A monthly report on pesticides and related environmental issues

Animated spider

Issue No. 135, May 1997

Open Forum:
In an attempt to promote free and open discussion of issues, The Agrichemical and Environmental News encourages letters and articles with differing views. To include an article, contact: Dr. Catherine Daniels, Food and Environmental Quality Laboratory, 2710 University Drive, Richland, WA 99352-1671, ph: 509-372-7495, fax: 509-372-7491,
E-mail: cdaniels@tricity.wsu.edu

 

Note: Based on instructions from WSU CAHE administration, information in this newsletter not originating from WSU contains a headline in the same color as the word "Note" at the beginning of this paragraph. This is to help ensure that readers can readily identify material obtained from a source outside WSU.

 

In This Issue

News and Notes

Pesticide Incident Reporting and Tracking Annual Report

Pesticide Container Collection

A New Insecticide in Orchard Pest Management

Officially Unofficial

Organophosphate Exposure Does Not Impair Nerve Function

Ag Groups Generous Supporters of Research

Allan Felsot

Man Convicted of 48 Counts of Illegal Pesticide Use

Federal Issues

Available Reports

State Issues

 Pesticide Notification Network

 

 

Note: The animated spider graphic appearing at this site is used with permission. Copyright and use information may be obtained at http://www.inscot.demon.co.uk

 

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News and Notes

Note: The AENews is accessible from the World Wide Web via http://picol.cahe.wsu.edu
Enter this address carefully, paying close attention to punctuation and spacing (no spaces between parts of the address). Some readers may experience difficulties accessing the site. These are believed to be related to the Internet and to on-line services, not the web site. If you are having a problem accessing the web page, please inform Dr. Catherine Daniels (ph: 509-372-7495, fax: 509-372-7491, E-mail: cdaniels@tricity.wsu.edu


USDA sees rise in use of Bt corn

The USDA recently cited industry sources that said U.S. use of genetically modified "Bt" corn will cover 5 million to 6 million acres in 1997 to 1998, up to 7% of the corn harvest in the United States.


WSCPR, WSU sponsoring pesticide forums

The WSU Applicator Training Program, WSU Pesticide Coordinator Program, and the Washington State Commission on Pesticide Registration are jointly sponsoring back-to-back conferences on pesticides October 22 and 23 in Yakima.

The first conference, the 2nd PNW Pesticide Issues Conference, will focus exclusively on the Food Quality Protection Act. The Washington Pest Management Conference, held the following day, will focus on exchange of information between researchers, extension specialists, commodity groups, and companies involved in development and sales of pest management tools.

2nd PNW Pesticide Issues Conference - This conference targets individuals working with pesticide issues, particularly consultants, agrichemical industry representatives, grower associations, pest management associations, environmental organizations, extension agents, educators, and regulators.

The major focus will be an in-depth look at The Food Quality Protection Act. Areas of discussion will include:

* Anticipated Residues - What does this mean?, Where is science currently?, and What might we anticipate in EPA policy?

* Reasonable Certainty of No Harm - What does it mean?, Where is science currently?, and What might we anticipate in EPA policy?

* Common Mechanism of Action - What does science currently support, and what might we anticipate in EPA policy?

* Impacts on Agricultural Production in the PNW - Major crops, major-minor crops, and minor crops.

Washington Pest Management Conference - This conference targets agrichemical industry representatives, grower associations, pest management associations, extension agents, researchers, and regulators.

This conference is intended as a forum for exchange of information between university researchers and extension specialists (problem solvers), commodity groups (in need of pest management solutions) and companies involved in pest control (providers of pest control solutions.) The conference will be structured in such a manner as to allow maximum exchange between meeting participants.

The conference will be restricted to 150 attendees. There will be additional restrictions on the number of attendees from each sector of interest (agchem, university, grower groups, etc.).

The conference will include break refreshments and lunch. A registration fee will be charged to cover costs. For a copy of the registration packet (to be mailed in August 1997), contact Lynda Troka, Pesticide Education Programs at WSU Pullman: 509-335-9204 or trokal@wsu.edu.


EPA dislikes waivers of liability

The EPA has unofficially requested the Washington State Department of Agriculture to withdraw a Section 24(c) registration, due to inclusion of a waiver of liability on the label. The registration is for use of cycloate (RoNeet) on a seed crop. The manufacturer required the waiver of liability as part of the label before allowing the registration to be submitted by the WSDA.

Waivers of liability (or indemnifications) are commonly used by companies to limit their liability on use of pesticides, usually herbicides, on crops grown on limited acreages. Waivers are used when growers want access to pesticides for use on minor, minor crops and insufficient data exists on effectiveness of the chemical or potential for crop damage. In exchange for access to the chemical, growers are required to agree not to sue the chemical company if the product does not work as expected by the growers.

Use of the waivers is considered critical to growers in states with minor crops. Washington has about two dozen state registrations that contain waivers as part of the label. Some states, particularly Colorado, have insisted that waivers of liability should not be contained on labels and that they are not enforceable by regulatory agencies. There currently exists a certain amount of disagreement from state to state on the appropriateness of waivers. States, such as Washington, rely on waivers heavily; this allows growers access to a variety of registrations that would have been otherwise unavailable. Until this recent action by EPA on the Washington Section 24(c) registration, EPA had largely stayed out of what was a state-level controversy. The EPA has not formally expressed an opinion on waivers of liability and so far has expressed opinion only in informal situations.

