Lead weights -- going the way of the Dodo bird?

[sactomags]

Rumors have been going around a bit that the government (I think it is just being tossed around in California ... where many things start and others follow) may be stepping in some time in the future to disallow lead weights for divers because they may get lost and the lead in the water can become toxic to the marine life. I know that latter is true, and I know many divers also "rescue" those lost weight belts/pockets, etc. This may also affect those who fish with lead weights.

So, what alternatives should we be looking at to replace the lead weights? Rocks don't fit in pockets too well, plus you are supposed to take nothing and leave only bubbles ... although I may joke about this, I also believe that it may become an issue.

Thoughts, anyone?

Margaret

 

[Scubaroo]

Wouldn't the government be better off doing something about the ridiculous number of plastic shopping bags, condoms, styrofoam beads, etc that end up in the ocean, causing real observable damage, rather than overhyped lead toxicity?

A stranded whale that died in Queensland Australia about 2 months ago was found to have over 8 square metres (about 86 square feet) of plastic sheeting in its gut, along with over 100 plastic shopping bags - all picked up during the course of feeding. I've never heard of a whale or a fish choking to death on a dive weight, or dying from lead toxicity caused from lost fishing weights.

Lead shot was gradually phased out in Australia from waterfowling, because it was found that in heavily hunted wetlands, birds were picking up the lead shot for use as gizzard stones, and slowly being poisoned. Somehow I don't think the odd lost weightbelt is going to have to same effect on sealife.

Are there any studies showing increased lead levels in the marine environment in areas of diver activity?

 

[Green_Manelishi]

How many "marine lifes" can pickup a 2lb lead weight from the
bottom and swallow it? PERHAPS there is a problem with
burst-open lead-shot filled "soft" weights but who truly knows.

One thing is for sure, the Nature-NAZIs have another cause
and *facts* will not deter them from their agenda.

 

[VTWarrenG]

As I understand it, and I may be wrong (I'll look up the MSDS when I get to work) lead in a solid bar form, like a diving weight, will not dissolve in water.

Even if it does, if you do the math, you'll see that even twenty pounds of dissolved lead in the ocean is completely negligible.

People have been blasting (literally) tons of lead, in the form of shot from shotguns, into the rivers and estuaries and bays of the world for hundreds of years now, in a sport called "waterfowl hunting." If there's any concern about correcting marine lead exposure, it'll have to start with the hunters' lead shot. The paltry few abandoned weight belts out there (there are usually only a couple of them in even the most heavily-dived spots) are a non-issue.

- Warren

 

[VTWarrenG]

Ok... here's some humbling information.

1) Lead, in metallic form, is insoluble in water. http://physics.okstate.edu/support/safety/msds/7439-92-1.html

2) According to Encarta, the world's ocean has a volume of 1,347,000,000 cu km, which is 1.347 x 10^21 L. Various environmental sites list the average concentration of lead in seawater as around 30 ng/L. (Some rivers have concentrations of up to 3,000 ng/L, where 100 ng/L or so is the threshold for safety.) Given this, we can realize that there are 40,410,000,000 kg (88,902,000,000,000 lb) of lead dissolved in the ocean. If there were some way to remove all the lead from the ocean, there'd be enough lead to make 4,445,100,000,000 20-lb lead weight belts.

Take comfort in the fact that the weight belt you dropped last week is only going to change ocean lead concentrations, if it dissolved completely (which it won't), by 22 billionths of a percent.

- Warren

 

[Scubaroo]

Good work VTWarrenG

 

[herman]

Warren,

Lead shot has been ban for waterfowl hunting in the US for about 10 years now, not that it was much of a problem in the first place.

 

[VTWarrenG]

Of course, my oh-so-mathemetical evaluation may have some pitfalls, too -- it is certainly possible (though unlikely) that some marine animals would regularly eat lead shot. Though the shot is not soluble in water, it IS soluble in their gastric juices. So, the animal would suffer the consequences of such snacking. In addition, it may be possible (though I have no idea where to find the info) that some marine organisms could anchor themselves on a solid lead weight, secrete chemicals which would dissolve the lead, and thus poison themselves. Either of these situations is pretty far-fetched though, and only very local in scope.

It seems that solid-form lead weights present no threat to the environment. Lead shot, simply because of its bite-size pieces and tasty appearance (subjectively speaking, of course), is probably higher on the threat list, but is only a significant threat in situations like the one given by bengiddins.

There are plenty of wrecks out there in shallow water that are literally chock-full of lead shot. Environmentalists have so far made no effort to retrieve the shot, despite how easy it would be.

If lead weights are phased out, it'll most likely be due to people's misunderstandings about lead -- it's only dangerous to people by ingestion. You've seen the Prop 65 signs in your LDS, right? "Lead is a known carcinogen, etc." If it gets phased out, it'll be because people are worried about their little toddlers nibbling on them -- not because lead presents any demonstrable large-scale threat to marine life.

- Warren

 

[VTWarrenG]

herman,

Excellent.

- Warren

 

[sactomags]

I'm going to keep all this info handy should it develop into anything more than rumors!

Thanks!
Margaret