|
真的非常感谢bigsking jj总结的特别好 还要感谢laipiyu，提供了kow的原文 KOW的那篇： Biomagnification means that the level of a toxin in animals' tissues rises as one moves up the food chain. For instance, as larvae eat algae, fish eat the larvae, and bigger fish eat smaller fish, the toxin present in the algae becomes increasingly concentrated; top predators like swordfish and polar bears end up with the highest doses in their tissues. This can happen with stable, fatsoluble chemicals that aren't easily excreted in urine or feces. Biomagnification was first studied in the late 1960s in aquatic food webs, explains Frank Gobas, professor at Simon Fraser University and leader of the study. To screen chemicals, scientists began using a property known as Kow, which indicates how readily a chemical dissolves in water compared with fat and thus predicts how easily it will move from a fish's blood lipids into water through its gills. Low-Kow, or more watersoluble, chemicals don't build up in the fish food chain and were assumed to be safe.
Environmental chemists realized, however, that this assumption might not hold in food chains involving mammals and birds because their lungs are in contact with air, not water. This means that many chemicals that are relatively soluble in water and therefore don't accumulate in fish might remain in the tissues of land animals if they aren't volatile enough to easily move from the lungs into the air (predicted by a property called Koa). Supporting this idea, some organic chemicals that don't biomagnify in fish appeared to be doing so in other wildlife and humans. 我做了一些解释，希望对大家有用 毒素在食物链上端会累积，也就是生物放大作用 这类毒素中有一类是比较稳定的脂溶性物质，不容易通过尿液粪便排出，会蓄积于体内。 科学家Frank最早发现了生物放大现象。 科学家们开始研究鱼类的生物放大现象，用到一个指标，Kow，注意，低kow是高水溶性（我感觉这里应该有题），毒素容易进入水中，排出。 但是，环境学家怀疑这一观点，因为鱼是生活在水中，所以可以用食物的水溶性来判断。 但是很多陆地动物要靠肺来呼吸，肺是和空气接触，所以毒素可能会蓄积在肺中，如果毒素挥发性差不能通过呼吸排出的话。最后一句话，一些不会在鱼类中蓄积的毒素可能会在陆地动物中蓄积。 Note：Kow是和水溶性相关的指标，看清是正比还是反比
[此贴子已经被作者于2008-5-6 9:22:38编辑过] | 
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2008-5-6 08:42:00
楼主