Lead toxicity

> From: Sara A Mchugh <saram at GAS_UUG.Arizona.EDU>
> Date: Thu, 21 Dec 1995 15:57:01 -0700 (MST)
> Subject: Re: Aquatic Plants Digest V1 #142
> How much lead in the water is toxic?
> Sara Ann McHugh

Difficult question to answer because although lead is poisonous, there is
not a magic number for toxicity. The more important question is
how much lead is in one's body. The risk of symptomatic lead poisoning
(plumbism) increases with blood lead concentration > 60 ug/dL whole bood.
In children, sustained blood lead concentration >40 ug/dL whole blood
increases the risk of long-term cognitive deficit. (source: Merck Manual,
16th edition)

"High-dose" lead sources include repetitive ingestion of chips of paint
containing lead, burning of lead-painted wood in home fireplaces or
stoves, ingestion of acidic foods and beverages stored in lead-glazed
ceramic ware, cottage industry manufactured items (lead-glazed ceramic
ware, leaded glass, etc.), inhalation of fumes of leaded gasoline, etc.
(source: Merck Manual, 16th edition)

Lead plant weights in an aquarium can be a problem IF:

1. The water in aquarium is highly acidic, AND
2. The water is not changed regularly, AND
3. You drink the water in the aquarium on a regular basis.

I don't think lead plant weights are a significant health risk. Let us put
this topic to rest. However, disposal of lead is still an environmental
problem. Let us avoid this problem by not purchasing lead weights.

Shiao Wang
sywang at whale_st.usm.edu