|| 97 sor
||Riaszto szunyogriasztok! (mind)
|| 47 sor
|+ - ||meadows-rovat (mind)
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YOU CAN'T LIVE ON THE POND AND HAVE THE POND
Les Kaufman called me from the Boston University Marine Program, sputtering
about Title Five. "How do you get people to care about little brown fish?" he
grumbled. "I always thought clean ponds were a New England thing. Now we're
turning the place into Texas, where you can't see three inches into the water,
and no one seems to care."
"Hey, slow down!" I cut in. "What are you talking about?"
"Title Five," he said. "You know, exotic wildlife isn't the only kind that's
endangered. The local stuff is in trouble too. Maybe the problem is that the
glaciers pretty much wiped away the local intrigue, so the backyard fauna
aren't so spectacular."
Dr. Les Kaufman normally studies the brilliantly colored and rapidly
disappearing cichlid fish of African lakes. What prompted this call, he
finally got around to telling me, was a meeting some time ago with Karsten
Hartel of Harvard, who studies the freshwater fishes of New England. Hartel
told Kaufman that he could hardly find the bridle shiner any more.
"Bridle shiner -- what's that?" I asked.
"It's a fish about two inches long, with a black stripe from nose to tail,"
said Kaufman. "Its scales are lined with black, so the upper part of its body
looks like wrought-iron grillwork. It used to be one of the most common fish
around here. Now the New England Aquarium has done a survey and found that
shiner is gone from three-fourths of the ponds it sampled in eastern
Massachusetts -- all ponds where the shiner had been known to occur. It made
me feel guilty; here I am floating around trying to save fishes in Africa and
ignoring my own back door."
He launched into an explanation of why New England waters are so clear. "Pond
life in this part of the world is basically a hostile affair. There aren't
many nutrients. When you swim out in the water, you're not suffocated by
plants or scum. The native fish like it that way. So do the people, or so I
The ponds are scumming up because of septic tanks, golf courses, roads, lawns,
all of which leach nutrients into the water. People unknowingly spread exotic
weeds as they move boats from pond to pond. Fishermen find native fish
uninteresting, so they bring in largemouth bass, walleye, muskie. All those
changes do in the bridle shiner.
"How?" I asked.
"Well, the nutrients cause the weeds and algae to multiply. They crowd out the
native vegetation, then they die back and make a slimy mess in the water. The
common treatment at that point is to drain the pond, dredge it and refill it.
By that time you've lost insects, fishes, amphibians. Whatever you've got
left, it's not a native system, hardly even a system."
The bridle shiner, the survey suggests, can survive in the presence of
introduced largemouth bass, as long as there's native vegetation on the bottom
for the shiner to hide in. It can survive in gopped-up water as long as there
are no bass. What the shiner can't seem to handle is the combination of bass
plus gop. Kaufman guesses that's because the gop creates floating weeds on the
surface, which shade out the bottom plants and destroy the shiner's habitat --
and muck up the pond for people, too.
"What does this have to do with Title Five, whatever that is?"
"The state is dragging its feet on listing the bridle shiner as a threatened
species. They're sorry about the loss of the fish, but they're afraid listing
it will upset developers, because then they'll have to obey Title Five."
"And what," I asked, losing patience, "would that mean?"
Title Five, it turns out, is a Massachusetts regulation intended to keep
development from overtaxing the waste treatment facilities of a community. If
it were strictly enforced, and if the nutrification of ponds were considered a
serious problem, houses couldn't be built right on the shores of ponds.
Drainage from lawns and septic tanks wouldn't be allowed to flow directly into
the water -- there would have to be buffer zones of vegetation to absorb
nutrients, or full-scale sewage systems to divert wastes entirely. Pondside
developments would be more regulated, less dense, more expensive.
I was beginning to picture the story some developer would make out of any
attempt to protect the bridle shiner. I could just hear it in a Congressional
hearing: crazy enviros stop a million-dollar lakeside building project to save
a worthless little fish that no one ever heard of. Kaufman was painting a
more complicated, more complete picture.
