March 2024

Apologies for the dearth of newsletters over the last nine months but we have been a bit busy – so lots to report on. 
In this edition, we have news about: 
•    The April and June waste classification courses & HazWasteOnline Certification
•    Updates to the GB MCL List 
•    Classifying PFAS compounds
•    Changes (for some) to the classification of Dioxins/Furans and the 12 WHO PCBs (dioxin-like PCBs)
•    New Statistics module 
•    Statistics Module Webinar  – 16 April 2024
•    New Features
     –    Batching hwol files
     –    2 new PAH double ratio plots and ellipse management
•    In Development    
     –    GIS module 
     –    Irish Soil Recovery Facilities – thresholds
•    HWOL Lab Liaison Group
•    Revised HWOL data file specification – V2.0

Our web-based training courses are held every 2 months. Once completed, your classification reports will show that you are CERTIFIED in waste classification and the use of HazWasteOnline. 

Information about the courses can be found here:
The next available dates are: 
•    3th- 4th April 2024 – Hazardous waste classification.
•    2nd April 2024- Refresher – for those who completed our 2-day course more than 3 years ago  

•    5th – 6th June 2024 – Hazardous waste classification.
•    4th June 2024 – Refresher – for those who completed our 2-day course more than 3 years ago.
If you wish to book a place, please follow the link to our online booking form:

 Updates to the GB CLP’s MCL list 

In the last 6 months there have been three updates to the original GB MCL list:

  • Version 2.0 – 20th October 2023 – revised 42 substances and added 61 new substances
  • Version 3.0 – 11th January 2024 –  updates for 90 substances, from ATP 14 and 15, that were not properly retained in GB law
  • Version 4.0 – 2nd March 2024 – new and revised classifications for 25 substances

HazWasteOnline’s database has been updated to reflect and record these changes.
Two examples of potential interest from the October revision:
•  vanadium pentoxide is now hazardous at 560.2 mg/kg of vanadium (HP7 Carcinogenic) whereas it was hazardous at  5,602 mg/kg vanadium (HP5, HP11).
•  tellurium and tellurium dioxide (HP10 toxic for reproduction, 0.3%) have been added 
Note that in the EU CLP (which impacts classifiers in all EU nations and Northern Ireland), these compounds had already been updated via ATP 18 in February 2022.

PFAS Compounds

We have been getting questions on how to assess the PFAS group of chemicals (which includes PFOS, PFOA and PFHxS) in HazWasteOnline and why not all the POPS, including PFOS, isn’t in our example waste stream template. 

1. The POPs included in the example waste stream template for soils are only the dioxins/furans and the 14 POPS referenced in the waste legislation (Decision 2014/955/EU) and subsequently in the WM3 technical guidance. With respect to classification of waste as hazardous/non-hazardous; if any of these 14 POPs exceeds the 50 mg/kg concentration limits or the 15 μg/kg (UK); 5 μg/kg (EU) limit (see below) for the dioxins/furans, then the waste is hazardous and the hazardous mirror entry is selected.

2. The POPs legislation (Regulation EC 850/2004; recast in Regulation (EU) 2019/1021), lists a further 7 POPS including PFOS, PFOA and PFHxS. If the waste contains any of the dioxins/furans or the 21 POPs above the stated POPs threshold, then the POPs legislation requires that the waste be incinerated and the POPs destroyed. This means that;
a. you can have waste classified as hazardous with one or more POPs above a POPs threshold that has to be destroyed, or
b. you can also have a waste classified as non-hazardous but with one or more of the non-WM3 specified POPS above a POPs threshold that has to be destroyed.

3. Entries for PFOS and PFOA are listed in Annex VI of the CLP (EU Table 3 or the GB MCL list) and can be added to a waste stream templates and/or a Job in HazWasteOnline. 

4. HazWasteOnline’s Wiki page: Persistent Organic Pollutants describes the POPs in the POPs legislation and the sub-set of POPs in WM3 in more detail. 

5. With respect to PFAS group of chemicals, HazWasteOnline’s Wiki page:  “The PFAS (PFOA, PFOS, PFHxS) group of chemicals” explains what these compounds are and which of the PFAS compounds specified in the POPs legislation can be found in the CLP Annex VI (Table 3 / MCL list) and which are not present in the CLP. Those that are not present would need to be self-classified by the classifier, with the relevant hazard statements added to a user-defined substance.

