Pesticides & their Non-Target Impacts:
Sources of Data & Information
Dr. Lois Levitan, Environmental Risk Analysis Program, Cornell University
The amazing development of the World Wide Web (WWW) over just the past few years has greatly changed the way we look for information about pesticides, and what we are likely to find. The WWW has increased the accessibility of pesticide data and information, and has also created new means for presenting, publishing and accessing it. Some materials on the WWW are simply electronic versions of paper documents—such as journal articles and reports—that are now afforded wider and more rapid distribution over the Internet. Other materials (like this report) can be printed as "flat text," but also contain the "live" links that give the "web" its name. Still other sources of information on the WWW have "search," "sort" and "display" features that are possible only in electronic format.
Web publication has resulted in a tremendous proliferation of data and information sources (which is not necessarily the same as an increase in data and information). It has also created a sometimes confusing redundancy, and the impression that virtually anything worth knowing about pesticides and their environmental health effects is well documented and understood. Alas, this is not the case.
Guide to finding information
This "guided tour" of pesticide data/information sources is intended to help in navigating through the array of available materials. Undoubtedly a number of sources and channels for accessing information have been left out, either due to ignorance of them or by design (i.e., to keep this "guide" relatively brief, some redundant sources are omitted). Most sources mentioned are accessible on the WWW, though several key or classic references are not. Links within the text are primarily to the accompanying annotated Bibliography, from which links are made to external web-based resources. A complementary article— Researching Health Effects of Pesticides on the Web—provides more detailed information about some of the databases mentioned here.
This "guide" begins by (i) clarifying terminology, then (ii) discusses where and how to find compilations of information about pesticides, before (iii) focusing more specifically on environmental and health effects information, and finally on (iv) accessing original sources that inform the evaluations, summaries and decisions about pesticide use. However, this progression is not strictly followed because many sources (particularly the multi-layered websites) bridge across several categories or "tiers" of information—from raw data to consumer Factsheets.
Tiers of information: Pesticide properties and non-target effects data/information are available at various levels of synthesis and summary, ranging from raw data collected from an individual study, to dataset compilations, meta-analyses and reviews of these data and studies, and to summary assessments of risk. When doing research about pesticides, it is important to understand what types of data and information are provided at each tier. It is also useful to be clear about which tier(s) of information are most relevant to you. For example, if you want an overview or general guidance about a pesticide, your needs may be met by a Factsheet or technical summary.
However, to address a specific or unusual question, you may need to look into the assumptions and conditions of the studies from which the summaries are drawn. For these purposes you will need to access original research reports (or possibly a review covering a number of related studies). For example, if you want to know how a pesticide is likely to behave in an urban setting, research reflective of this type of environment may be more informative than a study assuming agricultural or natural conditions. For some purposes (such as when a dataset contains a wide range of results for the same variable) it may be important to know which data are drawn from field studies rather than from lab experiments or projections from a predictive model. Details like these might be contained in notes to a dataset, but are more likely to be found only in a narrative description of the original study.
Pesticide active ingredients, other ingredients & formulated products
Active ingredients: The active ingredient (a.i.) of a pesticide is the chemical (or biological) claimed to have a toxic effect. A pesticide is typically known by three different names: the common name of the a.i. (e.g., glyphosate), the chemical name of the a.i. (e.g., isopropylamine salt of glyphosate), and the trademarked name of the formulated product (e.g., RoundUp Pro). Formulations typically combine the a.i. with other ingredients that play an auxiliary role to improve product efficacy.
Some active ingredients have several chemical forms. For example, at least five salts of glyphosate are active ingredients in registered pesticide products: the sodium salt, monammonium salt, diammonium salt, trimethyl sulfonium salt, as well as the isopropylamine salt. And the ester form of the herbicide 2,4-D is an emulsion, while its amines (e.g., dimethylamine salt, diethanolamine salt, and trimethylamine salt) form aqueous salt solutions. These various chemical forms may have different non-target effects as well as different physical properties, but these differences may be overlooked or misattributed in data sources and reports that do not differentiate among them.
