Arkansas Pesticide News
August, 2002; Volume 29
United States Department of Agriculture, University of Arkansas; and County Governments Cooperating
August, 2002; Volume 29
United States Department of Agriculture, University of Arkansas; and County Governments Cooperating
National News
Biotech/IPM/Advanced Technology News
Health and Safety
General Information
Registration News
Did You Know
Editors: Briggs Skulman, Department of Crop,
Soil,
and Environmental Sciences, Fayetteville
and Ples Spradley, Coop.
Extension Service, Little Rock.
This issue of the Arkansas Pesticides News has a diverse selection of articles covering topics from standard chemical control issues to the rapidly expanding realm of GM crops. The new pesticide regulations and technologies, as well as our "wake up" call from 911, leads to a wide range of topics and articles.
Where once we might have been concerned about proper use of agrochemicals,
we now find that we have to
worry about deliberate and intentional pesticide misuse as a weapon
that might target large segments of our population!
With this new concern all of us (chemical dealers in particular) will
have to be more vigilant, add better security and keep
more detailed records than previously. Two of this issue's articles
address new rules in North Carolina and proposed
U.S. legislation concerning pesticide/chemical security, while a third
briefly describes the possible use of pesticides in
a bombing.
Once are we past the concern for pesticides in the hands of terrorists,
we still have the problems of individuals
using agrochemical tools improperly (and paying the ultimate consequences).
We also have articles on the long standing
concerns about these materials in relation to human health and disease.
Atrazine risk assessment seems to still be an on-
going project at the EPA. It seems that the data is never quite what
the EPA wants and the article lists some areas of
concern due to these uncertainties. The major concerns listed are residues
in water (in some parts of the country) and
handler exposure, with the later being most of concern. Another article
talks further about the atrazine risk to longer term
handlers. Again following proper procedures when handling any chemical
"tools" is the best insurance against excessive
exposure and potential risks. Also, there is an article on the reassessment
of Sodium Acifluorfen some might find
interesting.
GM crops continue to be a much discussed topic. After the furor of whether
Monarch butterflies were being
decimated by BT corn pollen, there has been the worry of genes drifting
from GM corn into the native or wild germplasm
particularly in Mexico. This research is also being questioned, but
has made for negative publicity in the public forum.
Consequently, some of the promise of GM crops may go lacking for many
years to come. One of these possibilities is
exactly what most environmental groups indicate they want, reduced
use of chemical pest control agents. An article on
GM crops in Australia indicates that chemical usage is declining due
to the use of such crops. That's a good thing....isn't
it? Or should we instead be worrying about the resulting "Franken Foods"
as some European groups call GM crops?
Apparently, the Brazilian exporters are taking extreme measures to
prove their soy meal is biotech free.
Well maybe the answer is organically grown food. A recent study is out
that indicates that organic foods really do have
less pesticides. Of course one has to wonder, if you didn't apply anything
to the crop to begin with, doesn't logic indicate
that you wouldn't find any significant residues? Or as my teenage son
succinctly stated it the other day "Well....Duhh"!
Of course I'm being overly simplistic, pesticides could be present
from past application or have drifted onto the organic
crop. That's where vinegar comes in. Yes good old vinegar can be used
as an herbicide. If this catches on we may all
be able to buy our salad greens with a pre-applied vinegarette dressing.
Oh, you prefer Ranch! Sorry, about that. You'll
have to wait for that research to be completed (or started for that
matter). In the mean time let's hope they don't find that
vinegar is a health risk too!
Did you know that California has had a two year decline in pesticide use? Actual use in that state is at a ten year low.
Other articles in this APN issue examine the factors that affect pesticides
after application. Most people already are
aware of some of these factors, but there are some factors that may
not be as obvious, such as photodegradation or
adsorption to organic matter. Water quality issues are going to be
important in the future with states being asked for input
on water quality as pesticides go through the registration process.
Pesticide dealers in North Carolina must retain records restricted-use
pesticide sales following a March 22 decision
by the state's pesticide board.
Restricted-use pesticides are those that can only be purchased and
applied by certified applicators or people under
their supervision. The body's decision last month made permanent a
rule that was imposed temporarily in the wake
of Sept. 11 terrorist attacks.
The decision is designed to keep potentially dangerous chemicals out
of unauthorized hands. Under the rule,
pesticide deals must verify the buyer's identity and make sure the
buyer is currently a licensed or certified
applicator. In addition, dealers are required to keep sales records
for three years. The record should include:
Date of sale
Initials of sales clerk
Name of certified or licensed applicator
Certification or license number from card
Expiration date on card
Product brand name
EPA registration number
Number of individual containers
Size of individual containers
Total quantity sold.
Prior to Oct. 2, the day the emergency rule was implemented, dealers
were only required to retain sales records
if they sold to an employee who was working under the supervision of
a licensed applicator. After Sept. 11, board
members decided to require sales records from anyone who purchases
a restricted use pesticide, said James
Burnette, administrator of the North Carolina Department of Agriculture
& Consumer Services, Pesticide Section.
The board encourages dealers to remain on the lookout for suspicious
activity related to the sale of pesticides.
Suspicious activity could include:
Out-of-season requests for pesticides
Unusual requests for pesticides
Orders from an unfamiliar person who might not be in the pesticide
application business.
(Pesticide Reports May, 2002) (Pesticide & Toxic Chemical News,
Vol. 30, No. 23, April 1, 2002)
The most significant toxics-related legislation introduced since the terrorist attacks of Sept.11 would require the federal government to identify the most vulnerable domestic chemicals and oblige relevant parties to keep records on the potential for their accidental or criminal release.
If enacted, the Chemical Security Act of 2001, introduced Oct. 31 to
the Senate by Sen. Jon Corzine (D-N.J.),
would give EPA one year to identify "priority categories" of chemicals
and chemical sources based on their
proximity to population centers, their threat to national security
and to critical infrastructures, and the quantities
needed to cause serious harm. EPA would complete the task in consultation
with the State and Justice Departments
and appropriate local agencies.
S. 1602, which Corzine also introduced on behalf of Sens. Jim Jeffords
(I-Vt.), Hillary Clinton (D-N.Y.) and
Barbara Boxer (D-Calif.), would then give these agencies an additional
year to formulate regulations requiring the
owners and operators of prioritized chemical sources to take "adequate
actions" to minimize any threats they
identified.
