China
Africa
Explore chapters and articles related to this topic
Halogenated hydrocarbons
Published in Bev-Lorraine True, Robert H. Dreisbach, Dreisbach’s HANDBOOK of POISONING, 2001
Bev-Lorraine True, Robert H. Dreisbach
Carbon tetrachloride is metabolized to a trichloromethyl free radical (CCl3) which then forms chloroform, hexachloroethane, carbon monoxide, trichloromethanol, and eventually forms phosgene and carbon dioxide.
Screening Smokes: Applications, Toxicology, Clinical Considerations, and Medical Management *
Published in Brian J. Lukey, James A. Romano, Salem Harry, Chemical Warfare Agents, 2019
Lawrence A. Bickford, Harry Salem
Chemistry and generation. This smoke, sometimes referred to as HC smoke or Zn/HCE smoke, is produced by burning a mixture of equal parts of hexachloroethane (HCE, a chlorine donor) and zinc oxide with approximately 6% granular aluminum. The mixture is usually ignited by a pyrotechnic starter mixture, resulting in a self-perpetuating exothermic reaction and the generation of a dense white smoke containing ZnCl2, zinc oxychlorides, carbon dioxide, carbon monoxide, hydrogen chloride, tetrachloroethylene, and traces of phosgene (RAMC, 2002). ZnCl2 leaves the reaction zone as a hot vapor, and on cooling below the condensation point, it nucleates to form an aerosol that is hygroscopic. Hydrated ZnCl2 particles then scatter light and obscure vision. In view of the affinity of ZnCl2 for water, the aerosol probably consists of the hydrated forms of ZnCl2 under most atmospheric conditions (Katz et al., 1980). Some formulations may contain a small amount of (ca. 10%) calcium silicide and liberate silicon on combustion (Cullumbine, 1957). Increasing the proportion of calcium silicide raises the reaction temperature and the burning rate (Jarvis and Wart, 1971). Results from a study of Zn/HCE smoke characteristics during a military exercise gave MMAD measurements of the particles in the range 0.4–2.8 μm and thus, respirable (Young et al., 1989). In extensive field studies, DeVaull et al. (1989) found MMADs ranging from 0.77 to 1.05 μm (geometric standard deviation [gsd] 1.78–2.35). Simulated combat training during a military operation indicated that trainees were exposed to ZnCl2 in concentrations ranging from 0.02 to 0.98 mg m−3 during a 225 min period (Young, 1992). Zn/HCE smoke may be generated by grenades, candles, smoke pots, cartridges, and air-delivered bombs (RAMC, 2002). Zn/HCE smoke has also been used in fire-fighting exercises (ATSDR, 1994).
The environment and reproduction
Published in David K. Gardner, Ariel Weissman, Colin M. Howles, Zeev Shoham, Textbook of Assisted Reproductive Techniques, 2017
One by-product of in vitro fertilization (IVF) has been access to follicular fluid for studies demonstrating the presence of toxicants (76–79). The pesticides DDE, mirex, hexachloroethane, and 1,2,4-trichlorobenzene, along with PCBs, BPA, and phthalates, have been implicated in infertility, but have not consistently demonstrated adverse IVF or pregnancy outcomes. Variables examined include number of oocytes retrieved, recovered, and fertilized, cleavage rates, and pregnancy rates. In a Canadian study of 21 IVF couples, higher DDE levels correlated with failed fertilization, but higher follicular PCB levels correlated with pregnancy success (76). A study of IVF patients in 1984 showed that oocyte recovery and embryo cleavage rates were inversely related to chlorinated hydrocarbon concentrations (79), although a subsequent study showed a positive relationship (78). Most remarkable, however, is the fact that in all of these studies, pesticides are present in follicular fluid at the time of resumption of meiosis when chromosome susceptibility is at its highest. For the most part, follicular toxicant concentrations are lower than serum levels (68,76). Knowing the relationship between serum and follicle concentrations has allowed speculation on the fertility outcomes of non-IVF patients based on serum levels. Law et al. (80) pulled frozen third-trimester blood samples from 380 planned pregnancies recruited for the 1959–1965 Collaborate Perinatal Project and compared serum levels of PCBs and DDE with TTP and fecundability. Dose–response curves with proportional hazards suggested that as PCB and DDE levels increase, the probability of pregnancy decreases. Since DDE and PCBs are lipophilic, the serum levels obtained in this study were adjusted for maternal lipid volume (an appropriate adjustment not done in most published reports). Once adjusted, the increased TTP attributed to DDE disappeared and the PCB effect became considerably weaker, leaving no significant difference in TTP or fecundability based on either substance’s concentration (80). These results echo the findings of a cohort of Swedish fishermen from which multiple papers have been published showing no relationship between fish consumption (including persistent organochlorine and PCB exposure) and TTP, miscarriage rate, stillbirths, or subfertility (81). In the end, there is little evidence to support the association between DDE, PCBs, and subfertility. Once again, however, the presence of such toxic substances bathing the preovulatory oocyte is worrisome given the protective barrier the reproductive organs pose to the passage of most substances. More studies will be required in order to understand whether there is any adverse impact of these substances on oocyte DNA. However, a more recent study has shown that PCBs can reduce the number of antral follicles and increase follicular atresia with an end result of earlier menopause (82).
The Use of Trace and Essential Elements in Common Clinical Disorders: Roles in Assessment of Health and Oxidative Stress Status
Published in Nutrition and Cancer, 2019
David Calderón Guzmán, Hugo Juárez Olguín, Norma Osnaya Brizuela, Ernestina Hernández Garcia, Miroslava Lindoro Silva
Zn may have a role in the pathogenesis of allergic asthma. Recent studies suggest that serum levels of Zn and Se in patients with allergic asthma were lower than in the healthy control group while Cu concentration in sera of patients with allergic asthma was slightly higher than healthy controls (74). Serum zinc increases in patients with smoke inhalation lung injury and disease severity (75) suggest that after hexachloroethane (HC)/zinc chloride (ZnCl, smoke bomb) HC/ZnCl smoke inhalation, the level of serum zinc increase may be associated with the severity of lung and liver injuries. New reports about zinc showed that it was lower in the serum of people suffering from brucellosis (76), and zinc and iron sera levels decreased in the parasitized group with D. dendriticum. Zinc and cooper levels increase in diabetic patients compared to healthy controls (77), and confirm that diabetes is a metabolic disorder with some relationship to oxidative stress (OS). Although new studies in diabetes type 2, depicted decreased nitric oxide (NO) and magnesium (Mg) and suggest that the effects of glycemic status on trace element concentrations were evident since there is a significant negative correlation between Zn and Mg with fasting plasma glucose (78).
Pulmonary delivery of resveratrol-β-cyclodextrin inclusion complexes for the prevention of zinc chloride smoke-induced acute lung injury
Published in Drug Delivery, 2022
Wanmei Wang, Yan Liu, Pan Pan, Yueqi Huang, Ting Chen, Tianyu Yuan, Yulong Ma, Guang Han, Jiahuan Li, Yiguang Jin, Fei Xie
Smoke bombs composed of zinc oxide, hexachloroethane, aluminum powder, silicon powder, and black powder were prepared. An aliquot (3 g) of the smoke bomb was put in a transparent cube chamber (1 m × 0.8 m × 0.6 m) with a door. A mouse cage was equally divided into six zones with plates to ensure every mouse having independent space and equal inhalation of smoke. The mouse-loaded cage was placed in the chamber, the smoke bomb was ignited, and the door was closed. Three minutes later, the cage was withdrawn and all the mice were moved to a new clean cage.