🐟 Daphnia · Microalgae · Vibrio · Fish · Plants · Earthworms · Ames Test · OECD · EPA · ISO

Ecotoxicity & Bioassays

The integrated biological evidence that physicochemical analysis alone cannot provide.

Ecotoxicity testing — commonly called "bioassays" — measures the actual toxic or adverse effects of samples on living organisms. Biogroup has developed a wide variety of bioassay techniques covering multiple trophic levels: from bioluminescent bacteria and microalgae through cladocerans, fish, earthworms and terrestrial plants — all under OECD, ISO and US EPA validated methods.

A sample can comply with every physicochemical regulatory limit and still be toxic to the receiving ecosystem — because no chemical analysis can measure the combined effect of all contaminants present, or the synergistic interactions between them. The bioassay is the only test that answers the question that actually matters: "Does this harm the ecosystem?"

7 test organisms
Multiple trophic levels
OECD · ISO · EPA
Internationally validated
EC50 · LC50 · NOEC
Key toxicity endpoints
+35 years
Ecotoxicology expertise
⚠️ The limit of physicochemical analysis
A physicochemical analysis only measures what it knows to look for. An industrial effluent may contain hundreds of compounds — many without a specific regulatory limit — that act in combination to damage the receiving ecosystem. "In compliance" does not mean "not toxic".
✅ What the bioassay adds
The bioassay integrates the combined effect of all contaminants present — including unknown compounds, mixture synergisms and sub-threshold interactions. It answers the question that matters for environmental protection: does this matrix harm the organisms in the receiving ecosystem?
Matrices evaluated — what Biogroup tests
Ecotoxicity testing is applied to all environmental matrices
The appropriate test organism and method are selected based on the matrix and the regulatory or commercial objective.
🏭
Industrial effluents
Before and after treatment · permit compliance · EIA
🌊
Surface & groundwater
Rivers · streams · reservoirs · aquifers
🗑️
Waste leachates
TCLP extracts · landfill leachate · H14 hazard characteristic
🏞️
Soil extracts
Contaminated site characterisation · remediation validation
🧪
Chemicals & products
Chemical registration · REACH · product safety
Multi-species test battery — covering all trophic levels
From bioluminescent bacteria to fish — the full aquatic and terrestrial trophic chain
Different organisms occupy different positions in the food chain and respond differently to different contaminants. A comprehensive ecotoxicity evaluation should cover producers (algae), primary consumers (cladocerans), secondary consumers (fish) and decomposers (bacteria) — plus terrestrial organisms when the matrix or application requires it.
🦠
Decomposer · OECD 481 · ISO 11348-1/2/3 · DIN 38412-L34
Vibrio fischeri — Bioluminescence inhibition
Vibrio fischeri is a marine bioluminescent bacterium whose natural light emission is proportional to metabolic activity. Toxic compounds inhibit cellular respiration and reduce luminescence — the inhibition is measured photometrically as % reduction relative to controls. The fastest ecotoxicity test available — results in 15–30 minutes. Ideal for rapid screening and real-time effluent monitoring.
Endpoints: EC50 (15 min) · EC50 (30 min) · % inhibition
Duration: 15–30 minutes
Methods: OECD 481 · ISO 11348-1/2/3
Best for: Rapid screening · process control · effluent monitoring
🌿
Primary producer · OECD 201 · ISO 8692 · EPA 600/9-78-018
Microalgae — Growth inhibition (Pseudokirchneriella subcapitata · Selenastrum carpicornutum · Chlorella vulgaris)
Green microalgae are the primary producers of aquatic ecosystems — their inhibition has cascade effects on all higher trophic levels. The test measures the inhibition of photosynthetic growth over 72 hours by comparing the biomass (cell count or chlorophyll fluorescence) of treated cultures against controls. Particularly sensitive to herbicides, metals and nutrient-disrupting compounds.
Endpoints: EC50 (72 h) · NOEC · LOEC · growth rate
Duration: 72 hours
Methods: OECD 201 · ISO 8692 · EPA 600/9-78-018
Best for: Herbicides · metals · nutrient-disrupting compounds
🦐
Primary consumer · OECD 202 · ISO 6341 · EPA 821-R-02-012