Such actions might include the implementation of secondary containment, control or mitigation equipment, the physical fortification of facilities and efforts to improve background checks and employee training.
The bill would also give EPA and the State Dept. right of entry into chemical facilities and would allow them to make companies maintain records on potential chemical releases. These records would be made available to the public, except those portions that were shown to contain confidential business information or to contain information compromising national security.
Repeated failure to comply with the proposed laws would result in fines
of up to $50,000 per day and up to two years imprisonment. In introducing
the bill, Corzine said a number of recent studies indicate that chemical
facilities are especially vulnerable to terrorists attacks, including one
from the Centers for Disease Control that concluded that security at some
60 plants in Georgia, Nevada and West Virginia ranged from fair to very
poor. An additional study from the Justice Department is running two years
behind schedule and may not be completed until 2004, he noted. "Our
nation's industrial facilities face a real and credible threat of a
terrorist attack that could release dangerous chemicals into our
communities," Corzine said. "There is clearly a need to take the necessary
steps to reduce the risks posed."
(Pesticide Reports, December, 2001)
(Pesticide & Toxic Chemical News, Vol. 30, No. 2, November 5,
2001)
SUICIDE BOMBERS IN ISRAEL MAY BE MIXING PESTICIDES INTO THEIR EXPLOSIVES
A telltale sign of such a mixture is an odd aroma, which lingers around
the site of terrorist explosions. Israeli police
commissioner Shlomo Aharonishky told the New York Times that he is
not sure if this use of pesticides is entirely
intentional. "It was like someone took a container with pesticides
and used it as an explosive canister,"
Aharonishky said. "It wasn't intended to poison. But from other instances,
including intelligence information, we
know they are thinking about it." Aharonishky does not believe that
any pesticides that might have been used in
suicide attacks are acutely toxic. "Beyond that," he told the Times,"
as a result of the explosion, the small amount
of toxicity that the [pesticides] have breaks down. Still, there is
a certain possibility that it would have some effect."
(Pesticide Reports February, 2002) (Pesticide & Toxic Chemical
News, Vol. 30, No. 8, December 17, 2001)
NATURE PUBLISHED AN 'EDITORIAL NOTE' ACKNOWLEDGING
ARTICLE PUBLISHED LAST
YEAR ON CORN CONTAMINATION IN MEXICO WAS INADEQUATELY RESEARCHED
"Nature has concluded that the evidence available is not sufficient
to justify the publication of the original paper,"
the editors said, although they stopped short of demanding a retraction.
The article had reported that corn from the
southern state of Oaxaca contained transgenic material even though
Mexico has prohibited biotech corn plantings
since 1998. Biotech opponents seized on the study as confirmation that
thetechnology was spreading out of control.
Acknowledging the uproar over the findings, the Nature editors said
they had asked the University of California
scientists who authored the paper to obtain further data "that might
prove beyond reasonable doubt that transgenes
have indeed become integrated into the maize [corn] genome. The authors
have now obtained some additional data,
but there is a disagreement between them and a referee as to whether
these results significantly bolster their
argument." In its April 5 issue, Nature published two letters critical
of the original study and a rebuttal from the
authors along with the editorial note. Both letters cited methodological
flaws in the research. Authors David Quist
and Ignacio Chapela acknowledged that they might have misinterpreted
some data but insisted that none of the
criticism challenged their central finding that bioengineered corn
is growing in Mexico.
(Pesticide Reports May, 2002) (Pesticide & Toxic Chemical News,
Vol. 30, No. 24, April 8, 2002)
REPORTS THAT DNA FROM BIOENGINEERED CORN HAS BEEN
TRANSFERRED TO LOCAL
MEXICAN VARIETIES QUESTIONED
The International Maize & Wheat Improvement Center in Mexico study
could not detect the 35S promoter either
in historical accessions from its own seed bank or in samples collected
recently from the field. Results of the study
were published in this month's issue of Nature Biotechnology. The center,
which maintains an extensive seed bank,
supplies corn seeds on demand to research institutions and extension
services in developing countries. "We need
to be able to reassure our users that transgenes were not running rampant
through the seed bank, and we have
shown that," said David Hosington, director of the center's Applied
Biotechnology Center.
(Pesticide Reports March, 2002) (Pesticide & Toxic Chemical News,
Vol. 30, No. 12, January 14, 2002)
MONSANTO'S EFFORTS TO GAIN REGULATORY APPROVAL
FOR BIOTECH WHEAT SEED IN US
TAKING LONGER THAN EXPECTED
A Monsanto company executive told Reuters last month that Monsanto had
at one point anticipated introducing
a herbicide-resistant Roundup Ready spring wheat next year. The company
will now focus on meeting a later
deadline of 2005, Bill Pilacinski, regulatory affairs manager, said
during the Wheat Quality Council's annual
meeting in Kansas City, Mo. Monsanto intends to introduce the biotech
strain in top spring wheat growing states
in the United States and is also conducting field trials across Western
Canada. The company will also file for
regulatory approval in Canada, Japan and the European Union this year
and submit applications for approval in
other major wheat importing countries in late 2002 and 2003. (Pesticide
Reports April, 2002) (Pesticide & Toxic
Chemical News, Vol. 30, No. 19, March 4, 2002)
BRAZILIAN EXPORTERS ARE INVESTING HEAVILY TO
PROVE
THEIR SOYMEAL IS BIOTECH-FREE
Approximately 4.5 million metric tons of soymeal, or 45% of all exports,
will be certified as non-biotech in the
2002-03 marketing year (February - January), up 12%-15% from the year
before, according to certifiers and
crushing groups. Brazil is the only remaining major soy exporter that
bans the planting and sale of biotech crops.
