Pesticides risk from

To this point in the risk analysis process, XYZ Chemical commissioned a separate study to review the bulk pesticide operation and all potential risk reduction options and combination of options that could be implemented to manage the risk of this operation. This study determined that the combination of several risk reduction options reduced the bulk pesticide risk from higher risk to lower risk. While management thought it was important to reduce identified risks, the costs of the available options were not justifiable and so the movement of bulk pesticide from this Asian facility was stopped. 

Based on the experience gained during the past U to 5 years, it was demonstrated that no pesticides were canceled on the basis of unacceptably high levels of N-nitroso contaminants. It is anticipated that the EPA Nitroso Policy will improve pesticide products even further by a reduction or elimination of N-nitroso contaminants from potential sources. In this way, the human risk from these potentially hazardous chemicals will be minimized. 

In considering pesticide residues, it was clearly shown that crops from organic production systems contain no or significantly lower levels of pesticide residues than crops from conventional systems (Baker et al., 2002). However, while some scientists are concerned about the potential health impacts from such residues (Porter et al., 1999 Benbrook, 2002), pesticide legislators maintain that current pesticide risk assessments and pesticide registration procedures are adequate and that residues below the current legal limits can not have a negative health impact in humans (e.g. PSD, 2006). 

Pregnant women, infants and children face unique and possibly significant developmental and endocrine-system mediated risks from low-level pesticide exposure during critical windows of development, some with serious life-long consequences. 

In Tables 14.9 and 14.10, the last column reports the environmental impact points (EIPs) for typical applications of organic and conventional pesticides derived from the Pesticide Environmental Assessment System, or PEAS. This model produces relative rankings of risks based on defined use rates and use patterns (the formulation used to apply a pesticide, timing, target of the application, spray equipment used, etc). PEAS scores reflect an equal balancing of acute pesticide risks to farm workers, chronic risks via dietary exposure and exposures to birds, Daphnia and bees. 

EPA released the first case study of cumulative risks from 24 OPs in food for scientific review in mid-2000. Public comments were solicited and several scientific panel (SAP) meetings were held on various aspects of EPA s quantitative methods. In December 2001 a preliminary OP-CRA (cumulative risk assessment) was released, this time encompassing 30 OPs, additional foods, more residue data and all major routes of exposure. Public comments were solicited again and another series of SAP meetings were held. The revised final OP-CRA was issued in June 2002 after more than 20 SAP meetings and four rounds of public comment (US Environmental Protection Agency, 2002). It is the most sophisticated and data-rich pesticide risk assessment ever carried out. 

Strong data point to a dramatic shift of pesticide dietary risks from fresh fruits and vegetables grown in the US to those imported from abroad. As a nation, we have more work to do, and contentious decisions ahead if we are to markedly reduce pesticide dietary risks. 

US Environmental Protection Agency (20002). OPP Revised OP Risk Assessment -Cumulative Risk From Pesticides in Foods. l.C.l—1.C.24. 

Although bicyclophosphates do not inhibit acetylcholinesterase, they exhibit a synergistic toxic effect with materials that do. Individuals who have had previous exposure to cholinesterase inhibitors such as nerve agents and commercial organophosphate or carbamate pesticides may be at a greater risk from exposure to bicyclophosphates. 

A second risk zone corresponds to Monzon (17,042 inhabitants), a highly industrialized city in the middle Cinca River. Its industrial activity has caused the historical release of organic and inorganic compounds to the river coming from chlor-alkali industry, from production and utilization of solvents and organochlo-rine pesticides, and from the use of brominated flame retardants in the production processes. Very high concentrations of mercury have been recorded for sediment and fish samples in the downstream of Monzon [2-4]. 

The dietary risks from pesticides are frequently, although inappropriately, discussed in relation to the relative breakdown between legal and violative... 

In the calculation of chronic risks from pesticides in foods, the EPA frequently uses a deterministic approach to yield the theoretical maximum residue contribution (TMRC) for a pesticide. This value represents the maximum legal exposure to a pesticide, and assumes that ... 

