Environmental
Toxicology
Newsletter
"Published Occasionally at Irregular Intervals"
Arthur L. Craigmill
Extension Toxicologist
- Poisoning by an Illegally Imported Chinese Rodenticide Containing Tetramethylenedisulfotetramine New York City, 2002
- Veterans and Agent Orange: Update 2002
- Treated Lumber Can Be Recycled to Preserve Forests, Landfills
- If You Use Manure in Your Garden, Take Precautions
- Salmonellosis Outbreak Prompt Alfalfa Sprout Recall
- DPR Announces "Right-To-Know" Initiative, Releases Illness Data
- DPR Proposes New Regulations to Protect Ground Water
- Prevalence of Current Cigarette Smoking Among Adults and Changes in Prevalence of Current and Some Day Smoking - United States, 1996-2001
- Illegal Pesticide Products
Illegally imported foreign products can result in domestic
exposures to unusual toxic chemicals, and health-care providers might
not be able to provide appropriate therapy because the chemical ingredients
might not be listed or recognized even after translation of the product
label. This report describes the first known case in the United States
of exposure to a Chinese rodenticide containing the toxin tetramethylenedisulfotetramine
(TETS), a convulsant poison. The report of this investigation highlights
the need to prevent such poisonings through increased public education,
awareness, and enforcement of laws banning the importation of illegal
toxic chemicals.
On May 15, 2002, a previously healthy female
infant aged 15 months living with her family in New York City was
found by her parents to be playing with a white rodenticide powder
that they had brought from China and applied in the corner of their
kitchen. After 15 minutes, the child had generalized seizures and was
taken to an emergency department. Despite aggressive therapy with lorazepam,
phenobarbital, and pyridoxine, she had intermittent generalized seizure
activity for 4 hours and required intubation. After 3 days, the infant
was extubated successfully but appeared to have multiple neurologic deficits,
including absence seizures and possibly cortical blindness. The infant
was discharged in June; as of November 5, the infant remained severely developmentally
delayed and was on valproic acid therapy for seizure control.
Translation of the rodenticide package
labeling from Chinese to English did not clarify its contents (see
Figure 1 below). A search of the China National Poison Control Center's
(NPCC) website for rodenticides suggested that the ingredients might
have included sodium monofluoroacetate, fluoroacetamide, tetramethylenedinitrosotetramine,
or strychnine. However, an initial laboratory analysis was negative
for sodium fluoroacetate, fluoroacetamide, bromethalin, strychnine,
1,3-difluoro, 2-propanol, and carbamate insecticides.
On September 14, a snack shop owner in
China poisoned food in a competitor's snack shop with a rodenticide
identified as Dushuqiang, resulting in 38 deaths. Although Dushuqiang,
which contains TETS, has been banned for sale since the mid-1980s,
it is still widely available in China. Following news reports of this
incident, the New York City Poison Control Center conducted additional
laboratory testing of the product associated with the poisoning in New
York City and confirmed TETS in the product by gas chromatography-mass
spectrometry (GC-MS). TETS concentration was 6.4% weight/weight [w/w]
in one rodenticide packet and 13.8% w/w in another.
Editorial Note: TETS is a little-known, often unrecognized,
and highly lethal neurotoxic rodenticide that once was used widely.
An odorless, tasteless, and water-soluble white crystalline powder that
acts as gamma-amino butyric acid (GABA) antagonist, TETS, like picrotoxin,
binds noncompetitively and irreversibly to the GABA receptor on the
neuronal cell membrane and blocks chloride channels. The most common
routes of exposures are through ingestion and inhalation. TETS is not
registered by the U.S. Environmental Protection Agency for use in the
United States, and its importation, manufacture, and use in the
United States are illegal.
TETS meets criteria for inclusion in the list of extremely
hazardous pesticides maintained by the World Health Organization (WHO)
and is more lethal than WHO's most toxic registered pesticide, sodium
fluoroacetate. Multiple large intentional and unintentional
exposures in China have demonstrated the human toxicity of TETS. The
dose at which TETS kills 50% of mammals (LD50) is 0.1-0.3 mg/kg; a dose
of 7.0-10.0 mg is considered lethal in humans. TETS is potentially 100
times more toxic to humans than potassium cyanide and might be a more
powerful human convulsant than strychnine.
