Sequoia Scientific

Particle Tracer Studies

Sequoia Scientific has partnered with Partrac Ltd of Glasgow, Scotland to provide particle tracer studies.

Partrac has developed a method of coating particles with a fluorescent dye.  The dye is bound to the particles and does not come off when the particles are exposed to water. The particles can be manufactured with a range of size and density so as to better simulate real particles of interest.  The particles can also be made magnetic so that sampling can be done using large magnets.  In the past, tracer particles needed to be separated manually under a microscope.  A very slow and tedious process.  Using Partrac’s particles large samples of sediment can be processed quickly by adding a solvent to the sediment which brings the fluorescent dye into solution. Then a highly accurate optical fluorometer can be used to infer the amount of particles in the sediment.

Partrac provides specialist particle tracking services in support of a range of urban, fluvial, coastal and offshore environments. This provides information on source-sink areas, transport pathways, deposition centers, and particle flux.



  • Fluorescent, magnetic biodegradable tracer
  • Size range silts to cobbles
  • In situ capture

We help clients to define their problem, assess an appropriate particulate tracer and tracking approach, identify field collection methods and provide interpretive reports.

Partrac’s tracking capability is supported by our comprehensive in-house capacity for acquisition of supplementary data (e.g. flow, turbidity) together with numerical modeling. This enables us to provide an integrated service to map the transport of particulates in terrestrial, urban, fluvial and coastal environments.

  • Source – Sink Identification
  • Transport Pathway Visualisation
  • Environmental Impact Assessment
  • Soil Loss & Water Quality
  • Environmental Siltation Assessment
  • Particulate Flux Magnitude and Direction

Example Projects:

  • Contaminated sediment transport assessment (British Waterways)
  • Floc bed erosion/deposition (South Florida Water Management District)
  • Particulate run-off from road surface (Highways Agency)
  • Longshore drift rate assessment (Proudman Oceanographic Laboratory)
  • Assessment of Re-contamination of a Superfund site using sediment tracking.



All tracers are made from non-reactive natural materials and are non-hazardous. Material safety data sheets are available on request.

SIZE RANGE 0.050 – 25 mm

DENSITY RANGE 1005 – 4000 kg m-3


1) Normal colour

2) Fluorescent colour (yellow, pink, orange, blue [looks white in visible light])

3) Para-magnetic character (mass specific magnetic susceptibility, λ, 90,000 times beach sand)


Measurement of critical entrainment stress, settling velocity, size, density, avalanche angle

Unit cost is a function of order size, size distribution, density range and number of signatures.

Please contact us with your precise specifications.

CUSTOM ORDERS All our tracer batches are made to individual customers’ specifications.

Please contact us with your requirements.


Tel: +44 (0)141 552 3903

Software & Downloads