Risk Assessment: Short-Term Exposure at Various Ages

Disinfected water is the major source of haloacetic acids (HAAs) in humans, but their inter- and intra-individual variability for exposure and risk assessment applications is under-researched. Thus, we measured HAAs in cross-sectional and longitudinal urine and water specimens from 17 individuals. Five regulated HAAs—mono, di, and trichloroacetic acid (MCAA, DCAA, and TCAA) and mono- and dibromoacetic acid (MBAA and DBAA)—and one unregulated HAA—bromochloroacetic acid (BCAA)—were measured. Urinary DCAA, MBAA, DBAA, and BCAA levels were always below the limits of detection (LOD). Measured levels and interindividual variability of urinary MCAA were higher than urinary TCAA. Longitudinal urinary specimens showed MCAA levels peaked in after-shower specimens, while TCAA levels remain unchanged. Correlation between urinary MCAA and TCAA was moderate but statistically significant. The prevalence of MCAA and TCAA in urine suggest they can be considered as biomarkers of HAA. Peak urinary MCAA in post-shower specimens suggest MCAA captures short-term exposure via dermal and/or inhalation, while urinary TCAA captures long-term exposure via ingestion. However, further research is warranted in a large pool of participants to test the reliability of MCAA as exposure biomarker.

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Risk Analysis of Cellulose Nanomaterials by Inhalation: Current State of Science

Nanomaterials ◽

10.3390/nano9030337 ◽

2019 ◽

Vol 9 (3) ◽

pp. 337 ◽

Cited By ~ 12

Author(s):

James Ede ◽

Kimberly Ong ◽

Michael Goergen ◽

Alan Rudie ◽

Cassidy Pomeroy-Carter ◽

...

Keyword(s):

Risk Assessment ◽

In Vivo Studies ◽

Weight Of Evidence ◽

Short Term ◽

Multiwalled Carbon ◽

Potential Health ◽

Short Term Exposure ◽

Cellulose Nanomaterials

Cellulose nanomaterials (CNs) are emerging advanced materials with many unique properties and growing commercial significance. A life-cycle risk assessment and environmental health and safety roadmap identified potential risks from inhalation of powdered CNs in the workplace as a key gap in our understanding of safety and recommended addressing this data gap to advance the safe and successful commercialization of these materials. Here, we (i) summarize the currently available published literature for its contribution to our current understanding of CN inhalation hazard and (ii) evaluate the quality of the studies for risk assessment purposes using published study evaluation tools for nanomaterials to assess the weight of evidence provided. Our analysis found that the quality of the available studies is generally inadequate for risk assessment purposes but is improving over time. There have been some advances in knowledge about the effects of short-term inhalation exposures of CN. The most recent in vivo studies suggest that short-term exposure to CNs results in transient inflammation, similarly to other poorly soluble, low toxicity dusts such as conventional cellulose, but is markedly different from fibers with known toxicity such as certain types of multiwalled carbon nanotubes or asbestos. However, several data gaps remain, and there is still a lack of understanding of the effects from long-term, low-dose exposures that represent realistic workplace conditions, essential for a quantitative assessment of potential health risk. Therefore, taking precautions when handling dry forms of CNs to avoid dust inhalation exposure is warranted.

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A Caution for Monte Carlo Risk Assessment of Long Term Exposures based on Short-Term Exposure Study Data

Human and Ecological Risk Assessment An International Journal ◽

10.1080/10807039891284398 ◽

1998 ◽

Vol 4 (2) ◽

pp. 409-422 ◽

Cited By ~ 7

Author(s):

Edward J. Stanek ◽

Edward J. Calabrese ◽

Limin Xu

Keyword(s):

Risk Assessment ◽

Monte Carlo ◽

Study Data ◽

Short Term ◽

Exposure Study ◽

Short Term Exposure

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The Effect of Dimethyl Sulfoxide on In Vitro Platelet Function

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648027 ◽

1976 ◽

Vol 36 (01) ◽

pp. 221-229 ◽

Cited By ~ 16

Author(s):

Charles A. Schiffer ◽

Caroline L. Whitaker ◽

Morton Schmukler ◽

Joseph Aisner ◽

Steven L. Hilbert

Keyword(s):

Platelet Count ◽

Platelet Aggregation ◽

Dimethyl Sulfoxide ◽

Platelet Function ◽

Platelet Volume ◽

Short Term ◽

Platelet Factor ◽

Short Term Exposure ◽

Structural Abnormalities

SummaryAlthough dimethyl sulfoxide (DMSO) has been used extensively as a cryopreservative for platelets there are few studies dealing with the effect of DMSO on platelet function. Using techniques similar to those employed in platelet cryopreservation platelets were incubated with final concentrations of 2-10% DMSO at 25° C. After exposure to 5 and 10% DMSO platelets remained discoid and electron micrographs revealed no structural abnormalities. There was no significant change in platelet count. In terms of injury to platelet membranes, there was no increased availability of platelet factor-3 or leakage of nucleotides, 5 hydroxytryptamine (5HT) or glycosidases with final DMSO concentrations of 2.5, 5 and 10% DMSO. Thrombin stimulated nucleotide and 5HT release was reduced by 10% DMSO. Impairment of thrombin induced glycosidase release was noted at lower DMSO concentrations and was dose related. Similarly, aggregation to ADP was progressively impaired at DMSO concentrations from 1-5% and was dose related. After the platelets exposed to DMSO were washed, however, aggregation and release returned to control values. Platelet aggregation by epinephrine was also inhibited by DMSO and this could not be corrected by washing the platelets. DMSO-plasma solutions are hypertonic but only minimal increases in platelet volume (at 10% DMSO) could be detected. Shrinkage of platelets was seen with hypertonic solutions of sodium chloride or sucrose suggesting that the rapid transmembrane passage of DMSO prevented significant shifts of water. These studies demonstrate that there are minimal irreversible alterations in in vitro platelet function after short-term exposure to DMSO.

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