Logo
Prev
Bookmark
Rotate
Print
Next
Contents
All Pages
Related Articles
Browse Issues
Help
Search
Home
'
National Geographic : 1981 Nov
Contents
14 13 12 ALKALINE pH SEAWATER AND BAKINGSODA I IN ADIRONDACK O LAKES,1930 S DISTILLED WATER 98765 pH 6.5 6.0 LOUT). ). 5.5 wBr 4W PI:I. Po DIAGRAMBY N 5.0 4.5 TL NATIONAL GEOGR Despite the insidious ease with which acid rain precursors can travel, regions where its impacts are noticeable are, as yet, relatively few and predictable. They lie mainly in the industrialized belt of the Northern Hemi sphere, downwind from dense concentra tions of power plants, smelters, and urban sprawls. Often they are mountainous, and as such they frequently bathe in rains and snows. Well watered, these areas are typi cally clothed in forests and laced with lakes and streams. Their soils often are thin-a fragile flesh spread over a skeleton of glaci ated bedrock. This describes the Adirondack Moun tains almost perfectly. It also fits other acid rain hot spots, such as rock-ribbed Nova Scotia, where nine acidified rivers no longer support salmon reproduction, and the Canadian shield country of southern On tario and Quebec. Other vulnerable areas include the Great Smoky Mountains, hundreds of sensitive lakes in Wisconsin and Minnesota, the Pa cific Northwest, the Colorado Rockies, and the Pine Barrens of New Jersey. A striking parallel to New York's Adirondacks exists 660 IV , Scientific shorthandfor the level of acidity, apH scale (left, upper) rangesfrom highly acidic-battery acidat pH 1.0, right-to highly al kaline-lye atpH 13, left. Distilled water,atpH7.0, is neutral,neither acidic nor alkaline. Because pH values arelogarithmic,lemonjuice 2A o at pH 2.3 is ten times as acidic as ACIDIC vinegarat pH3.3. 035 Even uncontaminated rain is slightly acidic-pH5.6-contain ing carbonic acid formed by the reaction of water with carbon dioxide. Acid rainis anything less than that. A graphrelatingwateracidity to its aquatic effects (left, lower) shows mussels dying at pH 6.0, mayflies and smallmouth bass at pH 5.5, and so on. Acid-tolerant insects such as water boatmen and whirligig beetles survive and multiply even atpH3.5. WILLIAM H. BOND in Scandinavia, where galaxies of lakes glint among low mountains watered by acid pre cipitation drifting northward from Europe's industrial belt. Conversely, certain areas can tolerate acid fallout because of the neutralizing effect of their alkaline soils-a natural resistance known as buffering. Limestone regions such as the Allegheny Mountains enjoy this im munity. A similar buffering takes place in much of the Midwest, where alkaline dust blown from the West can also neutralize acid rain before it falls to the ground. Nature Far Outdone by Man How long have we had acidic rain? Prob ably since the first rains fell on a new-formed planet. Volcanic eruptions, forest fires, and even the slow bacterial decomposition of organic matter produce sulfur or nitrogen compounds. Lightning bolts form NOx from the nitrogen in earth's atmosphere. When administered in nature's measured doses, this atmospheric "pollution" can serve as a wholesome, gentle way of fertiliz ing the landscape. In good faith could Shakespeare extol the "gentle rain from National Geographic,November 1981 (j.4
Links
Archive
1981 Dec
1981 Oct
Navigation
Previous Page
Next Page