It is common to have a number of formulated products based on the same chemical form of an a.i. For example, at the time of publication of the US Environmental Protection Agency (EPA) summary on glyphosate (September 2003), the isoproplyamine salt of glyphosate was a.i. in 53 products and the monoammonium salt was a.i. in an additional seven. Different formulations of the same a.i. are likely to contain different "other ingredients" and, therefore, may behave differently in the environment.
Other ingredients: Very little information is publicly available about the surfactants, adjuvants and inert ingredients, which are lumped into a single "other" category on the pesticide label.
In the past, these ingredients were often collectively referred to as inerts. This was a somewhat confusing and inaccurate nomenclature because some of the "inert" ingredients are toxic in their own right and also because such ingredients are used to increase the toxic potential of the a.i. by helping it reach, penetrate or stick to its target, or to persist for a longer time.
Because of business confidentiality protections, manufacturers and formulators are not required to reveal which other ingredients are included in a pesticide product. A 1996 publication from the Office of the Attorney General of New York State, The Secret Hazards of Pesticides: Inert Ingredients, details this issue. The Inerts Disclosure Campaign of the Northwest Coalition for Alternatives to Pesticides ( NCAP) has pushed the envelope in seeking information about inerts and making it available to the public.
The US EPA's four lists of inert ingredients categorize "other" ingredients in terms of level of toxicity and how much information is known about them. Other EPA information about inerts (e.g., names of products no longer used) can be accessed by searching the Federal Register using "inert" as the search term. Thomson Publications is one of a number of print sources of more general information about pesticide adjuvants.
Formulated products: Most data about pesticide properties and effects are from studies of active ingredients. However, it is the trademarked formulations that are registered with the EPA Office of Pesticide Programs ( OPP), purchased by pesticide applicators, and applied in the environment.
Among the best sources for some types of information about pesticide formulated products (in addition to the EPA-approved pesticide labels covered in the following section) are pesticide manufacturers and the trade organizations that serve them (e.g., Crop Data Management Systems, CropLife America and CropLife International). Promotional and other literature from these sources typically refer to pesticides by the trademarked formulation name, often without referencing the active ingredient. Since the names of quite different formulated products are sometimes very similar, care must be taken that the product information pertains to the a.i. and product you expect. To ensure a correct link between a.i. and formulated product, it is useful to know the Chemical Abstract Services Registration Number (CASRN) for the a.i., the EPA registration number for the product you are looking for, and identifying information such as intended use and target pests (i.e., if the a.i. is a fungicide, but the formulation is an herbicide, then you should likely conclude that you are on the track of the wrong product).
Compilations of information about pesticide properties & non-target effects
Pesticide labels: Much of the publicly-accessible information about pesticide formulations is contained in the legally-mandated pesticide label, which must be approved through EPA's Pesticide Product Labeling System ( PPLS). The PPLS labels reflect all EPA decisions made during the pesticide registration process and contain a great deal of information about the properties and uses of the formulation. Labels are required to include legally-binding information about:
- what is in the product (active ingredients are listed by chemical name and percent of product; "other ingredients" are not individually named)
- claims for the pesticide's efficacy in controlling target pests
- how, where, when and why the pesticide can be used, and
- precautions and protections against human, animal and environmental non-target effects.
Full text of PPLS-approved labels for pesticides registered in the US and Canada are easily accessed on-line from the Crop Data Management Systems (CDMS) website. The Journal for Pesticide Reform article Pesticide Labels gives additional information about how to access and understand the text of a pesticide label.
If you go to the store to buy a pesticide, the label you see on the container will likely be designed for merchandising purposes and contain only some of the information in the PPLS-approved pesticide label. EPA's pesticide regulatory program allows for this so that formulated products can be marketed for specific conditions and purposes (e.g., instructions for mixing and use, and even the product name may be different for commercial and consumer uses of the same registered product). An EPA graphic explains what is in each part of a typical pesticide container label.