Dioxins/Furans and the 12 WHO PCBs (dioxin-like PCBs)

We have updated the two EU classification engines (EU WM3 v1.1.NI and EU/2018/C 124/01 and the corresponding example templates for soils in HazWasteOnline) to reflect the changes to the POPs legislation introduced by  Regulation (EU) 2022/2400. This legislation reduces the dioxins/furans threshold from 15 μg/kg to 5 μg/kg and also includes the 12 WHO dioxin-like PCBs in the calculations.

The two UK classification engines (WM3 v1.2.GB and WWM3 v1.1.NI) are unchanged as the UK government is undertaking a consultation as to these potential amendments and hasn’t updated the UK POPs regulation.

More information can be found in the HazWasteOnline Wiki

Statistics Module

We have recently finished building a statistics and graphing module for waste classifiers. The module is applicable for all chapters of the List of Waste except for those entries in Chapter 17 Construction and Demolition Wastes. 

The reason that it can’t be used for Chapter 17 wastes is that it is much more difficult to define a statistical population and we don’t currently have the tools to manage/enforce populations for soils, made ground, clinker layers etc. ]

The statistical analysis uses the parametric method described in WM3, Appendix D to work out the 90% confidence interval of the mean for both determinands and hazard properties. To manage cut-off thresholds, we have had to also apply the same method to managing determinands with results crossing the cut-off thresholds for additive hazard properties: effectively we assess the data for a determinand and use the 90% confidence interval to determine whether the determinand should be included in the additive calculations for HP14 HP8, HP6, HP5 or HP4. 

Three types of plot can be generated:
1. Statistical plot for individual determinands (Figure 1).

2. Statistical plots for both individual (Figure 2) and additive (Figure 3) hazard properties.

3. Series plots showing variation of one or more determinands by sample (Figure 4).
Figure 1. Presentation of the statistics for an individual determinand; in this example, it’s for the group entry; lead compounds. Note the Y-axis is in mg/kg and reflects the either the compound (or Note 1) concentrations

The plot has three areas to help understand and visualize the data:

1. Histogram of the data:
(a) HP threshold (red line labelled with Hazard Property) and
(b) HP cut-off (blue line labelled with Hazard Property), where relevant

2. Box Plot used to visualize the statistics: 
(a) Mean (black square) 
(b) Median (horizontal line in quartile box) 
(c) Upper & Lower Quartile (the rectangular box) 
(d) 90% confidence limit of the mean (vertical arrow) 
(e) Min/max range (whiskers in box plot), unless reset to show outliers which would be indicated by a black dot(s)

3. Statistics Table:  
(a) Number of data points
(b) Mean 
(c) Standard Deviation 
(d) RSD = relative standard deviation 
(e) IQR = Inter Quartile Range 
(f) 1.5 x IQR = Option to identify outliers and show as black dots 
(g) 90% confidence interval of the mean

The plot shows that the 90% confidence interval for this substance is above the  HP14 cut-off for H410 (0.1%) but below both the HP14 and HP10 hazardous thresholds (0.25%). [Note though that HP14 is additive so that when other ecotoxic substances are included in the HP14 assessment, they could exceed the HP14 threshold.
Figure 2. Presentation of the statistics for an individual hazard property; in this example HP10, showing four substances relative to the H360 threshold (0.3%). Note that the Y axis is now in %.

Figure 3.  Presentation of the statistics of a hazard property; in this example, all substances with ecotoxic hazard statements, analysed as per HP14’s Equation 3:

100 x Σ c H410 + 10 x Σ c H411 + Σ c H412 + Σ c H413 ≥ 25 %

In this example (based on only 6 samples), the analysis shows that the 90% confidence interval of the mean crosses the threshold for HP14, so this waste would be classified as hazardous by HP14.

Figure 4. Series plot that allows the concentrations one or more determinands to be displayed in a chart.

More information can be found in the HazWasteOnline Wiki.