In the latest development, the WSDA told the EPA it would not withdraw the Section 24(c) registration. This will result in the EPA having to either accept the 24(c) containing the waiver (allowing access to a herbicide that it has previously permitted to be used) or develop a new policy of prohibiting waivers, which would place dozens of registrations in jeopardy.


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Plastic pesticide container collection dates, requirements

  1. Must be multiple rinsed, so that no residues remain.
  2. Must be clean and dry inside and out, with no apparent odor.
  3. Hard plastic lids and slip-on lids must be removed.
  4. Glue-on labels may remain.
  5. The majority of the foil seal must be removed from the spout. A small amount of foil remaining on the container rims is acceptable.
  6. Half pint, pint, quart, one and two-and-a half-gallon containers will be accepted whole.
  7. Five-gallon containers will be accepted whole, if the lids and bails are removed.
  8. Special arrangements must be made for 30-gallon and 55-gallon containers, by calling (509) 457-3850 prior to the collection.

**Containers that do not meet the above specifications cannot be accepted.**

 

Washington Pest Consultants Association
Container Collection Dates

Please put these dates on your calendars and help notify pesticide users of the program, so that containers do not become a waste issue. Taking time to clean and recycle these reusable products can save money and prove that the industry is responsible in its use of pesticides.

Date

Site

Sponsor (contact)

Phone

Comments

June:

 

 

 

 

5 (8 a.m.-noon)

Wenatchee Tree Fruit Station

NCW F&DA (Jeff Heats)

Stemilt Growers (509) 662-3602

 

6 (8 a.m.-noon)

Wilbur-Ellis, Quincy

PNVA (Dale Martin)

(509) 787-4433

 

10 (8 a.m.-noon)

Tom Dent Aviation, Moses Lake Municipal Airport

CBCCA (Ron Turner)

(509) 787-3556

 

11 (8 a.m.-noon)

Wilbur-Ellis, Mattawa

Wilbur-Ellis (Al Hilliker), Wolfkill Feed & Fertilizer (Rick Florine), Othello Applicators (Steve George)

(509) 932-4988

 

(509) 932-4769

(509) 457-3850

 

12 (8 a.m.-noon)

Othello Airport

LCBF&DA (Greg Jackson)

(509) 545-1865

 

 13 (8 a.m.-noon)

Wilbur-Ellis, Eltopia

 Bleyhl Farm Service (Gary Herndon), Simplot Soil Builders (John Cullen), Monsanto (Ted Nullinger

 (509) 839-4200

(509) 837-6261

 

(509) 966-2363

 

 

 

 

 

 

July:

 

 

 

 

9 (8 a.m.-noon)

Colfax Grange

Cenex O Lakes (Tammy Haynes)

(509) 244-2507

 

22 (9 a.m.-3 p.m.)

Snipes Mtn. Transfer Station

Yakima County (Mark Nedrow)

(509) 574-2457

Cardboard accepted

23 (8:30 a.m.-3 p.m.)

Terrace Hts. Landfill

Yakima County (Mark Nedrow)

(509) 574-2457

Cardboard accepted

28 (8 a.m.-noon)

Wenatchee Tree Fruit Station

Farm Bureau (Dale Goldy)

 

 

29 (8 a.m.-noon)

Wilbur-Ellis, Chelan

Wilbur-Ellis (Brian Hendricks

(509) 682-5315

 

30 (8 a.m.-noon)

Wilbur-Ellis, Brewster

Wilbur-Ellis (Brian Hendricks

(509) 682-5315

 

31 (8 a.m.-noon)

Wilbur-Ellis, Tonasket

Wilbur-Ellis (Brian Hendricks

(509) 682-5315

 

 

For more information about plastic pesticide container collection, contact:

Steve George, WPCA Recycling Coordinator,
31 High Valley View St. Yakima, WA 98901
(509) 457-3850 or point your
World Wide Web browser to
http://www.wsu.edu:8080/~Ramsay/wpca.html

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Officially Unofficial

...Alan Schreiber

"Officially Unofficial" is a regular feature that may include information considered inappropriate by some.

Alan Schreiber

 

  • So far this year, WSDA has submitted 21 Section 18 emergency exemption requests and is preparing four more for submission to EPA. This is a record number for Washington. The reasons for this are complex. Only one exemption so far is due to FQPA. A maj or factor in the increased requests is increased capacity within WSU and WSDA to handle Section 18 requests. As WSDA expands its staff with increased funding provided by the Legislature and FQPA results in cancellations, the number of exemptions is expected to further increase.
  • In a related note, WSDA has had to declare seven crisis exemptions, another record number. Declaration of crisis for one third of exemptions is absolutely unheard of and is a direct result of the FQPA. EPA representatives stated on May 22 that they had issued more crisis exemptions in one week than they had in the past four months. Again, this is due to the FQPA. (If the employees of the WSDA Pesticide Management Division got to keep all of the money that was generated or saved due to the Section 18 requests that they processed, every one of them would be millionaires.)
  • Novartis has purchased Merck. It plans to keep the company largely intact.
  •  

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    Ag groups generous supporters of research

    Washington's commodity groups give five times the national average to support agricultural research, according to Jim Carlson, associate dean and associate director of the WSU Agricultural Research Center.