Pesticide property/effects summaries: In addition to the PPLS-approved pesticide labels, other summaries of the properties and effects of specific pesticides have been developed by government agencies, universities and environmental/health advocacy groups. Targeted for different audiences and purposes, they range from technical data sheets to consumer-friendly Factsheets. Their quality, comprehensiveness and currency vary considerably.
Many Factsheets targeted to consumer or occupational audiences are available on-line in a format that can be easily downloaded for printing and distribution. Sources include:
- US Environmental Protection Agency, Office of Pesticide Programs (EPA OPP)
- National Pesticide Information Center (NPIC)
- EXTOXNET (Extension Toxicology Network)
- Northwest Coalition for Alternative to Pesticides (NCAP)
- Pesticide Action Network
- State and local Departments of Health (e.g., about pesticides used for mosquito and other vector control)
- Land Grant University IPM and extension programs.
Technical summaries include Material Safety Data Sheets (MSDS), mandated by OSHA to provide occupational health and safety guidelines; and reports generated from the searchable Hazardous Substances Data Bank (HSDB) and the National Toxicology Program. Compendia designed as references for practitioners are another source of summary information, e.g., Meister's annual Crop Protection Handbook.
Comprehensive websites—US EPA Office of Pesticide Programs: The EPA OPP website contains a wealth of information. However—perhaps because it is trying to meet the information needs of so many user groups—it is somewhat unwieldy to navigate. Thus this guide references and links directly to a number of specific EPA resources.
In order to make regulatory decisions about how and where a pesticide may be used, EPA compiles a great deal of information about pesticide properties and non-target effects. Supporting evidence for EPA decisions, contact information for the appropriate EPA project manager, etc. are published in the US Federal Register (FR). Pertinent FR documents can be located by searching by name of product, either using the search function on the EPA site or by using a search engine such as Google (in the Google search box at http://www.google.com/ type: "[name of product] site:EPA.gov").
Whenever EPA announces an "action" regarding the regulation of a pesticide, a publicly-accessible docket is created to serve as the repository for documents used by EPA in its decision-making. To use the web-based EPA Docket, go to www.epa.gov/docket, click on "Quick Search" and type the pesticide name or the OPP number given in the Federal Register announcement.
EPA is in process of publishing comprehensive Reregistration Eligibility Decisions (REDs)—full risk analyses and summaries—for older chemicals first registered before 1984. Information about newer pesticide ingredients is compiled into Fact Sheets (now available for chemicals registered since FY 1997). EPA separately indexes information about biopesticides, which are products found in nature that affect pests by means other than toxicity (e.g., by suffocation or starvation).
Conventional chemical pesticides that EPA has identified as having reduced risk, or which are promoted as alternatives to organophosphates, are indexed in a table in OPP's 2003 workplan. Reduced risk criteria are described in a September 4, 1997 FR Notice: Guidelines for Expedited Review of Conventional Pesticides under the Reduced-Risk Initiative and for Biological Pesticides.
To stay abreast of what is going on within the Office of Pesticide Programs, OPP hosts several email listservs, including EPA Pesticide Program Updates, which is a periodic brief email newsletter, and EPA-PEST, which delivers full text of Federal Register pesticide documents.
Other comprehensive websites that contain, or link to, vast arrays of pesticide data and/or information include:
- California EPA Department of Pesticide Regulation (CA EPA DPR): Resources include product-specific, query-able databases, some of which were developed using the Federal EPA's Pesticide Product Information System (PPIS). Databases include the California Pesticide Use Reporting (PUR) database, Chemical Ingredients database, and pesticide Company Information database.
- Pesticide Action Network of North America (PANNA): Comprehensive PAN Pesticides Database of toxicity and ecotoxicity endpoints, "less toxic alternatives," etc. The database links to supporting documentation, and many other web-based resources.
