Browsing by Subject "arsenic"

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  • Mukherjee, A.B.; Bhattacharya, P. (NRC Research Press, 2001)
  • Suomi, J.; Tuominen, P.; Niinistö, S.; Virtanen, S.M.; Savela, K. (2019)
    AIMS Agriculture and Food 2019: Vol.4, No. 3, p. 778 - 793
    The exposure of Finnish 1-year-olds to cadmium, lead and inorganic arsenic via food and drinking water was determined. The food consumption data consisted of 3-day records from 1010 children aged 12 months, collected during 2002 to 2005 in Southwest Finland. One fifth of these children were still breastfed when the consumption data were collected and their exposure was assessed separately from the non-breastfed children. The heavy metal concentration data in foodstuffs were mainly analysis results from national authorities and they were mostly from the years 2005 to 2012. Dietary exposure assessment was performed probabilistically using the online program MCRA. With middle bound estimates, 89% of the non-breastfed and 56% of the breastfed children exceeded the tolerable weekly intake of cadmium. The benchmark dose (BMDL01) for neurological damage caused by lead was exceeded by 60% of the non-breastfed and by 50% of the breastfed children, while the lowest BMDL01 for cancer risk increase caused by inorganic arsenic was exceeded by 77% of the non-breastfed and by 61% of the breastfed children. The assessment did not include the unknown heavy metal exposure from breast milk. Heavy metal exposure differences between the boys and the girls were also assessed. Breastfed girls had significantly higher heavy metal exposure relative to their bodyweight than the breastfed boys, while in the non-breastfed group there were no differences by sex.
  • Kujala, Katharina; Laamanen, Tiina; Khan, Uzair Akbar; Besold, Johannes; Planer-Friedrich, Britta (Elsevier BV, 2022)
    Soil Biology and Biochemistry
    Arsenic (As) and antimony (Sb) from mining-affected waters are efficiently removed in two treatment peatlands (TPs) in Northern Finland. However, the exact mechanisms behind this removal are not well resolved. Thus, the present study combines results from microcosm experiments and pilot-scale TPs on the effects of microbes, temperature, and carbon substrate to elucidate the role of peat microorganisms in As and Sb removal. The main As and Sb species in TP inflow water are arsenate and antimonate. In peat microcosms, they were quantitatively reduced, however, at rates about 20–400 times lower than previously reported from pure cultures, likely due to excess of other terminal electron acceptors, such as nitrate and sulfate. Addition of the microbial inhibitor sodium azide inhibited reduction, indicating that it is indeed microbially mediated. Arsenite and antimonite (re)oxidation, which is in situ likely limited to upper, oxic peat layers, was likewise observed in peat microcosms. Only for antimonite, oxidation also occurred abiotically, likely catalyzed by humic acids or metals. Process rates increased with increasing temperature, but all processes occurred also at low temperatures. Monitoring of pilot-scale TPs revealed only minor effects of winter conditions (i.e., low temperature and freezing) on arsenic and antimony removal. Formation of methylated oxyarsenates was observed to increase As mobility at the onset of freezing. From different carbon substrates tested, lactate slightly enhanced arsenate reduction and antimonate reduction was stimulated by acetate, lactate, and formate. However, a maximum rate enhancement of only 1.8 times indicates that carbon substrate availability is not the rate-limiting factor in microbial arsenate or antimonate reduction. The collective data indicate that microorganisms catalyze reduction and (re)oxidation of As and Sb species in the TPs, and even though temperature is a major factor controlling microbial As and Sb reduction/(re)oxidation, low inflow concentrations, long water residence times, and the presence of unfrozen peat in lower layers allow for efficient removal also under winter conditions.
  • Kohl, Lukas; Meng, Meng; de Vera, Joan; Bergquist, Bridget; Cooke, Colin A.; Hustings, Sarah; Jackson, Brian; Chow, Chung-Wai; Chan, Arthur W. H. (2019)
    Wildfires are increasing in prevalence and intensity and emit large quantities of persistent organic and inorganic pollutants. Recent fires have caused elevated concerns that residual pollutants in indoor environments pose a long‐term health hazard to residents, however, to date no studies have investigated how long fire‐derived pollutants are retained in indoor environments. We quantified polycyclic aromatic hydrocarbons (PAHs) and toxic trace elements in ground ashes from the 2016 wildland‐urban interface fires in Fort McMurray (Alberta, Canada) and in house dust from 64 homes. We document residual arsenic pollution from local building fires, but found no evidence that forest fire ash remained in households 14 months after the fire. Overall, house dust pollutant concentrations were equal or lower than in other locations unaffected by wildfires. Given the current and future concerns over wildfire impacts, this study provides importance evidence on the degree of their long‐term effects on the residential environment.
  • Bender, Johannes; Skowronska, Agnieszka; Dolega, Anna; Nieger, Martin; Gudat, Dietrich (2021)
    Metathesis of N-heterocyclic chloroarsines with sulfur-based nucleophiles furnished thio-substituted 1,3,2-diazarsolidines and 1,3,2-diazarsolenes. Crystallographic and NMR spectroscopic studies revealed that a thiocyanato-diazarsolene exhibits a salt-like structure composed of weakly interacting thiocyanate and arsenium ions, while the remaining products formed neutral molecules. The structural data indicate that the heterocyclic framework induces an elongation of exocyclic As-S bonds that is more prominent in diazarsolenes than in diazarsolidines and parallels the bond polarisation effect established for N-heterocyclic phosphines. The NMR data suggest that diazarsolenes undergo facile inversion of the pyramidal configuration at arsenic, which was successfully modelled by DFT studies.