Direct Toxicity Assessment (DTA)


Ecotoxicity Testing

Ecospan undertake ecotoxicity testing forOyster ecotoxicity testing Direct Toxicity Assessment (DTA) tests and RBA testing of produced waters. We have over 25 years of experience of completing ecotoxicity testing using a wide variety of species ranging from bacterial and algal assays through to chronic invertebrate testing. Ecospan Environmental Ltd is MCerts approved by the Environment Agency to undertake all DTA tests with marine and freshwater species. We also have extensive experience of ecotoxicity risk assessment having successfully completed such projects for a multitude of large chemical manufactures and petrochemical sites.

Testing capabilities:
  Freshwater Species Marine Species
Algal Growth inhibition test Raphidocelis subcapitata (72 hour EC50) Skeletonema costatum (72 hour EC50)
Acute invertebrate Daphnia magna (48hour LC50) Tisbe battagliai (48hour LC50)
Acartia tonsa (48hour LC50)
Subleathal invertebrate   Crassostrea gigas Oyster Embryo development test (24 hour EC50)
Chronic invertebrate Daphnia magna growth and reproduction 21 day Tisbe battagliai reproduction(EC50)
Sediment reworker   Corphium volutator (10 day LC50)


Direct ToAlgae ecotoxicity testingxicity Assessment (DTA)

All complex effluent discharges to controlled waters over 10 m3/day are required to undergo DTA. This has been implemented by the EA and SEPA through Environmental Permitting Regulations (previously IPPC). All testing must be carried out by an MCERTS approved laboratory using designated methods. The results of these tests are used to determine the acute environmental risk associated with the discharge. Ecospan Environmental is MCERTS approved by the EA to undertake Direct Toxicity Assessment testing.

Our staff have extensive experience in DTA, having been involved in both the demonstration project and in the development of the technical guidance. Over the years we have established a good rapport with the regulators which enables us to design testing protocols tailored to each discharge and produce risk assessments detailing the potential impacts of the effluent. Our team also have experience of critically reviewing existing data to assess its quality and ensure businesses are not burdened by unnecessary testing. This often involves undertaking a comprehensive environmental risk assessment. If chronic or population effects need to be considered (e.g. discharge into a SPA or SSSI), Ecospan can design and undertake ecological surveys to quantify any impact on the receiving environment.

RBA testing

A Risk Based Approach (RBA) for the management of produced water (PW) discharges from offshore installations has been introduced by the Department for Energy and Climate Change in the UK. Ecospan Environmental Limited have the expertise to undertake ecotoxicity testing of produced water as required for RBA in accordance with published guidelines.

On-site testingAcartia ecotoxicity testing

Where toxicity could arise from multiple sources, or sites are required to investigate the sources of toxicity within their operation, our on-site testing service offers a very cost effective solution. Up to 100 samples can be tested over a working week enabling the toxicity contributions and variability from multiple drains to be fully investigated. The large number of samples that can be tested can also be used to identify the principal toxicant source(s). Additionally, toxicity identification evaluations (TIE) may be undertaken to characterise the type of toxicant present.

Recent Projects