Wig Zamore wrote in today as well, to add:
A quick check of PubMed yields two abstracts that may be of interest and are pasted in below. Basically, any very heavy inhaltion of particles is likely to be damaging but calcium carbonate and its trace elements are generally less toxic than many other forms of particulates, especially those with transition metals or organic toxins such as PAhs or substituted PAHs. - Cheers, Wig
Wig is well known around Somerville, where I live (and greater Boston!), but for some context, see this page: http://www.psr.org/environment-and-health/environmental-health-policy-institute/wig-zamore.html
He enclosed in his email:
1. Biol Trace Elem Res. 2017 Feb;175(2):466-474. doi: 10.1007/s12011-016-0769-1.
Epub 2016 Jun 10.
Trace Elemental Characterization of Chalk Dust and Their Associated Health Risk
Maruthi YA(1), Ramprasad S(2), Lakshmana Das N(3).
(1)Department of Environmental Studies, GITAM Institute of Science, GITAM
University, Visakhapatnam, AP, India. email@example.com. (2)Department of
Environmental Studies, GITAM Institute of Science, GITAM University,
Visakhapatnam, AP, India. (3)Department of Physics, GITAM Institute of Science,
GITAM University, Visakhapatnam, AP, India.
It is evident that chalk produces dust on use, i.e., particulate matter, which
will alter the air quality of classrooms and can cause health hazards in
teachers. The possible causes for health effects of chalk dust on teachers are
still unclear. Hence, the aim of this study is to estimate the concentration of
trace elements (Al, Cr, Mn, Fe, Co, Ni, Si, Pb) in chalk dust collected from
classrooms by using ICP-MS. Both suspended and settled chalk dust was collected
from selected classrooms. Suspended chalk dust was collected with PM2.5 filter
paper using fine dust sampler, and settled chalk dust was collected by placing
petriplates at a distance of 3 m from the board for a duration period of 30 min.
Scanning electron microscopy images of chalk dust were taken up. Potential health
risk analysis was also assessed. Results showed that Al, Fe, and Mn are in higher
concentration (>1000 ?g kg(-1)) in both settled and suspended chalk dust. Cr, Mn,
Fe, Co, and Ni were beyond the minimal risk levels in both settled and suspended
chalk dust. There are no minimal risk levels for the elements Al, Si, and Pb. The
concentration of trace elements in suspended chalk dust was higher than that in
settled chalk dust. The SEM images of PM2.5 filter papers (suspended chalk dust)
showed that all pores of the sampled filter papers are clogged with chalk dust.
The few SEM images of the settled chalk dust showed fibrous shape which is
associated with good-quality chalk whereas others showed circular and more
aggregated nature of chalk dust from low-quality chalk from which the dust
production will be very high. As observed from the result that the trace elements
concentration was high in the suspended chalk dust, the fact can be correlated
with the SEM images which have shown high density of absorbed chalk dust. With
reference to human health risk, dermal exposure was the main route of exposure
followed by inhalation and ingestion. Al (aluminum), Fe (iron), Si (silicon), and
Mn (manganese) are the major contributors for the non-carcinogenic effects. For
all the elements, the carcinogenic effect calculated (LADD) is within the global
acceptable limit (10(-6)-10(-4)).
PMID: 27283836 [Indexed for MEDLINE]
2. Chem Res Toxicol. 2009 Sep;22(9):1548-58. doi: 10.1021/tx900046x.
Investigation of the cytotoxic and proinflammatory effects of cement dusts in rat
van Berlo D(1), Haberzettl P, Gerloff K, Li H, Scherbart AM, Albrecht C, Schins
(1)IUF-Institut für Umweltmedizinische Forschung, Auf'm Hennekamp 50, D-40225
Exposure to cement dust, a specifically alkaline and irritant dust, is one of the
most common occupational dust exposures worldwide. Although several adverse
respiratory health effects have been associated with cement dust exposure, the
evidence is not conclusive. In the current study, cytotoxic and pro-inflammatory
effects as well as oxidative stress elicited by a number of cement dusts,
including a limestone and cement clinker sample, were tested using the NR8383 rat
alveolar macrophage cell line and primary rat alveolar macrophages. DQ12 quartz
and TiO(2) were included as positive and negative controls, respectively.
Cytotoxicity was determined by the
3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay and the lactate
dehydrogenase assay, oxidative stress was determined by measurement of the
depletion of total cellular glutathione, and electron spin resonance was applied
to determine reactive oxygen species (ROS) generation. The release of the
cytokines tumor necrosis factor-alpha (TNFalpha), interleukin-1 beta (IL-1 beta),
and macrophage inflammatory protein-2 (MIP-2) was determined by enzyme-linked
immunosorbent assay. None of the dust samples were found to cause toxicity to the
macrophages or notable glutathione depletion when compared to DQ12. The cement
samples also failed to activate macrophages for the generation of ROS and the
production of inflammatory cytokines IL-1 beta and MIP-2. In contrast, however,
most of the cement dusts were found to activate macrophage TNFalpha production,
and this was significantly associated with their content of CaO. Further research
is needed to determine the relevance of these in vitro observations for
occupational cement dust exposure settings.
PMID: 19697923 [Indexed for MEDLINE]