At one with nature
Some chemical companies have special reasons for caring about the sites where they carry out their operations, says Sarah Houlton
These days, all chemical companies have to be extremely careful about what they put out into the environment. Ever more stringent emissions legislation is only part of the reason - their neighbours are increasingly unlikely to tolerate the sort of black clouds and water pollution problems that were routinely created by chemical plants just a few decades ago. But some companies have an added need for care - they have a site of special scientific interest, or SSSI, on or right next to their plant.
A SSSI is an area that has interesting flora, fauna, geological or physiographical features, and under the 1981 Wildlife and Countryside Act, the government has a duty to designate as a SSSI land that fits these criteria. SSSIs are designated by English Nature, Scottish National Heritage, the Countryside Council for Wales or the Department of the Environment in Northern Ireland. The sites are given protection against operations that might damage them, such as drainage work, pesticide spraying or tree felling. The Countryside and Rights of Way Act increased the legal powers of the designating bodies to refuse consent for damaging operations, and to take action if neglect or inappropriate management lead to damage.
Just outside the busy coastal town of Harwich, in the Essex countryside, is a chemical factory. You'd be hard pressed to notice it from the road, or even on the mile-long drive down the access road from the gatehouse as you dodge the free-roaming pheasants and rabbits. But right in the heart of a 900 acre [3.6km2] site of woodland and arable farmland, lies exchem organics' fine chemical plant.
The site's industrial use began in 1905 when an explosives factory was built. With a dearth of large civil engineering contracts and the near-demise of the UK mining industry, the demand for explosives has plummeted. But the essential chemistries needed to make explosives, such as nitration, can be applied in other areas, and now much of exchem's plant is filled with energetic chemistry making fine chemicals as fuel additives and pharmaceutical intermediates.
The discovery of the rare Fisher's estuarine moth on the site in the 1960s led to its designation as a SSSI. The whole area is protected, with the exception of a 10 acre plot where the actual chemical production takes place. 'The SSSI is just metres away from our production facilities,' says exchem's CEO Malcolm Braithwaite. 'Because we're on a SSSI, we must look at our processing extremely carefully. We're classified as a top tier COMAH (Control of Major Accident Hazard regulations) site because of the explosives and oxidisers we use, and so we have to demonstrate to the Health and Safety Executive and the Environment Agency that we have procedures in place to manage any untoward incident that may occur'.
As well as the SSSI designation, Hamford Water, on which the plant is situated, is on the Ramsar Convention list of Wetlands of International Importance. In winter, it is home to a wide variety of birds, like redshanks, Brent geese, black-tailed godwits and ringed plovers. The company even 'adopted' three orphaned barn owl chicks a couple of years ago, and one returned this year with his mate to nest in one of the owl boxes on the site alongside two other breeding pairs. A growing colony of seals - 61 at the last count - lives on the mudflats. And the extremely rare southern marsh orchid grows on the site, along with large quantities of hog's fennel, on which the moth feeds.
exchem contracted environmental and engineering consultancy Entec to survey the fauna on the site around the end of the wastewater emission pipe. It reported that 'the animals found at each site around the sea wall were characteristic of a relatively unpolluted sheltered creek in south-east England'. Clearly, the measures taken at exchem to ensure the cleanliness and safety of its manufacturing operations are ensuring the continued health of the sensitive area in which it is situated. Indeed, exchem won the Chemical Industries Association's Responsible Care award for the Most Improved Site in 2000 in recognition of its environmental work.
A much larger site with SSSI protection is hidden behind a tree belt between the New Forest and Southampton Water. Esso's huge petrochemical complex at Fawley was developed after World War II on the site of a small 1921-built refinery. The developers had the vision to extend a strip of ancient woodland around the land side of the plant, and it now contains 46,000 trees and shrubs. April sees the ground within the tree belt covered by a carpet of bluebells, and it is home to deer, rabbits, and even snakes. It provides a very effective screen, to the extent that one can walk down the road past the trees and have no idea that there is a huge petrochemical complex a matter of metres away.
Perhaps the most remarkable part of the site, however, is the SSSI recovered saltmarsh sited right next to the plant's effluent outfalls. 'Although we operated up to the standards of the day when the modern plant first opened in 1951, there is no doubt we killed the saltmarsh,' says the site's environmental group head Dave Dando. By the 1960s and 1970s, management began to worry about the impact the plant's operations were having on the saltmarsh, and began an environmental monitoring and rejuvenation programme to improve the quality of the effluent put out into Southampton Water.
A saltmarsh is a marshy area that is overwashed by sea, and has been colonised by salt-tolerant plants. However, it is a complex ecosystem, where the plants that first colonise bare intertidal mud trap silt in their stems and roots. This gradually builds up the level of the marsh, and slowly other plants, less tolerant to the washing of the sea, move in. The nutrients that the marsh gains from the washing stimulate plant growth, creating a food source for invertebrates, fish and birds. Many migratory and over-wintering birds rely on this source of food, and others even nest on the saltmarshes.
