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Query: EC:3.4.23.17 (
PCE
)
1,301
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The purpose of this study was to examine the effects of industrial exposure to
mercury
and chlorinated hydrocarbons (CH) on the auditory pathway. To this effect, auditory brainstem responses (ABR) were recorded from 40 workers exposed to
mercury
, 37 workers exposed to CH and from a control group of 36 subjects that were never exposed to neurotoxic substances. The interpeak latency (IPL) of waves I-III, III-V and I-V were measured. The mean duration of exposure to
mercury
and CH was 15.5 (+6.4) and 15.8 (+7.2) years respectively. The air sample monitoring of
mercury
was 0.008 mg/m(3) (0.32 of the Threshold Limit Value - TLV(R) as published by ACGIH 2000). The mean average air sample monitoring was found to be 98 ppm for TCE, 12.7 ppm for
PCE
and 14.4 ppm for TCA which is respectively between 0.28 - 0.51 of the TLV(R) of CH. The mean blood
mercury
(B-Hg) levels were found to be 0.5mgr% (+0.3mgr%), which is 0.13 of the upper range of the permitted biologic exposure index (BEI) published by the ACGIH 2000. The mean urine samples levels of trichloroacetic acid were between 0.11-0.2 of the permitted BEI for the CH workers. The percent of workers exposed to
mercury
and CH workers with abnormal prolongation of IPL I-III was higher than the control group (42.5% and 33.8% vs. 18.0% respectively p<0.02). These results are consistent with other studies and show that ABR may provide a sensitive tool for detecting subclinical central neurotoxicity caused by CH and
mercury
...
PMID:Effects of Occupational Exposure to Mercury or Chlorinated Hydrocarbons on the Auditory Pathway. 1253 44
The genotoxic effects of
mercury
chloride and lead acetate were evaluated in vivo using the micronucleus (MN) assay on acridine-orange (AO) stained peripheral blood erythrocytes, gill and fin epithelial cells of Carassius auratus auratus. Fish were exposed to three different concentrations of
mercury
chloride (MC) (1 microg/, 5 microg/L and 10 microg/L) and lead acetate (LA) (10 microg/L, 50 microg/L and 100 microg/L) for 2, 4 and 6 days. A single dose of 5 mg/L cyclophosphamide was used as a positive control. In addition to micronuclei, nuclear buds (NBs) were assessed in the erythrocytes. The ratio of polychromatic and normochromatic erythrocytes (
PCE
/NCE) in peripheral blood was also evaluated to assess cytotoxicity. MN frequencies in all three tissues were elevated in fish exposed to both LA and MC. However, NBs showed different sensitivity to metal treatments. MN frequencies in both control and treated fish were highest in gill cells and generally lower in erythrocytes and fin cells.
PCE
/NCE rations decreased in relation to MC and LA treatments. The results of this study indicate that LA and MC have genotoxic and cytotoxic damage in fish and confirmed that AO staining is a suitable technique for in vivo MN test in fish.
...
PMID:In vivo genotoxicity of mercury chloride and lead acetate: Micronucleus test on acridine orange stained fish cells. 1788 80
Mercury
is a contaminant of global concern. The use of elemental
mercury
in various (former) industrial processes, such as chlorine production at chlor-alkali plants, is known to have resulted in soil and groundwater contaminations worldwide. However, the subsurface transport behaviour of elemental
mercury
as an immiscible dense non-aqueous phase liquid (DNAPL) in porous media has received minimal attention to date. Even though, such insight would aid in the remediation effort of
mercury
contaminated sites. Therefore, in this study a detailed field characterization of elemental
mercury
DNAPL distribution with depth was performed together with two-phase flow modelling, using STOMP. This is to evaluate the dynamics of
mercury
DNAPL migration and the controls on its distribution in saturated porous media. Using a CPT-probe mounted with a digital camera, in-situ
mercury
DNAPL depth distribution was obtained at a former chlor-alkali-plant, down to 9 m below ground surface. Images revealing the presence of silvery
mercury
DNAPL droplets were used to quantify its distribution, characteristics and saturation, using an image analysis method. These field-observations with depth were compared with results from a one-dimensional two-phase flow model simulation for the same transect. Considering the limitations of this approach, simulations reasonably reflected the variability and range of the
mercury
DNAPL distribution. To further explore the impact of
mercury
's physical properties in comparison with more common DNAPLs, the migration of
mercury
and
PCE
DNAPL in several typical hydrological scenarios was simulated. Comparison of the simulations suggest that
mercury
's higher density is the overall controlling factor in controlling its penetration in saturated porous media, despite its higher resistance to flow due to its higher viscosity. Based on these results the hazard of spilled
mercury
DNAPL to cause deep contamination of groundwater systems seems larger than for any other DNAPL.
...
PMID:The transport behaviour of elemental mercury DNAPL in saturated porous media: analysis of field observations and two-phase flow modelling. 2474 26
Mercury
is a contaminant of global concern due to its harmful effects on human health and for the detrimental consequences of its release in the environment. Sources of liquid elemental
mercury
are usually anthropogenic, such as chlor-alkali plants. To date insight into the infiltration behaviour of liquid elemental
mercury
in the subsurface is lacking, although this is critical for assessing both characterization and remediation approaches for
mercury
DNAPL contaminated sites. Therefore, in this study the infiltration behaviour of elemental
mercury
in fully and partially water saturated systems was investigated using column experiments. The properties affecting the constitutive relations governing the infiltration behaviour of liquid Hg
0
, and
PCE
for comparison, were determined using P
c
(S) experiments with different granular porous media (glass beads and sands) for different two- and three-phase configurations. Results showed that, in water saturated porous media, elemental
mercury
, as
PCE
, acted as a non-wetting fluid. The required entry head for elemental
mercury
was higher (from about 5 to 7 times). However, due to the almost tenfold higher density of
mercury
, the required NAPL entry heads of 6.19cm and 12.51cm for
mercury
to infiltrate were 37.5% to 20.7% lower than for
PCE
for the same porous media. Although Leverett scaling was able to reproduce the natural tendency of Hg
0
to be more prone than
PCE
to infiltrate in water saturated porous media, it considerably underestimated Hg
0
infiltration capacity in comparison with the experimental results. In the partially water saturated system, in contrast with
PCE
, elemental
mercury
also acted as a nonwetting fluid, therefore having to overcome an entry head to infiltrate. The required Hg
0
entry heads (10.45 and 15.74cm) were considerably higher (68.9% and 25.8%) than for the water saturated porous systems. Furthermore, in the partially water saturated systems, experiments showed that elemental
mercury
displaced both air and water, depending on the initial water distribution within the pores. This indicates that the conventional wettability hierarchy, in which the NAPL has an intermediate wetting state between the air and the water phases, is not valid for liquid elemental
mercury
. Therefore, for future modelling of elemental
mercury
DNAPL infiltration behaviour in variably water saturated porous media, a different formulation of the governing constitutive relations will be required.
...
PMID:Infiltration behaviour of elemental mercury DNAPL in fully and partially water saturated porous media. 2933 81