    "In fiscal year 1995-1996, Washington commodity commissions contributed over $4.7 million to support research at WSU, USDA, ARS and experiment stations in some other states," Carlson said.

    Comparing research support for several commodities (averaged over five years) to cash farm receipts (also averaged over five years) helps put the data in perspective.

    "Between 1991 and 1996, Washington's commissions contributed an average of $4.4 million, or 0.148% of cash farm receipts; the national average for all states between 1989 and 1993 was $37.7 million, or 0.025% of cash farm receipts," Carlson said.

    The chart compares national and Washington commodity group support for four commodities averaged over five years.

    "Other Washington agribusiness organizations and private benefactors also add support through gifts, grants and in-kind assistance," he said.

    But private-sector support is only one side of the research funding equation.

    "Washington's private sector funding focuses research on urgent problems. State and federal funds support the infrastructure and base programs necessary for pursuing today's high-tech research," he said.

    Commodity Research Support

    Unfortunately, cuts in federal and state research dollars have weakened the public side of the research funding equation in recent years, Carlson said. Washington now ranks 44th in state support for agricultural research, providing approximately $5.13 per $1,000 of cash receipts. The average for all states, $17.11, is more than three times the Washington figure.

    "We are facing complex challenges in an increasingly competitive global economy with more rigorous criteria for product quality and use. Meeting these challenges will require strong partnerships, not only with industry but with state and federal governments as well."

     

     

     

     

     

     

     

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    Man convicted of 48 counts of illegal pesticide use

    Source: Pesticide & Toxic Chemical News, May 7, 1997

    A federal jury on May 2 convicted Mississippi pesticide applicator Paul Walls on 48 counts of illegally using and selling methyl parathion. This is the second federal conviction involving illegal use of the pesticide in nearly half a dozen states that has prompted a multimillion-dollar federal cleanup effort.

    The U.S. District Court for the District of Mississippi found Walls guilty of spraying methyl parathion in 45 homes in Jackson County, Miss. The court also found Walls guilty of three counts of illegally distributing the pesticide, said Martin Topper of EPA's Office of Criminal Enforcement, Forensics and Training. Each of the 48 counts carries a maximum penalty of one year in jail and/or a fine of $100,000.

    EPA registered methyl parathion for use on cotton and other crops. Its use indoors is prohibited. There have been no confirmed human deaths from the pesticide, which affects the nervous system and can be deadly at high doses. Local papers in Hattiesburg, Miss. reported deaths of family pets and a sick stomach experienced by a 10-year-old girl who ate ice cream from a bowl allegedly contaminated by the pesticide.

    Walls is scheduled to be sentenced July 10. Among the issues the judge will consider in setting the sentence is the cost of Walls' actions and whether he is showing signs of remorse.

    Local newspapers reported that Walls said he did not know his actions were potentially harmful. Most of the sprayings for which Walls was convicted, however, occurred after he had signed a court order in which he agreed to stop spraying the pesticide indoors, Topper said. The government already has spent more than $6 million from the Superfund Trust Fund cleaning up fewer than half the properties Walls sprayed, he added.

    Remediation involves much more than cleaning sprayed areas, Topper explained. Because methyl parathion seeps into porous materials, remediation involves hiring special contractors licensed to remove contaminated materials and renovate the entire area. More than 1,600 individuals in Mississippi and Louisiana have been displaced due to spraying by Walls and another applicator, Dock Eatman. On March 13, Eatman was convicted in the same district court of 21 counts of spraying methyl parathion and permethrin (Ambush). Eatman is scheduled to be sentenced May 21.

    Federal courts have indicted one additional applicator in Ohio, and a search and seizure was recently conducted in Chicago as part of an ongoing investigation. State governments also are investigating dozens of additional cases in Mississippi, Louisiana and Arkansas. Remediating contaminated properties may cost several hundred million dollars, Topper said.

     

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    Available Reports

     

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    Pesticide Notification Network

    ...Jane Thomas

    Jane Thomas is coordinator of the Pesticide Notification Network at the Washington State University Food and Environmental Quality Laboratory.

    The Pesticide Notification Network is an information distribution system intended to disseminate pesticide registration and label change information to pesticide users across Washington. Operated by Washington State University for the Washington State Commission on Pesticide Registration, the PNN has now been operating for two and a half months. By far, the majority of the notifications that have been sent relate to issuance, revision, or cancellation of either Section 18 exemptions or Section 24(c) SLN registrations.

    Each PNN notification is sent to a list of individual contacts via either E-mail or fax. These individual messages are referred to as transmittals. To date, the PNN system has distributed 109 notifications covering 45 topics. The process of distributing these notifications involved sending nearly 900 transmittals.

    In addition to the Section 18 and 24(c) notifications, the system has also distributed notifications concerning manufacturers' voluntary product cancellations and use deletions. One example is PNN notification number 1997-60. Here, Bayer Corporation announced its intent to support the reregistration of triadimefon (Bayleton) but decided to request deletion of uses on wheat, grasses grown for seed, sugar beets, and cucurbits from all triadimefon labels.