The most recognizable clinical signs after a TETS exposure
are refractory seizures. Other potentially serious signs include coma
and possible electrocardiogram evidence of ischemia. Symptoms typically
begin within 30 minutes after exposure and can begin as long as 13 hours
after exposure. Severe poisonings are usually fatal within 3 hours. TETS
intoxication is determined rapidly from history and clinical suspicion.
TETS is registered with the Chemical Abstract Service Division of the
American Chemical Society as number 80-12-6, molecular weight 240, and
chemical formula of C4H8N4O4 S2. Every attempt should be made to identify
this chemical if it is suspected.
No proven antidote exists for TETS poisoning. Treatment should
follow accepted modalities for a poisoned, altered, or seizing patient.
Universal precautions should be taken to prevent secondary exposure
of health-care workers. If TETS is suspected, regional poison control
centers can provide information and guidance. A small study of rodents
conducted in China suggested that intravenous pyridoxine and dimercaptosuccinic
acid might be effective treatments. In China, charcoal hemoperfusion and
hemodialysis are used to provide extracorporeal removal in patients poisoned
with TETS.
This is the first known case of TETS poisoning in the United States.
The chemical's morbidity and lethality and the lack of a known antidote
present a danger to human health in areas where TETS might be imported
illegally, especially large urban areas with substantial immigrant
populations. The appearance of a banned or illegal substance presents
challenges to regulatory and enforcement agencies because of the increased
risk for unintentional and intentional exposures. Poisoning caused
by TETS exposure can be prevented with heightened public health education,
increased awareness, and adequate enforcement by customs, border, and
regulatory agencies.
REF:Centers for Disease Control and Prevention
Morbidity and Mortality Weekly Report, March 14, 2003 / 52(10);199-201
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5210a4.htm
A re-evaluation of evidence now supports
an association between exposure to herbicides used during the Vietnam
War and the development of a specific form of leukemia in veterans,
says a new report from the Institute of Medicine (IOM) of the National
Academies. The report is the latest update in a series examining the
health effects of defoliants – including Agent Orange - and chemicals
that contaminate them.
As part of its biennial update, the committee that
wrote the report reassessed six studies of herbicide exposure that provided
information on chronic lymphocytic leukemia (CLL) among other health effects.
The reexamination revealed sufficient evidence of an association between
exposure to chemicals sprayed in Vietnam and risk of developing CLL.
In previous updates on the health risk to veterans posed by exposure to Agent Orange and other chemicals used in Vietnam, IOM had considered all forms of leukemia collectively when examining research on links between herbicide exposure and risk of cancer. The combined evidence was found to be inadequate or insufficient to determine whether any association exists between leukemia and exposure to the herbicides or their contaminants. However, although classified as a form of leukemia, CLL shares many traits with Hodgkin’s disease and non-Hodgkin’s lymphoma, both of which previously have been found to be associated with herbicide exposure. Both CLL and lymphoma originate from malignant Bcells, and CLL can transform into an aggressive non-Hodgkin’s lymphoma known as Richter’s Syndrome.
“The similarities between CLL and lymphoma—which
we have long known to be associated with exposure to the types of chemicals
used in Agent Orange and other defoliants—began to raise questions about
whether CLL should be considered separately from other forms of leukemia,”
said committee chair Irva Hertz-Picciotto, professor of epidemiology,
University of North Carolina, Chapel Hill, and University of California,
Davis. “At the request of the Department of Veteran Affairs, we looked
into the matter, and our reassessment indicates that CLL is indeed a
special case. The data are sufficient to support a link between herbicide
exposure and this type of cancer.”
The committee’s new assessment of CLL is based on evidence from six studies that looked at cancer rates, including specific forms of leukemia, and other health effects among agricultural workers exposed to herbicides, as well as individuals who reside in agrarian settings. The risk for CLL was found to be elevated in those whose occupations involved handlings of or exposure to the types of herbicidal chemicals also used during the Vietnam War.
