Methylmercury in fish: understanding effects and identifying approaches to decrease exposure

在过去的200年里，人类用汞污染了地球表面。当汞到达地表水(海洋、湖泊、河流)时，它可以转化为甲基汞，在鱼类体内积累到高浓度并造成毒性。食用受污染的鱼是人类接触甲基汞的主要方式，对健康有害。加拿大的所有省和地区，除了努纳武特，都有由于甲基汞而导致的鱼类消费建议。这项研究的第一个目标将是研究影响汞向甲基汞转化或“甲基化”的环境过程。在不列颠哥伦比亚省，我们将研究是什么决定了空气中最终有多少汞可用于湖泊的甲基化。在魁北克，我们将研究向湖泊输送硫酸盐(酸雨)如何影响甲基化。在努纳武特，我们将研究湖泊变暖实际上可能如何导致一些甲基汞转化回无机汞。最终，我们希望充分了解这些过程，以便能够建议管理做法，以降低鱼类中的甲基汞浓度，从而取消对消费的限制。这项研究的第二个目标将是研究甲基汞对鱼类本身的影响。鱼是宝贵的资源，不仅对人类，而且对生态系统本身也是如此，直到最近才知道甲基汞对鱼类也有毒性。我们将研究甲基汞如何影响魁北克湖泊中重要鱼类物种(大眼鱼、北方狗鱼)的繁殖、生长和生存。这些信息将有助于适当管理受到甲基汞污染的体育和商业渔业。

During the past 200 years, humans have contaminated the surface of the Earth with mercury. When mercury reaches surface water (oceans, lakes, rivers), it can be transformed to methylmercury, which accumulates to high concentrations in fish and causes toxicity. Consumption of contaminated fish is the major way humans are exposed to methylmercury and it is detrimental to health. All provinces and territories in Canada, except Nunavut, have fish consumption advisories due to methylmercury. The first objective of this research will be to study the environmental processes that influence the transformation, or "methylation", of mercury to methylmercury. In British Columbia, we will study what determines how much mercury in the air is eventually available for methylation in lakes. In Quebec, we will study how the delivery of sulfate (acid rain) to lakes influences methylation. In Nunavut, we will study how the warming of lakes may actually cause some methylmercury to be transformed back to inorganic mercury. Ultimately, we wish to understand these processes well enough to be able to recommend management practices to reduce methylmercury concentrations in fish to the point that restrictions on consumption can be lifted. The second objective of this research will be to study the effects of methylmercury on the fish themselves. Fish are valuable resources, not only for humans but also intrinsically for ecosystems, and it wasn't known until fairly recently that methylmercury causes toxicity in fish, too. We will study how methylmercury affects the reproduction, growth, and survival of important fish species (walleyes, northern pike) in lakes of Quebec. This information will be useful for the proper regulation of sport and commercial fisheries that are contaminated with methylmercury.