Gevare van loodvergiftiging

My beskeie mening as iemand wat jag (miskien nie soveel soos ander nie, maar darem 10 keer per jaar), natuurbewaarder en chemikus is die volgende:

Rakende die loodkwessie: die gebruik van lood in projektiele is standaardpraktyk oor die wêreld heen omdat die soortlike gewig (digtheid) van lood net onder die van goud en wolfram lê en dienooreenkomstig die gewenste massa per volume verskaf om 'n effektiewe projektiel te maak.

1. Lood is een van die sg. swaarmetale wat op sekere natuurlewe 'n ernstige impak het en kan hê. Dis 'n gedokumenteerde feit dat die Kaliforniese kondor se feitlike uitsterwing deels aan loodkoeëls toegeskryf kan word. Uit my eie werk met aasvoëls is die ervarings as volg:
as 'n kransaasvoël Gyps coprotheres slegs vyf gram lood van 'n tipiese koeël inkry, is die voëls gewaarborg om binne vyf weke of selfs korter te vrek.
Twee jong King vultures Sarcorampus papa is in die Nasionale Dieretuin in Pretoria dood nadat hulle klein Diana-loodkoeëls ingekry het omdat kinders windpistole in die Dieretuin ingeneem en afgevuur het.
My student, dr. Erica van Wyk, het op vyf spesies aasvoëls gewerk en die bloedtoksikologie ondersoek en die resultate was kommerwekkend want meeste van die eksemplare wat in die ondersoek gebruik is het sub-letale vlakke van lood in hul sisteme gehad.

2. Lood vir haelgeweerjag is in die hele Kanada en verskeie VSA state verban as gevolg van loodkontaminasie.

3. Daar is geen rede om te glo dat lood nie nadelig op aasdiere sal inwerk nie: ek het verskeie aasvoëls in my lewe verloor as gevolg van loodvergiftiging, as gevolg van jag, as gevolg van kwes, ens.

4. As mens 'n X-straalfoto van 'n bok se blad neem waardeur 'n gewone loodkoeël is, dan sal jy nooit ooit daardie vleis gebruik nie want die spikkels lood is soos 'n mosaiek in die vleis. Om sulke vleis vir jou hond aan te bied is stadige moordpleeg.

5. Lood is 'n bio-akkumulatiewe metaal wat met tyd saam in die organisme opbou tot dit toksiese vlakke bereik en daarna sal die organisme kliniese simptome vertoon en vrek indien drastiese terapie nie toegepas word nie. Om lood uit 'n organisme te loog, verg spesialisbehandeling en glo my dat ek met jare se ervaring nog nie daarin kon slaag om 'n aasvoël suksesvol te behandel nie, selfs nie saam met 'n span bekwame veeartse nie.

6. Suiwer koper projektiele is juis ontwerp om die drukprobleem met monolitiese koeëls te bowe te kom. Alhoewel die snelheid van die projektiele hoër is as die van loodkernkoeëls is die resultate in die jagveld ongelooflik. Ek het nog nooit 'n koeël uit enige dier gehaal nie en die skote het almal die diere effektief en netjies gedood. Vleisskade is uiters gering en lood is AFWESIG in die proses.

7. As 'n bewaringspersoon kyk ek skeef na mense wat nie van hulle oeroue tradisies wil afwyk nie en steeds voortgaan met praktyke wat onaanvaarbaar uit 'n moderne oogpunt is. Daar is te veel mense op die aarde en as elkeen sy of haar tradisies wat negatief vir die natuur is wil handhaaf, is die aarde oppad na 'n uitwissing van alle lewe.

8. Soos ons in Engels sê: 'by all means', skiet jou loodkernprojektiele op die skietbaan waar die lood gevang word, maar in die jagveld het die jagter 'n verantwoordelikheid om die natuur te bewaar en nie die plek vol ekstra toksiene te pomp nie.

Skrywer: Prof Gerhard Verdoorn.
Bron: SA Jagter / Hunter November 2006.

Om dit 'n stappie verder te voer:
Hoekom die moontlikheid van loodvergiftiging, hoe gering ookal, op ons skietbane te laat voortleef?
Dit terwyl suiwer koperkoeëls soos GS Custom se geweldige, hoë graad van eenvormigheid van een vervaardigingslot tot die volgende dit moontlik maak om soveel minder koeëls hoef weg te skiet om akkuraatheid elke keer te toets.
Gebruik die beste en kry die beste resultate!

HawkWatch -
Hunting and fishing result in the deposition of thousands of tons of lead into the North American environment every year. While foraging, wildlife species can be exposed to lead and may die of lead poisoning. Such mortalities have been documented in a wide array of birds including waterfowl, shorebirds, piscivores, songbirds, and raptors. Poisoning of California Condors, Common Loons, Trumpeter Swans, and Bald Eagles is of special concern because it may have population-level effects.

Recent research reveals that legislation banning the use of lead shot in waterfowl hunting has reduced the amount of waterfowl lead poisoning and the extent of Bald Eagle lead poisoning. Such declines demonstrate that switching to nontoxic shot can protect wildlife populations and improve the environment.