    The PNN notification was sent to the list of contacts representing the crops being deleted. The notification message provided these people with an address to which they could submit written comments on the planned action. This type of notification can help the agricultural industry by providing the appropriate information needed to comment on a proposed action or ruling.

    The PNN has also distributed notifications containing miscellaneous regulatory and product information. In one case (PNN # 1997-48), the PNN notified contacts for the tree fruit industry that the Washington State Department of Agriculture (WSDA) was concerned about the possible distribution of ammonium thiosulfate as a blossom thinner.

    Another example of a "miscellaneous" notification was PNN notification number 1997-114. Here, the PNN warned contacts representing selected tree fruit crops that active ingredients in Merck & Co. products AgriMycin 17 and Mycoshield may have naturally degraded over time. The notification provided a copy of the letter from the manufacturer discussing the problem and directions for how to obtain product replacement.

    The next step toward full implementation of the network will be to begin sending notifications about new Washington product registrations. This phase, slated to begin later this summer, will commence with the Pesticide Information Center On-Line (PICOL) label database beginning to record 1997 product registrations.


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    1996 Annual Report --

    Pesticide Incident Reporting and Tracking Panel 

    This article is from the 1996 Annual Report of the Pesticide Incident Reporting and Tracking Review Panel. This annual report was prepared by the Washington State Department of Health, Environmental Health Programs, Office of Toxic Substances and submitted to the Washington Legislature.

    1995 Data Summary

    Washington State Department of Agriculture

    In 1995, WSDA responded to 259 complaints about possible violations of state or federal regulations concerning pesticide management. One hundred thirty-eight (53%) complaints were related to pesticides, and 56 of these resulted in violations. Thirty-one additional violations were identified in non-pesticide activities such as record keeping, licensing, and inspections for wood destroying organisms (termites, ants, fungi, etc.).

    Complaints occurred statewide, but Spokane, Yakima and King counties reported the highest number of complaints. This pattern is similar to prior years. In 1995, 40% of all WSDA complaints involved agriculture, 32% commercial and industrial activities, 15% residential activities, and 13% involved other activities such as pesticide record keeping.

    The number of complaints has decreased significantly from 197 in 1993 and 1994, respectively, to 64 in 1995. This is the fifth consecutive year WSDA has seen a decrease in the total number of complaints.

    Department of Labor and Industries

    In 1995, L&I Consultation and Compliance Services Division conducted 24 pesticide-related investigations; 21 resulted in violations. The Claims and Administration Program received 245 pesticide-related claims. Medical benefits were paid for 134 of the claims, 98 were rejected, time loss was paid on nine, and one claimant was kept on salary. Three claims are pending.

    Department of Health

    In 1995, DOH investigated 399 incidents involving 503 people. These numbers are similar to those reported in prior years. Most reports were received from other agencies and the Washington Poison Control Center. Sixty-four percent of the reports were from eastern Washington. Eighty-one percent of the 503 individuals sought health care.

    Following investigation, a determination is made regarding the relationship between reported symptoms and pesticide exposure. There were 216 (43%) definite, probable or possible pesticide exposures. This was similar to the number of such cases reported in prior years. King and Yakima counties each reported the greatest number (31) of definite, probable or possible cases. In 1995, 85 definite, probable or possible cases occurred occupationally in agriculture. Forty-seven (55%) occurred in the fruit production industry, which is very labor intensive and uses significant amounts of pesticide. Forty-nine (59%) of the 85 cases involved the activity of pesticide application.

    Recommendations for 1997 activities

     

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    Success: a new insecticide
    for orchard pest management

    Source: IPM Update, The Newsletter of Pheromone-based Orchard Pest Management.
    May 1, 1997. Vol. 2, No. 6

    Success is the brand name of an insecticide resulting from fermentation of the actinomycete bacterium Saccharopolyspora spinosa. A DowElanco scientist on vacation (or so we were told) discovered the microorganism inside a rum barrel in the Caribbean.

    When cultured, the bacterium was found to have insecticidal properties.

    These properties stem from the production of naturally derived active molecules called spinosyns, from which the compound's proposed common name spinosad is derived.

    Spinosyns have shown good insecticidal activity against a number of insect orders, including thrips, beetles, caterpillars, wasps and flies. The spinosyns and their mode of action are unique and unrelated to any other available insecticides; this makes them valuable in a resistance management program. The insecticide acts quickly; susceptible insects show signs of poisoning within an hour or two and die within a few days.

    Success has many qualities that make it well suited for use in integrated pest management programs. It acts as both a contact and stomach poison, but is much more active if eaten. It has relatively short contact residual activity and degrades rapidly in the environment. It has some trans-laminar activity (absorbed locally into the leaf), which extends its activity against leaf feeders like leafrollers and accounts for its effect on leafminers.

    It is a relatively "soft" pesticide; it has almost no activity against many beneficial insects, including lady beetles, lacewings, predatory bugs and parasitic wasps. Dried residues, however, have a small effect on bees. This risk can be minimized by spraying when bees are not present. Some parasitic wasps, such as the leafroller parasite Colpoclypeus florus, are more sensitive than honeybees; research is continuing in Washington on the full impact of Success on these wasps. The product is practically non-toxic to mammals and birds. It is somewhat toxic to aquatic invertebrate organisms.