Esso's regeneration of the saltmarsh at Fawley is proof that it is possible to remediate serious pollution problems. Part of the solution was to reduce the amount of oil that was put out in the effluent; Dando says that the oil level in the effluent exiting the outfalls is now a mere 5 per cent of the level it was in 1980. The legal limit for oil in the effluent was 60-70mg l-1; the Environment Agency's limit is now 5mg l-1, and the typical amount in the outfalls now is 0.7mg l-1. The two main outfalls each put out 7000-10,000m3 per hour, so the absolute volume of oil is now minimal compared with three decades ago.
However, active intervention was also needed for the saltmarsh to recover. Esso employed specialist marine biologists, who began a programme of transplanting clumps of Spartina marsh grass from healthy areas. Over several years, the grass spread naturally, both by seeding and from the roots, and now forms a healthy carpet on top of the marsh.
In the real world, an oil spill is always a possibility, regardless of how much care is taken, and Esso has established a plan for cleaning up any spill on the marsh causing as little damage as possible. Perhaps surprisingly, Dando says that they would not go onto the marsh to clean it off. 'This would cause even more damage,' he explains. 'Instead, we would encourage the oil to come back off the saltmarsh, maybe by cold water washing with a hose, and then pick it up once it reaches Southampton Water.'
But what about the birds that roost and feed there - how would they be protected from the oil? 'Simple - we'd put up bird scarers to chase them off,' he explains. 'Last time it happened, we flew falcons. It was originally suggested as a joke - but it worked.' The oil would cause some die-back in the plants, he adds, but the roots would survive and they would soon grow back.
Today, the saltmarsh is very healthy, with about 95 per cent plant cover. Its regeneration proves that it is possible for sensitive natural sites to co-exist with the chemical industry. It just takes a realisation that some practices of the past are unacceptable, and with thought and care there is no reason why a chemical plant should be detrimental to the environment.
One of the UK's largest chemical complexes is also in close proximity to a large expanse of sensitive environment. Teesside is home to numerous chemical factories and a surprising amount of flora and fauna on the SSSIs that surround the factories. Before the Industrial Revolution and the advent of the railways brought industry to the Tees estuary, hundreds of common seals bred on Seal Sands, and the estuary was home to many species of birds. But little attention was paid to the environmental consequences of the developments, and the seals departed in the middle of the 19th century.
Back in 1988, ICI and the Nature Conservancy Council (now English Nature) established Inca, the Industry and Nature Conservation Association. Its aim is 'to ensure that the growth of industry and commerce occurs in partnership with nature conservation, and as part of that process to enhance the natural environment so that everybody in Teesside can benefit from prosperity in an improving environment'. As well as local industry, its members include the Environment Agency, the National Rivers Authority, local authorities, the Royal Society for the Protection of Birds and other wildlife groups. 'All of the companies directly on the estuary are members, as are most of the others nearby,' says Inca's industrial ecology consultant Ken Smith. 'And the new companies who have bought parts of ICI, like Huntsman and DuPont, joined straight away as they realised the benefits'.
Nature has proved rather more resilient than could have been anticipated. For example, the alkaline soil created by the old slag and lime slurry areas are home to various types of orchid, which provide a spread of colour when they flower. Many species of birds are regular visitors, with waders like dunlins, ringed plovers and curlews being joined by Sandwich terns passing through on their migratory journeys. And a colony of rare little terns live on the nearby beaches. The seals became regular visitors once more in the 1960s. Harbour seals are now breeding there again, and about 70 now live on the estuary, alongside a handful of grey seals that have migrated from the Wash in search of fish.
A big influence on the return of the seals was the clean-up of the river water. When they disappeared, it contained maybe 2 per cent cyanide. This largely came from the local steelworks' coke ovens, and killed the fish that the seals fed on. Almost all of the coke ovens have now gone, and the one that remains puts out much cleaner effluent, so now cyanide levels are minimal.
The past three decades or so have seen a huge improvement in water quality in the Tees. 'Back in the 1960s in ICI's environmental department, we reckoned that the biological oxygen demand on the Tees was around 500t a day, which meant that there was an 8km stretch of river around Middlesbrough and Stockton that was almost totally deoxygenated,' explains Smith. 'At some times during a hot day in the summer, there was zero oxygen in the river. So industry and the river authority got together to clean the river up. Our target was to get migratory fish, particularly salmon and sea trout, back into the river by 2000. I didn't think we'd make it, but they began to migrate up the Tees again in 1997. It took around 30 years to clean the river up enough to attract the fish back.'
Smith was instrumental in Inca's establishment in his role as ecologist at ICI, and explains that one area where Inca has had very noticeable benefits is in the avoidance of public inquiries. 'All parties go into a public inquiry with entrenched views, and it costs a fortune, much of which goes to the lawyers. Amoco wanted to build a pipeline from the North Sea to fire a new gas-fired power station for the Wilton complex. However, it had to come through a sand dune at South Gare that is designated a SSSI. Before Inca, this would certainly have led to a public inquiry. But by working with Amoco, we managed to avoid the inquiry. The pipeline was put in and the sand dune restored. This was in the early 1990s - and now you cannot tell that there is a pipeline there'.
Source: Chemistry in Britain
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Science writer, Journalist (freelance based in London)
Department of chemistry at the University of Cambridge