ABSTRACT
Mercury is a toxic and non-essential metal in the human body. Mercury is ubiquitously distributed in the environment, present in natural products, and exists extensively in items encountered in daily life. There are three forms of mercury, i.e., elemental (or metallic) mercury, inorganic mercury compounds, and organic mercury compounds. This review examines the toxicity of elemental mercury and inorganic mercury compounds. Inorganic mercury compounds are water soluble with a bioavailability of 7% to 15% after ingestion; they are also irritants and cause gastrointestinal symptoms. Upon entering the body, inorganic mercury compounds are accumulated mainly in the kidneys and produce kidney damage. In contrast, human exposure to elemental mercury is mainly by inhalation, followed by rapid absorption and distribution in all major organs. Elemental mercury from ingestion is poorly absorbed with a bioavailability of less than 0.01%. The primary target organs of elemental mercury are the brain and kidney. Elemental mercury is lipid soluble and can cross the blood-brain barrier, while inorganic mercury compounds are not lipid soluble, rendering them unable to cross the blood-brain barrier. Elemental mercury may also enter the brain from the nasal cavity through the olfactory pathway. The blood mercury is a useful biomarker after short-term and high-level exposure, whereas the urine mercury is the ideal biomarker for long-term exposure to both elemental and inorganic mercury, and also as a good indicator of body burden. This review discusses the common sources of mercury exposure, skin lightening products containing mercury and mercury release from dental amalgam filling, two issues that happen in daily life, bear significant public health importance, and yet undergo extensive debate on their safety.
Subject(s)
Humans , Biological Availability , Biomarkers/blood , Blood-Brain Barrier/metabolism , Body Burden , Dental Amalgam/chemistry , Environmental Exposure , Mercury/chemistry , Mercury Compounds/chemistry , Skin Lightening Preparations/chemistryABSTRACT
The present study investigated with the distribution of mercury chloride in muscle, liver and gills of Hoplias malabaricus contaminated through intraperitoneal injection (6 µg in 0.1mL of PBS) for a period of 24, 48, 72 and 96h. The liver, gill and muscle were analyzed for mercury content in an ICP/AES (Varian Liberty II) with vapor generating accessory (VGA 77). The muscle and liver tissues presented the same contamination pattern increasing concentrations in 24 h of exposure with a decrease in Hg concentration with 72 h and a new increase in Hg concentrations with 96 h of exposure. The Hg concentrations in contaminated organisms were always higher than the control although only for liver samples the difference was statistically significant. Liver samples always presented higher Hg contents when compared with gill and muscle samples.
ABSTRACT
Flow injection on-line sorption preconcentration and separation in a knotted reactor (KR) was coupled to cold vapor atomic fluorescence spectrometry for the determination of trace mercury in mineral water. Mercury was preconcentrated by on-line formation of mercury diethyldithiocarbamate complex (Hg-DDTC) and absorption of the resulting neutral complex on the inner walls of a knotted reactor. A 20%(V/V) HNO3 solution heated by electromagnetic induction heating technique was used as eluent to remove the absorbed Hg-DDTC from the KR, and then the vapor mercury generated by mixing the resulting solution and KBH4 was determined on-line by cold vapor atomic fluorescence spectrometry. The 20% HNO3 was employed as both the efficient eluent and the required acidic medium for subsequent mercury vapor generation in our work. Using 20% HNO3 instead of conventional organic solvent as eluent, the proposed method is simple, easy operational and environmentally friendly. Under the optimal experimental conditions, the sample throughput was approximatively 30/h with an enhancement factor of 35. The detection limit of mercury was 2.0 ng/L. The precision(RSD, n=11) was 2.2% at the 0.1 μg/L Hg2+ level.
ABSTRACT
This study was to determine the effects of Sodium-N-[4-methoxybenzyl]-D-glucamine-N-dithiocarbamate(MeOBGDTC) on the nephrotoxicity of mercury and histopathological change in rats pretreated with mercuric chloride 48h earlier. In a firsts experiment, 3 groups were given a single injection i.p. of 3.5 micromol/kg of HgCl2 mixed with 1microCi of 203Hg2+ in a final volume of 0.5ml of physiologic saline. Subsequently the rats also received the chelator, 1 mmol/kg of MeOBGDTC, at 1h in group 2 (HgCl2-MeOBGDTC 1h) and 12h in group 3 (HgCl2-MeOBGDTC 12h) after injection of mercuric chloride. The results showed that the injection of chelating agent at 1h after mercury injection significantly decreased mercury level in plasma. But not significant in renal cortex. In a second experiment, rats were divided into 4 groups, one group was control group, others were mercury injected group. MeOBGDTC was also administered to mercury-injected rats as described above. The changes in renal function were determined by measurement of proteinuria, plasma creatinine and urinary osmolality. The results showed that the injection of mercuric chloride increased the excretion of urinary protein and plasma creatinine, and decreased the urinary osmolarity. However, the injection of chelating agent at 1h after mercury injection significantly decreases the toxic effects of mercury. Finally, histopathological change at the light microscopic level was comparable effect of chelating agent on nephrotoxicity of mercury. Minimal morphological alterations were seen in kidney of rats of HgCl2-MeOBGDTC 1h. The HgCl2-MeOBGDTC 12h caused necrotic change of the proximal tubule at cortical-medullary junction. These changes were more common and more severe at the HgCl2 alone.