    Success is expected to be especially valuable for controlling leafrollers. Work by WSU's Dr. Jay Brunner with Success on pandemis and obliquebanded leafrollers, the two principal orchard leafroller pests in the Pacific Northwest, has demonstrated that Success is highly active against both leafroller pest species, even at rates as low as 0.04 lbs. of active ingredient per acre. Only 1 to 2 ppm were needed to kill 50% of first instar larvae in laboratory bioassays. Excellent control was obtained, even when large larvae were treated in mid-summer field trials. Significant residual activity on neonate larvae was found up to 21 days after treatment, when higher rates were used.

    Trials in 1996, in which air blast sprayers were used, showed Success to be highly active against both spring and summer larvae, when the insecticide was applied either as a dilute or concentrate spray. The single best timing appeared to be at petal fall; much better control resulted from this single application than with a delayed dormant Lorsban spray.

    DowElanco expects to have Success registered for apples this year, perhaps by July. This could allow it to be used against the summer generation larvae that begin to hatch in late June or early July. If this registration is delayed, Success may first be used in apple orchards in the spring of 1998.

    Other new pest control procedures for leafrollers are or will soon be available. These include leafroller mating disruption and use of the insect growth regulator Confirm. With the introduction of Success and the continued use of existing controls such as Bts and Lorsban, effective leafroller control in orchards could quickly become "softer" and much easier to obtain.

     

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    Organophosphate exposure
    does not impair nerve function

    Chronic exposure to low levels of organophosphate pesticides (OPs) did not impair peripheral neurological function in Washington state farmworkers, according to a study by several researchers at the University of Washington, Seattle.

    Lawrence Engel, Matthew Keifer, Harvey Checkoway and Thomas Vaughan of the University of Washington and Lawrence Robinson of the Harborview Medical Center, Seattle performed the study. The researchers presented their findings at the American Public Health Association meeting in New York City.

    Engel, Keifer, Checkoway and Vaughan designed the study to investigate neurophysiological effects of chronic low-level exposure to organophosphates among agricultural workers exposed to foliar organophosphate residues. The authors stated that, "An estimated 600 million people worldwide are regularly exposed to pesticides, the most toxic of which are the organophosphates."

    For their cross-sectional investigation, Engel and the other researchers studied 67 farmworkers in Washington state exposed primarily to organophosphates on the job during the course of a single season and 68 unexposed reference subjects matched in age, gender, ethnicity and education. The neurophysiological examination included sensory and motor nerve conduction, as well as neuromuscular junction testing. Erythrocyte cholinesterase activity was measured at the time of the examination.

    The study results demonstrated no statistically significant neurological differences between exposed and reference groups. The authors said that farmworkers and reference subjects had similar sensory nerve latency and amplitude (sural), motor nerve conduction velocity (ulnar), and neuromuscular junction function (ulnar).

    The study found no relationship between duration of exposure and electrophysiological measures of nerve function. Researchers did find that hemoglobin-adjusted erythrocyte cholinesterase activity was significantly lower in the farmworker group, but this effect was not associated with differences in neurological function.

    The study authors concluded that the lack of neurophysiological effects may reflect the low levels of exposure or may be due to the small sample size or to a history of prior farm work among a large proportion of reference subjects. 

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    Metals in food:

    Natural abundance, soil amendments as contributors

    ...Allan Felsot

    Allan Felsot is an environmental toxicologist at the Washington State University -- Tri-Cities Food and Environmental Quality Laboratory.

    Humans for thousands of years have extracted metals from the earth, ushering in periods of technological development like the Iron and Bronze Age. Forests were cleared to provide fuel to support metalworks, while potentially toxic elements locked below the surface were spread around, causing contamination of soil and water. The use of lead for food utensils and vessels and plumbing pipes resulted in high levels of lead exposure leading to chronic disease that has been documented from long before the Roman Empire into the 20th century. But exposure was not strictly due to mining, manufacturing, and the use of metals in utensils and plumbing. Prehistoric bones contain lead, suggesting a "natural" exposure to metals, perhaps through diet.

    Consuming metals might seem repulsive, but metals like copper, zinc, chromium and iron are needed for the proper functioning of enzymes common to all life; plants must absorb them from the soil and animals must obtain them from their diet. Cadmium and lead are not essential to life, but their natural occurrence in soils makes exposure unavoidable; plants absorb them along with essential metals. Whether nonessential metals are hazardous depends on the degree of exposure.

    Defining potential hazards of metals depends on studies of their environmental chemistry and toxicology. Environmental chemistry delineates the pathways and extent of exposure, and toxicology evaluates the potential health effects and estimates the exposure levels least likely to cause harm. The idea of a link between degree of exposure and biological effect is at least 500 years old; it was explained by the Swiss physician, Paracelsus, and translated simply as, "Dose makes the poison".

    The adage is simply illustrated by considering that, whenever plants are eaten, low levels of naturally occurring lead are consumed apparently without effect; yet, cooking and storing food in ceramics finished with leaden glazes resulted in chronic exposures to levels of lead high enough to cause widespread disease. Numerous toxicology experiments have proven as sound biochemical principle that there is a level of exposure that results in one dose with no effect on an organism and another dose that can have adverse health effects.

