Bioassay of Surface Quality/Chesapeake Bay, Maryland

摘要

For millennia, fresh water streams have been used by human communities as aconvenient device for flushing away wastes, thereby increasing the carrying capacity of the local terrain. This worked well until large scale commercial farming and the industrial revolution allowed unprecedented population densities. The intense concentration of people in the 19th and 20th centuries, and the ability of modern populations to collect and concentrate chemical elements and compounds at both the landscape and the biosphere scale, as well as to physically modify entire watersheds, has greatly altered the status of a very high percentage of the earth's streams. The industrial development of entirely new chemical compounds, many of which are toxic or carcinogenic, and are routinely available on farms and in homes, has considerably aggravated control of water pollution.