Calcium Chloride
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United States Department of Agriculture Agricultural Marketing Service | National Organic Program Document Cover Sheet https://www.ams.usda.gov/rules-regulations/organic/national-list/petitioned Document Type: ☐ National List Petition or Petition Update A petition is a request to amend the USDA National Organic Program’s National List of Allowed and Prohibited Substances (National List). Any person may submit a petition to have a substance evaluated by the National Organic Standards Board (7 CFR 205.607(a)). Guidelines for submitting a petition are available in the NOP Handbook as NOP 3011, National List Petition Guidelines. Petitions are posted for the public on the NOP website for Petitioned Substances. ☒ Technical Report A technical report is developed in response to a petition to amend the National List. Reports are also developed to assist in the review of substances that are already on the National List. Technical reports are completed by third-party contractors and are available to the public on the NOP website for Petitioned Substances. Contractor names and dates completed are available in the report. Calcium Acetate Crops 1 2 Identification of Petitioned Substance 3 4 Chemical Names: 24 Full Measure CalTM 30 5 Calcium Acetate 25 ReflectionsTM 6 Calcium Diacetate 26 7 Acetic Acid, Calcium Salt CAS Numbers: 8 Calcium (II) Acetate 62-54-4 (Calcium Acetate) 9 Calcium Ethanoate 5743-26-0 (Calcium Acetate Monohydrate) 10 Calcium Acetate Monohydrate 114460-21-8 (Calcium Acetate Hydrate) 11 Calcium Diacetate Hydrate 12 Calcium Diacetate Monohydrate Other Codes: 13 Acetic Acid, Calcium Salt, Monohydrate EC No. 200-540-9 (Calcium Acetate) 14 EC No. 611-528-1 (Calcium Acetate 15 Other Names: Monohydrate) 16 Lime Acetate FEMA No. 2228 17 Acetate of Lime ICSC No. 1092 18 Lime Pyrolignite RTECS No. AF7525000 19 Vinegar Salts UNII No. Y882YXF34X (Calcium Acetate) 20 UNII No. 7ZA48GIM5H (Calcium Acetate 21 Trade Names: Monohydrate) 22 PhosLo® 23 ProcalAmine® 27 Summary of Petitioned Use 28 29 The petitioners are requesting to add calcium acetate, the salt resulting from the neutralization of acetic acid with 30 calcium hydroxide or calcium carbonate, to Title 7 of the Code of Federal Regulations section 205.601 (7 CFR 31 205.601) as a “synthetic substance allowed for use in organic crop production.” 32 33 Calcium acetate acts as a soil amendment, plant micronutrient, pH adjuster, and preventative of sunscald. 34 Calcium acetate provides a water-soluble and bioavailable source of the essential micronutrient calcium for plant 35 absorption. When used as petitioned, calcium acetate is applied as an aqueous mixture with calcium carbonate 36 (limestone) and a surfactant. The combination of calcium acetate and calcium carbonate serves to increase soil 37 alkalinity (pH adjustment). The petitioned mixture also prevents sunscald by blocking direct sun exposure and 38 lowering soil temperature. 39 40 Characterization of Petitioned Substance 41 42 Composition of the Substance: 43 Calcium acetate is an organic salt that is found as a component in the metabolic pathways of a variety of 44 animals, including humans (EFSA 2009, EFSA 2012). Commercial forms of calcium acetate are 45 manufactured by the neutralization of acetic acid with either calcium carbonate or calcium hydroxide salts 46 (EPA 2010a, Hawley 2016). The petitioned substance is hygroscopic (absorbs water) making most 47 commercial sources calcium acetate hydrates (including water molecules), although anhydrous calcium 48 acetate (calcium acetate without water incorporation) is also available (Capot 2013, ILO 2002, Merck 1996, 49 EU 2012, Perry 2011, PubChem 6116, PubChem 82163, Sigma-Aldrich 2016, Sigma-Aldrich 2018). 50 51 Source or Origin of the Substance: 52 Calcium acetate is a naturally occurring substance, which is produced and broken down in the metabolic 53 cycles of a range of humans and animals; however, it is most commonly manufactured by the ___________________________________ September 14, 2018 Technical Evaluation Report Page 1 of 15 Compiled by Savan Group for the USDA National Organic Program Technical Evaluation Report Calcium Acetate Crops 54 neutralization of acetic acid with calcium carbonate (limestone, Equation 1) or calcium hydroxide 55 (hydrated lime, Equation 2) (EFSA 2009, EFSA 2012, EPA 2010a, Hawley 2016). 56 O O O 2+ + H2O + CO2 + 2+ CO 2- Ca Ca 3 - - OH O O acetic acid calcium carbonate calcium acetate water carbon dioxide 57 Equation 1 O O O + (2) H2O + - Ca OH- Ca2+ OH 2+ - - OH O O acetic acid calcium hydroxide calcium acetate water 58 Equation 2 59 60 Properties of the Substance: 61 Calcium acetate is commercially available as a solid in >98% purity in anhydrous, monohydrate, and 62 hydrate forms. However, the anhydrous form (calcium acetate) is hygroscopic (absorbs water/moisture), 63 and since the substance is used in an aqueous mixture, the monohydrate or hydrate forms are more likely 64 to be used for the petitioned application (Merck 1996). The properties of the commercially-available forms 65 of calcium acetate are summarized in Table 1. 