OFFICE OF UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON , D.C. 20460

CHEMICA L SAFETY AND POLLUTION PREVENTION MEMORANDUM

SUBJECT:
TO:

FROM:

Approved By: PC Code : 0 19401 DP Barcode: D419150 June 5, 20 14 EFED Preliminary Risk Assessment to Classify Registered 4-CPA Uses as 

### De Minimus Risk to Listed/Non-Listed Species and "No Effects " Determination Molly Clayton, Chemical Review Manager Tracy Perry, Team Leader Risk Management and Implementation Branch 3 Pesticide Re-Evaluation Division Office ofPesticide Programs (7508P) Edward Odenkirchen, Ph.D., Senior Science Advisor 

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**~** Environmental Risk Branch 1 Environmental Fate and Effects Division Office ofPesticide Programs (7507P)



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### ~ Sujatha Sankula, Ph.D ., Branch Chief 

### -=:...- Environmental Risk Branch 1 Environmental Fate and Effects Division Office ofPesticide Pro grams (7507P) The Environmental Fate and Effects Di vis ion (EFED) is issuing this memorandum as a followup to the presentation to the Science Policy Council/Risk Management Forum on April23, 2014 , in which a case was m ade to classify the registered uses of4-CPA as pr esenting de minimus risk to threatened and endangered species by virtue that the use was indoors and so did not constitute a potentially complete exposure pathway to non- ta rget organisms. The Forum disagreed with EFED's recommendation that registered uses of4-CPA present no environmental risks to li sted and non-li sted species based on t he expectation that spent greenhouse mung bean soaking solution could go down wastewater drains , in accordance with the pesticide label. This document more fully explores this exposure pathway and is based on Science Policy Council/Risk Management Forum discussions and a subsequent May 22, 20 14 memorandum on the subject (USEPA 20 14)
. 

### The Office ofPesticide Program ' s Science Policy Council/Ri sk Management Forum recently determined that some chemicals scheduled to undergo Registration Review may not require

1detailed r isk assessments if it can be demonstrated that they are likely to pose minimal or no risks to listed species. The questions (criteria) considered for de minimus classification include: 1. Are exposure pathways reasonably expec t ed to be incomplete between the us e site and potential environmental receptors (i.e. federally listed species)? 2. Is the pesticide of low tox ici ty such that it is reasonable to expect that appreciable environmental loading would be necessary to produce environmental effects? 3. Is the use ofthe pesticide so low in quant i ty that it is unreasonable to expect significant environmental loading in a particular area? 4. Is the distribution of the pesticide use site so diffuse that it is unreasonable to expect significant environmental loading of the pesticide? Not all criteria must be met for de minimus status to be granted; chemicals will be evaluated on a case-by-case basis and the criteria will be we i ghted accordingly. Background The pest i cide 4-CP A is a plant growth regulator used exclusively as a soaking agent for mung bean sprouts in greenhouse operations to prevent root formation and thereby improve the sorting

and han d ling of the mung bean sprouts for packaging. All of the use occurs indoors. 4-CP A is applied in a dilute solution of 2 to 3 mg/1 active ingredient to a water bath to soak batches of

about 3500 pounds of beans. Once the beans have soaked for several hours, they are washed to remove the surface residues, and are then germinated indoors for seve r al days. After sprouting, the hulls and roots are discarded, and the remaining portion is packaged and sold for human consumption. Criterion #1 -Complete Exposure Pathways Spent mung bean soaking solution can be disposed of down municipal wastewater drains, consequently , i t is logical to assume that some amount of 4-CPA will eventually continue to receiving waters. Therefore, the consideration of a completely closed indoor system with no reasonable pathway to non-target organisms is not supportable. Criterion #2- Low Toxicity While there is little empirically determined toxicity information, the ECOSA R quantitative structure activity program provides predictions that are informative and suggest a low likelihood for significant toxicity to aquatic organisms, the taxa most likely to be exposed via a wastewater discharge scenario. In many cases the predicted toxicity would be well above the solubility limit of the compound. And in almost all cases the predicted toxicity is in the range of low toxicity to practically non-toxic. 2ECOSAR Class Organism Duration End Pt Neutral Organics-acid :Fish 96-hr LCSO Neutral Organics-acid : Daphnid 48 -hr LCSO Neutral Organics-acid :Green Algae 96-hr EC50 Neutral Organics-acid :Fish ChV Neutral Organics-acid : Daphnid ChV Neutral Organics

- acid : Green Algae ChV Neutral Organics-acid :Fish (SW) 96-hr LC50 Neutral Organics-acid : Mysid 96

-hr LC50 Neutral Organics-acid :Fish (SW) ChV Neutral Organics-acid : Mysid (SW) ChV Note: 

## * = asterisk designates: Chemical may not be soluble enough to measure thi s predicted effect. If the effect level exceeds the water solubili ty by 1 OX, typicaliy no effects at saturation (NES) are reported.

--> Acid moeity found: Predicted values multiplied by 10


### Criterion #3 -Low Quantity Used mg/L Crmm} 1621.886 

## * 918.599 677
. 173

158 .063

88.957 176.3 44 2041.500 

## * 1545.543 

## * 217.926 134.677

The Science Policy Council and Risk Management Forum concluded that the total amount of4- CP A used annuall y is about 20 lb. 

### Criterion #4- Highly Diffuse Use 

### Site The Science Policy Council and Risk Management Forum reasoned that the 20 lb of 4-CPA used annually is spread throughout the year. For instance, if production were to occur 50 weeks a year, then only 0.4lb of 4

-CPA would be used each week (dilute solutions of2 to 3 mg ai/L per 3500 pounds ofbeans)
. During the soaking period, the mung beans would absorb 2 to 3 times their weight (and volume) of the solution. The Forum reasoned that less than half of the 4-CPA amount would be left unabsorbed and would likely be subj ect to significant dilution before possible release or disposal. Dilution rates were assumed to be extensive because food processing li nes run more or J ess continuously and the few thousand gallons of spent soaking solution are reasonably expected to be di luted with the entire processing facility's wastewater discharge.



### 3From the above reasoning, the Forum concluded that the 20 lb of 4-CPA used annually would be greatly dispersed over t im e and diluted. I f any 4 - CP A is disposed of through sanitary sewer systems, the concentration of the active ingredient arriv i ng at a pub li cally owned treatment works in a n indi vidual release would be minimal. It shou l d be noted that even the starting so l ution concentration of 2 to 3 mg/L, without dilution from process water, i s well below estimated toxicity thresholds. Conclusion Based on the type and extent of use, the low expected toxicity shown by QSAR, and the highly diffuse nature of the use site coup l ed with extremely l ow annual usage, EFED concludes that effects on the environment are not reasonab l y expected to occur via the registered uses of 4- CP A. Therefore , EFED has reached a "no effects" determination for listed species for registered uses of 4-CP A. Given that the thresho ld for e f fects t o listed species is lower than non-listed species, EFED determined that effects to non-target, non-listed species are un li kely as wel l. Sources C ited USEPA. 2014 . MEMORANDUM from : Science Po li cy Counci l/Ri sk Management Forum De Minimis Subgroup to : R ic hard Keigwin , Jr. Division Director, PRO , Donald Brady, Division Director , EFED, Dana Vogel , Acting Division Director, HED, Yu-Ting Guilaran , Division Director, BEAD ECOSAR. vl.l l C l ass - specific Estimations SMILES : O = C(O)COc(ccc(cl)CL)cl. 4