However, clients in Europe and Japan are increasingly demanding proof
that their imports are biotech-free in order
to meet strict labeling standards. Importers are upset by reports that
illegal biotech soybeans have spread
throughout southern Brazil, accounting for as much as 25% of the national
crop. (Pesticide Reports April, 2002)
(Pesticide & Toxic Chemical News, Vol. 30, No. 19, March 4, 2002)
Australian broad-acre farmers are growing more crops with fewer chemicals
per hectare. However, due to
increased planting, the total value and volume of agricultural chemicals
has increased, according to a report by the
Australian Academy of Technological Sciences and Engineering. According
to the report, the cost of chemicals
as a percentage of farm costs nearly tripled from 2.6% in 1989 to 6.7%
in 1999. However, the study also found
that the use of some crops, such as genetically modified cotton, are
helping to reduce overall chemical usage.
Between 1996 and 1999 cotton planting increased 70% while chemical
usage rose only 40%. Even increased
plantings of wheat, oats and barley were greater in proportion than
the increase in chemicals used to spray them.
According to the report, each year, Australian farmers use:
10,000 tons of insecticides
30,000 tons of herbicides
4,000 tons of fungicides
800 tons of plant growth regulators
The impact of chemicals off the farm is significant, the report notes.
Although endosulphan levels in surface water
dropped steadily during the 1990s, they still exceed government standards
about 10% of the time.
John Radcliffe, spokesman for the Commonwealth Scientific and Industrial
Research Organization, said the
introduction of new 'soft' chemicals, both GM and non-GM, will lead
to an 80% drop in pesticide use by 2004,
easily outstripping the 40-50% reduction seen for Bt cotton. Soft chemicals
are, however, newer and more
expensive. They target only the pests or weeds that are aimed at, unlike
so-called hard chemicals that kill
everything in sight.
"We are trying to develop even more selective chemicals for specific
purposes rather than going around sterilizing
the entire countryside," Radcliffe said.
To achieve significant reductions in pesticide use, growers need to
band together to better manage, for example,
rotations of groups of pesticides at various crop growth stages, said
Radcliffe. Nonetheless, chemical-resistant
weeds continue to dog the industry. Radcliffe said a recent survey
by his organization found that two thirds of
farmers believe weed problems are getting worse. Adding to the problem
is that there is still no detailed, publicly-
available data on individual pesticide use, said Radcliffe, though
he is actively pursuing the government to set up
a comprehensive pesticide use reporting system.
"Herbicide resistance is reported to affect up to 10% of the cropping
area nationally, and that area is expected to
increase," he added. Resistance is particularly bad in Western Australia,
the nation's largest grain growing state.
There, resistance by annual rye grass to herbicides can be up to 96%
in areas of heavy cropping. Some farmers
have reported rye grass resistance to herbicides after only three doses
of a chemical. CSIRO scientists acknowledge
that the area has the worst incidence of herbicide resistance in the
world.
The problem is primarily the result of rye grass that was introduced
and nurtured 100 years ago as a livestock feed.
However, in the past 10 years livestock has become uneconomical compared
with crops, and rye grass has emerged
as a big problem for farmers now trying to sow crops over former grasslands.
(Pesticide Reports June, 2002)
(Pesticide & Toxic Chemical News, Vol 30, No 28, May 6, 2002)
In Enterprise, Ala, local police say a woman and her 35-year-old grandson
were found dead two weeks ago. The
deaths, which police suspect were the result of an accidental pesticide
poisoning, are still under investigation.
Police say the pesticide involved contains aluminum phosphide, which
releases a deadly gas when exposed to air.
Pesticides that contain aluminum phosphide are not available to the
public and should only be used by trained and
licensed applicators, according to the EPA. Aluminum phosphide products
are used to control insects and rodents,
but are applied primarily at facilities where grain and other commodities
are transported, processed and stored,
according to a press release issued by EPA. (Pesticide Reports March,
2002 )(Pesticide & Toxic Chemical News, Vol.
30, No. 15, February 4, 2002)
PARKINSON'S DISEASE MIGHT BE CAUSED BY AGRICULTURE CHEMICALS
The news service quotes a Henry Ford Health System neurologist as saying
that, compared with people who had
no history of pesticide exposure, individuals exposed to herbicides
had a four times greater chance of developing
Parkinson's. People exposed to insecticides had three and a half times
the chance. The study also found that
farmers are 2.8 times more likely than the general population to develop
the disease.
Researchers behind the project say a cause-and-effect relationship
between the disease and the chemicals must be
identified, first by coding for genetic variants, analyzing biochemical
actions between pesticides and genes and
the calculating individuals' ability to metabolize the chemicals. Second,
experts must find a way to quantify
people's lifetime exposure to pesticides.
(Pesticide Reports March, 2002)
(Pesticide & Toxic Chemical News, Vol. 30, No. 14, January 28,
2002)
EPA issue a press release regarding pesticide labeled for aquatic use.
This is in response to the lawsuit of
Headwaters, Inc. v. Talent Irrigation District.
EPA has "[T]he Administrator shall not require a [Clean Water Act]
permit...for discharges composed entirely of
return flows from irrigated agriculture." EPA states "The statement
confirms that lawful application of aquatic
herbicides to ensure flow in an irrigation canal in a manner consistent
with a federally-approved product label does
not require a Clean Water Act permit." Although this decision clears
up legal use of aquatic pesticides, it does not
clear up the question about non-aquatic pesticides being required to
have a Clean Water Act permit. This would
arise form the non-aquatic pesticides being found in water due to any
reason.
(Pesticide Reports April, 2002) (EPA Headquarters Press Release, March
29, 2002)
Although atrazine is one of the most studied pesticides in the United
States, there are still some significant
uncertainties in the database, according to the revised risk assessments
of the nation's most popular number one
crop protection chemical.
EPA's Office of Pesticide Programs has held a technical briefing on
the revised health, occupational and ecological
assessments. Once a Notice of Availability for the documents is published
in the Federal Register, OPP will open
a 60-day comment period. If the heavy attendance at the technical briefing
is any indication, public comments on
the revised assessment could be massive. Once the comments are in,
OPP will begin developing risk mitigation
proposals for the triazine herbicide.
Many of the risks identified in the revised assessment might be mitigated
by additional study data. However, as
the database stands, there are already volumes of data on atrazine,
said Lois Rossi, director of OPP's Special
Review and Reregistration Division. "There's more data than we need
for a re-registration decision," Rossi pointed
out. "Also, much of the data are different from what we usually see
in support of a registration. It's a very complex
assessment." Rossi outlined the conclusion of the assessment as follows:
Dietary risks are acceptable.
