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

Bio-accumulation

The ability of a substance to bio-accumulate – to be captured and accumulated – in a living organism like a fish is determined by the ‘bio-concentration-factor’ (BCF) of the substance. This factor determines the ratio between the concentrations of the substance in the organism and the concentration in the surrounding environment – typically water.

The BCF is influenced by the size of the molecule and the ability to dissolve in fat. Substances with high solubility in fatty substances and small molecule size will have high tendency to bio-accumulate. Such substances might accumulate to a level where the toxic properties of the substances might be serious for the organism.

A commonly used method to assess the tendency of the substance to bio-accumulate, is to study the distribution of the substance between the phases in an octanol / water system. This distribution is expressed by the ‘octanol water distribution coefficient’ P_ow which is the ratio between the concentrations in the two phases.

Organic substances with P_ow-values over 1000 are normally considered as potentially bio-accumulating. This value is often expressed by the 10-log of the P_ow – that is logP_ow.

In addition, the substance’s solubility in water is often used as an indicator, such that high solubility will mean low tendency to bio-accumulate. Solubility in water of more than 2000 ppm is considered to indicate that no risk of bio-accumulation exists.

This method is not relevant for substances with a surface activity. Such substances will stay in-between the fatty substance and the water in a test on the distribution of the substance between the phases in an octanol / water system.

 

 

 

Explanatory notes on environmental properties of chemicals:

Bio-degradation

Ecotoxicity

Bio-accumulation

 

- an explanatory note:

Info on specific substances

The Detergent Ingredient Database (the DID-list) provides information on aerobic and anaerobic degradation of the most commonly used substances.

The HERA project ‘Human and Environment Risk Assessment on ingredients of household cleaning products’, includes a valuable section with in depth assessment of specific detergent ingredients.