ANSWER: May 24 2012 Dear Sir,

I empathise with the long road you have trod to still not have the perfect hydrotherapy set-up for your son.

Yours' is the first diving weight enquiry I've had since I wrote the answer at Are there any lead-free Diving Weights on the market in Australia or overseas? so I've just web-searched some answers today and found the following on Wiki:

Weight belt

Weight belts are the most common weighting system currently in use for recreational diving.[1] Weight belts are often made of tough nylon webbing, but other materials such as rubber can be used. Weight belts for scuba and breath hold diving are generally fitted with a quick release buckle to allow the dumping of weight rapidly in an emergency.

A belt made of rubber is called a Marseillaise belt. These belts are popular with freedivers as the rubber contracts on descent as the diving suit and lungs are compressed, keeping the belt tight throughout the dive.[2]

Solid belt weight and pouches holding lead shot for scuba diving.

The most common design of weight used with a belt consists of plain, rectangular lead blocks with two slots in them threaded onto the belt. These blocks can be coated in plastic, which further increases corrosion resistance. These weights are often marketed as being less abrasive to wetsuits.

Some weight belts contain pouches to contain lead weights or round lead shot: this system allows the diver to add or remove weight more easily than with weights threaded onto the belt. The use of shot can also be more comfortable, as the shot moulds to the diver's body. Weight belts using shot are called shot belts. Each shot pellet should be coated to prevent corrosion by sea water, as use of uncoated shotgun shot here for sea diving would result in the lead eventually corroding into powdery lead chloride.

[END OF WIKI EXTRACT, FROM http://en.wikipedia.org/wiki/Diving_weighting_system ]

I also found an interesting discussion board thread at http://www.diveoz.com.au/discussion_forums/topic.asp?ARCHIVE=true&TOPIC_ID=18888 and if the topic had not been closed off in 2008, I would certainly have added the following points to the discussion:

- lead most definitely can be absorbed via the skin, especially if the skin is wet. I have just emailed you our "Info Pack 58 - References on skin absorption of lead" to support that statement;

- a little bit of lead is still too much. My administrator has just updated and emailed you our "Info Pack 56 - References on skin absorption of lead" to support that statement;

- if all the ways that were tried by all the contributors to that discussion board, failed to stop lead oxide dust being spread into the environment (by wearing down or breaking through a coat of paint or plastic and duct tape etc) then these methods are obviously inadequate for use of the weights in a chlorinated pool, especially if the users of that pool are prone to swallowing the pool water.

It seems that chlorinated water will over time corrode any metal, so perhaps glass marbles would suffice as weights? As long as they can be coated with a thick durable coating, that might be your best bet.

You can see a photo of such a coating at Lead-Free and Hazard Reduction Products & Services with the following:

"FSW fishing sinkers are available for worldwide distribution on ebay [http://shop.ebay.com.au/jbek1/m.html?_nkw=&_armrs=1&_from=&_ipg=25 ] and have a specially formulated outer durable polymer coating (patent pending) which has the health benefit of very little or no handling contact with lead, also the environmental benefit of very little or no lead leaching in either salt or freshwater. FSW sinkers are available in three colours and luminous, in a huge variety of sizes and shapes."

Or you can contact Paul Hodson, Fishing sinker maker , FSW.

I hope this helps. It would be wonderful if you could let me know how you get on.

Cheers

Yours Sincerely

Elizabeth O'Brien

EMAIL TWO Sent: Friday, May 25, 2012 7:58 PM

Dear Sir,

I’m so glad you raised the question of granite. That reminded me that I once came across a stone supply company for aquariums. Presumably such stones would have to be non-toxic (for the sake of the fish) and might be able to be included inside the headrest.

The lead in fishing sinkers and diving weights is inorganic lead which is just as deadly as organic lead if you get it into you! A lead assessor once told me there’s enough lead in one fishing sinker to kill thousands of children, if they each ate a tiny portion of it.

My colleague found bismuth fishing sinkers are available for purchase online but according to http://en.wikipedia.org/wiki/Bismuth there are some toxics concerns with bismuth. Encouragingly however, the ATSDR – www.atsdr.cdc.gov - does not have a bismuth toxicology fact sheet. They’re the ones I usually turn to for the low-down on toxics.

I’ve sent a request for other non-lead chlorine-tolerant weight ideas to several hundred toxics campaigners globally so I will forward any more suggestions that come in.

Cheers

Elizabeth

EMAIL THREE Sent: Sunday, May 27, 2012 11:53 AM

Subject: Substitution - a chlorine-safe substitute for lead weights

Dear Sir,

I’ve received the following three replies which suggest three solutions: swimmers’ in-pool training weights, sand or beach stones. [I’ve web-searched and emailed an inquiry re: in-pool training weights to a swimmers’ equipment supply company in Australia and will send you the reply if it is useful.] Plus: “check with people in the occupational therapy and rehabilitative medicine field.” What do you think?

Elizabeth

 EGROUP ANSWER ONE From: Dr Alison Bleaney Sent: Friday, May 25, 2012 9:50 PM

What do swimteams use for training weights in their training pools? Would that do? Or just stones from the beach??

Ali, Tasmanian Public and Environmental Health Network (TPEHN), Tasmania, Australia

EGROUP ANSWER TWO From: Eric Uram Sent: Friday, May 25, 2012 10:17 PM

The recreational fishing industry and non-toxic hunting folks have replaced lead sinkers and shot with two metals – bismuth and tungsten. While I cannot give you any direct knowledge about their behavior in a chlorine pool, I might suggest that plain old ordinary (high quality) silica sand might be the best option – besides being highly resistant to any chemical interactions, it is non-toxic, fairly dense and would readily conform to contours. So, would present a safer (and cheaper) option than using metals, etc.

Eric Uram

Executive Director

www.safeminds.org

EGROUP ANSWER THREE From: A scientist Sent: Friday, May 25, 2012 9:00 PM

Subject: Substitution - safe inexpensive materials with a higher density than water

In general, sand is often used as a weight for items in water and has the flexibility to be formed as needed. "Play sand" that is distinguished from sand used for construction is usually of a higher quality, though still requires rinsing. A case made of heavy tightly woven cloth (e.g., cotton duck, canvas) case will keep the sand from moving out of the cloth, once it is rinsed free of ultrafine particles and disinfected (probably via rinse with the same chemicals that is are used in the spa). As with anything used in a spa setting, it needs to be disinfected regularly, or kept in a plastic bag inside the cloth case in order to prevents bacteria from growing in the material. Depending on the degree of chlorination in the water, that may be a greater or lesser issue.

He may want to check with people in the occupational therapy and rehabilitative medicine field for additional ideas on this.