Cladocera — Daphnia magna · Ceriodaphnia dubia · Daphnia pulex
Daphnia magna is the global reference organism for aquatic ecotoxicology — the most sensitive freshwater invertebrate to a wide range of industrial contaminants. The acute test measures immobilisation at 24 h and 48 h; the chronic test (21-day OECD 211) measures reproduction and survival. Ceriodaphnia dubia provides a shorter-duration chronic endpoint (7 days) more appropriate for effluent samples. EC50 is calculated by Probit analysis.
Endpoints: EC50 (24 h & 48 h) · NOEC · LOEC · reproduction
Duration: 24/48 h (acute) · 7–21 days (chronic)
Methods: OECD 202 · OECD 211 · ISO 6341
Best for: Industrial effluents · metals · pesticides · H14 classification
🐟
Secondary consumer · OECD 203 · OECD 210 · ISO 7346
Fish — Danio rerio · Oncorhynchus mykiss · Pimephales promelas
Fish are the aquatic vertebrates most used as bioindicators of environmental quality and the organisms the general public most readily associates with ecological damage. Danio rerio (zebrafish) is the standard laboratory model; Oncorhynchus mykiss (rainbow trout) is used for cold-water assessments and is particularly relevant for discharge permits into fishing rivers. Acute test: LC50 at 96 hours. Chronic test: OECD 210 (early life stage).
Endpoints: LC50 (96 h) · NOEC · LOEC · sub-lethal effects
Duration: 96 h (acute) · 28–60 days (chronic)
Methods: OECD 203 · OECD 210 · ISO 7346
Best for: EIA · river discharge permits · litigation support
🪱
Terrestrial ecosystem · OECD 207 · ISO 11268 · OECD 208
Earthworms — Eisenia fetida · E. andrei
Eisenia fetida is the standard test organism for terrestrial soil ecotoxicology. The acute test determines LC50 at 14 days; the chronic test measures reproduction and biomass over 28 days. Critical for contaminated soil classification, sludge land application assessments and H14 ecotoxicity characteristic under Ley 24.051. Organic contaminants bioaccumulate in earthworm tissue — a pathway to higher terrestrial predators.
Endpoints: LC50 (14 d) · reproduction NOEC · biomass
Duration: 14 days (acute) · 28 days (chronic)
Methods: OECD 207 · ISO 11268-1/2
Best for: Contaminated soil · sludge application · H14
🌱
Terrestrial producer · OECD 208 · ISO 11269 · EN 13432 Annex E
Phytotoxicity — Lactuca sativa · Allium cepa · Lycopersicon esculentum · Zea mays · Glycine max · Brassica oleracea · Avena sativa · Lolium perenne · Cucumis sativus · Daucus carota
Seed germination and root elongation tests with a diverse panel of monocots and dicots — the broadest phytotoxicity assessment available. Lactuca sativa (lettuce) and Allium cepa (onion) are the most sensitive and widely used species. Critical for compost and soil amendment quality certification under IRAM 29421:2019 / EN 13432 (Annex E: plant growth test). Also applied to contaminated soil characterisation and irrigation water assessment.
Endpoints: % germination · root elongation EC50 · NOEC
Duration: 5–14 days
Methods: OECD 208 · ISO 11269 · EN 13432 Annex E
Best for: Compostability · soil quality · sludge · irrigation water
🧫
Cellular level · ISO 10993-5 · OECD TG 129 · MTT / Neutral Red
Cytotoxicity — mammalian cell lines in vitro
Cell viability assessment using mammalian cell lines — MTT reduction (mitochondrial activity) or Neutral Red uptake (lysosomal integrity). Provides information on toxic potential at the molecular level and complements the ecological tests when human health risk assessment is also required. Particularly applied to complex matrices (leachates, concentrated extracts) where standard chemical analysis cannot identify all toxicants.
Endpoints: IC50 · % cell viability · dose-response curve
Duration: 24–72 hours
Methods: ISO 10993-5 · OECD TG 129
Best for: Complex matrices · emerging contaminants · health risk
Ames Test — mutagenicity and carcinogenicity screening
The Ames Test — rapid mutagenicity and carcinogenicity screening
A biological assay to evaluate the mutagenic potential of chemical compounds — and by extension, their carcinogenic potential.
How the Ames Test works
