Paying at the Park, PCBs and Chlorinated Paper.

What are the pros and cons of charging national park entry fees?

--Robert Hill, Pensacola, FL

In some ways, national parks' twin goals of preserving American ands while opening them up to visitors are paradoxical. As more and more visitors pour into parks and campgrounds with cars and food, keeping lands and wildlife in their original, pristine state presents more of a challenge.

One of the obstacles to meeting this already difficult goal is money. According to the National Park Conservation Association, "For more than a generation, parks have been on a budgetary starvation diet." But in 1996, the Recreational Fee Demonstration Program began allowing the Forest Service, Bureau of Land Management (BLM), National Park Service and the Fish and Wildlife Service to charge admission fees to their lands on a trial basis. Eighty percent of the revenue generated by this program is reinvested in the park to protect natural resources and build and maintain campgrounds, facilities and trails.

Some supporters say the program also benefits taxpayers, since only those who use the parks have to pay for them. Lee Larson of the BLM says, "The program has been a great success. I don't know what we'd do without it."

But not everyone gives such rave reviews. The American Lands Alliance and the Sierra Club worry that the program could turn national parks into commercial enterprises, and that the recreational fees provide incentives to develop the land. CONTACT: American Lands, [phone], www.ameri canlands.org.

What are PCBs, and how do they harm the environment?

--Dale Roach, Waterford, MI

Polychlorinated biphenyls (PCBs), which are man-made substances, are most commonly used in manufacturing transformers and capacitators, but they are also found in such products as carbonless copy paper, pigments and casting waxes. Though banned by the Environmental Protection Agency in 1977 due to adverse health and environmental effects, PCB problems are still ubiquitous. According to Janet Kwiatkowski, an environmental analyst with the Connecticut Department of Environmental Protection (CT-DEP), PCBs are "no longer used in industry, but have now entered the environment."

The effects of PCBs are still being studied. The CT-DEP reports that not only are PCBs "resistant to degradation," but they also tend to "bioaccumulate" in the food chain. Fish, for example, absorb PCBs in the water. Over a lifetime, the levels of PCBs in their tissues become much greater than levels in the surrounding water. When birds swallow these fish, toxins are passed on to their tissues, thus bioaccumulating up the food chain. A recent U.S. Fish and Wildlife Service study shows that high exposures to PCBs can cause death in adult and baby birds, and lower exposures may cause reproductive and fertility problems. CONTACT: Environmental Protection Agency, [phone], www.epa.gov/pbt/pcbs.htm.

What environmental and health problems are associated with chlorine production and its use in the paper industry? --Misty Landletter, Tempe, AZ

Chlorine is most readily associated with swimming pools, but some uses of the element can be much more dangerous. Chlorine-gas-based paper-bleaching processes release dioxins and furans, which the Environmental Protection Agency (EPA) lists as "priority persistent bioaccumulative and toxic chemicals." Once dioxins enter the environment, they tend to enter our food supply as well. People's main exposure to dioxin, which the EPA characterizes as a likely human carcinogen, is from consuming animal fat in beef, pork, poultry, fish, milk and dairy products. Animals are not immune to the f effects of this toxic chemical either. Among other problems, dioxins can alter their hormone systems and fetal development, reports the EPA.

Recently, however, paper producers have be gun to discover that it's possible to produce bright white paper without using chlorine-gas-based bleach. Elemental Chlorine-Free (ECF) bleaching uses chlorine dioxide, a process that releases only undetectable levels of dioxins into the environment. The Chlorine Free Products Association (CFPA) notes that though nearly 60 percent of paper mills still use chlorine gas, many are switching to chlorine dioxide. It is also possible to bleach paper through an oxidation process that uses no chlorine at all. The CFPA now labels products as Totally Chlorine Free (TCF), which means no chlorine or chlorine-containing compounds are used in its production, or Processed Chlorine Free (PCF), which labels recycled paper that has not been re-bleached with chlorine. CONTACT: CFPA, [phone], www.chlo rinefreeproducts.org.

Send your questions about environmental issues, from the personal to the political, to Ask E, P.O. Box 5098, Westport, CT 06881, or by e-mail to [e-mail]. Please keep your questions brief and type them double-spaced. Include your full name, address and a daytime phone number.