66 67 Table 1: Properties of Calcium Acetate 68 Compound Calcium Acetate Calcium Acetate Calcium Acetate Hydrate Monohydrate CAS No. 62-54-4 114460-21-8 5743-26-0 Molecular Weight 158.17 g/mol 158.17 g/mol 176.18 g/mol Appearance Colorless-white Solid Brown, gray, or white crystalline solid solid powder General Properties Very Hygroscopic, Hygroscopic, Hygroscopic, Slight odor of acetic Slight odor of acetic Slight odor of acetic acid acid acid Solubility Soluble in water, N/A Soluble in water, slightly soluble in slightly soluble in alcohols alcohols Melting Point 160 oC (decomposes) N/A N/A (decomposes) Density 1.5 g/cm3 N/A N/A 69 Sources: (Capot 2013, ILO 2002, Merck 1996, EU 2012, Perry 2011, PubChem 6116, PubChem 82163, Sigma- 70 Aldrich 2016, Sigma-Aldrich 2018) 71 72 Specific Uses of the Substance: 73 Calcium acetate is petitioned for use as a soil amendment. Calcium acetate is a water-soluble salt for use as 74 a bioavailable source of the essential micronutrient calcium (Ca2+) (Merck 1996, EU 2012, Peacock 2005, 75 Perry 2011, PubChem 6116, PubChem 82163, Sigma-Aldrich 2016, Sigma-Aldrich 2018). Calcium is an 76 important micronutrient for plant growth, providing important structural rigidity to cell walls and 77 membranes, protection from microbial diseases, and proper regulation of cellular transport and enzyme 78 function (Bennett 1993, Frizzel and Loosemore 2010, Helper 2005, Hirschi 2004, Marschner 1995). The 79 petitioned substance improves the delivery of calcium compared to other calcium treatments (e.g., lime) September 14, 2018 Page 2 of 15 Technical Evaluation Report Calcium Acetate Crops 80 due to its increased water solubility (Frizzel and Loosemore 2010, Peacock 2005). When the petitioned 81 substance is combined with insoluble calcium carbonate, the mixture acts to further improve the 82 fertilization method by delivering immediate calcium nutrition with calcium acetate and prolonged 83 nutrition from calcium carbonate (Frizzel and Loosemore 2010). Furthermore, calcium acetate has been 84 reported to increase plant absorption of calcium ions (Ca2+) compared to salts with other organic and 85 inorganic anions (e.g., lactate, citrate, oxalate, chloride, nitrate) (Borchert 1986). 86 87 Calcium acetate is also petitioned for adjustment of soil pH. Acetate is the conjugate base of the weak 88 organic acid acetic acid (Equations 1 and 2); therefore, the application of acetate will act to establish a buffer 89 and increase the alkalinity (and raise the pH) of the soil by reacting with both strong and weak acids. 90 However, the applied mixture will consist of ~5% calcium acetate, with the remaining calcium content in 91 the form of calcium carbonate. Calcium carbonate is naturally produced and exists in many forms, 92 including mineral deposits (e.g., limestone, calcite, and marble) and as a structural component of bones and 93 shells (e.g., eggshells, seashells) (USDA 2018, USGS 2008). Calcium carbonate will also react as a base, 94 neutralizing strong and weak acids and resulting in the formation of a new calcium salt, water, and carbon 95 dioxide (CO2) gas (as seen with the neutralization of acetic acid in Equation 1) (Al Omari et al. 2016, EFSA 96 2011, Holman and Stone 2001, Oates 1998). Although calcium carbonate has very low water solubility, the 97 ionic compound is broken up by acids, greatly increasing the solubility of the calcium cation and providing 98 access to the basic properties of the carbonate anion (EFSA 2011, Oates 1998). 99 100 Calcium acetate is petitioned for use as an aqueous mixture that also includes calcium carbonate, xanthan 101 gum (as a stabilizer), and in some cases humic acid. This mixture of substances is not completely soluble, 102 and its suspended solid particles shield plants from ultraviolet radiation and regulate plant temperature. 103 Sunscald occurs when exposure to sunlight overheats crops and results in scar formation (Piskolczi et al. 104 2004). These scars are visible on the surface of the crop, and persist into sub-surface layers, affecting the 105 color, taste, and properties of the crop before and after harvest (Lurie and Watkins 2012, Piskolczi et al. 106 2004, Schrader et al. 2001). The aqueous mixture — which includes the petitioned calcium acetate, calcium 107 carbonate, and the surfactant xanthan gum — is petitioned for protection of crops from sunscald. This 108 protective property is due to the opaque nature of the mixture, largely due to the presence of insoluble 109 calcium carbonate in the final formulation, which protects plants from ultraviolet radiation while 110 simultaneously regulating plant temperature (Frizzel and Loosemore 2010). 111 112 Calcium acetate has been used in animal feeds for nutritional purposes as well as a preservative and 113 veterinary medicine due to its mild anti-microbial effects (EFSA 2012). Calcium acetate has also been 114 established for a range of other non-agricultural applications, including cosmetics and various household 115 products (EFSA 2012).