Manganese

Oberdoerster, G.; Cherian, G

doi:10.1007/978-1-4613-0961-1_11

Cited by 12 publications

(6 citation statements)

References 40 publications

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“…(3) Archibald and Tyree (4) proposed that Mn can produce varying toxicities contingent upon oxidation state. Oberdoster and Cherian (5) reported that they believed that Mn 3+ and Mn 4+ were the most toxic. However, the World Health Organization (6) report that “little is known about the relative toxicity of different Mn compounds.”…”

Section: Introductionmentioning

confidence: 99%

Manganese Fractionation Using a Sequential Extraction Method to Evaluate Welders’ Shielded Metal Arc Welding Exposures During Construction Projects in Oil Refineries

Hanley

Andrews

Bertke

et al. 2015

Journal of Occupational and Environmental Hygiene

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The National Institute for Occupational Safety and Health (NIOSH) has conducted an occupational exposure assessment study of manganese (Mn) in welding fume of construction workers rebuilding tanks, piping, and process equipment at two oil refineries. The objective of this study was to evaluate exposures to different Mn fractions using a sequential extraction procedure. Seventy-two worker-days were monitored for either total or respirable Mn during stick welding and associated activities both within and outside of confined spaces. The samples were analyzed using an experimental method to separate different Mn fractions by valence states based on selective chemical solubility. The full-shift total particulate Mn time-weighted average (TWA) breathing zone concentrations ranged from 0.013 – 29 for soluble Mn in a mild ammonium acetate solution; from 0.26 – 250 for Mn0,2+ in acetic acid; from non-detectable (ND) – 350 for Mn3+,4+ in hydroxylamine-hydrochloride; and from ND – 39 micrograms per cubic meter (μg/m3) for insoluble Mn fractions in hydrochloric and nitric acid. The summation of all Mn fractions in total particulate TWA ranged from 0.52 to 470 μg/m3. The range of respirable particulate Mn TWA concentrations were from 0.20 – 28 for soluble Mn; from 1.4 – 270 for Mn0,2+; from 0.49 – 150 for Mn3+,4+; from ND – 100 for insoluble Mn; and from 2.0 – 490 μg/m3 for Mn (sum of fractions). For all jobs combined, total particulate TWA GM concentrations of the Mn(sum) were 99 (GSD=3.35) and 8.7 (GSD=3.54) μg/m3 for workers inside and outside of confined spaces; respirable Mn also showed much higher levels for welders within confined spaces. Regardless of particle size and confined space work status, Mn0,2+ fraction was the most abundant followed by Mn3+,4+ fraction, typically >50% and ~30-40% of Mn(sum), respectively. Eighteen welders’ exposures exceeded the ACGIH Threshold Limit Values for total Mn (100 μg/m3) and 25 exceeded the recently adopted respirable Mn TLV (20 μg/m3). This study shows that a welding fume exposure control and management program is warranted, especially for welding jobs in confined spaces.

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Section: Introductionmentioning

confidence: 99%

Manganese Fractionation Using a Sequential Extraction Method to Evaluate Welders’ Shielded Metal Arc Welding Exposures During Construction Projects in Oil Refineries

Hanley

Andrews

Bertke

et al. 2015

Journal of Occupational and Environmental Hygiene

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“…The progress in nanotechnology in recent years has revolutionized modern science and technology and, in the meantime, provoked calls for research into the potential adverse effects of nanomaterials 1–7. Of particular concern is the very real possibility that nanomaterials produced in research laboratories, and associated with consumer products, will eventually be discharged into the environment.…”

Section: Introductionmentioning

confidence: 99%

Real‐Time Translocation of Fullerene Reveals Cell Contraction

Salonen

Lin

Reid

et al. 2008

Small

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Carbon-based nanomaterials possess unique structural, mechanical, and electronic properties that are exploited in numerous applications. The fate of nanomaterials in living systems and in the environment is largely unknown, though there is a reason for concern. Here it is shown how the interaction of fullerene with natural phenolic acid induces cell contraction. This phenomenon has a general applicability to carbon-based nanomaterials interacting with natural amphiphiles. Atomistic simulations reveal that the self-assembly of C(70)-gallic acid (GA) favors aggregation. Confocal fluorescence microscopy shows that C(70)-GA complexes translocate across the membranes of HT-29 cells and enter nuclear membranes. Confocal imaging further reveals the real-time uptake of C(70)-GA and the consequent contraction of the cell membranes. This contraction is attributed to the aggregation of nanoparticles into microsized particles promoted by cell surfaces, a new physical mechanism for deciphering nanotoxicity.