Risks from residues in drinking water exceed the agency's level of
concern for intermediate and chronic exposure
in some community water systems.
Risks from residential exposure are problematic for some homeowners,
depending on the application equipment.
Intermediate-term risks for some handler scenarios are a concern, and
there's a "very limited" risk in some post-
application scenarios.
Even with the reams of data available for atrazine, additional data
is being generated, Rossi said. Although some
of the data submitted in response to the preliminary assessment were
deemed unacceptable by OPP, the revised
assessment adds the following refinements and data submissions, among
others:
OPP performed a probabilistic drinking water assessment.
Additional data from such studies as the "hand press" study were incorporated
Some registrants discussion of the probabilistic, ecological risk assessments
was added.
A number of important uncertainties remain in the assessment. Here are
a few of them:
Some of the drinking water monitoring data is suspect, which has led
to uncertainties in the risk assessment.
There is limited behavioral data available for residential application
practices, so EPA used a combined
"macro/micro activity" approach.
OPP was unable to find any data on exposures from atrazine/fertilizer
mixtures, rights-of-way sprayer exposure
data or crop-specific transfer coefficients, when performing the occupational
assessment.
Uncertainties in the ecological assessment are due to: the need to
confirm reports of recovery from atrazine
effects, reports of resistance to the effects, and reports of sub-lethal
endocrine and olfactory effects on aquatic
organisms and amphibians.
More research is needed on the occurrence and levels of the chlorotriazine
metabolites, which are considered
equal in toxicity to the parent. Rossi added that additional data could
impact the risk assessment. This data
includes: water trend analysis data provided by the registrant, additional
water monitoring data and benefits data.
Although the technical briefing was not intended to discuss new risk
mitigation measure in addition to those
imposed over the last 10 years, Rossi noted the following possibilities:
Reduce use rates
Eliminate or restrict uses
Eliminate specific formulations
Require vegetative buffers and setbacks
Restrict application methods
Apply regional use restrictions
Require additional data on surface water monitoring and endocrine and
olfactory effects.
Registrants argue that the low-dose endocrine disruption has not been
confirmed. The olfactory issue (i.e., the
pesticidal disruption of navigation among fish) has been raised with
respect to diazinon. However, registrants of
that compound argue that monitoring has not detected levels sufficient
to result in such effects. It remains to be
seen how or if OPP will mitigate olfactory effects on the basis of
the reports on atrazine.
Rossi noted that EPA's Office of Water will be included in the risk
management decisions because atrazine is also
regulated by Office of Water. The OW will start the process of updating
its Health Advisory Document in response
to the revised risk assessment.
Under the terms of its legal settlement with the Natural Resources
Defense Council, OPP must issue its interim
Reregistration Eligibility Decision by August. The RED will remain
interim until a cumulative risk assessment of
three triazine herbicides and their metabolites is completed.
(Pesticide Reports June, 2002) (Pesticide & Toxic Chemical News,
April 22, 2002, Vol. 30, No. 26)
Workers handling large amounts of atrazine over an intermediate time
period face the greatest health risks, says
a revised EPA assessment of the atriazine herbicide. The agency's Gary
Bangs presented the findings during an
April technical briefing. The findings reveal that most occupational
atrazine risks could be reduced through the
use of protective equipment.
Bangs, an industrial hygienist with the Health Effects Division of
EPA's Office of Pesticide Programs, noted that
atrazine is a "very popular, useful chemical" with about 174 different
labels. "The exact number is hard to pin
down because it changes frequently," he noted.
Labels are based on four formulations. The occupational assessment
was performed on their uses for field crops,
tree crops and turf. Along with handlers, the assessment looked at
post-application workers such as scouts and turf
management professionals.
The assessment identified few concerns for short-term handler exposure
if Personal Protective Equipment is worn,
or engineering controls are in place. However, the assessment registered
risks of concern for all intermediate-term
exposures to handlers and sugarcane scouts. "Intermediate term" is
defined as a period of 30 days to six months.
Currently, agricultural atrazine labels require the following PPE:
long sleeved shirt
long pants
shoes and socks
waterproof and chemical-resistant gloves
protective eyewear for mixer/loaders
Although Bangs didn't detail the Margins of Exposure tallied for any
of the scenarios assessed by HED, here are
the overall findings for handlers:
Short term (1-30 days): Half the MOEs were unacceptable without gloves.
With gloves, only 13% of the MOEs
raised any concerns
Intermediate term (30 days to six months): One-third of the MOEs were
unacceptable even with maximum PPE.
With engineering controls, 15% of the
scenarios still registered MOEs of concern.
HED is concerned about workers handling fertilizer mixed with atrazine,
although there aren't any data available
for scenarios involving this mix. For the post-application worker assessment,
HED evaluated data on the atrazine
uses for corn, sorghum, sugarcane and trees. Re-entry exposure was
assessed using turf-residue study data. In the
short-term, post-application scenarios, only sugarcane scouting registered
unacceptable MOEs. All intermediate-
term, post-application MOEs were acceptable.
Although atrazine is believed to be a potent endocrine disruptor, its
acute effects are classified as moderate.
Symptoms of acute exposure include abdominal pain, diarrhea and vomiting,
eye irritation, irritation of mucous
membranes and skin reactions which are typically mild. From 1993 to
1998, Poison Control Centers tallied the
following reports:
75 illnesses
186 adult non-occupational illnesses
64 juvenile non-occupational illnesses
Most of the reports, said Bangs, involved skin and eye irritation. He
added that, in comparison to other herbicides,
the PCC data indicated that atrazine registers numerically more complaints.
The complaints, however, are more
likely to be minor. Based on human and animal data gathered from 1984-1991,
the National Pesticide Telephone
Network ranks atrazine 33 rd (among all pesticides) in health-related
reports on atrazine, Bangs noted. Besides
the shortfall in exposure data on fertilizer/atrazine mixtures, HED
lacks data on transfer coefficients for specific
crops and exposures to right-of-way applicators. Aside from that, there
is a rich database on handler exposures,
and HED confidence in it is high.
