Ecotoxicity testing
NCIMB offers ecotoxicity testing using its multispecies microbial tests MARA and LumiMARA. The tests offer benefits in comparison to single species microbial testing, and are recommended by the UK’s Department of Business, Energy and Industrial Strategy (BEIS), as part of their preferred approach to the management of produced water from offshore installations.
MARA and LumiMARA for whole effluent testing of produced water
NCIMB's MARA and LumiMARA assays are used for whole effluent toxicity testing as part of a risk-based approach to produced water management. We offer a MARA and LumiMARA testing service at our Aberdeen laboratories.
The Oslo and Paris Commission (OSPAR) Recommendation 2012/5 required contracting parties, of which the UK is one, to implement a risk-based approach for the management of produced water from offshore installations. NCIMB’s MARA and LumiMARA bioassays are recommended by the UK’s Department of Business, Energy and Industrial Strategy (BEIS), as part of their preferred approach to achieving this. BEIS provide more information about the UK's risk-based approach programme, and guidance for the oil and gas industry on their website.
OSPAR is the organisation that manages international cooperation on the protection of the marine environment of the North-East Atlantic.
Trialled with samples from 15 offshore facilities
Increase the genetic diversity of ecotoxicity testing with one multispecies test
Using MARA and LumiMARA as an alternative to toxicity testing with a single species of bacteria is a very simple means of increasing the breadth and genetic diversity of toxicity testing, and may give more robust results. Test results have been found to be highly reproducible.
Our work with oilfield clients has illustrated additional benefits of using MARA to manage effluents. For example, MARA and LumiMARA can be used to track changes in the toxicity profile of produced water following changes in additives such as corrosion inhibitors. We have also undertaken work to evaluate the potential of using MARA and LumiMARA to assess biocides efficacy.
MARA and LumiMARA testing procedure
The MARA test includes ten species of bacteria and one yeast, freeze dried in a micro-titre plate. During testing the microorganisms are exposed to a concentration gradient of the test sample and incubated for 18 hours along with growth media and redox dye. Growth of the microorganisms is then measured by assessing reduction of the dye through the use of a scanned image or plate reader and NCIMB’s MARA analysis software.
LumiMARA uses 11 species of naturally occurring bioluminescent bacteria. When these bacteria are exposed to toxins, their luminescence is reduced and this can be used as a rapid and direct measure of toxicity. The bacteria are exposed to a concentration gradient of test sample and incubated for 15 minutes before the plate is read using a luminometer.
Plate readings from MARA and LumiMARA are used to calculate the microbial toxic concentration (MTC). MTC is a measure of inhibition equivalent to an EC50 value. It is used for MARA and LumiMARA because it has a number of benefits including elimination of interpolation errors of classic EC50 determination.
Risk based approach to produced water management
All substances present in produced water will contribute to the total environmental risk, and implementation of a risk-based approach requires measurement of known substances to be combined with whole effluent toxicity testing, in order to assess the impact of unknown substances and the combined effects of all components. While companies operating in the UKCS had historically been undertaking chemical analysis as part of the biannual testing program, whole effluent toxicity testing was a new requirement.
Need chemical analysis to complement your ecotoxicity testing?
We can undertake a range of chemical analyses at our laboratories in Aberdeen including:
- Total hydrocarbon content
- Chemical oxygen demand (COD)
- Biological oxygen demand (BOD)
- pH
- Sulphide/sulphate
- Chloride/chlorine
- Dissolved oxygen
- Total suspended solids
We can also source and manage additional services where required in order to deliver comprehensive, bespoke, one-stop-shop waste and effluent testing package.