    The potential biological effects of metals illustrate a less-often-heard corollary to "Dose makes the poison." Paracelsus had discovered that, while large doses of some substances were toxic, small doses were curative. This observation is especially germane to understanding the need for certain metals in the human diet. The consequences of deficiencies in metals like iron are well known, but our understanding of just how much zinc, copper or chromium humans require is less certain.

    Plants have the same requirements as humans for common nutrients (e.g., forms of nitrogen and phosphorus) and metals like zinc. Soils may not provide enough of what cultivated plants need, however, and successful agriculture relies on soil amendments to improve fertility and tilth. These amendments, whether inorganic fertilizers or organic composts, contain a natural abundance of the same essential and nonessential metals that occur in soils. Adding fertilizers to soil increases the probability that plants will absorb larger amounts of potentially toxic metals as well as essential ones.

    Between the 1950s and 1980s, use of inorganic fertilizers grew exponentially, but thereafter use leveled off. Organic fertilizers in the form of digested municipal sewage sludges, commonly known as biosolids, have been increasingly applied since the 1970s. Reviews of lead and health effects have not considered soil amendments a potential source of metal exposure. While human exposure to metals, especially lead, has been determined to have increased significantly since prehistoric times, dietary sources of increased exposure are thought to be the result of using leaden vessels and pipes after food or water has reached the consumer. EPA analyses during the 1980s found at least half of the lead burden in crops to be due to deposition of airborne lead, largely produced from combustion of gasoline containing the anti-knock additive, tetraethyl lead.

    Plants in the absence of soil amendments would still contain nonessential metals; concerns about food quality and quantity necessitate vigilance over the sources and amounts of metals in the diet. The basic question is: Have nonessential metals in the diet (particularly lead, cadmium and arsenic), and thus risks of adverse health effects, been altered by soil amendments associated with soil fertility management? The answer lies in an understanding of the expected natural abundance of metals in soils and plants, how metal content changes when soil is amended, and an examination of dietary trends in metal intake during the last 20 years.

    Metals Are Natural Soil Constituents
    Metals are present in all rocks underlying the world's arable soils. Over time, bedrock erodes and creates soils with metal compositions characteristic of the parent rock. When metals are present at less than 1% of soil content (i.e., 10,000 ppm), they are called trace elements. The natural abundance of trace elements in soil varies across the world, but expected ranges have been characterized (Table 1). Given that much early research on natural abundance of elements occurred prior to the widespread use of synthetic soil fertility amendments, the ranges and means shown in Table 1 would presumably represent soils untouched by amendments.

    Table 1. Content (ppm) of selected elements in earth's crust and soils

    Element (Symbol)

    Average in Earth's Crust

    Common Range for Soils

    Essential

    Chromium (Cr)

    100

    1 - 1,000

    Cobalt (Co)

    25

    1 - 40

    Copper (Cu)

    55

    2 - 100

    Iron (Fe)

    60,000

    7,000 - 550,000

    Manganese (Mn)

    950

    20 - 3,000

    Molybdenum (Mo)

    2.3

    0.2 - 5

    Nickel (Ni)

    75

    5 - 500

    Selenium (Se)

    0.09

    0.1 -2

    Tin (Sn)

    2

    2 - 200

    Vanadium (V)

    135

    20 -500

    Zinc (Zn)

    70

    10 - 300

    Nonessential

    Aluminum (Al)

    81,000

    10,000 - 300,000

    Arsenic (As)

    5

    1 - 50

    Beryllium (Be)

    2.8

    0.1 - 40

    Cadmium (Cd)

    0.2

    0.01 - 0.70

    Lead (Pb)

    13

    2 - 200

    Mercury (Hg)

    0.1

    0.01 - 0.3

    Titanium (Ti)

    6,000

    1,000 - 10,000

    From Lindsay, 1979, Chemical Equilibria in Soils. Wiley, New York

     

    Relying on metal content of bedrock to predict content in a specific soil may be inadequate for regions where the soil has formed from materials eroded at distant sites. For example, much of Washington state is underlayed with basalt, an igneous rock formed as a result of volcanic activity. Basalt tends to be characterized by low levels of cadmium, but its lead content is similar to the average amounts present in the earth's crustal rocks (Table 1). Actual levels of cadmium and lead in Washington soils, however, have been influenced by deposition of eroded sediments that originated in the mountains of Wyoming and Montana during periods of glaciation and washed across the Columbia Basin in repeated ancient floods.

    Soil Amendments Contain Metals
    In addition to expecting a range of natural concentrations of trace elements in agricultural soils, fertilizers and digested or composted municipal sewage sludges (biosolids) are applied to supply nutrients or organic matter. Whether nutrients are supplied by inorganic amendments (for example, ammonium nitrate, rock phosphate, potassium chloride) or as organic amendments (compost, biosolids), metals will be present.

    Fertilizers containing rock phosphate will have a natural abundance of arsenic, cadmium and lead. A recent survey of elemental content of different kinds of fertilizers showed that the phosphate component of fertilizers contributes the highest levels of arsenic, cadmium and lead (Table 2).