(Pesticide Reports June, 2002) (Pesticide & Toxic Chemical News,
April 22, 2002, Vol. 30, No. 26)
Do organically-grown foods contain fewer residues of toxic crop pesticides
than conventionally-grown foods do?
The answer is an emphatic yes, according to a scientific study published
today in the peer-reviewed journal Food
Additives and Contaminants. The study team included analysts from Consumers
Union (CU), the Yonkers, NY-
based publisher of Consumer Reports magazine, and from the Organic
Materials Research Institute (OMRI), an
independent research, education and evaluation organization in Eugene,
OR.
Organic foods are grown without most synthetic chemical inputs used
in conventional farming, and many
consumers who buy organic do so to avoid dietary pesticides. But the
issue has been surprisingly controversial,
with some conservative and media commentators claiming organic foods
have just as many residues as foods
grown conventionally.
"We have shown that consumers who buy organic fruits and vegetable
are exposed to just one-third as many
residues as they'd eat in conventionally-grown foods, and the residues
are usually lower as well," said Edward
Groth III, Senior scientist at CU and one of the paper's co-authors.
The paper published today is the first detailed analysis of pesticide
residue data in foods grown organically and
conventionally. "Until now, the scientific community had few empirical
data to answer this question," explains
Charles Benbrook, a consultant to CU and co-author of the paper. "But
in the last few years, enough good data
have become available to do a rigorous analysis."
The authors obtained and analyzed test data on pesticide residues in
organic and non-organic foods from three
independent sources: Tests done on selected foods by CU in 1997; surveys
of residues in a wide array of foods
on the US market conducted by the Pesticide Data Program of the US
Department of Agriculture in 1994 through
'99; and surveys of residues in foods sold in California, tested by
the California Department of Pesticide Regulation
in 1989 through '98. The combined residue data sets covered more than
94,000 food samples from more than 20
different crops; 1,291 of those samples were organically grown. "We've
pulled together the best available data on
residues in organic produce to generate a clear picture of the category
as a whole," says co-author Karen Benbrook,
who carried out much of the data analysis for CU.
The USDA data show that 73 percent of conventionally grown foods had
at last one pesticide residue, while only
23 percent of organically grown samples of the same crops had any residues.
More than 90 percent of the USDA's
samples of conventionally-grown apples, peaches, pears, strawberries
and celery had residues, and conventionally-
grown crops were six
times as likely as organic to contain multiple pesticide residues.
The California data (based on tests with less
sensitive detection limits) found residues in 31 percent of conventionally
grown foods and only 6.5 percent of
organic samples, and found multiple residues nine times as often in
conventional samples. CU tests found residues
in 79 percent of conventionally grown samples and 27 percent of organically
grown samples, with multiple
residues ten times as common in the former. The levels of residues
found in organic samples were also consistently
lower than levels of the same pesticides found in conventional samples,
in all three sets of residue data. "The
results are remarkably consistent across all three data sets," says
Brian Baker of OMRI, a co-author of the study.
"If we take the results as a whole, the evidence is very convincing
that- as you'd expect- there are fewer residues
by far in organically grown foods."
The USDA and CU tests also included some samples of "green labeled"
foods foods that are not organically
grown, but are marketed with claims based on reduced pesticide use,
or "no detectable residues." Foods in this
category had residues in 47 percent of USDA samples and 51 percent
of CU samples intermediate between results
for organic and conventional crops.
The authors explored reasons why organic foods contain any pesticide
residues at all. When they excluded residues
of persistent, long-banned organochlorine insecticides such as DDT
from their analysis of the USDA data, the
fraction of organic samples with residues dropped from 23 to 13 percent.
Most residues in organic foods (and some
residues in conventional foods) can readily be explained as unavoidable
results of environmental contamination
by past pesticide use, or by "drift" (sprays blown in from adjacent
non-organic farms). Some tested samples may
also have been mislabeled as organic, either because of fraud or because
of lapses in maintaining the identity of
foods as they moved from the farm to point of purchase. Some problems
represent opportunities for producers to
improve their performance, says Baker. What about residues of natural
pesticides, used by some organic (and non-
organic) farmers? Critics of organic agriculture have suggested that
residues of natural pesticides in organic foods
pose risks comparable to those of residues of conventional crop chemicals
in non-organic foods. The paper
concludes there is no current evidence to support that assertion, although
the authors see this as an interesting
question that should be pursued with better data.
"At present there is no good residue data on the botanicals and other
natural pesticides, and some of those
substances definitely should be more fully evaluated for potential
toxic effects," says Groth. But he emphasized
that "There is now no objective evidence of a problem with residues
of natural pesticide, whereas health risks
associated with residues of conventional pesticides in foods are well
established and the focus of substantial
regulatory efforts. While the analysis for this study was conducted
with no funding from outside sources, the CU
database that made that portion of the analysis possible was developed
with partial support in recent years by since-
completed grants from the Pew Charitable Trusts, the Joyce Foundation,
and the W. Alton Jones Foundation.A
summary of the study can be found at http://www.consumersunion.org.
The full paper can be purchased (obtained
free by press) from the publisher of Food Additives and Contaminants;
go to http://www.biosciencearean.com for
a link to the paper.
Note: The vast majority USDA PDP residues detected are well below tolerance
levels.
(Pesticide Reports June, 2002) (Food Industry Environmental Network,
May 8, 2002)
Some home gardeners already use vinegar as a herbicide, and some garden
stores sell vinegar pesticides. But no
one has tested it scientifically until now. Agricultural Research Service
scientists offer the first scientific evidence
that it may be a potent weedkiller that is inexpensive and environmentally
safe perfect for organic farmers. ARS
researchers Jay Radhakrishnan, John R. Teasdale and Ben Coffman in
Beltsville, Md., tested vinegar on major
weeds common lamb's-quarters, giant foxtail, velvetleaf, smooth pigweed
and Canada thistle in greenhouse and
field studies. They hand-sprayed the weeds with various solutions of
vinegar, uniformly coating the leaves. The
researchers found that 5- and 10-percent concentrations killed the
weeds during their first two weeks of life. Older
plants required higher concentrations of vinegar to kill them. At the
higher concentrations, vinegar had an 85- to
100-percent kill
rate at all growth stages. A bottle of household vinegar is about 5-percent
concentration.
