Letters: May 2023

Crustacean mortality event

The March 2023 edition contained an article commenting on the crustacean mortality event, which occurred between September and December 2021 in the North East of England. As members of the independent panel that produced the report, we feel that this article misrepresents the work of the panel and makes unsubstantiated insinuations of the panel’s independence.

The timescale for the panel to review data was very short, and undertaking new work was not an option. However, available data was scrutinised and discussed, with a large number of requests for additional information as the panel progressed its work. On the basis of the available information a number of possible scenarios were rigorously evaluated to identify the most likely causes and implications for recurrence. No potential cause was ‘dismissed’, as the article states, but was assessed for likelihood, as defined by the Intergovernmental Panel on Climate Change likelihood scale. While a previously unknown pathogen was deemed to have the highest probability of causing the mortality event, it was still given a likelihood of ‘About as likely as not’ (33–66% probability). The panel was as frustrated as any other parties not to be able to identify the cause of this tragic event.

Pyridine continues to be identified by other parties as a likely cause of the mortality events but there is no credible evidence for this. As the report states, seawater measurements by the Environment Agency and York University made during and beyond the incident period did not detect pyridine. Very low levels were observed in sediments in Teesmouth. Modelling based on the release of a large volume of pyridine was considered by the panel but found to be significantly below the level required for crab mortality, while the dredging volumes were several orders of magnitude lower than those required to release pyridine concentrations at toxic levels. Pyridine is soluble in water and an assertion that it could sorb preferentially to sediment particles and spread through the coastal water column in that way is contrary to the known characteristics of this chemical.

Finally, the assertion of Dr Caldwell that the panel was not independent was reported uncritically, casting aspersions on the professionalism and integrity of panel members. All members were invited to join, and the composition of the panel reflected the need for a range of expertise and experience. It is routine for governments and external organisations to request input from academic researchers and consultants where they have the expertise and infrastructure to provide input and undertake the research required. Any potential conflicts of interest were requested at initial meetings and are published as Annex B to the report.

The mass mortality of crustaceans in this incident was tragic and the desire of the local fishing community to find a credible cause is understandable. However, uncritically accepting an article that questions the integrity of other professionals without foundation and makes assertions on the role of a chemical that do not stand up to scrutiny, does not represent progress. Chemistry World is the magazine of the Royal Society of Chemistry, and this article falls below the standards our community can reasonably expect.

Mark Fitzsimons CChem FRSC
Marine Institute, University of Plymouth, UK

Crispin Halsall CChem FRSC
Lancaster Environment Centre, Lancaster University, UK

Editor’s response: Our article sought to convey a number of different scientific viewpoints on this case. As well as covering the report’s findings and the criticisms of the report, it included comment from an independent expert, whose opinion was that the panel’s conclusion was reasonable. However, the article’s simplification of the panel’s assessments of likelihood led to inaccuracy. And the inclusion of the comment that the panel was not wholly independent should at least have been presented with the additonal context of the panel’s membership. We apologise for any suggestion that panel members did not conduct themselves with integrity. 

Mentoring memories

Recent letters of longevity and contrasts of early experiences of laboratory life compared with today make interesting reading, further emphasised by the report of Donald Sarfas’s great age and (probable) record of 78 years of Royal Society of Chemistry membership. As Sarfas’s lab assistant from late 1950 for two years, memories are strong.

I joined ICI Dyestuffs at Blackley, UK, in 1949 as a 16-year-old, first supervised by the martinet Harold France. The teaching was rigorous, disciplined and meticulous. Glassware at the time was mostly assembled with corks and bungs, whereas our bench had the best assembly of ground glass joint equipment in Blackley (kept in locked cupboards, each marked with ‘HF’, much to the chagrin of all others), made possible by Dr France’s control of the site’s annual Quickfit and Quartz budget. Disagreeing with Dr France was a major error. It resulted in ever-increasing expertise with cork borers.

Working for Mr Sarfas was much less demanding, most days involving little more than setting up four simultaneous open-beaker experiments, filtering, drying and powdering the products for submission to the dyehouse for ongoing testing. Nevertheless, much else was learned. I enrolled at night school for the Ordinary National Certificate (ONC), with inputs from Mr Sarfas (he also taught ONC classes two nights a week), and eventually progressed to Higher National Certificate and a target of Licentiate.

After two years’ interruption for National Service and a transfer to the pharmaceutical division at Alderley Park, career progress was meagre: still only one grade higher than lab assistant. Without a university degree, the chance of promotion was virtually zero. It was time for a change, the key being a one-year conversion course to chemical engineering, advertised by the newly created Bradford College of Advanced Technology.

As a junior engineer for Manchester-based Petrocarbon Developments (PCD), the post swiftly evolved into establishing an R&D group, its mandate to investigate and develop a breathtaking number of widely differing inquiries. The opportunity resulted in several commercially exploited solutions, and the reward for my success was a company-supported PhD.