It has been demonstrated that pesticides are frequently encountered in foods, although typically at levels not considered to cause concern from the regulatory community. When placed into perspective with other food safety risks, the dietary risks from exposure to pesticides are considered to be far lower than the... 

Spittler, T. D. Bourke, J. B. in "Risk Determination for Agricultural Pesticide Workers from Dermal Exposure" Honeycutt, R. C., Ed. ACS SYMPOSIUM SERIES, American Chemical Society Washington, D.C., in preparation. 

The UK Pesticide Safety Directorate (PSD) has decided to use the TEF approach for assessment of combined risk from exposure to mixtures of acetyl cholinesterase inhibitors (organophosphate (OP) compounds and carbamates) (PSD 1999). Despite clear differences in the action of carbamates and OP compounds, the index compounds selected for all acetyl cholinesterase inhibitors were either aldicarb (carbamate) or chlorpyrifos (OP). The POD for determining relative potency was predetermined as the dose level that produced 20% inhibition of red blood cell cholinesterase in a 90-day dietary study in rats. 

From the standpoint of practical regulatory assessment, it would be desirable to reach a consensus on the selection of methods for routine use for pesticide risk assessments while recognizing that there may be scientific reasons for preferring alternative methods in particnlar cases. Such a consensus does not yet exist. Further case studies are required, covering a range of contrasting pesticides and scenarios, to evaluate the available methods more fully. While a consensus is lacking, it is important that reports on probabilistic assessments clearly explain how their methods work and why they were selected. 

An approach that is sometimes helpful, particularly for recent pesticide risk assessments, is to use the parameter values that result in best fit (in the sense of LS), comparing the fitted cdf to the cdf of the empirical distribution. In some cases, such as when fitting a log-normal distribution, formulae from linear regression can be used after transformations are applied to linearize the cdf. In other cases, the residual SS is minimized using numerical optimization, i.e., one uses nonlinear regression. This approach seems reasonable for point estimation. However, the statistical assumptions that would often be invoked to justify LS regression will not be met in this application. Therefore the use of any additional regression results (beyond the point estimates) is questionable. If there is a need to provide standard errors or confidence intervals for the estimates, bootstrap procedures are recommended. 

Bayesian methods are very amenable to applying diverse types of information. An example provided during the workshop involved Monte Carlo predictions of pesticide disappearance from a water body based on laboratory-derived rate constants. Field data for a particular time after application was used to adjust or update the priors of the Monte Carlo simulation results for that day. The field data and laboratory data were included in the analysis to produce a posterior estimate of predicted concentrations through time. Bayesian methods also allow subjective weight of evidence and objective evidence to be combined in producing an informed statement of risk. 

Fascination with the hypothetical risks from pesticides may increase cancer risks. Fruits and vegetables are of major importance for reducing cancer if they become more expensive because of reduced use of synthetic pesticides then consumption is likely to decline and cancer to increase. The effects of such policies will be most notable on people with low incomes who must spend a higher percentage of their income on food, and who already eat fewer fruits and vegetables. 

The many worst-case assumptions built into cancer risk assessments are there because of policy decisions, not because of scientific ones, and they confuse attempts to allocate money effectively for public health. For example, EPA estimates of synthetic pesticide residues in the diet have used the theoretical maximum human residue that is anticipated under the most severe field application conditions, which is often a large overestimate compared to the measured residues in food. Despite the EPA s estimated high risks from exposures to several pesticides, the U.S. Food and Drug Administration detected no residues of those pesticides in the food samples in its Total Diet Study.59... 

So although there is no doubt that the presence of pesticide residues and food additives is significantly different between organic and conventional foods, there are no generally accepted volumes of data showing that the difference in composition makes a difference to the health of consumers. However, a more precise estimate of the magnitude of risk from pesticide residues or food additives may not make much difference to the view of many consumers, who do not want to take any risk, no matter how small, when not associated with clear benefits for themselves (Torjusen et al. 2004). 

The toxicological risks from residues of synthetic pesticides in food are minimal because of careful food safety legislation and regulation. 

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