Canada thistle, one of the most tenacious weeds in the world, proved
the most susceptible; the 5-percent
concentration had a 100-percent kill rate of the perennial's top growth.
The 20-percent concentration can do this
in about 2 hours. Spot spraying of cornfields with 20-percent vinegar
killed 80 to 100 percent of weeds without
harming the corn, but the scientist stress the need for more research.
If the vinegar were sprayed over an entire
field, it would cost about $65 per acre. If applied to local weed infestations
only, such as may occur in the crop
row after cultivation, it may only cost about $20 or $30. The researchers
use only vinegar made from fruits or
grains, to conform to organic farming standards.
(Pesticide Reports June, 2002) (Food Industry Environmental Network,
May 18, 2002)
One key characteristic of pesticides such as insecticides and miticides
is the mode of activity,or mode of action.
This term indicates both where the active ingredient works inside the
insect or mite, generally referred to as site
of action, and how it kills them. It is important to understand the
mode of action of insecticides and miticides to
implement a proper rotation schedule.
Insecticides and miticides have different modes of activity. These pesticides
are categorized into chemical
classes based on their mode of activity. Most target the insect or
mite nervous system, as with acetylcholinesterace
inhibitors and gamma-aminobutyric acid (GABA) blockers. Examples include
organophosphates (Orthene and
Duraguard), carbamates (Mesurol and Closure), and macrocyclic lactones
(Avid). Some insecticides and miticides
act on target sites where energy is produced, such as the mitochondrial
electron-transport inhibitors (METI). An
example of these is the pyridazinones (Sanmite).
Besides understanding the mode of action, greenhouse managers also need
to be aware of the factors that may
influence the effectiveness of insecticides and miticides. Several
factors may interfere with an insecticide or
miticide before it reaches the site of action; these include environmental,
transportation, and biochemical factors.
Examples of each type of factor are explained as follows.
Environmental Factors
In volatilization, the liquid material leaves the application surface
by evaporating into the vapor phase and moves
into the air. Volatility, or evaporative characteristics, depends on
formulation, temperature, and relative humidity.
For example, higher air temperatures generally result in faster volatilization.
A problem occurs when an insecticide or miticides volatilizes before
it actually penetrates the insect or mite
cuticle, which may reduce the time the material is active. This effect
is why it is generally recommended to apply
nsecticides and miticides during cooler periods (early morning or late
afternoon) to reduce loss due to volatility.
Photolysis/photodegradation refers to breakdown of an insecticide or
miticide due to sunlight (ultraviolet light).
The breakdown time depends on the chemical and physical characteristics
of the material. Photodegradation
reduces the time that the material is active; therefore, it is generally
recommended to apply insecticides and
miticides on cloudy days.
Wash off refers to the insecticide's or miticide's being washed off
the plant foliage. Wash off is most likely to
occur under mist propagation. In addition, overhead irrigation, either
by hand or with an automated irrigation
system, can wash the material off the foliage before it has worked
or penetrated the leaves. This point is especially
important for foliar-applied systemic insecticides or for those insecticides
and miticides with translaminar (within
the leaf) movement. Allowing the spray application to dry before irrigation
results in better kill.
Transportation Factors
Penetration refers to the ability of an insecticide or miticide to move
through the skin or cuticle to reach the target
or receptor site. Some insects, including mealybugs and scales, have
a waxy coat-ing that makes it difficult for the
insecticide to penetrate. It is generally recommended to time sprays
when the young (crawlers) are present because
they do not have a hard covering.
Another factor that may reduce penetration is molting, or shedding of
the old skin. If an insect or mite molts before
the material penetrates, no control can occur. This effect may be more
pronounced during warmer times of year,
when mites and insects usually molt more frequently.
Adsorption is the ability of an insecticide to bind to and be retained
on the surface of growing-medium particles.
Though this trait may prevent material from being leached, the particle
charges may tie up the active ingredient
and prevent it from being taken up by plant roots, thus resulting in
reduced efficacy. The length of time the active
ingredient is tied up by the medium depends on the insecticide's chemical
characteristics.
Soil-applied systemic insecticides such as Marathon (imidacloprid) are
susceptible to tie-up by growing mixes
containing bark as their major component. This effect is especially
likely after the growing medium has the
opportunity to dry out, which leads to the active ingredient's binding
more tightly to the growing-medium particles,
making it difficult to release even if irrigated. Natural soil mixes
or soils high in organic matter have the same
effect. Using growing medium with low amounts of bark and organic matter
prevents this.
Biochemical Factors
Activation refers to the ability of the active ingredient to work by
binding to the target site within an insect or mite.
Many insecticides and miticides attack target sites in the nervous
system. However, insects and mites may be able
to modify these target sites, which prevents the active ingredient
from binding to the target site, resulting in no
control.
In detoxification, insects and mites can prevent the active ingredient
from reaching the target site by breaking apart
the active ingredient. Piperonyl butoxide (PBO) is a synergist that
is sometimes added to insecticides such as
pyrethroids, especially natural pyrethrins, to prevent certain insects
from breaking down the material. If the active
ingredient is broken down before reaching the target site, then it
may be excreted by the insect or mite.
Knowing the mode of activity of an insecticide or miticide is important
for implementing a rotation schedule that
is effective in controlling insects and mites. However, it is just
as important to understand the environmental,
transportation, and biochemical factors that may influence the effectiveness
of an insecticide or miticide.
(Illinois Pesticide Review Vol 2002, Issue 1, January, 2002)
Although its tallies are qualified as preliminary, the California Department
of Pesticide Regulation is reporting that
statewide pesticide use declined for the second straight year in 2000
- down to the lowest point in nearly a decade.
Officials say the decline is evidence that pesticide users are turning
to reduced-risk strategies. But the decline
didn't apply to all crops and pesticides. Some, like almonds, wine
grapes and raisins, saw declines, but others,
including rice, experienced increases.
DPR issued summaries of pesticide-use reporting data for 2000. The
massive documents are based on reporting
data, which under California law must be annually submitted to the
department by agricultural and other pesticide
applicators. The summaries have been released before the majority of
error corrections, which could have a
significant impact on the findings, have been finished.