Webinar – Statistics Module

We will be holding a lunchtime webinar to demonstrate the new statistics module.  It will be at 12:30 on Tuesday 16th April, using Zoom. 

If you are able to attend, please send an email to and we will send you a Zoom invite.

New features

There have been a number of new features added since the last newsletter:

1. Create a .hwol batch file to process multiple files

A simple tick box has been added to each .hwol file listing in the lab files page (Packages Edition) which allows you to process two or more files at the same time and create a batch file. This is more efficient and reliable than creating an equivalent batch file via a text editor.

2. PAH double ratio plots

PAH double ratio plots can be used to indicate the source of your hydrocarbon contamination and also whether you have more than one population (source) of PAHs/hydrocarbon contamination.

The existing PAH double ratio plot has been upgraded by:

  • Adding two new double ratio plots:
    • BaA/BaP v Fluoranthene/Pyrene
    • Chrysene/BaP v Fluoranthene/Pyrene
  • Adding the ellipses from Costa & Sauer 2005 1 to all three plots
  • Adding three new (HazWasteOnline 2023) ellipses for:
    • Pyrolyzed/incinerated municipal waste – mainly plastics
    • Refined coal tar in road paving materials (blacktop)
    • wood dust
  • Adding the ability to select which ellipses to show on a given plot
  • Adding a tick box to include one or more plots in your PDF report.

1 Costa, H.J. and Sauer, T.C. (2005). Forensic Approaches and Considerations in Identifying PAH Background. Environmental Forensics, 6, 9-16.
The example below shows the PAHs from samples of blacktop where the paving materials were bound together with a coal tar derivative rather than a bitumen binder. The majority of the results are within HazWasteOnline’s Refined Coal Tar /  Binder ellipse.

The same data are plotted below using the BaA/BaP v Fluoranthene/Pyrene ratio plot.

Note how using different ratio plots can help identify different populations. For this example, the ratios plot in/near both “Refined Coal Tar / Binder” ellipses but in only one of  Costa & Sauer’s “Urban Background” ellipses.

In development for 2024

1. Collections

Many subscribers (and also ourselves) want a way of collecting Jobs together to better manage them in HazWasteOnline; this might be to collate different areas of site investigation covered by multiple Jobs, to manage multiple Jobs for a given client or just for archiving old Jobs. Collections will also be able to contribute to the GIS module described below.

2. GIS module

We are building a GIS module to allow the spatial locations of samples and their haz/non-hazardous outcome to be shown on a site map and included in the report. As the Environment Agencies require a sampling plan, this will help meet that requirement. Using Collections, you will also be able to have different Jobs (samples) on the same GIS map.

The first version will use OpenStreetMap for the base maps (covers UK and ROI) and allow you to enter sample locations to populate the map. Other data sets such as the British Geological Survey’s soil geochemical data of England and Wales will be added as we locate the resources.

3. Irish Soil recovery facilities & thresholds

We are working to provide Irish subscribers with the ability to screen (and report) their lab results against the various prescribed thresholds for licensed soil recovery facilities in the Republic of Ireland.

As a follow on to this work, we are also planning to add the ability for classifiers to add their own thresholds to allow them to screening their data for other requirements they may have. 

HWOL data file specification V2.0

We have recently published a new version of the .hwol data file specification (Version 2.0 can be found here). The improvements will allow the HWOL labs to better document various parameters including;

1. Non-grindable/inert materials

Wastes can have material variously described as for example, stones >10mmm, “non-grindables” or “inerts” in them. These might be stones or nails etc. in a soil; glass, brick fragments, knives, forks, screws etc. in a bottom ash or copper wire and brass connectors in a heavy plastics waste stream.

Most lab reports don’t document whether any material has been removed or not, or if it has been removed whether the results have been corrected accordingly. This change will mean that we will understand what every labs does and correct accordingly to further optimise the classification.

2. Results above the upper limit of detection

Sometimes the results of tests can be above the upper limit of detection for a given test – for example a lab may report that a pH is greater than 12 but not the actual pH because the result is outside their calibration limits. This gives the waste classifier a challenge as HazWasteOnline cannot assess what is effectively an unknown number.

The revised specification will ensure that all labs report the >LOD results the same way, meaning that we will be better able to advise the classifier as to what to do.