- Pesticide Management Education Program, Cornell University (PMEP): bibliographic database of pesticide-related articles, summaries of physico-chemical properties and health effects of pesticide active ingredients, and the New York State pesticide sales and use database.
- Wright and Sielaty law firm's Pesticide.net website claims to be the world's most comprehensive source of continuously updated pesticide-related news and regulatory information of general interest to pesticide professionals, with particular focus on legal information. By reviewing the complete Federal Register they claim to find and post documents that are overlooked by EPA.
These and other such websites have greatly changed the landscape for secondary research on pesticides. Previously it was both much more difficult to figure out where to look and far more difficult to access data/information. Print sources were often out-of-date by the time they were published, and remained on the shelves long past their currency (unlike electronic versions that can be regularly updated). Comparisons among data points and statistical manipulation of them were next to impossible without going through the tedium of copying numbers by hand onto a spreadsheet drawn on a piece of paper! However, greater access via the web has not altered the realities of data gaps, low confidence ratings for some of the existing data, and the limitations of the regulatory endpoints to address challenging questions about the role of pesticides in modern life, e.g., about long term effects of ongoing low exposures to chemical mixtures.
Pesticide health and environmental effects
Reviews and compilations: The EPA REDs are a valuable set of in-depth reviews of health and environmental effects for selected pesticides and classes of pesticides. Other in-depth sources of pesticide environmental/health effects include:
- Handbook of Pesticide Toxicology, vol. 2 (2nd ed. 2001).
- Reviews of Environmental Contamination and Toxicology (formerly Residue Reviews)
- World Health Organization's Pesticide Evaluation Scheme (WHOPES), which has completed "specifications" for several dozen pesticides
- Agency for Toxic Substances and Disease Registry (ATSDR), Division of Toxicology, which has developed "toxicological profiles" for more than 250 pesticides and other hazardous substances found at National Priorities List (NPL) sites.
Some reviews focus on pesticides as a risk factor for cancer. The December 2002 Report on Carcinogens details toxicological information about pesticides and other substances that are known or appear likely to cause cancer. Cornell University's Program on Breast Cancer and Environmental Risk Factors in New York State (BCERF) has developed a set of Critical Evaluations and shorter Factsheets for about a dozen pesticides, based on in-depth review of the pesticide health effects literature (particularly re: cancer risk factors).
Recognition and Management of Pesticide Poisonings provides toxicological information from a medical perspective.
Accessing original studies: All of the summaries and compilations referred to thus far are based on data and information gathered from disparate studies of particular health and environmental effects. Targeted bibliographic databases—such as DART/ETIC (focusing on the developmental and reproductive toxicology research literature) and TOXLINE (covering much of the standard journal literature in toxicology)—are particularly useful in identifying pertinent research articles. These health effects databases can be accessed using TOXNET or PubMed, both search vehicles of the National Library of Medicine (NLM).
Ecological and non-human health effects research is not as neatly organized. However, research published in the agricultural (and related) literatures can be identified using the National Library of Agriculture's Agricola bibliographic database.
The National Libraries serve as information portals, or gateways, as well as repositories. With the advent of on-line networked library catalogues, a number of such information portals can be accessed while sitting in an armchair at home. Others pesticide information gateways to consider (in addition to those previously mentioned in the section on comprehensive websites) are the
- US EPA Online Library System (OLS);
- US EPA Substance Registry System (SRS);
- World Health Organization's Library database (WHOLIS); and the
- Extension Toxicology Network (EXTOXNET) resources of a consortium of universities.
Scientific literature and "gray literature": The original studies, reports and compendia identified by these bibliographic databases may be drawn from either the "scientific literature" or the "gray literature," (although specific databases may draw from only one or the other). The term "scientific literature" typically refers only to articles published in peer-reviewed academic journals. These materials can be accessed through academic libraries, either in paper or—increasingly—in electronic format. Abstracts of these articles are often available to the general public on the WWW, but full text more often requires a subscription to the journal (which university research libraries will likely have or be able to access for you).