The ability of researchers to pinpoint the health risks faced by individual veterans is hampered by inadequate information about exposure levels of troops in Vietnam. Most information comes from studies of civilians who have been exposed on the job or in industrial accidents to herbicides or their contaminants. However, most veterans probably experienced lower levels of exposure than people who have worked with these chemicals over long periods in occupational or agricultural settings, and it is difficult to say precisely which troops may have been exposed to larger amounts.
CLL is the most common form of leukemia, with roughly
7,000 new cases diagnosed in the United States last year. However, it
is among the rarer forms of cancer, making it difficult to do large-scale
studies to determine causes. There are no accurate estimates of how
many Vietnam veterans have been diagnosed with CLL.
The committee’s congressionally mandated report also reaffirms findings from previous IOM updates. In addition to non-Hodgkin’s lymphoma, Hodgkin’s disease, and now CLL, there is sufficient evidence of a link between exposure to chemical defoliants or their contaminants and the development of soft-tissue sarcoma and chloracne in veterans. Also, scientific studies continue to offer limited or suggestive evidence of an association with other diseases in veterans—including Type 2 diabetes, respiratory cancers, prostate cancer, and multiple myeloma—as well as the congenital birth defect spina bifida in veteran’s children.
U.S. forces sprayed Agent Orange and other defoliants over parts of south Vietnam and Cambodia beginning in 1962. Most large-scale sprayings were conducted from airplanes and helicopters, but considerable quantities of herbicides were dispersed from boats and ground vehicles or by soldiers wearing back-mounted equipment. A 1969 scientific report concluded that one of the primary chemicals used in Agent Orange could cause birth defects in laboratory animals. The U.S. military therefore suspended the use of Agent Orange in 1970 and halted all herbicide spraying in Vietnam the following year. The committee’s work is sponsored by the U.S. Department of Veterans Affairs.
Read the full text of Veterans and Agent Orange: Update 2002 for free on the Web as well as over 2,500 other publications from the National Academies. Printed copies will be available for purchase from the National Academies Press; tel. (202) 334-3313 or 1-800-624-6242 or on the Internet at http://www.nap.edu. (Food Industry Environmental Network e-mail update, January 28, 2003)
REF: Pesticide Reports, Oklahoma State Cooperative
Extension, March 2003.
The use of Chromated Copper Arsenic (CCA) treated wood
has garnered a great deal of media attention over the past few years
due to possible environmental and public safety concerns. "Another concern
of this material has just recently gained attention from researchers,
environmentalists, and government organizations," says Bob Smith, Virginia
Tech's wood science and forest products associate professor in the
College of Natural Resources. "That is the amount of CCA-treated wood
being removed from people's homes and businesses and going to the nation's
landfills."
Chromated Copper Arsenate, or CCA as it
is commonly known, is the chemical compound used to pressure treat wood
in order to resist attack from insects and decay. Smith explains that
CCA can typically extend the life of wood in an outdoor environment by
30 to 40 years, thus saving the forest resource. “Since the early 1970's,
CCA-treated wood has been used in approximately 80 percent of residential
decks built in the United States,” Smith states.
The Environmental Protection Agency (EPA)
and the wood preserving industry have voluntary removed the use of CCA
for the treatment of wood in residential applications starting in January
2004. "This will end much of the media hype in the possible adverse side
affects that CCA may produce because of the arsenic in its formulation,"
predicts Virginia Tech's wood science research assistant, Dave Bailey. "However,
another concern is the amount of CCA-treated wood that could end up in
landfills, especially from residential decks. Several researchers across
the country have indicated that the amount of discarded CCA-treated wood
reaching landfills is increasing and the tonnage is expected to rise
substantially over the next several decades."
Research performed at Virginia Tech by
the wood science and forest products department and the USDA Forest
Service in Blacksburg, Va., have estimated that 1 billion board feet
of CCA-treated wood is removed from residential decks and disposed primarily
in landfills each year. Researchers from other universities have examined
the possible leaching of CCA chemicals from wood in to unlined landfills,
in hopes to determine if the rate of CCA chemical leachate will contaminant
groundwater supplies. "This research could cause tighter regulations
on the disposal of CCA-treated wood, and force the cost of disposing old
decks to increase over the next few years," explains Smith.
