In December 1991, a venous blood lead level (BLL) of 50 ug/dL
was detected in a 46-year-old Ohio man during a routine pre-employment
examination. He was referred to a university-based pharmacology and
toxicology clinic for further evaluation; clinic physicians investigated
the case. Although a repeat BLL obtained 1 month later was 51 ug/dL, he
reported no exposure to known sources of lead during the interim.
However, he reported numbness of his fingers and palms, tinnitus, and a
possible decrease in his ability to perform basic arithmetical
calculations.
A comprehensive occupational and environmental history obtained
at the time of the second BLL test revealed no apparent source of his
lead exposure. Although he had been employed for approximately 20 years
as a microwave technician during military service and while employed at
a television station, he reported no history of exposure to lead from
soldering or welding. He had no activities or hobbies associated with
exposure to lead or lead products, no previous bullet or birdshot
wounds, and he denied drinking illicitly distilled alcohol or using lead
additives in his car.
His residence was built in 1974 (after lead was banned from use
in residential paint) *, and household water was obtained from a well.
In January 1992, blood lead testing of family members revealed levels of
5 ug/dL for his wife and less than 5 ug/dL for his 17-year-old child.
His only medication was ranitidine **, which he had used for the
previous 1-1/2 years for "indigestion." He reported occasional cigarette
smoking.
Although results of a neurologic examination were normal,
neuropsychiatric testing on March 13 demonstrated mild memory deficits,
as evidenced by abnormalities on verbal and figural memory tests.
Because of these abnormalities, beginning March 13, he was treated for
19 days with dimercaptosuccinic acid (DMSA), an oral chelating agent,
and on April 4, his BLL had decreased to 13 ug/dL. However, BLLs on May
15 and July 23 were 49 ug/dL and 56 ug/dL, respectively.
During a July 1992 follow-up clinic visit, he mentioned that for
approximately 20 years he had habitually chewed on the plastic
insulation that he stripped off the ends of electrical wires. Samples of
the copper wire with white, blue, and yellow plastic insulation were
obtained and analyzed for lead content. The clear plastic outer coating
(present on all colors of wire) and the copper wire contained no lead;
however, the colored coatings contained 10,000-39,000 ug of lead per
gram of coating. *** On receipt of these results, he was instructed
immediately to discontinue chewing the wire coating.
In January 1993, when his BLL was 24 ug/dL, he reported
subjective improvement in his symptoms; follow-up neuropsychiatric
testing is pending.
Reported by: M Kelley, MD, P Walson, MD, D Thorton, PhD, Ohio
State Univ and Children's Hospital, TJ Halpin, MD, State Epidemiologist,
Ohio Dept of Health. Div of Surveillance, Hazard Evaluations, and Field
Studies, National Institute for Occupational Safety and Health, CDC.
Editorial Note
Editorial Note: This report likely represents the first
documented case of lead poisoning following ingestion of lead as a
consequence of chewing on plastic wire coatings. Plastic coatings
previously have been associated with lead exposure in the burning of
lead-containing plastics during repair of a storage tank (1), the
production of plastics (2,3), and the manufacture and use of stabilizers
and pigments in the plastics industry (4). Although lead exposure also
can occur among workers who burn the plastic coating off copper wire to
recycle the copper, lead intoxication by this route has not been
reported (5).
Lead compounds may be employed in the production of colored
plastics (in which lead chromates are used as pigment) and in the
manufacture of polyvinyl chloride (PVC) plastics (in which 2%-5% lead
salts {including lead oxides, phthalate, sulfate, or carbonate,
depending on the desired quality of the final product} are used as
stabilizers). Although environmental regulation has reduced considerably
the amount of lead used in the United States in the manufacture of PVC
plastics, manufacturers of electrical wire and cable continue to produce
PVC stabilized and/or pigmented with lead compounds (6).
More than 573,400 U.S. workers are employed in occupations
involving electrical work. Among these workers, potential for excessive
exposure to lead may result from inhalation of fumes generated during
lead soldering (7). Because the plastic coating from wires is usually
removed by mechanical stripping, ingestion of lead from these plastic
coatings is probably uncommon. Nonetheless, the findings in this report
remind occupational and other health-care providers of the need to be
aware of this potential source of lead exposure. In addition, workers
should be warned of the potential hazard of chewing plastic coatings or
other plastic products that may contain lead.
References
1. Skillern CP. Experience with burned lead-in-plastic material. Am
Ind Hyg Assoc J 1969;30:648-9.
2. CDC. Lead chromate exposures and elevated blood lead levels in
workers in the plastics pigmenting industry -- Texas, 1990. MMWR
1992;41:304-6.
3. Ong CH, Ong HY, Khoo NY. Lead exposure in PVC stabilizer
production. Appl Ind Hyg 1989;4:39-44.
4. CDC. Surveillance of elevated blood lead levels among adults --
United States, 1992. MMWR 1992;41:285-8.
5. Liss GM, Halperin WE, Landrigan PJ. Occupational asthma in a
home pieceworker. J Occup Med 1986;41:359-62.
6. The Vinyl Institute. Characterization of lead in plastics
products in municipal solid waste, 1970 to 2000. Prairie Village,
Kansas: Franklin Associates, Ltd, 1990.
7. NIOSH. Health hazard evaluation report no. HETA 90-075-2298.
Cincinnati: US Department of Health and Human Services, Public Health
Service, CDC, 1993.
* 16 CFR section 1303.2. Ban of lead-containing paint and
certain consumer products bearing lead-containing paint.
** Ranitidine alters gastric acidity, which theoretically can
influence gastrointestinal absorption of lead.
*** Samples were analyzed using graphite furnace atomic
absorption spectroscopy, following dissolution of the plastic coating in
tetrahydrofuran.
-----------------------------------------
This message (including any attachments) may contain confidential information intended for a specific individual and purpose. If you are not the intended recipient, delete this message. If you are not the intended recipient, disclosing, copying, distributing, or taking any acti
-------------------------------------------------------------------------------Leadfee Mail List provided as a service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Leadfree
To temporarily stop delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL
Search previous postings at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-------------------------------------------------------------------------------
on based on this message is strictly prohibited.
|