Reports not published in the peer-reviewed scientific literature are called "gray literature." "Gray literature" is frequently the only source of pesticide efficacy and non-target effects data because results of studies submitted to EPA for the regulatory process rarely appear in the scientific literature. There seem to be several reasons: (a) Academic journals have become less interested in publishing routine studies. (b) Over the past decades, efficacy and effects research have increasingly been performed by private consultants who are not motivated to publish in academic journals. (c) Because of business confidentiality interests, pesticide manufacturers are not eager for the details to be in the public domain. Sometimes the manufacturer or contractor will provide the studies upon request, but often they are accessible only from the EPA by going through the Freedom of Information Act (FOIA) request process, which can be cumbersome and slow.
Although in some circles there is a stigma associated with the "gray literature," and an assumption that there is a big discrepancy in the quality of science, this is not necessarily so since studies performed for purposes of pesticide registration follow protocols and standards set by the EPA. In addition, much of the literature that reviews and critically evaluates individual studies is published only as "gray literature."
The WWW seems to have contributed to adding a legitimacy—sometimes deserved and sometimes not—to materials published electronically without prior publication in the peer-reviewed literature. As noted in the opening paragraphs, in part this is because much of the material on the WWW could not effectively be published in the flat text of traditional journals.
Bodies of evidence: When going to the primary sources—i.e., the reports of basic, scientific research— in either the "scientific" or "gray" literature, it is important to understand that any single study is at best a partial contribution to a body of evidence that can be used to determine the extent and significance of a hazard or risk. No one study is likely to make a definitive case. Multiple studies—each shedding light on a related aspect of a question, perhaps looking at different test organisms or at a different range of exposures—are needed to fully inform a judgment.
In order to evaluate the broader body of knowledge, health effects or physico-chemical data from individual studies may be
- compiled into a numeric or categorical dataset (i.e., typically a tabular list of test results for a set of pesticides),
- re-examined as part of a meta-analysis (i.e., a composite analyses of data points from multiple studies), and/or
- incorporated into a review or a survey of the topical literature.
Quantitative datasets: Something is lost and something gained by creating composite numeric or categorical datasets.
What is gained? Datasets contain data from many more than are endpoints than are typically evaluated in any one study. Such composite datasets are an almost essential stepping stone between isolated data points and a risk-based decision about how a pesticide should be used, based on environmental or health effects.
What is lost in creation of numeric databases? A nuanced appreciation of the assumptions and specific conditions of the particular studies, and a consistency that is highly desirable when comparing alternatives. For example, when I was trying to create a dataset of pesticide impacts on soil biota, it became apparent that the relative risk ranking of pesticides changed considerably depending on which species of earthworm was used as the test organism, what type of soil or "soil-less" media was used (e.g., a mix of agricultural soils, sterile glass beads, or a specific soil type), and what method was used to expose the earthworms to the chemicals (e.g., injection, application to the soil surface, or to the earthworm).
Data requirements: Risk is a function of both hazard and exposure [risk= f(hazard, exposure)]. To assess risk, or the relative risk of different pesticides, it is important to draw both from data on hazards—i.e., the harmful things that can happen, such as cancer, asthma, skin rash, developmental problems, etc.—and data that are surrogates or measures of exposure.
Data sources for indicators of exposure: Exposure is very difficult to measure directly, so various other measurement endpoints are typically used, all of which tend to be "blunt" (rather than "precise") indicators of exposure. These surrogate indicators of exposure include pesticide sales and use data, application dosages, and fate-and-transport data (i.e., what happens to a pesticide after application, where it goes, how fast it degrades).
