- Aquatic Ecotoxicology
- OECD 202: Daphnia sp., Acute Immobilisation Test
- OECD 211: Daphnia magna Reproduction Test
- OECD 235: Chironomus sp., Acute Immobilisation Test
- OECD 218/219: Sediment-Water Chironomid Toxicity Test Using Spiked Sediment/Spiked Water
- OECD 233: Sediment-Water Chironomid Life-Cycle Toxicity Test Using Spiked Water or Spiked Sediment
- OECD 225: Sediment-water Lumbriculus Toxicity Test Using Spiked Sediment
- OECD 242: Potamopyrgus antipodarum Reproduction Test
- OECD 243: Lymnea stagnalis Reproduction Test
- OECD 203: Fish, Acute Toxicity Test
- OECD 215: Fish Juvenile Growth Study
- OECD 212: Fish, Short-term Toxicity Test on Embryo and Sac-fry Stages
- OECD 231: The Amphibian Metamorphosis Assay
- OECD 236: Fish Embryo Acute Toxicity Test
- OECD 210: Fish, Early-life Stage Toxicity Test
- OECD 229 Fish Short Term Reproduction Assay and OECD 230 21-day Fish Assay
- OECD 240 Medaka Extended One Generation Reproduction Test (MEOGRT)
- OECD 241: Larval Amphibian Growth and Development Assay
- OPPTS 850.1500: Fish Life Cycle Toxicity Test
- OÈCD 234 Fish sexual development test
- Storage Stability Studies
- OPPTS 830.6302, OPPTS 830.6303,and OPPTS 830.6304: Physical State, Colour and Odor at 20 °C and at 101.3 kPa
- EU A.1: Melting temperature/range
- EU A.2: Boiling temperature
- EU A.3: Relative density (liquids and solids)
- EU A.4: Vapour pressure
- EU A.5: Surface tension
- EU A.9: Flashpoint
- EU A.10: Flammability (solids)
- EU A.12: Flammability (contact with water)
- EU A.13: Pyrophoric properties of solids and liquids
- EU A.16: Relative self-ignition temperature for solids
- EU A.17: Oxidising properties
- OECD 114: Viscosity of Liquids
- Environmental Fate
- Terrestrial Ecotoxicology
- Non-target arthropod testing with the parasitic wasp (Aphidius rhopalosiphi)
- Non-target arthropod testing with the lacewing (Chrysoperla carnea)
- Non-target arthropod testing with the ladybird beetle (Coccinella septempunctata)
- Non-target arthropod testing with the predatory bug (Orius laevigatus)
- Non-target arthropod testing with the predatory mite (Typhlodromus pyri)
- Non-target arthropod testing with the rove beetle (Aleochara bilineata)
- Non-target arthropod testing with the carabid beetle (Poecilus cupreus)
- Non-target arthropod testing with the wolf spider (Pardosa spec.)
- OECD 213/214: Honey bees, Acute Oral and Acute Contact Toxicity Test
- Honeybee: Chronic Feeding Tests
- OECD 237: Honey Bee Larval Toxicity Test, Single Exposure
- Effects on Honey Bee Brood (Apis mellifera) - Brood Feeding Test -
- OECD Draft TG: Honey Bee Larval Toxicity Test, Repeated Exposure
- OECD 75: Honey Bee Brood Test under Semi-field conditions
- EPPO 170: Honey Bee Field Study – do plant protection products effect honey bee colonies?
- Acute Oral and Contact Toxicity to the Bumblebee, Bombus terrestris L.
- Ecological Modelling
- Quality Assurance
- Testing of Potential Endocrine Disruptors
- Aquatic Ecotoxicology
- Who we are
- Company history
- Our Certificates
OECD 221: Lemna sp. Growth Inhibition Test
Lemna gibba is a representative species for higher aquatic plants. The plants are small, easy to cultivate and sensitive towards chemicals. Testing of Lemna is required for plant protection products acting as an herbicide or a plant growth regulator. The Lemna test is also considered as a suitable alternative to an algal test (OECD 201) for strongly coloured substances. If your product shows considerable toxicity, a Lemna recovery study or a test with other higher aquatic plants e.g. Myriophyllum or Glyceria may be indicated.
We sustain our own laboratory culture of Lemna gibba. The plants are kept in exponential growth by transferring them regularly into new test vessels.
Course of the test
Depending on the properties of your substance, Lemna studies can be performed in a static test design without test item renewal. For precipitating or degrading substances a semi-static test design with renewal of the test item is suitable. Usually, a dose response study is performed. The exposure duration is 7 days with assessments usually on day 3 and 5. The number of fronds will be counted and the dry weight will be determined at the end of the test.
Test substance concentrations are analysed at test start and test end to verify the dosage of the test item. A toxic reference, tested twice per year, proves the sensitivity and suitable condition of the test system. The focus of our studies is the determination of the EC50 and the no observed effect concentration (NOEC). Depending on the usage of your product and its environmental fate properties, duration and number of exposure and recovery periods can be adapted.
Where on the basis of the standard Lemna test a high risk to aquatic plants is identified, a recovery study can be useful to provide further information on the extent of effects of the test item to aquatic higher plants.
After a defined time of exposure, e.g. after seven days as the standard exposure period, the fronds are rinsed and 12 fronds are transferred into pure test water without test item. The growth of the control plants is compared to the growth of the plants previously exposed to the test item. The recovery periods may be extended until a recovery in growth is observed.
NOEC, LOEC and EC50 (EC20, EC10) for yield and growth rate based on frond number and dry weight.
Guidelines and literature
- OECD Guideline 221: Lemna sp. Growth Inhibition Test
- Commission Regulation (EC) No 761/2009, Annex, Part C, C.26.: "Lemna sp. Growth Inhibition Test", Official Journal of the European Union (EN)
- OECD Guideline 23: Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures