantly correlated with the high probability of blastocyst formation (RR: 1.7, 95 % CI: 1.14∼2.52).

CONCLUSION

Our results reveal that Cr, Ba and Pb may affect TSC, TMC and MII oocytes. Moreover, Ba, Cr, As, Hg and Tl in serum and Mo in seminal plasma were related to fertilization results, good embryos, blastocyst formation, high-quality embryos, and pregnancy and live birth rates. Tl in FF may related to the quality of embryonic development, Ba was an important risk factor which closely related to the outcomes of IVF in both male and female. Through our detection and statistical analysis of clinical samples, it is shown that although not all elements will affect the outcome of IVF the key elements we have selected need to arouse our attention, which benifit to the diagnosis and prevention of clinical infertility.

A year in the salt marsh: Seasonal changes in gill protein expression in the temperate intertidal mussel Geukensia demissa

Organisms living in temperate and polar regions experience extensive seasonal changes in the physical and biotic environment, including temperature, insolation, and food availability, among other factors. Sessile intertidal organisms respond to such seasonal fluctuations largely through physiological and biochemical means, because their behavioral responses are severely limited. In this study, we used a proteomic approach to examine changes in seasonal protein expression of gill from the intertidal mussel Geukensia demissa, a keystone species of the western Atlantic salt marsh, over the course of one year. Gill tissue of mussels collected in summer had the greatest number of proteins significantly increased in abundance (37 of 592 spots detected on two-dimensional polyacrylamide gels), although autumn mussels revealed a comparable proportion of up-regulated proteins (31 spots). In contrast, the number of proteins changing in abundance in winter and spring mussels were substantially smaller (15 and 9, respectively). Identification of these proteins revealed both expected and unanticipated changes to the proteome. Maintenance of gill cilia dominates in the summer when filter-feeding is most active, as evidenced by cytoskeletal proteins such as tektin-4 and tubulin isoforms; a signal of protection from heat stress is also present in summer (e.g., heat shock cognate 70). In autumn oxidative stress protection (peroxiredoxin-5 and manganese-containing superoxide dismutase) and aerobic ATP synthetic capacity (ATP synthase subunits a and delta) appear to increase. In winter a signal of cold-induced oxidative stress is apparent (Mn-SOD and NADP-dependent isocitrate dehydrogenase), perhaps in association with heavy metal toxicity and exposure to pathogens. Gill tissue from spring shows relatively little environmental acclimatization, other than a possible increase in protein synthesis capacity.

Neuroprotective effect of Costus afer on low dose heavy metal mixture (lead, cadmium and mercury) induced neurotoxicity via antioxidant, anti-inflammatory activities

Humans are constantly exposed to heavy metals due to their ubiquity in the environment. Hence, this study investigated the possible protective effect of Costus afer aqueous leaf extract (CALE) against low dose heavy metal mixture (LDHMM)-induced neurotoxicity. Male albino rats were divided into 6 equal groups. Group 1 served as the normal control receiving only deionized water. Group 2 served as the toxic control receiving on metal mixture (20 mg/kg PbCl2, 1.61 mg/kg CdCl2 and 0.40 mg/kg HgCl2), groups 3, 4 and 5 were co-treated with metal mixture and CALE (750, 1500 and 2250 mg/kg body weight, respectively) and group 6 was treated with metal mixture and ZnCl2. All treatments were administered through oral gavage for 90days. Oxidative stress biomarkers [malondialdehyde (MDA), superoxide dismutase (SOD), glutathione content (GSH) and catalase (CAT)], inflammatory cytokines [interlukin-6 (IL-6) and interlukin-10 (IL-10)], histopathological changes and heavy metal concentration were determined in brain of rats. Results indicated that LDHMM significantly increased (p < 0.05) the lipid peroxidation marker (MDA) and the pro-inflammatory cytokine (IL-6), while lowered levels of the oxidative biomarkers (SOD, CAT and GSH) and anti-inflammatory cytokine (IL-10). Also, LDHMM caused some histopathological changes such as reactive gliosis and glia cell proliferation. LDHMM elevated the lead, cadmium and mercury concentrations in the brain. Severity of the distorted cortical parameters were ameliorated by CALE administration. The CALE induced significant protective effect on LDHMM-mediated neurotoxicity in a dose-dependent manner which may be a result of its antioxidant anti-inflammatory and metal chelation mechanisms.

