Alternative to formaldehyde as preservative in water samples




General Section



Electricity, steam, gas water supply and sewage treatment
Scientific research and development


Durability agent
Embalming agent


Manual activities involving hand contact

Product category

laboratory chemicals


preserving macroinvertebrates in fresh water samples


A well-known preservative, formaldehyde, is also a carcinogen and a sensitiser. Its use for preserving macroinvertebrates in fresh water samples can be substituted by freezing parts of the samples and using ethanol for the other parts.

Substituted substances


CAS No. 50-00-0 EC No. 200-001-8 Index No. 605-001-00-5

Chemical group


Classification: hazard statements

H350 May cause cancer
H341 Suspected of causing genetic defects
H331 Toxic if inhaled
H311 Toxic in contact with skin
H301 Toxic if swallowed
H314 Causes severe skin burns and eye damage
H317 May cause an allergic skin reaction

Other adverse effects

The substance is: 1 carcinogen (IARC) as listed in the Substance Database according to SUBSPORT Screening Criteria (SDSC).

Alternative Substances


CAS No. 64-17-5 EC No. 200-578-6 Index No. 603-002-00-5

Chemical group


Classification: hazard statements

H225 Highly flammable liquid and vapour

Other adverse effects

The substance is: 1 carcinogen (IARC), as listed in the Substance Database according to SUBSPORT Screening Criteria (SDSC).

Reliability of information

Evidence of implementation: there is evidence that the solution was implemented and in use at time of publication

Reason substitution

skin/respiratory sensitizing
other toxic effects
physical hazards

Other type of alternative

Preservation (part) of biological samples by freezing.

Hazard Assessment

Substance to be substituted: Formaldehyde is: a 2A carcinogen (IARC), 1A or 1B carcinogen (CLP Regulation), a sensitiser (H317, H334; CLP Regulation) as listed in the Substance Database according to SUBSPORTplus Screening Criteria (SDSC). Alternative substance: Though ethanol is listed as IARC carcinogen in beverages, under the conditions of use is less hazardous than formaldehyde.

Description of Substitution

Macroinvertebrate bioindicators are used in evaluating the biological quality of water. Traditionally the biological material of the samples is preserved using formaldehyde, which is both a carcinogen and a sensitiser. An alternative method published by the Direction Regionale de l’Environnement (DREN) Lorraine-France uses less hazardous means. It consists in elutriating the samples and separating a floating part concentrated in invertebrates which is preserved in ethanol and a sedimented part (sand, stones) that is frozen on the spot. Samples that are too small to elutriate are preserved entirely in ethanol, those that cannot be elutriated (sludge) are entirely frozen.

Case/substitution evaluation

The report published by DREN evaluates the method as feasible and easy to apply. Freezing part of the samples lowers the consumption of ethanol considerably. In the same time ethanol preserved some taxonomic groups better that would be deteriorated or destroyed if only freezing would be used. The chemical risk of the method is lowered by using the alternative to formaldehyde.

State of implementation

In use

Date and place of implementation


Availability ofAlternative

Alternatives available on the market

Type of information supplier



INSTITUT NATIONAL DE RECHERCHE ET DE SÉCURITÉ pour la prévention des accidents du travail et des maladies professionnelle ), France,

Type of publication and availability

Fact sheet freely available

Publication source: author, company, institute, year

The Fact sheet was developed by CNAMTS and INRS, France and published by INRS on its website in 2011

Publication source

Type of publication and availability

Date, reviewed

December 11, 2020