دانلود کتاب علم و فناوری محیط زیست

The history of any subject is the means by which the subject is studied so that, hopefully, the errors of the past will not be repeated. In the context of this text, environmental management and environmental awareness are not new, both having been practiced in pre-Christian times. What appears to have been available and known became lost and/or forgotten during the so-called Dark Ages and remained virtually lost until recent times.

As a result of the rebirth of environmental awareness, governments in a number of nations have passed legislation to deal with waste materials. In the United States, which is used as an example throughout this text, such legislation has included the following: (1) Toxic Substances Control Act of 1976; (2) Resource, Recovery, and Conservation Act (RCRA) of 1976 (amended and strengthened by the Hazardous and Solid Wastes Amendments (HSWA) of 1984; and (3) Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980.

It will be a surprise to many, and perhaps no surprise to a few, that environmental regulations are not new to civilization. Few people seriously discount the need for environmental regulations, but many will debate the levels at which they are proscribed-citing the cost as an unfair burden in a highly competitive economy. Regulation is, of course, a necessary step, but unfortunately, it provides no real incentive for proactive improvement. Regulation is still interpreted as a license to avoid the external costs of environmental impact. In contrast to this position, recent experience has demonstrated that systematic elimination of waste and environmental impact can provide net economic and VWUDWHJLF EHQH¿WV VXFK DV L KLJKHU TXDOLW\ SURGXFWV LL PRUH HI¿FLHQW RSHUDWLRQV DQG

(iii) goodwill of an informed public who will expect a cleaner and healthier environment. As regulations become more demanding and the public more aware and concerned, this incentive for environmentally conscious actions will become increasingly apparent.

Human activities have released a large number of chemicals in the environment from industrial activities and domestic activities that are detrimental to health when coming into contact with the human body. Many of these chemicals are toxic in nature and cause serious health problems in humans. Carcinogenic chemicals cause cancer, whereas many others cause various types of allergies in the skin and respiratory system. Pesticides and a host of other chemicals enter the food chain through which it reaches the human body and affects it adversely. Metals such as lead, mercury, and arsenic are introduced into the environment by industrial and domestics. These substances are toxic and cause various ailments when they enter the human body, along with food or water.