Spectroscopic speciation of selenium in the environment

硒是必需的微量在饮食中，以维持人类和其他动物的健康。硒是许多必需酶所必需的，并已被证明可以预防癌症。硒还与包括砷、汞和镉在内的几种令人关注的元素有重要的相互作用，在许多情况下降低了它们的毒性。加拿大的草原土壤富含硒，出产有价值的硒强化作物。然而，“充足”和“过量”硒之间的饮食水平差异可能小于任何其他元素。环境中相对较低水平的硒可以在生态系统中生物积累，特别是在鸟类和鱼类中造成缺陷。在加拿大，人们越来越关注环境中硒含量的升高，特别是与采矿活动有关的硒含量。因此，环境中的硒对加拿大来说既是一种资产，也是一种负债。当土壤硒含量高时，作物中的硒含量就会增加，这可能会增加其营养价值，从而增加其向低硒地区出口的价值。然而，受采矿影响地区的硒含量升高可能会威胁到我们原始的北方环境，特别是对鱼类和鸟类造成问题。硒的这两个方面对加拿大都有重大的经济影响。

Selenium is essential in trace amounts in the diet to maintain the health of humans and other animals. Selenium is required for many essential enzymes and has been shown to provide protection against cancer. Selenium also has important interactions with several elements of concern, including arsenic, mercury and cadmium, in many cases reducing their toxicity. Canada's prairie soils are rich in selenium, yielding valuable selenium-fortified crops. However, the difference in dietary levels between "sufficient" and "excess" selenium is perhaps smaller than for any other element. Relatively low levels of selenium in the environment can bioaccumulate within an ecosystem, causing defects especially in birds and fish. There is growing concern in Canada over elevated selenium in the environment, especially associated with mining activities. Selenium in the environment is thus both an asset and a liability for Canada. When high soil selenium leads to crops rich in selenium, this may increase their nutritional benefit and hence their value for export to regions with low selenium status. However, elevated selenium in mining impacted areas may threaten our pristine northern environments, causing problems especially in fish and birds. Both aspects of selenium have significant economic consequence for Canada.