     

    Table 2. Trace element content (ppm) of different fertilizers

    Fertilizer

    Arsenic

    Cadmium

    Lead

    Urea

    <0.4

    <0.2

    <0.4

    Ammonium nitrate

    <0.4

    <0.2

    <0.4

    Phosphates

     

     

     

    ammonium phosphate

    10 - 16

    <0.2 - 4.6

    2.9 - 13

    superphosphate

    15 - 16

    5.0 - 6.2

    11 - 13

    rock phosphate

    17 - 21

    1.3 - 49

    4.6 - 29

    Potassium chloride

    <0.4

    <0.2

    <0.4 - 1.0

    Corn Leaves

    2.5

    0.3

    0.7

    Manure

    6.8

    0.7

    7.5

    Compost (cow manure)

    3.0 - 5.2

    0.4 - 0.5

    2.6 - 5.4

    Austinite (sewage sludge)

    9.4

    3.3

    87

    Data are from Raven and Loeppert, 1997, J. Environ. Qual., 26:551-557

     

    The trace element content of inorganic fertilizers will tend to reflect the parent ore from which the minerals are derived. Organic fertilizers contain arsenic, cadmium, and lead (Table 2) and contribute to the metal content of soils. Metals in corn le aves reflect soil conditions and uptake of soluble forms; metals in cow manures are indicative of food chain transfer.

    Of all organic fertilizers, digested municipal sewage sludges contain the highest concentrations of metals (Table 2). Biosolids have been tested for at least 30 years to determine the safety of their disposal on agricultural land. Land application of biosolids is not just a matter of waste disposal; crops benefit from the high levels of nutrients and organic matter. Long-time concerns about application of metals concentrated in sewage sludge has led to the development by the EPA of numerical guidelines (written in 40 CFR Part 503) for maximum metal loads permitted on agricultural fields. The criteria were developed to reduce to negligible levels the hazard of plant toxicity and food chain accumulation.

    In comparison to the metal loads added by application of biosolids, additions of metals in fertilizers are small. For example, using information from fertilizer analyses in the early 1970s, total annual additions of cadmium and lead would be approximately 26 g/ha, compared to 40 kg/ha in biosolids. In estimating possible hazards from adding amendments, metal content of fertilizer is insignificant compared to that of biosolids.

    Trends in Dietary Exposure
    If the tremendous increase in use of fertilizers of all kinds since the 1950s has affected the natural abundance of metals in food, then one would predict the higher metal content of food to be reflected in historical trends in dietary intake. During the last 30 years, the FDA has published information about dietary intake of metals in the peer-reviewed scientific publication Journal of the Association of Official Analytical Chemists. The analysis has been conducted under an FDA program known as the Total Diet Study. The objective is to estimate the dietary intake for pesticides, industrial chemicals, toxic elements, radionuclides, and essential minerals and compare this level with recommended or acceptable levels for daily intakes. These are based on levels estimated to protect against adverse effects. For pesticides, the recommended levels are known as acceptable daily intakes (ADI) and are based on application of a 100-fold safety factor to a no observable effect level (NOEL) determined in rodent feeding studies. For metals, a provisional tolerable daily intake (PTDI) is used. Margins of safety are not used for two reasons: all foods naturally contain metals, and some of these are essential. For nonessential toxic metals, daily intakes are based on levels causing chronic poisoning as observed in humans. Recommended protective guidelines based on human epidemiological evidence may preclude incorporation of margins of safety.

    Once metal contents are analyzed in foods representative of a typical U.S. market basket and prepared as the "average" consumer would prepare them, concentrations are multiplied by the weight of specific foods eaten daily as estimated from national surveys. The metal content eaten is summed over all foods and expressed as micrograms (g) per day.

    The trend in total dietary arsenic, cadmium and lead consumption for all foods appears lower in the 1980s than in the 1970s (Figure 1). Lead was consumed more than other metals, reflecting its greater natural abundance in soil and its atmospheric depos ition largely from the use of leaded gasoline. Lead consumption seems to have dropped following reductions and final elimination of gasoline lead additives.


    The adult provisional tolerable daily intake (PTDI) for arsenic, cadmium and lead is 126, 60 and 216 g/day, respectively. Neither exposure during the 1970s nor that of the 1980s was above this level. Because data used to estimate dietary exposure a re analogous to repeated sampling from an ongoing experiment, the downward trends and levels under the PTDI suggest that soil amendments have not significantly influenced dietary trends. If amendments were introducing significantly more metals into the diet than expected from background levels, then one would hypothesize that the more widespread applications of sewage sludge disposal on agricultural lands in the 1980s would have resulted in either no reduction in metal intake from levels in the 1970s or perhaps even an increase in intake. Because the trend is clearly downward, soil amendments seem to be trivial factors in influencing exposure to metals.

     

    Conclusions
    All soils, and therefore all food, will have a natural abundance of trace metals, some of which are essential to life's biochemistry and some of which are toxic at chronically high concentrations. Soil amendments, whether organic (i.e. biological) or inorganic (minerals) materials, are necessary to replenish soil fertility and supply nutrients that are taken up and removed by the harvested crop and which, therefore, are not recycled. All amendments, whether organic or inorganic, have a natural abundance of trace metals. Long-term studies with fertilizer, however, show a negligible impact of fertilizer metals on metal content in soil.