The Ames Test uses specially engineered strains of Salmonella typhimurium that are unable to synthesise histidine (his⁻). When exposed to a mutagenic compound, the DNA is damaged and reverse mutations (revertants) occur at an increased rate — the revertant colonies grow on histidine-free medium and are counted. The test is performed with and without metabolic activation (rat liver S9 fraction) to detect both direct mutagens and promutagens that require metabolic activation to express their mutagenicity.
Why the Ames Test matters
Since cancer is frequently linked to DNA damage, the Ames Test also serves as a rapid surrogate assay for carcinogenic potential. Standard carcinogenicity tests in rodents take 2–3 years and cost hundreds of thousands of dollars. The Ames Test provides a preliminary indication in days — at a fraction of the cost — and is a required component of many chemical registration dossiers (REACH, US EPA, OECD 471).
Regulatory references: OECD 471 · EPA OPPTS 870.5100 · ICH S2(R1) · REACH Annex VII · EC Directive 2004/73/EC
Key ecotoxicological endpoints — what we calculate and report
Biogroup reports determine, calculate and interpret all standard ecotoxicological endpoints
EC₅₀
Effect Concentration 50%
Concentration causing 50% effect (immobilisation, growth inhibition, luminescence reduction) in the exposed population. The most widely used acute ecotoxicity endpoint.
LC₅₀
Lethal Concentration 50%
Concentration causing 50% mortality. Used for fish, invertebrates and earthworm acute tests. Calculated by Probit or logistic regression.
IC₅₀
Inhibitory Concentration 50%
Concentration causing 50% inhibition of the measured response (growth, photosynthesis, bioluminescence). Used for bacteria, algae and in vitro assays.
NOEC
No Observed Effect Concentration
Highest test concentration at which no statistically significant effect is observed relative to controls. Requires statistical analysis (Dunnett's or Williams' test).
LOEC
Lowest Observed Effect Concentration
Lowest test concentration at which a statistically significant effect is observed. The NOEC/LOEC pair defines the effective range.
FD / TU
Dilution Factor / Toxic Units
FD = minimum dilution factor at which the sample is not toxic. TU = 100/EC50. Direct input for effluent treatment design and discharge limit negotiation.
When ecotoxicity testing is required or recommended
⚖️ Required by regulation
• H14 hazardous characteristic — Ley 24.051 / Decree 831/93
• EIA for industrial projects discharging to surface water
• Discharge permits in environmentally sensitive receiving water bodies
• REACH chemical registration (Daphnia, algae, fish)
• Compostability certification — IRAM 29421:2019 / EN 13432
• Pesticide registration (SENASA / EPA ecotoxicity data)
✅ Recommended by good practice
• Effluent treatment validation — before and after treatment
• Remediation monitoring — verify cleanup goal achievement
• Due diligence — environmental liability assessment of contaminated sites
• Routine effluent monitoring — real-time quality control
• Product development — chemical and formulation safety screening
• Ecological risk assessment — contaminated sites (RBCA)
Reference methods and organisations
Internationally validated methods applied at Biogroup
OECD
Organisation for Economic Co-operation and Development
201 · 202 · 203 · 207 · 208 · 210 · 211 · 471 · 481 · TG 129 — the global standard for ecotoxicology
ISO
International Organization for Standardization
6341 · 7346 · 8692 · 10993-5 · 11268 · 11269 · 11348 — European and international methods
US EPA
Environmental Protection Agency
Method 600/9-78-018 · 821-R-02-012 · WET (Whole Effluent Toxicity) · SW-846 · OPPTS 870
ASTM
American Society for Testing and Materials
Standard bioassay methods for aquatic toxicology and sediment testing
IRAM / SW-846
Argentine and hazardous waste
IRAM standards · EPA SW-846 hazardous waste test methods (H14 ecotoxicity characteristic)
Related services
Daphnia · Microalgae · Vibrio · Fish · Earthworms · Plants · Ames Test · OECD · EPA · ISO
Need ecotoxicity testing for your effluent, waste or product?
From a single Daphnia EC50 to a full multi-trophic bioassay battery with the Ames Test — Biogroup delivers ecotoxicological evidence under the internationally validated methods accepted by Argentine and international regulators.
Request ecotoxicity testing →
📞 +54 341 425-6431 📞 +54 341 447-4486 ✉ biogroup@biogroup.com.ar 📍 3 de febrero 920 · Rosario, Argentina Mon–Fri 08:00–17:00