Các kim loại được tìm thấy trong môi trường có nguồn gốc từ nhiều nguồn khác nhau. Nguồn này bao gồm: tự nhiên thời tiết của vỏ trái đất, khai thác mỏ, đất xói mòn, công nghiệp xả, dòng chảy đô thị, nước thải xử lý nước thải, sâu bệnh hoặc bệnh kiểm soát các đại lý áp dụng cho các nhà máy, hậu quả ô nhiễm không khí, và một số của Kể từ khi cuộc Cách mạng công nghiệp, việc sử dụng các kim loại đã là một trụ cột của nền kinh tế ở nhiều nước phát triển, đặc biệt là. | Chapter 12 Soil and Water Pollution - Environmental Metals and Metalloids INTRODUCTION The metals found in the environment are derived from a variety of sources. Such sources include natural weathering of the earth s crust mining soil erosion industrial discharge urban runoff sewage effluents pest or disease control agents applied to plants air pollution fallout and a number of Since the Industrial Revolution the use of metals has been a mainstay of the economy in many developed countries particularly the . However the increase of mining for metal ores as well as the combustion of coal as an important energy source in many countries has led to the health and exposure risks to workers and the public becoming of increasing concern. While some metals found in the environment are essential nutritionally others are not. The latter include some heavy metals a group of metallic elements that exhibit certain chemical and electrical properties. Heavy metals generally have a density greater than 5 g cm3 2 and an atomic mass exceeding that of calcium. Most of the heavy metals are extremely toxic because as ions or in certain compounds they are soluble in water and can be readily absorbed into plant or animal tissue. After absorption these metals tend to bind to biomolecules such as proteins and nucleic acids impairing their functions. For a long time the effects of toxic heavy metals on living organism were considered almost exclusively a problem of industrial exposure and of accidental childhood poisonings. Until recently much of the literature concerning the subject dealt with experiments relating to exposure of children to lead-based paint. Although significant progress has been made in reducing the levels of a number of toxic metals in the environment as exemplified by the marked reduction in atmospheric lead Pb pollution in the past three decades problems with heavy metals still exist in many parts of the world. According to the . Centers for Disease
