Other groups

Introduction

Why be concerned?

Supplier progress

Potential impacts

Functional groups

Substance list

Legislation / REACH

FAQs

Related Links

Wash with care

Environmental assessment of laundry detergents

Other substances

This section includes a presentation of miscellaneous substances sometimes found in detergents preparations and these substances have several different functions:

Alkalis

Alkalis improves the laundering effect of laundry detergents by increasing the pH. Alkalis, like meta-silicate, also act as corrosion inhibitors of the washing machine or dishwasher.

The environmental impacts of alkalis are of very little significance since they are generally neutralised to harmless salts. The main concern is skin irritation and etching effects.

Sodium hydroxide and Silicates are examples of substances used in laundry detergents are.

CMC – Carboxy Methyl Cellulose

The purpose of adding CMC is to enhance the soil-suspending power of the synthetic surfactants, as these substances do not have the same ability to suspend the soil as soap used in the past. As a result CMC is widely used as an additive to most laundry detergents containing anionic or non-ionic surfactants. Alternatives include various long chain polymers such as polyacrylates.

CMC is readily degradable and has no known adverse effects on aquatic organisms.

Enzymes

Enzymes are complex protein molecules that catalyse the breakdown of specific soiling substances. They have a wide application in household detergents, but are rarely used in industrial laundries. The reason for this is the fact that industrial laundries prefer faster high temperature recipes and hence the short reaction time reduces the effect and the high temperature will destroy the enzymes.

From an environmental point of view enzymes are harmless. Due to the protein nature they may create allergic reactions but since they are normally encapsulated such effects are rarely seen. They are readily degradable and have no negative affects in the aquatic system.

Foam reducers

The purpose of adding foam reducers is to reduce foam. Examples are fat-alcohols and silicone oils. Many such substances bio-degrade slowly.

Optical brighteners

Optical brighteners (Fluorescent Whitening Agents - FWAs) are conjugated aromatic molecules which have the property of absorbing UV-light and emitting blue light, a phenomenon known as fluorescence. They are used as a dye in white fabrics to increase the whiteness. In detergents they are sometimes added by to maintain the level of optical brightener in the fabric otherwise reduced due to gradual washout.

The optical brighteners most commonly used are seven different substances (FWA I-VII) which are anionic derivatives of diamino stilbene or distyryl biphenyl, except for one which is a triazolyl stilbene derivative.

Optical brighteners show very poor degradability in tests performed in the laboratory. The substances have not been found to bio-accumulate in neither plants nor animal tissue. In waste water treatment plants they accumulate in the sludge which may then be are applied to farmlands and thus, the optical brighteners are conveyed to the terrestrial environment. Their long term effects in the terrestrial environment are unknown.

Perfumes

Perfumes may be included in fabric softeners, but in most industrial laundries perfumes are not used. During recent years some perfumes have been identified as having the potential to create allergic reactions or skin irritation.

A new regulation from the EU lists a number of substances that must be declared by the manufacturers of cosmetics (see box). Thus caution should be used if detergents are scented, to minimise possible irritant properties from identified problem perfumes.

All perfumes should be approved by IFRA – the International Fragrance Association. A list of banned perfumes or perfumes with restricted use — very similar to the EU list shown — can be found on the association’s web-site: www.ifraorg.org

Preservatives / biocides

Preservatives are rarely used in powder detergents but may be found in liquid detergents or paste detergent mixtures.

Due to the nature of these substances - and in fact the reason to add them to the detergent mixtures - they are toxic. They are added in very small amounts and are normally readily degradable.