Nevertheless, the unverified data show that pesticide use in California
last year totaled 188 million lbs. - a decline
of 15 million lbs. from 1999 and the lowest reported total since 1992.
The summaries note that "all factors
contributing to the 2000 decline cannot be pinpointed due to the preliminary
nature of the data provided to compile
[the documents]." Nevertheless, DPR Director Paul Helliker describes
the initial results for 2000 as promising.
"We are encouraged that overall pesticide use shows a decline for the
second consecutive year," Helliker said in
a DPR press release. "We always stress that pesticide applications
vary from year to year depending on weather,
pest problems and other factors - but we are most encouraged by evidence
that farmers and other pesticide users
are turning to reduced-risk strategies."
The summaries note that production agriculture, the major category
of use subject to reporting requirements, was
responsible for most of the overall decrease in use. Applications for
production agriculture dropped by 14.2 million
lbs. DPR notes that the use of reduced-risk chemicals - as measured
by both pounds applied and acres treated-
jumped 50% in 2000. "DPR has made speedy registration of reduced-risk
chemicals a top priority, and these
statistics show that the market is ready to accept new products that
better protect people and the environment,"
Helliker said.
With respect to the universe of pesticides registered with DPR, the
summaries note that, "since 1994, the reported
pounds of pesticides applied has fluctuated from year to year with
no general increasing or decreasing trend. An
increase or decrease in use from one year to the next or in the span
of a few years does not necessarily indicate a
general trend in use; it simply may reflect normal variations. Short
periods of time - i.e., three to five years - may
suggest trends, such as the increased pesticide use from 1994-1998.
However, the overall decrease in pesticide
pounds applied from 1998-2000, and the fact that no other increases
during any part of this time period were
statistically significant, suggests no general increasing trend in
pesticide use in California."
(Pesticide Reports December, 2001) (Pesticide & Toxic Chemical
News, Vol. 30, No. 1, October 29, 2001)
In a promising development for State Lead Agencies, the EPA Office of
Pesticide Programs has announced plans
to request state input on water quality issues raised during pesticide
registration. Donald Stubbs, from OPP's
registration division, offered the federal perspective on the initiative
during a meeting of the State FIFRA Issues
Research & Evaluation Group earlier this month. The plan will help
states address potentially significant impacts
to water quality themselves before they are asked to register the products.
The registration division has been
gathering water-quality input for several years, said Jim VanderBrook,
water quality section chief for the
Wisconsin Department of Agriculture. However, the imminent formation
of the Water Quality Registration Review
Team will make the solicitation process much more formal.
The Review Team will flag screening-level data on active ingredients
(AI) that have the potential to build up in
ground or surface water at levels greater than 50% of its Drinking
Water Level of Comparison. A DWLOC is the
upper limit of acceptability for pesticide levels in drinking water
after human exposures from other pathways, such
as dietary sources, are estimated.
The screening data will be supplied by OPP's Environmental Fate and
Effects Division. An AI that raises concerns
among Review Team members will be referred to the SFIREG Water Quality
and Pesticide Disposal Committee.
The committee will assign interested members to serve on an ad hoc
review group.
The ad hoc groups will be specific to the AI in question. Group members
will be expected to solicit input from
surrounding states or counties whose waters, due to the proposed use-pattern
of the AI, could be put at risk. "The
groups will identify potential impacts, propose mitigation measures
and recommend monitoring protocols,"
VanderBrook said. He noted that registrants are anxious for decisions
on their application and stressed that ad hoc
groups should finish their work within 30 days. "We're trying to build
a partnership with the states so we're both
on the same page. If a state needs a more restrictive label, we'll
be aware of it," said Donald Stubbs, chief of the
RD Herbicide Branch. "For this to work, we'll need registrant permission
for EFED to allow the ad hoc groups to
see all of the environmental fate data [which is confidential during
the application process]."
One registrant observer suggested the OPP vet the proposed Review Team
process with American Crop Protection
Association members. Bob Fugitt of DuPont Agricultural Products, agreed.
"Involving industry early on, especially
with the issue of data-sharing, will help facilitate the process,"he
added. "It would also help us to head off 'scope
creep,' where more and more issues are brought to the table." The Review
Team and ad hoc committees will be
looking at the potential affects of metabolites as well as their parents.
Stubbs said OPP hopes to start using the new
program in 2002. (Pesticide Reports February, 2002) (Pesticide &
Toxic Chemical News, Vol. 30, No. 8, December
17, 2001)
Pointing to some possible cancer risks, EPA has requested risk mitigation
ideas for theherbicide sodium
acifluorfen. The request for proposals, along with a Notice of Availability
for the revised health and ecological
assessments, was published in the April 12 Federal Register (67 FR
17994).
EPA's Office of Pesticide Programs will accept comments on the assessments
for 60 days. Registered by BASF
Corp. and Bonide Products Inc., sodium acifluorfen is used on soybeans,
peanuts and rice for post-emergent weed
control. It is also used as a spot weed-killing treatment for driveways,
sidewalks and patios. All told, about 1.5
million lbs of active ingredient are applied annually.
Although the diphenyl ether herbicide is classified as a B2 , or "probable"
human carcinogen, its cancer risks stem
mainly from drinking water exposure. OPP says registrant studies on
its carcinogenesis might eventually lead to
a cancer re-classification, but for now, the drinking water exposures
remain a concern. Moreover, OPP has
requested a Developmental Neurotoxicity Study, which might also affect
the findings of the revised health
assessment. Also known as Blazer and Tackle, sodium aciflurfen is classified
asseverely toxic to the eyes,
moderately toxic to the skin and slightly toxic when inhaled or ingested.
Its cancer classification is based on a
statistically significant increase in the incidence of liver tumors
and stomach tumors in mice. According to a memo
from OPP's Health Effects Division, the dose that led to the B2 ranking
has been recalculated to reflect a
misapprehension about the original 1988 studies.
HED had assumed that the test material was a 24% aqueous solution when,
in fact, it was pure sodium acifluorfen.
Nevertheless, the revised dose still led to concerns about residues
in drinking water. Part of the reason is due to
another pesticide, lactofen, which breaks down into sodium acifluorfen
in the environment.