"This isn't about saving one fish. It's a clearcut case where the loss of an
animal goes along with something of deep value to people -- crystal clear
ponds." Clear ponds. The very asset that makes building projects worth a
million dollars. The goose that lays the golden eggs.
"Look, it's very simple," Kaufman said. "Anyone can understand it. You can't
put houses right on the pond and still have the pond."
(Donella H. Meadows is an adjunct professor of environmental studies at
|+ - ||Riaszto szunyogriasztok! (mind)
Elso olvasasra ugy tunhet, hogy a KORNYESZ olvasoitol mind
foldrajzilag, mind erdeklodesuk szempontjabol talan egy kisse tavol esik
a kovetkezo hir. De mivel nyakunkon a nyar es a szunyogok, nem
felesleges egy ujabb toxikologia rejtely lehetseges megoldasara felhivni
Jol ismert, hogy a Kuwait iraki megszallasat koveto Perzsa-obol
haboruban resztvett 750 ezer katonabol mintegy 3000 hazateres utan
rejtelyes idegrendszeri tuneketre (memoriazavarok, fejfajas, levertseg,
izomfajdalmak, reszketes) panaszkodott Ezt az un. Perzsa-obol haboru
szindromat (POHSz) nem okozhatta sem kemiai sem biologia fegyver,
mivel ezeket az irakiak bizonyithatoan nem hasznaltak. Abou-Donia
(Duke Egyetem, Durham, NC, USA) es munkatarsainak frissen kozolt
vizsgalata szerint a tunetek a katonak altal rendszeresen hasznalt
harom vegy/gyogy/szer egymast potencirozo hatasabol eredhetnek.
(Erdekessegkent: a munkat a valamikori elnokjelolt texasi Ross Perot
tamogatta. Hallo, Palotas J., hol vagy?)
Az idegrendszeri mergezeseknel modellkent gyakran hasznalt
tyukokkal vegzett kiserletek azt mutattak, hogy a foszfortartalmu harci
gazok hatasat kivedo piridostigmin gyogyszer, a pl. katonai ruhazatba
impregnalt permetrin, egy piretroid tipusu rovaroloszer es a kozismert
rovarriaszto dietil-toluamid (DEET) egyutt joval mergezobbek, mint
kulon-kulon. A magyarazat: a piridostigmin meggatolja a permetrin es a
DEET nemtoxikus anyagokka valo lebomlasat. Igy tehat a korabban
biztonsagosnak itelt alkalmazasi dozisban az idegmergek joval
nagyobb mennyisege jut kozponti es periferias idegrendszerbe, ami mar
jellegzetes toxikus tuneteket valt ki. Figyelemre melto, hogy mar ket
anyag koktelja is potencirozo hatasu!
Itt utalok a KORNYESZ 237-re, melyben ugyancsak onmagaban
artalmatlannak itelt anyagok egymast igen erosen potencirozo
hatasarol olvashatunk (igaz, az ott emlitett hormonhatasu vegyuletek
mas biokemiai tenyezok miatt okoznak galibat).
Mivel emberekre vonatkozo adatok a fenti szerekkel kapcsolatban
meg nem allnak, rendelkezesre, egyes kutatok szerint a POHSz
kialakulasaban mas tenyezok (pl. vakcinak altal kivaltott
immunrendszeri zavarok) is kozrejatszhattak.
Szoval, figyelem: nyari kirandulasaink, strandolas alatt csinjan
banjunk a rovarriasztokkal (is): ne kenjunk / spricceljunk magunkra
egy egesz dobozt. A szunyogcsipesnek Magyaro.-n persze nincs
komolyabb kovetkezmenye, de mi legyen a veszelyesebb rovarok, a
virusos betegsegeket terjeszto kullancs elriasztasaval??
Hazai aktualitasu kornyezettoxikologiai kerdes: mi tortenik a borre
kent es a vizzel lemosodo, illetve vizelettel kiurulo es igy a kornyezetbe
kerulo evi esetleg tobb szaz kg DEET-tel? Vajon ez az anyag is
hozzajarul-e a balatoni halpusztulashoz?? (Ott is permeteznek