Understanding your WAC colour-coding

Chemtech Environmental’s WAC reports are designed to highlight when a value exceeds one of the limits provided by the standard. Below are some notes to enable you to understand how and why the numbers achieve a colour so that you can best interpret your results.

In the example below, there are two results where the 10:1 mg/kg value does not have any colour-coding active. Antimony has achieved a value below the limit of detection (LoD) which in turn is below the Inert Waste limit. Similarly, Arsenic has a result of 0.019 which is below the Inert Waste limit of 0.5, therefore the box does not change colour.

If there is a higher Antimony result, as per the report below, the box will change colour. With a 10:1 mg/kg result of 0.084, results have now exceeded the Inert Waste limit but are still within the threshold of Non-reactive Hazardous Waste, so the cell is highlighted in yellow to indicate the result is above the Inert Waste limit (also highlighted in yellow).

This same rule is applied with Non-reactive Hazardous Waste and Hazardous Waste. Once a limit has been exceeded, it will be colour-coded according to correspond with the heading above the limit values as demonstrated below.

Basically, a result will be coloured to the lowest of the threshold values exceeded. If it’s blank, then no breaches are recorded.

We provide this colour-coding system to all WAC reports by default but if you’re not a fan, we can turn it off too! Contact us at or give us a call on 01207 528578 and we’ll get it sorted for you.

EBI : ‘Who We Are’

Cawood joined Ensign-Bickford Industries (EBI) last year as part of its Diagnostic Solutions Group. As part of the Cawood group we are looking forward to growing significantly and further expanding our capabilities and capacity with EBI’s support. With services spanning pet food science, space and defence, and diagnostic solutions, EBI is a global science and technology leader. To learn more about who they are and what they do, grab a brew and take 5 minutes to watch the video.

Chemtech are Tickled Pink

It’s not often we get the inside track on why we’re carrying out testing or details of the wider project. So we were delighted to learn recently that one of our customers has landed a contract with London Zoo. The first samples have arrived and apparently they’re from the Flamingo enclosure. More samples from different animal enclosures to follow soon…

NEW: 2D Chromatograms

As we move towards the use of GCxGC-FID for TPH-CWG analysis we will be changing how we supply chromatograms. Traditional GC-FID methods would provide either a single trace/chromatogram for total TPH or two separate traces/chromatograms detailing the aromatic and aliphatic constituents. With GCxGC we can effectively do both in a single image.

GCxGC uses 2D imaging as we have two ‘dimensions’ of separation during the chromatographic process. Analytes are separated over time as is traditional, but using a second polar column each time the separated fraction is then split further into the various aliphatic and aromatic species.

The 2D image here is a Diesel and Mineral Oil Standard. The peaks split in the horizontal direction over the 26-minute run time but there is a second axis of separation as those peaks are further spread out based on the nature of the species present.

Along the back of the ‘box’ there is a single white trace which is the equivalent of the more traditional Total TPH trace; essentially a sum of all the various species present.

We’re Supporting Willow Burn

We’re delighted to announce that we have selected Willow Burn Hospice as our chosen charity to support this year. And what better timing as they launch Willow Week (9-15 May); an annual fundraising and awareness week which was launched in 2020 to shine a light on the vital work of the hospice.

Willow Burn was founded over thirty years ago by two local women who recognised a need for improved end of life care for residents of rural County Durham.

Their aim is to relieve physical and emotional distress and control symptoms, provide care comfort and compassion at the end of life to embrace and support patients, and their families and friends to achieve this. Vital services include a range of holistic day care, in-patient services and family support and bereavement counselling services.

As a company with a philosophy of care at it’s core, we could think of no better pairing and look forward to contributing to the fantastic efforts of staff and volunteers at Willow Burn.

01207 528 578

Unit 6 Parkhead
Greencroft Industrial Park
County Durham



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