Week of 3/29/2009

Dear EarthTalk: I am looking at possibly buying a house that is very close to a gasoline station. Is it safe to live so close to a gas station? What concerns should I have? I have toddler and infant babies.

—Ranjeeta, Houston, TX

Despite all the modern health and safety guidelines they must follow, gas stations can still pose significant hazards to neighbors, especially children. Some of the perils include ground-level ozone caused in part by gasoline fumes, groundwater hazards from petroleum products leaking into the ground, and exposure hazards from other chemicals that might be used at the station if it’s also a repair shop.

Ozone pollution is caused by a mixture of volatile organic compounds, some of which are found in gasoline vapors, and others, like carbon monoxide, that come from car exhaust. Most gas pumps today must have government-regulated vapor-recovery boots on their nozzles, which limit the release of gas vapors while you’re refueling your car. A similar system is used by the station when a tanker arrives to refill the underground tanks. But if those boots aren’t working properly, the nearly odorless hydrocarbon fumes, which contain harmful chemicals like benzene, can be released into the air.

Higher ozone levels can lead to respiratory problems and asthma, while benzene is a known cancer-causing chemical, according to the National Institutes of Health (NIH). The quest to reduce ozone levels has led the state of California to implement a more stringent vapor-recovery law, effective April 1, 2009, which requires that all gasoline pumps have a new, more effective vapor-recovery nozzle.

Gas stations can pose significant hazards to nearby residents. Some of the perils include ground-level ozone caused in part by gasoline fumes, carbon monoxide from car exhaust, groundwater pollution from oil and gas leaking into the ground or from leaking underground storage tanks, and exposure hazards from other chemicals that might be used if the station is also a repair shop.© Getty Images

Underground gasoline storage tanks can also be a problem. The U.S. Environmental Protection Agency (EPA) estimates that there are some 660,000 of them from coast-to-coast. Many a lawsuit has been filed against oil firms in communities across the country by people whose soil and groundwater were fouled by a gas station’s leaking underground storage tank. In the past, most tanks were made of uncoated steel, which will rust over time. Also, pipes leading to the tanks can be accidentally ruptured.

When thousands of gallons of gasoline enter the soil, chemicals travel to groundwater, which the EPA says is the source of drinking water for nearly half the U.S. If buying a home, consider its potential loss in value if a nearby underground storage tank were to leak. Gasoline additives such as methyl tertiary-butyl ether (MTBE), which has been outlawed in some states, make the water undrinkable—and that is only one of 150 chemicals in gasoline. Repeated high exposure to gasoline, whether in liquid or vapor form, can cause lung, brain and kidney damage, according to the NIH’s National Library of Medicine.

Spilled or vaporized gasoline is not the only chemical hazard if the station is also a repair shop. Mechanics use solvents, antifreeze and lead products, and may work on vehicles that have asbestos in brakes or clutches. Auto refinishers and paint shops use even more potentially harmful chemicals.

In today’s car-centric world, we can’t escape exposure completely, because these chemicals are in our air just about everywhere. But by choosing where we live, keeping an eye out for spills, and pressuring the oil companies to do the right thing for the communities they occupy, we can minimize our exposures.

CONTACTS: U.S. EPA; National Institutes of Health.

Dear EarthTalk: Do zoos have serious programs to save endangered species, besides putting a few captives on display for everyone to see?

—Kelly Traw, Seattle, WA

According to the Association of Zoos and Aquariums, Species Survival Plan (SSP) programs have helped bring several endangered species back from the brink, including black-footed ferrets, California condors and red wolves, like the one pictured here. Other programs for lowland gorillas, Andean condors, giant pandas and snow leopards, among others, have not had such clear success.© ucumari, courtesy Flickr

Most zoos are not only great places to get up close to wildlife, but many are also doing their part to bolster dwindling populations of animals still living free in the wild. To wit, dozens of zoos across North America participate in the Association of Zoos and Aquarium’s (AZA"s) Species Survival Plan (SSP) Program, which aims to manage the breeding of specific endangered species in order to help maintain healthy and self-sustaining populations that are both genetically diverse and demographically stable.

The end goal of many SSPs is the reintroduction of captive-raised endangered species into their native wild habitats. According to the AZA, SSPs and related programs have helped bring black-footed ferrets, California condors, red wolves and several other endangered species back from the brink of extinction over the last three decades. Zoos also use SSPs as research tools to better understand wildlife biology and population dynamics, and to raise awareness and funds to support field projects and habitat protection for specific species. AZA now administers some 113 different SSPs covering 181 individual species.

To be selected as the focus of an SSP, a species must be endangered or threatened in the wild. Also, many SSP species are "flagship species," meaning that they are well-known to people and engender strong feelings for their preservation and the protection of their habitat. The AZA approves new SSP programs if various internal advisory committees deem the species in question to be needy of the help and if sufficient numbers of researchers at various zoos or aquariums can dedicate time and resources to the cause.

AZA’s Maryland-based Conservation and Science Department administers the worldwide SSP program, generating master plans for specific species and coordinating research, transfer and reintroductions. Part of this process involves designing a "family tree" of particular managed populations in order to achieve maximum genetic diversity and demographic stability. AZA also makes breeding and other management recommendations with consideration given to the logistics and feasibility of transfers between institutions as well as maintenance of natural social groupings. In some cases, master plans may recommend not to breed specific animals, so as to avoid having captive populations outgrow available holding spaces.

While success stories abound, most wildlife biologists consider SSP programs to be works in progress. AZA zoos have been instrumental, for instance, in establishing a stable population of bongos, a threatened forest antelope native to Africa, through captive breeding programs under the SSP program. Many of these captive-bred bongos have subsequently been released into the wild and have helped bolster dwindling population numbers accordingly.

Of course, for every success story there are dozens of other examples where results have been less satisfying. SSP programs for lowland gorillas, Andean condors, giant pandas and snow leopards, among others, have not had such clear success, but remain part of the larger conservation picture for the species in question and the regions they inhabit.

CONTACTS: AZA’s Conservation & Science Program.

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