To help reduce the burden on landfills
and the demand of timber harvested for use by the wood industry, research
is being conducted at the Brooks Forest Products Laboratory at Virginia
Tech to extend the useful life of used CCA-treated material. This research
has evaluated the amount of useful material that a deck contains, which
instead of ending up in a landfill could be re-used.
'The research has calculated the amount
of CCA-treated wood in a residential deck prior to demolition, and then
determined the amount of usable CCA-treated material capable of being
recycled," notes Bailey. "We have determined that over 80 percent of a
discarded CCA-treated deck can be recovered into useable lumber such as
5/4” radius edge decking, 1”x6” boards and 2”x4”, 2”x6”, and 2”x8” lumber."
The physical and mechanical properties
of the spent CCA-treated wood were also evaluated, to verify if this
used material can perform to needed standards. The chemical retention
levels (the amount of chemicals in the wood) of the used CCA-treated
wood were similar to that of new CCA-treated wood found in many local
home improvement centers. The strength of the old wood was also tested
for comparison to new CCA-treated wood. The mechanical tests concluded
that the strength properties of the discarded CCA-treated wood, destined
for the landfill, were similar as new CCA-treated wood.
A variety of products were made from the
used CCA-treated wood that could be easily produced by the deck owner,
recycling companies, or local community organizations. Some of the
products manufactured included different residential decks and deck
components, such as railings, steps, or posts, trellises, trash can
containers, pallets, and outdoor furniture such as chairs, benches,
porch swings, and utility tables. The new guidelines regarding CCA for
treated lumber does not affect wood currently in service. The EPA has
suggested that the lumber be coated with a protective barrier if small
children will be be exposed to the material. EPA recommends an oil-based
transparent stain be applied on a regular basis. For more information on
the ruling, visit the website (www.epa.gov/pesticides/factsheets/).
Other products that could also be produced
are landscaping components, such as planter boxes, raised flowerbeds,
and retaining walls, material for parks and recreation facilities,
such as sign posts, trial guides, and walking bridges. Many homeowners,
community organizations, and governments could find the products made
from used CCA-treated wood of equal quality compared to using new CCA-treated
wood, and more cost effective.
Smith says, “We are currently evaluating
what it would take for landfill managers to be willing to separate
out the CCA-treated wood to sell or donate to parties that could recycle
the materials into the useable products we have identified. Our research
has helped to recognize the potential of discarded CCA-treated wood.
It could certainly reduce the burden on landfills and lessen the demand
of our forests by extending the life of current forest products.”
REF: http://www.cnr.vt.edu/cnr_webpages/news/022503.htm
Tobacco use, particularly cigarette
smoking, is the leading preventable cause of death in the United
States and is responsible for approximately 440,000 deaths each
year. One of the national health objectives for 2010
is to reduce the prevalence of cigarette smoking among adults
to <12%. To examine the prevalence of smoking for the 50 states,
the District of Columbia (DC), Guam, Puerto Rico, and the Virgin
Islands, CDC analyzed data from the 2001 Behavioral Risk Factor
Surveillance System (BRFSS). This report summarizes the results
of that analysis, which indicate that, during 2001, the median adult current
smoking prevalence was 23.4% for the states and DC, and 12.5% for
Guam, Puerto Rico, and the Virgin Islands. During 1996-2001, the
prevalence of current smoking was relatively stable in 41 states
and DC, and the proportion of current smokers who were some day
smokers increased significantly in 31 of those states and DC.
"Current smokers" were defined as those who reported having smoked >100
cigarettes during their lifetime and who currently smoked every day or some
days. "Some day" smokers were current smokers who responded that they smoked
some days. Data on current smoking have been available since 1996. Because
the only safe alternative to smoking is cessation, interventions
should target all smokers to help them quit smoking completely.