    Historical trends in dietary intake show that exposure to arsenic, cadmium and lead has decreased since the mid-1970s. The total daily intakes for children and adults are below the recommended maximum daily intake levels. Because dietary intake data are based on yearly repeated sampling of randomly collected food that is prepared as at home, the downward trend in metal intake suggests that soil amendments have had neither a measurable impact on residues in food nor on dietary intake.

     

     

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    Federal Issues

    Tolerances

    The following tolerances were granted by EPA since the last report (April 1997). These data do not mean that labels have been registered for these uses. These pesticides must not be used until labels are registered with EPA or a state department of agriculture.

    *Key

    A = adjuvant

    FA = feed additive

    I = insecticide

    D = desiccant

    FM = fumigant

    IN = inert

    D/H = desiccant, herbicide

    G = growth regulator

    N = nematicide

    F = fungicide

    H = herbicide

    P = pheromone

    R=rodenticide

    V = vertebrate repellent

     

     

    Chemical

    Petitioner

    Tolerance (ppm)

    Commodity (raw)

    (F) Propamocarb Hydrochloride

    FQPA

    0.5(a)

    Potatoes

    0.1(a)

    Cattle, goat, hogs, horse, sheep; fat, meat, mbyp(except kidney and liver)

    0.1(a)

    Milk

    (H) Imazapyr

    American Cyanamid

    0.05

    Corn, field; forage (silage), grain, stover

    (IN) Phosphinothricin Acetyltransferase

    Dekalb Genetics

    exempt

    In or on all raw agricultural commodities

    (I) Bacillus thuringiensis subspecies kurstaki CryIA(c)

    Dekalb Genetics

    exempt

    In or on all raw agricultural commodities

    (H) Glyphosate

    Monsanto

    200

    Aspirated grain fractions

    1

    Corn, field; forage, grain

    100

    Corn, field, stover

    0.01

    Grain crops (except wheat, corn, oats, and grain sorghum

    20

    Oats, grain

    15

    Sorghum, grain

    40

    Sorghum, grain, stover

    (H) Sethoxydim

    IR-4

    4(b)

    Asparagus

    1(b)

    Carrots

    2(b)

    Cranberries

    30(b)

    Peppermint and spearmint, tops (stems and leaves)

    (H) Clopyralid

    DowElanco

    10

    Corn, field, fodder

    3

    Corn, field, forage

    1

    Corn, field, grain

    1.5

    Corn, field, milling fractions

    (I) Kaolin

    EPA

    exempt(c)

    Apples, apricots, beans, cane berries, corn, cranberries, cucurbits, grapes, melons, nuts, ornamentals, peaches, peanuts, pears, peppers, plums, potatoes, seed crops, small grains, soybeans, strawberries, sugar beets, and tomatoes

    a = Time limited tolerance expires March 15th, 1999

    b = Time limited tolerance expires December 31, 1998

    c = Time limited tolerance expires December 31, 1999


    Emergency Exemptions (Section 18) 

     Specific exemptions have been granted for the following uses:

     

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    State Issues

    Special Local Needs (Section 24c)

    The Washington State Department of Agriculture has granted label registration to the following pesticide uses under the provision of Section 24(c) amended FIFRA.


    SLN cancellations

    The following Washington Special Local Need (SLN) registration has been voluntarily canceled by the registering company:

     


    EPA increases processing fees

    The EPA has increased fees charged for processing tolerance petitions for pesticides under the Federal Food, Drug, and Cosmetic Act (FFDCA). The change in fees reflects a 3.33 % increase in locality pay for civilian Federal General Schedule (GS) employees working in the Washington, DC/Baltimore, MD metropolitan area in 1997. Effective date for the change is June 9, 1997. For further information, contact: Edward Setren, Immediate Office, Office of Pesticide Programs, Environmental Protection Agency, telephone number (703) 305-5927,

    E-mail:setren.Edward@epamail.epa.gov.
    Sonya Brooks at telephone (703) 308-6428,
    E-mail: brooks.sonya@epamail.epa.gov.

    Supplementary Information: The EPA is charged with administration of section 408 of the Federal Food, Drug, and Cosmetic Act (FFDCA). Section 408 authorizes the agency to establish tolerance levels and exemptions from the requirements for tolerances for food commodities. Section 408(o) requires that the agency collect fees as will, in the aggregate, be sufficient to cover the costs of processing petitions for pesticide products, i.e., that the tolerance process be as self-supporting as possible.

    The current fee schedule for tolerance petitions (40 CFR 180.33) was published in the Federal Register on May 3, 1996 (61 FR 19850) (FRL-5365-2) and became effective on June 3, 1996. At that time the fees were increased 2.54%, in accordance with a provision in the regulation that provides for automatic annual adjustments to the fees based on annual percentage changes in federal salaries. The specific language in the regulation is contained in paragraph (o) of Sec. 180.33.

     

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    Contributors to the Agrichemical and Environmental News:

    Alan Schreiber, Allan Felsot, Catherine Daniels, Mark Antone, Eric Bechtel

    Contributions, comments and subscription inquiries may be directed to: Dr. Catherine Daniels, Food and Environmental Quality Laboratory, Washington State University, 2710 University Drive, Richland, WA 99352-1671, ph: 509-372-7495, fax: 509-372-7491, E-mail: cdaniels@tricity.wsu.edu


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