Aquat Chem Toxicol Metal分享 重金属环境化学、生态毒理学、水生生态学



已有 3733 次阅读 2010-3-8 09:46 |个人分类:科研笔记|系统分类:科研笔记

Aquatic Toxicology 97 (1): 1-2. doi:10.1016/j.aquatox.2010.02.015

1. 用“metal”替代 “heavy metal”。heavy metal的定义非常模糊,使用heavy metal相比于metal并没有给读者提供更多的信息。

2. toxin指由生物体产生的有毒物质,toxicant指人为污染物。金属显然是toxicant。在aquatic toxicology这个领域,大部分时候也都该使用toxicant。

3. 虽然我们常说dose-response curve,其实我们应该用concentration-response curve,原因是我们并不知道dose是多少。dose特指到达生物体内结合位点的物质的量,需要深入的机理研究才能知道。


Uses of phrases
Mikko Nikinma(a) and Daniel Schlenk(b),
a Department of Biology, University of Turku, FI-20014 Turku, Finland
b Department of Environmental Sciences, University of California at Riverside, Geology Building, Riverside, CA 92521, USA

We have earlier discussed about the use of term “gene expression” in aquatic toxicology. In addition to the use of that term, there are several others for which accurate and unequivocal use would be beneficial. We discuss these and the reasons why we think that their use as we point out is important (at least in our opinion). We also welcome the readers of Aquatic Toxicology to send us any comments on the use of different terms. Maybe all of us together can eventually get the field to use definitions accurately and with no chance of misinterpretation.

1. Metals (not heavy metals)

Many authors use the term heavy metal for any toxicologically important metal. Several reviewers have pointed out to us that the term heavy metal is ill defined. We could not agree more. Heavy metal may be a definition suitable for heavy metal rock music, but when does a metal become heavy? On the basis of different manuscripts all the metals except sodium, magnesium, potassium and calcium are called heavy. Consequently, we have received manuscripts that use the phrase heavy metal for both low- and high-density metals and metals in vastly different places in the periodic table. Thus, writing heavy metal instead metal does not add to the information content. In fact, writing only metal, and whenever needed, using the accurate identity of the metal is much more informative. Consequently, we suggest that all the authors of Aquatic Toxicology leave the use of heavy metal to rock music.

2. Toxins and toxicants

Classical mammalian toxicology has indicated that there is a definite distinction between a toxin and a toxicant. The former is a term referring to a compound that is derived from a biological source. For example, microcystins are great examples of toxins produced by cyanobacteria. Benzene or carbon tetrachloride are not toxins. While they may be present in nature in relatively small amounts, they are examples of classical anthropogenic compounds. There are some gray areas particularly with regard to synthetic chemicals that are identical to natural products. Examples here would include nicotine or pyrethrins. When the source of the chemical is biological (i.e. plant extract), the compound is a toxin. Conversely, if the compound is synthetically derived and its entry into the environment is a result of man, then the compound is a toxicant. Also, metals tend not to originate from biological sources and would thus be considered toxicants. When in doubt, one may use the term xenobiotic, as it includes both toxins and toxicants as long as the compound is not naturally occurring to the environment. So, the next time your aquatic organism is being exposed to environmental toxins, hopefully they will be only be swimming in a sea of venom…or saxitoxin.

3. Concentration (normally not dose)

Another premise of toxicology that was stated more than 500 years ago by Paracelsus was that the “dose makes the poison”. We constantly use the term “dose–response” curve to describe the causal links between biological effects and exposure. The common use of dose in aquatic toxicology stems from mammalian toxicology. In the mammalian literature, when a compound is provided in the diet or injected into the animal, one normally, and quite rightly uses the term dose which indicates the amount entering the animal (it may not be absorbed into tissues, but can, e.g., pass through the alimentary canal unchanged). LD50 (lethal dose) is then a term to describe the dose of a compound that kills 50% of the exposed population. Interestingly, when animals are treated through inhalation, the term is modified to the “concentration” that affects 50% of the population. The reasoning behind this distinction is the fact that when mammals are exposed to air, the dose (i.e. amount entering the animal) is not known. All that can be measured is the concentration in the air. A similar situation exists for aquatic organisms. Whenever an organism is exposed to a chemical in water, we know the concentration of chemical in water. There is a dramatic difference between “dose” and “concentration”. Rarely do we know the “dose” of a compound in an aquatic organism even if the chemical is measured within the organism. This uncertainty is primarily due to whether the compound is bioavailable to a specific molecular target within the organism. Multiple investigators have attempted to derive “dose” through a host of toxicokinetic studies pioneered by McKim and Heath 1983) and perpetuated by others (e.g., Kleinow et al., 2008). Consequently, it is imperative to note that when dealing with aquatic organisms, the proper terminology is “concentration-response” or “concentration-dependent” change. It is our hope that continued studies based upon understanding mechanisms of disposition within organisms will eventually allow us to grasp “dose” and it is these studies that we wholeheartedly welcome for submission to Aquatic Toxicology.

Kleinow et al., 2008 K.M. Kleinow, J.W. Nichols, W.L. Hayton, J.M. McKim and M.G. Barron, Toxicokinetics in fishes. In: R.T. Di Giulio and D.E. Hinton, Editors, Toxicology of Fishes, CRC Press, Boca Raton, FL (2008), pp. 55–152.

McKim and Heath, 1983 J.M. McKim and E.M. Heath, Dose determinations for waterborne 2,5,2′,5′-[14C]tetrachlorobiphenyl and related pharmacokinetics in two species of trout (Salmo gairdneri and Salvelinus fontinalis): a mass-balance approach, Toxicol. Appl. Pharmacol. 68 (1983), pp. 177–187. Abstract | View Record in Scopus | Cited By in Scopus (6)

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