In 2001, the median prevalence of
current smoking in the 50 states and DC was 23.4%. Prevalence was highest
in Kentucky (30.9%), Oklahoma (28.8%), West Virginia (28.2%), Ohio
(27.7%), Indiana (27.5%), Nevada (27.0%), South Carolina (26.2%),
and Alaska (26.1%), and lowest in Utah (13.3%), California
(17.2%), Massachusetts (19.7%), Idaho (19.7%), Nebraska
(20.4%), Oregon (20.5%), Hawaii (20.6%), Connecticut (20.8%),
and DC (20.8%). Current smoking prevalence was 9.8% in the Virgin
Islands, 12.5% in Puerto Rico, and 31.4% in Guam.
Editorial Note: The median prevalence of current smoking
did not change substantially during 2000-2001. However, smoking
prevalence varied among the states, DC, Guam, Puerto Rico, and
the Virgin Islands. As in 2000, during 2001, Kentucky and Nevada
remained among the states with the highest prevalence, and Utah,
California, and Puerto Rico remained among all areas with the lowest
prevalence.
During 2001, the national health objective for 2010 of <12%
of adults smoking cigarettes was achieved only in the Virgin
Islands (9.8%). The low prevalence of smoking in the Virgin Islands,
Puerto Rico, and Utah might be the result of stronger social and
cultural norms against tobacco use compared with other parts of
the country.
The findings in this report document that even though current
state-specific smoking rates have not declined significantly since
1996, the pattern of smoking has changed. Factors that might
have contributed to the shift include increased retail price
of cigarettes and smoking bans in public places. Massachusetts
and California have reported other changes in smoking patterns.
An independent evaluation of the Massachusetts Tobacco Control
Program reported a decline in smoking prevalence from 22.6% in 1993
to 20.9% in 1999, with a small but significant decline in the
proportion of persons reporting smoking daily (81% in 1993 compared
with 79% in 1999). Data collected through the California Tobacco
Survey indicated that, along with overall decreases in prevalence
of current smoking, the proportion of current smokers who were
some day smokers increased significantly from 25.9% in 1992 to
32.1% in 1996 and from 32.1% in 1996 to 36.4% in 1999.
The data in this report are consistent with characteristics
of some day smokers observed in the 1997 and 1998 NHIS, except
for the higher prevalence of some day smoking among men and the higher
prevalence of some day smoking reported by respondents aged >65
years in BRFSS. Although some smokers appear to be reducing their
cigarette consumption, results from a recent large cohort study
indicate that reduction of daily tobacco consumption by >50%
without quitting did not decrease mortality rates from tobacco-related
diseases compared with smokers who continued to smoke heavily
(>15 cigarettes per day). States are encouraged to implement
comprehensive tobacco control programs such as those implemented
in California and Massachusetts during the 1990s, which encourage
smokers to stop smoking completely.
REF: Centers for Disease Control and Prevention,
Morbidity and Mortality Weekly Report, April 11, 2003 /
52(14);303-307
► New Agriculture Fact
Book is Now Available
"Agriculture is integral part of
our nation’s economic and social fabric," Veneman said. “This new publication
provides useful information on a variety of topics including homeland
security, conservation, biotechnology, organic foods and energy sources.”
The Agriculture Fact Book 2001-2002
includes general information and statistical data about American food
consumption, the agricultural sector and rural America. The book also
describes USDA’s wide-ranging programs and services, such as farm programs;
exports; rural development, food safety; nutrition; management of land,
water, and forests; protecting U.S. borders from pests and diseases;
and scientific agricultural research.
As part of USDA’s effort to provide
information through the Internet, the Agriculture Fact Book 2001-2002
can be accessed through the web at http://www.usda.gov/factbook. The
site includes links and other media that provide further information
about agriculture, food, conservation, nutrition, food safety and related
issues. Hard copies of the publication are available for sale by the
Government Printing Office and can be ordered online at http://bookstore.gpo.gov/.