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“…However, it is well established that blood and urine Mn levels show only poor correlation with exposure and are thus both considered to be of questionable reliability as biomarkers of exposure (Oberdörster and Cherian 1988).…”

Section: Studies In Humansmentioning

confidence: 99%

“…It is noteworthy that the relatively short half-life of Mn in blood (less than 5 min) and the low rate of excretion in urine (Oberdörster and Cherian 1988) make relating Mn exposure to observed effects challenging. Smargiassi and Mutti (1999) also noted that blood Mn was not a reliable indicator of Mn exposure because, as a result of its short half-life, it changes little with exposure, while Mn in urine is representative of less than 1% of the daily absorbed amount (Sarić et al 1977).…”

Section: Evidence Of Genotoxicity and Mutagenicitymentioning

confidence: 99%

“…Smargiassi and Mutti (1999) also noted that blood Mn was not a reliable indicator of Mn exposure because, as a result of its short half-life, it changes little with exposure, while Mn in urine is representative of less than 1% of the daily absorbed amount (Sarić et al 1977). Given these considerations, the reliability of measurements of Mn levels in blood or urine as accurate markers of Mn exposure is questionable (Oberdörster and Cherian 1988). In a review in 2004 of relevant occupational exposure studies (IEH 2004), it was found that urinary and blood Mn levels varied substantially in both control and exposed groups, although most studies reported a significant difference between urinary and blood Mn levels between the control and exposed groups.…”

Section: Evidence Of Genotoxicity and Mutagenicitymentioning

confidence: 99%

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The Mutagenicity and Carcinogenicity of Inorganic Manganese Compounds: A Synthesis of The Evidence

Assem

Holmes

Levy

2011

Journal of Toxicology and Environmental Health, Part B

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Manganese (Mn), a naturally occurring element present in many foodstuffs, is an essential trace element with many biological functions. In industry, inorganic Mn compounds have a range of different applications, although the majority of Mn is used to make alloys and steel. For the general population, the major source of exposure to Mn is dietary, although drinking water may constitute an additional source in some regions. However, in occupationally exposed humans, inhalation of Mn is likely to be an important additional route. In general, Mn and its inorganic compounds are considered to possess low mutagenic or carcinogenic potential compared with some heavy metals. In this review, an up-to-date analysis of the available published studies on the carcinogenic and genotoxic potential of inorganic Mn is provided (organic Mn compounds are not considered). The current literature indicates that Mn may be weakly mutagenic in vitro and possibly clastogenic in vivo, with unknown genotoxic effects in humans; the possible mechanisms underlying these effects are discussed. The experimental evidence on carcinogenicity (quantitative increase in incidence of thyroid tumors in mice but not rats) does not provide any clear evidence, while the available occupational and environmental epidemiological evidence is equivocal as to whether exposure to inorganic Mn is associated with a significant cancer risk. Hence, it is concluded that there is insufficient evidence to indicate that inorganic Mn exposure produces cancer in animals or humans.

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Manganese

Cited by 12 publications

References 40 publications

Manganese Fractionation Using a Sequential Extraction Method to Evaluate Welders’ Shielded Metal Arc Welding Exposures During Construction Projects in Oil Refineries

Manganese Fractionation Using a Sequential Extraction Method to Evaluate Welders’ Shielded Metal Arc Welding Exposures During Construction Projects in Oil Refineries

Real‐Time Translocation of Fullerene Reveals Cell Contraction

The Mutagenicity and Carcinogenicity of Inorganic Manganese Compounds: A Synthesis of The Evidence

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