Import tolerances

Where a crop which constitutes a part of the US diet is not grown in sufficient quantity in the USA to warrant the cost to obtain a US registration, an import tolerance is required. Crops that are grown extensively in Latin America, such as coffee, banana. 

Bananas are chosen for the example below, which is taken from the Import Tolerance Guidelines. 

Approximately 99.8% of all bananas available in theUSA are imported. The highest consumption level for any population sub-group is 0.96% of the diet for infants. Based on information given in the Import Tolerance Guidelines, a minimum of 12 trials would be required. 

The purpose of an import tolerance and its impact on the global registration process should be explained. The official protocol document should be reviewed in general, and practical discussion should center on the worksheet and the hands-on tasks that the personnel at the meeting will be performing. 

Pesticide residues consist of chemicals that might occur in a commodity as a result of application of a pesticide. Such chemicals typically correspond to compounds for which a regulatory agency has or will set a tolerance, i.e., a maximum residue limit, specific to the commodity. In either a field study or a market basket survey, residues to be determined will be those which result from application of the specific pesticide that the study is intended to support. A market basket survey, however, might be intended to support not just one but several different pesticides of the same or different chemical classes. In addition, a market basket survey might include pesticides not used in the USA but for which import tolerances exist. For example, some uses of the parathion family of pesticides on food products have been abandoned in the USA but remain in other countries that export the products to the USA. A market basket survey offers a means to evaluate actual dietary exposures to residues of such pesticides. In addition, tolerance expressions frequently include multiple compounds, all of which must typically be determined in residue field trials. The sponsor of the market basket survey must decide whether to analyze for all compounds in the applicable tolerance expression or to restrict the program to selected analytes, such as the active ingredient. 

These chemicals have been cancelled or proposed for cancellation. They will be included in the organophos-phate risk assessment if import tolerances remain after other tolerances are revoked. 

Plant Protection Products, and the Establishment of Maximum Residue Limits and Import Tolerances). 

U.S. tolerances is the responsibility of the U.S. Food and Drug Administration (FDA). In the absence of a specific tolerance, residues must be below detectable levels. Based on modifications to FFDCA mandated by the Food Quality Protection Act (FQPA) of 1996, several new elements were introduced to the EPA tolerance process. These include the need to consider the special sensitivity of infants and children, the potential exposure via multiple routes of exposure (i.e., aggregate exposure from dietary and non-dietary sources), and the potential for exposure to other pesticides and chemicals with a common mechanism of toxicity (i.e., cumulative exposure). Under FQPA, the EPA was also required to complete a reevaluation of all existing tolerances during a 10-year period. Domestically established M RLs apply also to imported commodities, but there is an established (if somewhat slow) process for evaluation of residue data from other countries in support of import tolerances. 

Most of the aforementioned shortcomings are associated with the low operating temperature, limited mainly due to the electrolyte used. A PEMFC technology operating above 100°C is desirable. First of all, the kinetics of both electrode reactions are enhanced and this can in principle lead to the use of lower amount of the expensive noble metal on the electrodes. More importantly, tolerance of the catalyst to fuel impurities (CO, sulphide) is dramatically enhanced, broadening the options for the feed gas. The CO poisoning effect is temperature dependent due to the weaker CO adsorption on the Pt surface. The CO tolerance has been found to increase from 10-20 ppm of CO at 80°C to 1000 ppm at 130°C and up to 30000ppm at 200°C. This can simplify the overall power system, reduce its cost and volume and improve the transient response capacity, reliability or maintenance-free operation of the system. ... 

Additionally, the EPA requires import tolerances to be established for residues of unregistered pesticides present on imported commodities. This prevents what some have termed the circle of poison or allowing the export of unregistered pesticides only to have them return as residual on imported agricultural products. 

---