IN THE LAST FEW WEEKS, the Reagan Administration has stepped up its war on the environment. Its lobbying for the long-expected assault on the Clean Air Act is chugging along steadily. And among the proposals the Department of the Interior and the Environmental Protection Agency have recently put forth for Congressional consideration are plans to sell hundreds of millions of acres of federally held lands, in an effort to defray part of the staggering federal deficit.

The Administration has also announced that it hopes to enhance American mineral production by opening up huge tracts of government lands for exploitation. In light of the relaxed strip mining regulations sought by President Reagan, Interior Secretary James G. Watt and the other members of the Rape America Today coalition, these developments have placed America's natural heritage in danger unseen since the days of the Dust Bowl.

The latest Administration environmental proposal marks the opening of the battle on a new front: the government now wants to gut the Clean Water Act of 1972, which is currently up for renewal. In line with this wish, the EPA has announced it will press Congress for 14 alterations in the act.

But while supporters parade the changes as making federal regulations more feasible, the outlined program would, in reality, make the act a dead letter. Most important, the Administration wants to excise the central clause of the act--the one requiring national standards for the treatment of industrial wastes. It also proposes to extend permits for discharging wastes from five to 10 years, and to cede to municipal or state authorities the power to determine tolerable levels of toxicity in local waters

It is hard to imagine a more dangerous agenda. With the wholesale destruction of North American streams and lakes at the hands of acid rain already underway, with every week bearing a host of new tales of illegal or forgotten chemical dumpings and with every new report of the myriad threats to health created by technological advances, the last thing this nation needs is the Administration's effort to contaminate more water and ruin more rivers and ponds.

What's more, the reasoning behind the campaign to amend the act is spacious. The union of Republicans and industrial state Democrats who support the changes in the act contend it will stimulate the economy and create jobs. Yet this seems merely a smokescreen to salvage ailing and uncompetitive industries, the legislators and bureaucrats who favor the changes are ignoring recent reports which demonstrate that regulation creates more hobs than it eliminates.

They also fail to realize that investment in pollution control more than pays for itself in health cost savings. And the idea that local authorities could effectively regulate waste disposal is absurd, it seems none of those who militate for relaxed standards are aware that the wind blows and the rivers run, spreading pollution from one noxious pipe or smokestack all over the country. It is for just these sorts of problems that we have a federal government.

The various forces lined up against the environment are, at this year's Congressional battles will be fought on the issues of tion have a good measure of bipartisan support for the amending of the Clean Air and Water Acts. The great likelihood that this year's Congressional battles will be fought on the issues of the budget military spending and the economy--and the general dissatisfaction with the economy--mean environmental issues will get short shrift and could be fodder for political deals

But the path is clear. If Americans do not speak out quickly and loudly in favor of a clean America, if the alliance of politicians, bureaucrats and industrialists is not defeated, then the country could be well on its way to becoming uninhabitable.