Pesticides, product tests

All pesticide products created for use by homeowners and farmers in the U.S. must be registered by EPA. This process includes extensive testing to determine the toxicity of the product and its potential for threatening the... 

All equipment to be used at the field site should be calibrated at or near the field laboratory or field site prior to the application of the test substance (pesticide product). Most weather equipment will have been calibrated at the manufacturer and can be checked for functionality prior to the worker exposure/re-entry test by comparing weather readings from the nearest airport or National Oceanic and Atmospheric Administration (NOAA) weather reporting station with the weather readings compiled by the portable weather station. Hand-held weather instmments could also be checked with current weather reading from local airports or NOAA facilities. 

The test substance is generally defined as the formulated pesticide product which is being applied to a crop or field and for which worker exposure is being assessed. 

The test substance should be stored in a locked facility at or near the test site. Most pesticide products are manufactured to withstand extreme temperatures, therefore most test substances used for re-entry and worker exposure studies may be stored under ambient conditions. One should read the label of the product carefully to discern if there are any extraordinary storage conditions required for the pesticide product. Temperatures at the test substance storage location should be monitored daily using a max/min thermometer or similar device that can record daily fluctuations of temperatures. 

Mirex residues were detected in food samples analyzed as part of the FDA Pesticide Residue Monitoring Studies conducted from 1978--1982 of 49,877 food samples and from 1982-1986 of 49,055 food samples however, the frequency of detection was unspecified but was <1 and 2% respectively (Yess et al. 1991a, 1991b). A similar 1985 analysis of foods grown in Ontario, Canada, failed to detect any mirex or photomirex in any of the vegetable, fruit, milk, egg, or meat products tested (Davies 1988). Mirex was also detected in the FDA Pesticide Residue Monitoring Study from 1986-1987 however, the frequency of detection was unspecified but less than 1% (FDA 1988). 

Data on exposure and environmental fate are needed, not to determine toxicity, but to provide information that may be useful in the prediction of possible exposure in the event that the chemical is toxic. These tests are primarily useful for chemicals released into the environment such as pesticides, and they include the rate of breakdown under aerobic and anaerobic conditions in soils of various types, the rates of leaching into surface water from soils of various types, and the rate of movement toward groundwater. The effects of physical factors on degradation through photolysis and hydrolysis studies and the identification of the product formed can indicate the rate of loss of the hazardous chemical or the possible formation of hazardous degradation products. Tests for accumulation in plants and animals and movement within the ecosystem are considered in Section 21.7. 

Numerous nonplasticizer uses of DEHP have been reported. However, it is not clear to what extent these uses arc, or have ever been, important. These include 1he use of DEHP as a solvent in erasable ink, as an acaracide in orchards, as an inert ingredient in pesticide products, in cosmetics, in vacuum pump oil, as a component of dielectric fluids in electrical capacitors, to detect leaks in respirators, and for use in testing of air filtration systems (HSDB 1990 Mannsville Chemical Products Corporation 1990 NTP 1989). 

The WHO Pesticide Evaluation Scheme (WHOPES), set up in 1960, is the only international programme that promotes and coordinates the testing and evaluation of pesticides intended for public health use. The International Code of Conduct on the Distribution and Use of Pesticides (2) constitutes the framework for WHOPES in promoting the safe handling and use, efficacy, cost-effective application and quality control of pesticide products/formulations for public health use. WHOPES develops specifications for pesticides and application equipment for use in international trade and quality control. 

Testing of pesticide products is important because, where products meet their specifications, they can be expected to be effective and to pose no unexpected risks in use. 

Many of the formulations for plant protection are designed to help the active substance to penetrate the cuticle of plant leaves or insects. It is therefore not surprising that these formulations sometimes enhance the skin absorption in humans. To account for this in Europe, EC Directive 91/414 for pesticides requires testing of both the active substance and the formulated product (EEC, 1991). The United States Environmental Protection Agency (USEPA) requires that the vehicle system duplicates that used in the field (USEPA, 1998). Since many pesticides are... 

The EPA had concerns similar to those of the FDA. Under section 4 of the Toxic Substances Control Act (TSCA), the EPA evaluates laboratory data submitted to the agency regarding tests of the health effects of chemical substances and mixtures. Also, under authority of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the EPA evaluates laboratory test data relating to hazards to humans arising from the use of a pesticide product when the agency evaluates pesticide registration applications. 

First of all, there is the scope of GLP as it is defined in the OECD Principles, and which states that GLP encompasses the non-clinical safety testing of test items contained in pharmaceutical products, pesticide products, cosmetic products, veterinary drugs as well as food additives, feed additives, and industrial chemicals. These test items are frequently synthetic chemicals, but may be of natural or biological origin and, in some circumstances, may be living organisms. The purpose of testing these test items is to obtain data on their properties and/or their safety with respect to human health and/or the environment. (OECD, 1998). GLP is thus applicable to safety studies in two major areas Effects on human health and on the environment. These two areas may share some types of studies that have to be conducted in order to test the safety of the respective test item, but other study types may exclusively be required for one or the other area. 

The initial step in the safety evaluation of a pesticide product is the determination of its acute toxicity (Table I). Laboratory animals, usually rats and rabbits, are exposed to a single dose of the test substance. Toxic effects resulting from ingestion,... 

The basic framework for labeling the human hazard of a pesticide product rests on four toxicity categories established by testing the product in five different acute toxicity test systems Oral (ingestion), dermal (absorption through the skin), inhalation, eye irritation, and skin irritation. The toxicity categories range from I, the most toxic, to IV, the least toxic. 

Our laboratory investigations indicated that the purity of the dinitro compounds prepared by homogeneous or direct nitration would not exceed 90 2%. On the other hand, achieving product purity between 95 and 98% using the traditional sulfonation process followed by nitration was no problem. Since the pesticide DNBP was required to be at least 95% pure, the direct nitration process could not be adopted for that product. In this particular case, the client needed approximately a 22% solution of DNOC in styrene. Product testing by the user indicated that the DNOC purity requirement for the styrene monomer stabilizer solution was not critical as long as it exceeded 90%. The final formulation contained 22 to 24% DNOC in styrene. The product met the specifications, was tested by the user, and performed well in field tests. The product also had no chlorinated compounds present even in trace amounts as specified by the user. 

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