An automated computer vision based preliminary study for the identification of a heavy metal (Hg) exposed fish-channa punctatus

Fishes available in the market may be cultured either in fresh or contaminated water bodies. Heavy metals are one of those contaminants which may cause menace to fish health and thereby affect the health of living beings consuming them. The identification of heavy metal residues in fish samples is a challenging task and may require expensive and sophisticated instruments and testing. This paper investigates visual changes which may be used as benchmark for differentiating between fresh water and heavy metal exposed fishes. The proposed method is an automated non-destructive image processing method for identifying visual changes which can be used to differentiate between controlled (untreated) and heavy metals exposed (treated) fishes. The eye of the fish from digital images is considered as focal tissue that was automatically segmented using the Circular Hough Transform and adaptive intensity thresholding. Post segmentation, a potential feature is identified and transformed into mathematical parameters for classification of a fish sample as fresh or heavy metal exposed water fish. The proposed method can identify and translate the potential visual feature for ease of understanding. The accuracy of the proposed method is high, and computation time elapsed indicates the possibility of using such algorithm for real time detection in related field.

Population-based mortality data suggests remediation is modestly effective in two Montana Superfund counties

The health effects of living in proximity to Superfund sites with ongoing remediation were evaluated for residents of two contiguous Montana counties, Deer Lodge and Silver Bow. Deer Lodge and Silver Bow are home to the Anaconda Smelter and Silver Bow Creek/Butte Area Superfund sites, respectively. Established by the Environmental Protection Agency in 1983, both sites have had ongoing remediation for decades. Employing county level death certificate data obtained from the Centers for Disease Control and Prevention WONDER site, sex and age-adjusted standardized mortality ratios (SMRs) for composite targeted causes of death were calculated using observed versus expected mortality for both counties, and compared to the expected mortality from the remaining Montana counties. Cancers, cerebro- and cardiovascular diseases (CCVD), and organ failure were elevated for the two counties during the study period, 2000-2016, with SMRs of 1.19 (95% CI 1.10, 1.29); 1.36 (95% CI 1.29, 1.43); and 1.24 (95% CI 1.10, 1.38), respectively. Neurological conditions were not elevated for the two counties (SMR = 1.01; 95% CI 0.89, 1.14). Time trend analyses performed using Cox regression models indicate that deaths from cancers (HR = 0.97; p = 0.0004), CCVDs (HR = 0.95; p ≤ 0.0001), and neurological conditions (HR = 0.97; p = 0.01) decreased over the study period. While the ecological approach applied limits the interpretation of our results, our study suggests that while mortality is elevated, it is also decreasing over time for these two Superfund sites.

Characterization and function analysis of Hsp60 and Hsp10 under different acute stresses in black tiger shrimp, Penaeus monodon

Heat shock proteins (Hsps) are a class of highly conserved proteins produced in virtually all living organisms from bacteria to humans. Hsp60 and Hsp10, the most important mitochondrial chaperones, participate in environmental stress responses. In this study, the full-length complementary DNAs (cDNAs) of Hsp60 (PmHsp60) and Hsp10 (PmHsp10) were cloned from Penaeus monodon. Sequence analysis showed that PmHsp60 and PmHsp10 encoded polypeptides of 578 and 102 amino acids, respectively. The expression profiles of PmHsp60 and PmHsp10 were detected in the gills and hepatopancreas of the shrimps under pH challenge, osmotic stress, and heavy metal exposure, and results suggested that PmHsp60 and PmHsp10 were involved in the responses to these stimuli. ATPase and chaperone activity assay indicated that PmHsp60 could slow down protein denaturation and that Hsp60/Hsp10 may be combined to produce a chaperone complex with effective chaperone and ATPase activities. Overall, this study provides useful information to help further understand the functional mechanisms of the environmental stress responses of Hsp60 and Hsp10 in shrimp.

E-cigarettes: Are we renormalizing public smoking? Reversing five decades of tobacco control and revitalizing nicotine dependency in children and youth in Canada

An electronic cigarette (e-cigarette) is a battery attached to a chamber containing liquid that may (or may not) contain nicotine. The battery heats the liquid and converts it into a vapour, which is inhaled, mimicking tobacco smoking. The e-cigarette does not rely on tobacco as a source of nicotine but, rather, vaporizes a liquid for inhalation. E-liquids are often flavoured and may contain nicotine in various concentrations, although actual amounts are seldom accurately reflected in container labelling. The deleterious effects of nicotine on paediatric health are well established. The use of e-cigarettes in the paediatric age group is on the rise in Canada, as are associated nicotine poisonings. E-devices generate substantial amounts of fine particulate matter, toxins and heavy metals at levels that can exceed those observed for conventional cigarettes. Children and youth are particularly susceptible to these atomized products. Action must be taken before these devices become a more established public health hazard. Policies to denormalize tobacco smoking in society and historic reductions in tobacco consumption may be undermined by this new 'gateway' product to nicotine dependency.