Residues in drinking water are not a concern for risks other than cancer.
The acute, Drinking Water Level of
Comparison to dietary residues is 600 ppb for females age 13-50. The
acute, surface- and groundwater water level
of total acifluorfen (including lactofen metabolite) has been modeled
at 18.9 ppb and 15.7 ppb, respectively.
The DWLOC for chronic drinking water exposure is:
455 ppb for the general population
120 ppb for females age 13-50
40 ppb for infants and children.
By contrast, the chronic concentrations of total acifluorfen surface-
and ground-water were modeled to be 4.0 ppb
and 15.7 ppb, respectively.
The chronic drinking water concentration for ground water exceeded
the cancer DWLOC of 2.8 ppb. This, says
OPP, means that lifetime cancer risks are of possible concern. That
alone has driven the aggregate health-risk
assessment for cancer, which combines residue exposures from food,
drinking water and residential uses, beyond
the agency's threshold of concern.
In the acute dietary exposure assessment, HED applied the full, FQPA
10X safety factor to females age 13-50
because of the DNT data gap and evidence of increased susceptibility
following in utero exposure to rats. In the
chronic dietary assessment, a 3X uncertainty factor was applied to
the subpopulation because of the DNT data gap,
as well. Neither the acute nor chronic exposure assessments, however,
yielded a concern for females age 13-50.
Chronic cancer risk worked out to be 5.2 X 10 -9 , which is well within
the 1 X 10 -6 threshold of concern for a 70-
year lifetime. Cancer risk from residential exposures, which was 4.5
X 10 -8 , was not of concern, either.
Cancer risk to workers did not raise a concern in most scenarios, even
if their level of protection was minimal.
Risks of concern, moreover, are adequately addressed with the addition
of personal protective equipment already
specified on the label (i.e., long-sleeve shirt, long pants, goggles
and a hat). Cancer risks in post-application
scenarios were all greater than 5.9 X 10 -6 on the day of application,
but less than 1 X 10 -6 on days 2-to-4
depending, the assessment says, on the scenario and data source. Currently,
the labeled reentry interval for sodium
acifluorfen is 48 hours.
Non-cancer risks to workers in short- and intermediate-term scenarios
were not a concern in most scenarios even
with only baseline protection except for flaggers. However, with the
addition of PPE, all scenarios exceeded the
target. Although OPP's Environmental Fate and Effects Division does
not have concerns for acute exposures to
terrestrial animals, freshwater and estuarine animals or aquatic plants,
it is concerned about the acute risks to birds
and mammals when sodium acifluorfen is applied at a rate greater than
0.25 lb/acre. EFED is uncertain, however,
about risks to freshwater and estuarine animals.
"The acute toxicity data do not suggest a risk concern," the Division
says. "However, EPA does not have sufficient
information to assess chronic risk. A No Observed Adverse Effects Level
could not be determined in a chronic
fish toxicity study because the lowest dose resulted in an effect namely,
reduced larvae weight."
EFED notes that the maximum levels of sodium acifluorfen in surface
water is 100 times lower than the Lethal
Concetration50 for rainbow trout and bluegill sunfish. Nevertheless,
because sodium acifluorfen is persistent in
water, EFED is not prepared to dismiss the possibility of chronic effects
on aquatic animals.
(Pesticide Reports June, 2002) (Pesticide & Toxic Chemical News,
Vol. 30, No. 27, April 29, 2002)
A nationwide pesticide information service funded by EPA for consumers,
the National Pesticide Telecommunications Network
(NPTN), recently changed its name to the National Pesticide Information
Call toll-free, (800)858-7378, daily from 8:30 a.m. to 6:30 p.m. (Central)
or go to the Web site at npic.orst.edu to obtain comprehensive information
on specific pesticide chemicals, including toxicological and medical information.
(Illinois Pesticide Review Vol. 2002, Issue 2, March 2002)
"Distributions of 2,4-D in Air and Surfaces Inside Residences after
Lawn Applications: Comparing Exposure Estimates from
Various Media for Young Children" published in Environmental Health
Perspectives concludes that homeowner applicators and
active dogs are most likely to track the herbicide indoors. Using samples
of indoor air and swipes of floors, table tops and window
sills at 11 occupied and two unoccupied homes before and after application,
researchers found that re-suspension of floor dust
led to the greatest amount of 2,4-D in air and on tables and window
sills.
(Pesticide Reports January, 2002) (Pesticide & Toxic Chemical News,
Vol. 30, No. 5, November 26, 2001).
Naturally occurring soil bacteria contain enzymes that can break down
pesticides into harmless compounds, researchers at
Australia's CSIRO entomology have determined.
A recent enzyme field trial on a cotton farm "showed spectacular reduction
of organophosphate [OP] residues by 90%," says
CSIRO's Robyn Russell. She adds that "there's no single enzyme that
will break down every one of the agrochemicals... but we
believe that there's a bacterium for practically every organic pollutant."
A team of scientists from CSIRO Entomology, CSIRO Molecular Science
and Orica Australia Pty Ltd "have isolated enzymes to
biodegrade OPs, carbaryl, many synthetic pyrethroids and endosulfan,"
CSIRO said.
"First," Russell notes, "the enzyme has to be identified. Then it's
a process of isolating the enzyme within the bacterium and
cloning it into a common bacterium such as Escherichia coli, which
can in turn be reproduced in large quantities. Once there is
sufficient volume, the E. coli is killed off, and the enzymes which
have been produced by the bacterium are collected and applied
to the contaminated water.
"Alternatively," Russell continues. "if the yield of enzyme is high
enough, we can produce the enzyme by growing the natural
bacterium from which we isolated the enzyme in the first place. Either
way, we will need to follow all the necessary regulatory
requirements before we trial our enzymes in the field."
The search for enzymes, CSIRO says, "also extends to pesticide-resistant
insects and the means they use to survive insecticide
applications. Post-harvest treatment of chemically sprayed fruit and
vegetables will also be possible using biodegrading enzymes.
Early trials by the team have achieved over 90% residue reductions
on commodities treated with an organophosphate insecticide.
(Pesticide Reports December, 2001) (Pesticide & Toxic Chemical News, Vol. 29, No. 52, October 22, 2001)