REF: USDA News Release No. 0101.03
FDA is alerting firms manufacturing mineral
mixes and mineral premixes for use in animal feed that minerals that
are by-products or co-products of industrial metal production may
contain dioxin. Recently, FDA found that some of these by-products
or co-products contained high levels of dioxin, and requested that the
specific products be recalled. In March 2002, FDA requested a recall
of protected minerals and mineral premixes because of high levels of
dioxin. In the 2002 case, the source of the dioxins was related to the
high temperature process used in making the protected minerals. The Agency
believes that in the current case the process used to produce brass resulted
in the dioxin contamination of zinc oxide. FDA will be actively checking
these and similar products for dioxin.
Dioxins are ubiquitous, low level environmental
contaminants. With cumulative exposure, they are potential carcinogens
and may cause reproductive or developmental health problems. Environmental
sources of dioxin pollution have been markedly reduced over the past
decade. The result has been a significant reduction in overall dioxin
exposure to the public. Presently, the primary source of human exposure
to dioxins is through food.
Earlier this year, FDA’s food and feed
surveillance programs detected elevated levels of dioxin in a feed and
traced the dioxin to a mineral component of that feed. The implicated
zinc oxide and zinc oxide premixes that were used in livestock, aquaculture,
and poultry feed contained extremely high levels of dioxin. A recall
of these products and feed containing the zinc oxide has been implemented.
An additional mineral component (copper oxide) is also being investigated
as a possible source of dioxin. Both mineral components currently under
investigation are reclamation products from industrial metal production.
FDA's public health objective is to reduce
the level of exposure to dioxin in the animal and human foods by finding
and stopping sources of added dioxin from entering the food supply.
To further reduce public exposure to dioxins, FDA will continue its
food and feed surveillance programs, and continue investigating whether
other products from industrial metal production that are used as feed ingredients
are a source of dioxin.
REF: FDA/CVM Update March 12, 2003
Since 1994, when Congress passed the Animal Medicinal
Drug Use Clarification Act of 1994 (AMDUCA), veterinarians in the U.S.
have enjoyed legitimate extra-label use (ELU) privileges. Veterinarians
can safeguard ELU privileges by following AMDUCA, and by educating clients
(particularly food animal producers) on AMDUCA and prudent drug use principles.
This article outlines key points of AMDUCA in plain language.
The Current List of Drugs Prohibited From Extra-Label
Use (As listed in 21 CFR 530.41). These drugs (both animal and human),
families of drugs, and substances are currently prohibited for extra-label
uses in all food-producing animals, (including horses intended for human
food):
Conclusion
AMDUCA legalized extra-label use of approved animal
and human drugs in animals when that use is under the supervision of
a veterinarian and in accordance with FDA regulations. AMDUCA provided
veterinarians with privileges comparable to those generally enjoyed by
physicians. Veterinarians can protect these privileges by complying with
AMDUCA, and understanding the permitted and prohibited extra-label drugs
and uses (including compounding). For more information on AMDUCA, other
regulations and policies, and to request hard copies, please visit the
CVM Home Page, http://www.fda.gov/cvm/
default.html, and look under Quick Index. Notices of proposed rulemaking
and final rules, such as additions to prohibited drug list, are announced
by Federal Register notices and posted on the CVM Home Page, http://www.fda.gov/cvm/default.html
and the FDA Dockets Advanced Publication Display website, http://www.accessdata.fda.gov/scripts/oc/ohrms/index.cfm.
REF: FDA Veterinarian, March/April 2003 Vol. XVIII,
No. II
The FDA Center for Veterinary Medicine (CVM) supports recent action by the Association of American Feed Control Officials, Inc. (AAFCO) in recommending to State feed control officials that enforcement action be initiated to remove from distribution animal products containing comfrey. AAFCO’s guidance to State feed control officials on March 3, 2003, follows the announcement made at AAFCO’s Annual Meeting in August 2002, that comfrey, determined to be a health and safety concern in animals, is recommended for removal from all animal feeds.
AFCO’s Enforcement Strategy for Marketed Ingredients
Task Force identified comfrey as the target ingredient. This Task Force
based its selection on published scientific information provided
by CVM. Comfrey has been shown to cause liver damage in humans and in
animals. Due to safety concerns, the FDA advised manufacturers on July
6, 2001, that comfrey should not be used in human dietary supplements.
REF: FDA Veterinarian, March/April 2003 Vol. XVIII,
No. II