During this period PCD was acquired by Burmah Oil, resulting in an even more rapid promotion to Head of Group R&D on my return: the result of serendipity, seeking opportunities, but – most importantly – the support of a series of excellent mentors.

Ken Jones
Via email

Allotrope hopes

Regarding the new study that challenges the traditional free electron gas model, it is simplistic to say metals crystallise in face-centred cubic, hexagonal or body-centred cubic structures. Many metals have more than one allotropic form, some metal structures change with temperature and some have orthorhombic, monoclinic or more complex forms. For example, a form of gallium has 40 atoms per unit cell.

Interatomic forces ‘encourage’ metal atoms to crystallise into closest or near to closest packing. We do not need a theory to explain why metals crystaIlise into simple forms, what we need is a theory to interpret why some metals, for example uranium, crystallise into many complex allotropes. Although there are errors in its fundamental assumptions, the Drude–Sommerfeld free electron gas model helps us understand Ohm’s law. There are other models such as the soft sphere model of metals that have been used to calculate reliably bond lengths, work functions, enthalpy of formation of M^x+ ions, densities, coefficients of expansion etc and to show there are four components in metallic bonding. I wait with anticipation for the writer to enlighten me on how this new model can explain why manganese has so many allotropes and α-manganese has 58 atoms per unit cell. 

Peter Lang
Woodford Green

PVC processing

The article on generating chlorine for practical uses from waste streams of PVC articles shows the benefits of ongoing R&D projects on well-established materials and, in particular, how waste can be used for the (re)generation of chemicals that are critical for society.

However, some parts of the article were less accurate. In particular it states that ‘despite huge amounts of PVC being made every year it is widely considered the most hazardous plastic and is not usually recycled’. Suspension PVC resin – which accounts for the majority of PVC resin used and includes the mainstream applications of pipes and widow profiles – is about 99.7% weight by weight PVC and as such is not classified as hazardous under the classification, labelling and packaging (CLP) regulation. Thermal processing can indeed degrade the polymer, but this is why it is never used unstabilised. While some additives, such as the DEHP mentioned in the article, have been classified as hazardous these are now generally absent from the market (apart from, importantly, in recycling streams) and have been replaced by non-hazardous alternatives. There is also no mention of the Vinyl+ project which has developed recycling streams throughout Europe and the UK and now accounts for over 800,000 tonnes of recycled PVC in Europe. I don’t think this is ‘not usually recycled’.

Of course PVC can be recycled: it’s a thermoplastic! It’s true that some of the recycling streams can present challenges but this arises from the fact that PVC particles are generally long-life ones, so material in the recycling streams is often from the 1906s and 1970s and representative of the markets and technologies of that day. As the title of the article indicates, that is no reason not to look for innovative ways of finding solutions, something that the industry continues to do unabated.

Chris Howick CChem FRSC
Via email

History repeats itself 

Reading about glycol-contaminated cough syrup reminded me of a similar adulteration to sweeten poor quality Austrian white wine with ‘trace’ amounts of diethylene glycol in 1985. At the time, some brands even won gold medals !

Fortunately, there were no reported health problems but the UK popular press sensationalised it as contamination with the more toxic car radiator antifreeze – ethylene glycol – and Austrian wine disappeared from UK shelves.

Alan Dillarstone FRSC CChem
Via email

Patent court pending

I applaud your publicising the biggest shake-up in the European patent landscape for years, the Unified Patent Court (UPC). That said, this shake-up (which has now been postponed to June 2023) introduces two related but fundamentally distinct concepts which should not be conflated.

One is the UPC itself: as indicated, this will be a centralised court for litigating granted European patents, with decisions (like central revocation – a key risk for patentees) being enforceable across all UPC member states. This markedly contrasts with current piecemeal country-by-country litigation.

It was decided (not without controversy) that all patents granted under the European Patent Convention (EPC), including those already granted, will fall under the UPC’s jurisdiction by default. Enter the seven-year transition period: within this period, or pre-emptively within the ‘sunrise period’, patentees can ‘opt-out’ their European patents, removing them from the jurisdiction of the UPC and its associated risks.

The other concept, the Unitary Patent (UP), will be a single patent right applying to all UP states. In contrast to the article’s wording, the UP will always be optional; patentees wishing to validate ‘traditionally’ with bundles of separate national rights in UP states will always be able to do so. Importantly, litigating UPs will only be possible at the UPC: UPs cannot be opted-out.

Additionally, UPs do not (for now) avoid the need for further translations. Indeed, patentees seeking a UP must file (within a notably short timeframe post-grant) a human-made translation of the entire patent specification into another EU language. ‘Traditional’ validation in many EPC states requires only the patent claims to be translated, or no translation at all.

Finally, it is worth remembering that beyond the UPC/UP states (the UK, for example), the European patent system will remain business as usual.

Pip Hellier MRSC
Martock, UK

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