Innospec: ENVIOMET^® C — a Readily Biodegradable, Environmentally Friendly Chelating Agent for Agricultural Applications

Author: Paolo Fortunati, Sales Manager Agrochemicals EMEA at Innospec Performance Chemicals

Modern agriculture needs to embrace technological innovation to provide sustainable solutions, to guarantee global food security and enable effective environmental stewardship. Innospec continuously look to improve the sustainability profile of products and help customers respond to environmental challenges through innovation and improved product performance.

Chelating agents are used as carrier systems for delivering essential micronutrient elements directly to crops. The aim is to overcome problems that may limit bioavailability of micronutrients to plants, by maintaining the nutrient elements in a soluble state and to prevent incompatibility problems in tank mix.

Innospec has developed ENVIOMET^® C to meet the needs for both excellent chelating performance combined with readily biodegradable properties and low environmental impact.

ENVIOMET^® C is a (S,S’) Ethylenediamine-N,N’-disuccinicate (abbrev. EDDS), commercially available in liquid and powder form.

Readily biodegradable

ENVIOMET^® C is based on a single enantiomerically pure isomer of L-aspartic acid with an optical purity >99%[S,S]. The S,S form of EDDS has been subject to multiple studies and is readily biodegradable according to the stringent OECD Ready Biodegradation Test Guideline 301B (CO2 Evolution - Modified Sturm Test) as shown in Figure 1.
 

Figure 1. OECD 301B Ready Biodegradability data for EDDS

When released into the environment, ENVIOMET^® C rapidly biodegrades undergoing complete mineralization to harmless by-products (CO₂ and water) within a short timeframe.

Thanks to its excellent biodegradability characteristics and favorable toxicity profile to terrestrial species, ENVIOMET® C has a low impact on the soil micro and macro fauna.

Classification and Labelling

ENVIOMET^® C is not classified as dangerous to the environment according to the Globally Harmonised System (GHS) or EU Regulation (EC) No 1272/2008 on the classification, labelling and packaging of substances and mixtures (EU CLP).

Table 1. Health and Environmental Properties of ENVIOMET^® C

Stability constants

Chelation is a process in which free metal ions combine with ligands to form metal complexes.  The ability of a chelant to bind metal ion is determined by stability constants. The larger the stability constant, the stronger the chelation effect.

Table 2. Stability constants for EDDS compared with biodegradable and conventional chelating agents

IDHA = Imidodisuccinicacid / EDTA = Ethylenediaminetetraaceticacid / DTPA = Diethylenetriaminepentaaceticacid
1. A.E. Martell, R.M. Smith, NIST Critically selected stability constants of metal complexes (NIST standard reference database 46, Version 7.0, 2003). Log K values as determined at an ionic strength of 0.1M and at a temperature of 25°C or if not available at 20°C.
2. Miguel A Sierra, et al., Dalton Trans. 2004 Nov 7;(21):3741-7.

ENVIOMET^® C chelating agent has a low affinity with calcium and magnesium that will result in more stable chelated micronutrients when diluted in hard water and/or applied to calcareous soils.

Field trials

Use of the versatile ENVIOMET^® C will generate high quality fertilizers, which may be used in many cropping situations including arable crops, horticulture, orchards, ornamental gardens and for seed dressing, easily absorbed through leaves and roots.
The efficacy of Fe-EDDS in comparison to Fe-EDTA chelates was tested on Maize and Soybean. Growth trials (80 plants) have indicated that EDDS is as effective as EDTA in delivering iron metal to soyabean and maize plants in foliar feeding applications.
Maize (Zea mays 1. [monocot]) and Soyabean (Glycine max 1. [dicot]) plants grown in calcareous soil were each treated with 0.01% and 0.005% of Fe(EDDS) and Fe(EDTA) as foliar sprays in order to compare their effectiveness in alleviating Fe deficiency symptoms.

Figure 2. Field trials comparing performance of Fe-EDDS with Fe-EDTA

a.Maize (Zea Mays)

b.Soyabean (Glycine max)

The results obtained suggest that 0.01% Fe(EDDS) was the better foliar treatment for soyabean and maize deficient in iron. The work also suggests that application of iron as Fe(EDDS) may be a safer source because it does not produce the leaf scorching associated with higher levels of Fe(EDTA). The results showed a very good response of all plants to EDDS application, better in comparison to EDTA.

Organic farming

The use of ENVIOMET^® C is consistent with the principles of sustainable agriculture. Thanks to its biodegradability, it is particularly recommended for organic certified products. In this regard, the Research Institute of Organic Agriculture (FiBL), one of the World’s leading institutes in the field of organic agriculture, recommends EDDS as chelating agent in its European Input List for fertilizers, soil conditioners and crop management tools.

Global Regulatory Status

ENVIOMET^® C is listed on all major global chemical inventories (Europe, US, Canada, China, Australia, New Zealand, Korea, Japan, Philippines and Taiwan). It is registered and fully compliant with EU Regulation 1907/2006 (EU REACH).

ENVIOMET^® C140 and ENVIOMET^® C265 are approved inert ingredients, exempted from the requirement of a tolerance in accordance with US EPA 40 CFR § 180.

EDDS is included in the list of authorized organic chelating agent for micro-nutrients by Commission Regulation (EU) 2016/1618 amending Regulation (EC) No 2003/2003 which designs EU fertilizers.

To know more about ENVIOMET^® C, visit Innospec website:
https://innospec.com/agrochemicals/biodegradable-chelating-agents/
Contact Innospec at: agrochemicals@innospecinc.com

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