Similar regulations are being established to minimize lead deposition associated with upland game hunting and fishing. Available alternatives provide hunters and anglers with options that allow them to perform well, to excel at their sport, and to minimize lead exposure to wildlife. Because hunters and anglers cherish the outdoors and value wildlife, they may find that the increased cost of ammunition and tackle is offset by the knowledge that they are helping to protect wildlife from lead poisoning. This recognition may begin to fuel voluntary shifts to nontoxics in areas without regulatory restrictions.

To facilitate such shifts, HawkWatch will engage in an outreach effort to expose sports enthusiasts to the dangers of lead tackle and ammunition and to the benefits of using nontoxic alternatives.

Lead poisoning eyed as threat to California condor -
By John Ritter, USA TODAY - Posted 10/23/2006.

One of the great feel-good environmental stories of the past 30 years is the recovery of the majestic California condor, North America's largest bird, a scavenger-turned-billboard for the campaign to save endangered species.

On the brink of extinction, saved by a captive-breeding program, the condor population has grown from just 22 birds in 1982 to 289 today; 135 are in the wild and more are released every year.

Even so, condors have failed to gain a secure foothold in the hills and deserts of California and Arizona because of lead poisoning, the most often diagnosed cause of death, environmentalists say.

Environmental groups say the most likely source is condors' eating of game that was shot by hunters using lead bullets. Frustrated that most hunters have not switched to substitutes, the Natural Resources Defense Council (NRDC) and other groups notified California officials in July that they will sue under the Endangered Species Act to force a ban.

At a meeting of state fish and game staff this month to discuss potential hunting-rule changes to recommend, the groups again asked for a ban on lead ammunition. A decision is likely early next year. Lead shot used in shotguns to hunt waterfowl has been prohibited since the 1980s.

Andrew Wexler of the NRDC's endangered species project says, "The commissioners have a historic opportunity. It's a mystery why they've resisted a ban because the scientific evidence is so overwhelming."

That evidence isn't conclusive, says Steve Williams, president of the Wildlife Management Institute, whose goal is to restore North American wildlife. "There are other potential pathways for lead," says Williams, a former director of the Fish and Wildlife Service in the Bush administration. "I wouldn't speculate on what those other sources may be." He's "happy to learn that hunters are taking action on their own" but says more study is needed.

Many hunters who have tried alternatives, mainly copper bullets that don't poison wildlife, find them as good or better than traditional ammunition, though more expensive. A high-performance copper bullet costs $2 to $2.50, about $1 more than lead.

At a "free shoot" last weekend at a range near Pinnacles National Monument in Central California — prime condor habitat — hunters and ranchers were invited to try copper bullets. In questionnaires filled out afterward, more than 90% approved.

Alternative efforts
Some groups, such as the National Shooting Sports Foundation, oppose a ban, though they support efforts to reduce lead exposure in condors and other animals that feed on carrion, eagles among them. These groups say voluntary hunting practices would achieve the same goal, including removing carcasses from the field and burying "gut piles," an animal's inedible portions.

"Clearly hunters have shown in studies that they're very willing to adopt one of those management steps," says Rick Patterson, director of the shooting foundation, which sets standards for firearms and ammunition manufacturing. He says studies have shown that some hunters resist the added cost of copper bullets.

Under the microscope
The coalition that threatened the lawsuit says a July study that analyzed blood of condors in the wild and compared it with blood of captive birds proves that lead from bullets is poisoning and killing condors.

The study in the journal Environmental Science & Technology was the first to identify a lead isotope in bullets bought at retail outlets in condor country and then match it to lead found in condor blood. Twenty of 26 condors sampled had high lead levels, and many exceeded levels toxic to humans.

"It's very analogous to situations we still encounter with kids who eat chips of lead-based paint," says Donald Smith, a professor of environmental toxicology at the University of California, Santa Cruz, who worked on the study. "The chip might be small but have very high levels of lead in it, and it doesn't take much to cause lead poisoning."

Supporters of a lead ban say hunters and their families also are at risk. Studies in Greenland and Canada have found elevated lead levels in people who eat seabirds and other animals shot with lead ammunition. On contact, a lead bullet fragments into tiny pieces and powder that disperses well beyond the wound.

"Subsistence hunters especially who hunt for most of their protein, if they have kids in the household, to me that's a significant potential risk," Smith says.

Condors, flying as high as 15,000 feet with 9-foot wingspans, spot a meal and go straight to the bullet wound, because that's the easiest place to feed. They'll eat almost any dead mammal, from a squirrel to a cow.

California's fish and game commission last year rejected an emergency ban on lead bullets, and bills in the Legislature to outlaw them in hunting died twice. Groups such as Ventana Wildlife Society urge an approach like Arizona's. The state offered free non-lead bullets to hunters last year in areas frequented by condors. Nearly two-thirds accepted them, and condor lead-exposure rates fell 40% from 2004, according to Arizona's game and fish department.

Ventana wants California lawmakers to approve $200,000 a year for five years to pay for coupons that hunters could redeem for free or reduced-price non-lead bullets. "That's a million bucks. Big deal," says Ventana's president, Kelly Sorenson. "Compared to the total cost we're spending on the condor recovery program, it's a small price to pay."

That program, involving state and federal agencies, zoos, foundations and universities, has cost at least $40 million, the U.S. Fish and Wildlife Service says.

"No sensible decision can be made any longer without taking into account not only the world as it is, but the world as it will be." ~ Isaac Asimov.