Sources of sales and/or usage data include the:
- National Pesticide Use Database—update published November 2002 based on data circa 1997, National Center for Food and Agricultural Policy (NCFAP);
- Pesticide Industry Sales and Usage report based on 1998-1999 market estimates, US EPA;
- Agricultural Chemical Usage Reports, USDA National Agricultural Statistics Service (NASS);
- California Pesticide Use Reporting (PUR) database, California EPA Department of Pesticide Regulation;
- Pesticide Use Information for New York State, database, Cornell Pesticide Management Education Program (PMEP).
- Food and Health Organization (FAO) website, which can be searched for international pesticide usage data.
- Toxic Release Inventory (TRI) annual estimated releases of toxic chemicals to the environment.
The quantity of pesticide used is sometimes estimated from the application rate permitted by the pesticide label. This can lead to a high estimate because applicators are permitted, and frequently do, apply at rates lower than the label rate. Quantities estimated from area planted (multiplied by the permitted application rate) are also likely to be high because this surrogate for exposure assumes that pesticides are applied wherever permitted, which is also not the case.
Sources of pesticide environmental fate data include the:
- OSU Extension Pesticide Properties Database, which summarizes several other pesticide properties datasets. The OSU database covers a larger set of pesticides, but provides only a summary value for each endpoint.
- Pesticide Properties in the Environment, a 1995 book that provides greater detail than the OSU summary dataset, with a range of values and references for each entry.
- US EPA Environmental Fate Database, containing data on pesticide product chemistry, metabolism, degradation, leaching, bioaccumulation and dissipation collected from the environmental fate studies submitted by pesticide manufacturers in support of the registration of pesticide products. The EFD database is one of a set of five environmental effects databases that EPA has been developing since 2000 for public access. Several of the others are "incident reporting" datasets that provide data for another surrogate indicator of exposure.
- Syracuse Research Corporation's suite of Environmental Fate Databases (SRC EFD), which includes databases for physico-chemical properties used as indictors of fate and transport (e.g., LogKow, degradation rates, etc.). The SRC EFD databases are not specific to pesticides.
Sources of hazards data: The complex and complexity of hazards data is greater than first meets the eye because there are many types of hazards, an array of vulnerable organisms, and variability in susceptibility within populations. Without elaborating further, let it suffice to say that these factors partially explain why there are multiple hazard data sets.
EPA's Pesticide Ecotoxicity Database contains 15,000 summary records of ecotoxicological effects of about 680 pesticide active ingredients. Each record contains test results for one organism from one ecotoxicity study and includes data on measurable endpoints such as the LD50. or the NOEL. Other ecotoxicity datasets include the Manual of Acute Toxicity for...66 Species of Freshwater Animals, the Canadian National Water Research Institute's COMPUTOX database with more than 2000 entries for effects of organic chemicals and several Beneficial Insects datasets.
Human health effects databases include the:
- Chemical Carcinogenesis Research Information System (CCRIS)
- EPA's List of [Pesticide] Chemicals Evaluated for Carcinogenic Potential
- GENE-TOX, genetic toxicology (mutagenicity)
- EPA's Integrated Risk Informations System (IRIS) with oral reference doses and inhalation reference concentrations for chronic noncarcinogenic health effects; and hazard identification, oral slope factors, and oral and inhalation unit risks for carcinogenic effects
- International Toxicity Estimates for Risk (ITER) hazard/risk database, which provides side-by-side tabular comparisons of risk values from several sources
- Pesticide Action Network's PAN Pesticide Database with both hazard and exposure endpoints
- World Health Organization's Recommended Classification of Pesticides by Hazard..., which creates hazard categories on the basis of acute toxicity endpoints
Other data sources for assessing pesticide impact are described in Pesticide Risk Indicator factsheets and publications developed by the Cornell Environmental Risk Analysis Program.
Bibliography
An annotated, alphabetical listing of pesticide data and information sources for use in evaluating pesticides and developing pesticide risk indicators. The bibliography opens in a second browser window.
