This review covers the toxicology of mercury and its compounds. Special attention is paid to those forms of mercury of current public health concern. Human exposure to the vapor of metallic mercury dates back to antiquity but continues today in occupational settings and from dental amalgam. Health risks from methylmercury in edible tissues of fish have been the subject of several large epidemiological investigations and continue to be the subject of intense debate. Ethylmercury in the form of a preservative, thimerosal, added to certain vaccines, is the most recent form of mercury that has become a public health concern. The review leads to general discussion of evolutionary aspects of mercury, protective and toxic mechanisms, and ends on a note that mercury is still an "element of mystery."

The Toxicology of Mercury and Its Chemical Compounds

Environmental fate and toxicity of ionic liquids: a review.

Utilization of natural polymers has attracted increasing attention because of the consumption and over-exploitation of non-renewable resources, such as coal and oil. The development of green processing of cellulose, the most abundant biorenewable material on Earth, is urgent from the viewpoints of both sustainability and environmental protection. The discovery of the dissolution of cellulose in ionic liquids (ILs, salts which melt below 100 °C) provides new opportunities for the processing of this biopolymer, however, many fundamental and practical questions need to be answered in order to determine if this will ultimately be a green or sustainable strategy. In this critical review, the open fundamental questions regarding the interactions of cellulose with both the IL cations and anions in the dissolution process are discussed. Investigations have shown that the interactions between the anion and cellulose play an important role in the solvation of cellulose, however, opinions on the role of the cation are conflicting. Some researchers have concluded that the cations are hydrogen bonding to this biopolymer, while others suggest they are not. Our review of the available data has led us to urge the use of more chemical units of solubility, such as ‘g cellulose per mole of IL’ or ‘mol IL per mol hydroxyl in cellulose’ to provide more consistency in data reporting and more insight into the dissolution mechanism. This review will also assess the greenness and sustainability of IL processing of biomass, where it would seem that the choices of cation and anion are critical not only to the science of the dissolution, but to the ultimate ‘greenness’ of any process (142 references).

Ionic liquid processing of cellulose

Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in ...

Biological Activity of Ionic Liquids and Their Application in Pharmaceutics and Medicine.

Ionic liquids were initially proposed as replacements for conventional organic solvents; however, their chemistry has developed remarkably and offers unexpected opportunities in numerous fields, ranging from electrochemistry to biology As a consequence of ionic liquids advancing towards potential and actual applications, a comprehensive determination of their environmental, health and safety impact is now required This critical review aims to present an overview of the current understanding of the toxicity and environmental impact of the principal ionic liquid groups, and highlights some emerging concerns Each cation type is considered separately, examining the significance of the biological data, and identifying the most critical questions, some yet unresolved The need for more, and more detailed, studies is highlighted (176 references)

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Ionic Liquids: A Pathway to Environmental Acceptability

Treatment of pregnant mice ip with 5 mg/kg ochratoxin A on one of gestation days 7–12 resulted in increased prenatal mortality, decreased fetal weight (with the exception of those treated on day 9), and various fetal malformations. Exencephaly and anomalies of the eyes, face, digits, and tail were the most common defects. The most severe malformations were complete median facial clefts associated with exencephaly and eye defects. Skeletal defects also were noted involving the ribs, vertebrae, and skull.

Teratogenic effects of ochratoxin A in mice

Single intraperitoneal injections of sodium arsenate in Swiss-Webster mice on one of days 6 to 12 of gestation resulted in increased fetal resorptions. Decreased fetal weights and a spectrum of fetal anomalies were noted in litters treated on days 6 to 11. Malformations induced were day-dependent and included exencephaly, micrognathia, protruding tongue, agnathia, open eye, exophthalmos, anophthalmia, missing pinna, cleft lip, hydrocephalus, umbilical hernia, eventration, ectrodactyly, micromelia, and shortened or twisted tail and twisted limb, or both. Skeletal defects such as fused vertebrae and fused and forked ribs were also seen.

Teratogenic effects of sodium arsenate in mice.

There is significant public concern about the potential health effects of exposure to mercury vapour (Hg0) released from dental amalgam restorations. The purpose of this article is to provide information about the toxicokinetics of Hg0, evaluate the findings from the recent scientific and medical literature, and identify research gaps that when filled may definitively support or refute the hypothesis that dental amalgam causes adverse health effects. Dental amalgam is a widely used restorative dental material that was introduced over 150 years ago. Most standard dental amalgam formulations contain approximately 50% elemental mercury. Experimental evidence consistently demonstrates that Hg0 is released from dental amalgam restorations and is absorbed by the human body. Numerous studies report positive correlations between the number of dental amalgam restorations or surfaces and urine mercury concentrations in non-occupationally exposed individuals. Although of public concern, it is currently unclear what adverse health effects are caused by the levels of Hg0 released from this restoration material. Historically, studies of occupationally exposed individuals have provided consistent information about the relationship between exposure to Hg0 and adverse effects reflecting both nervous system and renal dysfunction. Workers are usually exposed to substantially higher Hg0 levels than individuals with dental amalgam restorations and are typically exposed 8 hours per day for 20–30 years, whereas persons with dental amalgam restorations are exposed 24 hours per day over some portion of a lifetime. This review has uncovered no convincing evidence pointing to any adverse health effects that are attributable to dental amalgam restorations besides hypersensitivity in some individuals.

The potential adverse health effects of dental amalgam.

Pregnant golden hamsters were injected ip with 2.5–20 mg/kg ochratoxin A on one of gestation days 7–10. The largest dosages when given on day 7, 8, or 9 increased prenatal mortality and on day 9 diminished fetal growth. Malformations, such as micrognathia, hydrocephalus, short tail, oligodactyly, syndactyly, cleft lip, micromelia, and heart defects occurred, but no skeletal malformations were noted. These results add to the prenatal effects of ochratoxin A previously reported in mouse, rat, and chicken embryos.

Prenatal effects of ochratoxin a in hamsters

Single intraperitoneal injections of sodium arsenite were given to albino Swiss-Webster mice on one of days 7–12 of gestation. Two dose levels were used: 10 or 12 mg/kg. Arsenite treatment resulted in high rates of fetal deaths and tended to decrease fetal weights-compared with H2O injected controls. Arsenite induced a variety of fetal malformations on gestation days 7–10; the most common were exencephaly, micrognathia, open eye, tail defects and skeletal anomalies of the ribs and vertebrae. Defects were similar to but less numerous than those caused by sodium arsenate.

Ronald D. Hood

Papers

Teratogenic effects of ochratoxin A in mice

Teratogenic effects of sodium arsenate in mice.

The potential adverse health effects of dental amalgam.

Prenatal effects of ochratoxin a in hamsters

Effects of sodium arsenite on fetal development.