Copper in the spoil may bond with sulphur to producecopper sulphide, and reacts with ferric sulphate and water toproduce copper sulphate, iron sulphate and sulphur. Thesulphur then may bond with oxygen and water to producesulphuric acid as can be seen in the final equation.

Cu2S + 2 Fe2(SO4)3 + 2H2O ⇒ 2CuSO4 + 4FeSO4 + S

2S + 3O2 + 2H2O ⇒ 2H2SO4

From these equations it can be seen that many of thecompounds are reproduced, which means that some of thesereactions are cyclic. This can make it difficult to stop thereactions, which needs to be achieved fully, to completelyreclaim the site.

The effects to humans are very small, apart from the mineworkers, who may have inhaled metals through the collierydust and would have been at far greater a risk underground.The effects of the metals on vegetation can be more damaging.Only species tolerant to the metals and their compounds willbe able to locate on the spoil and the species present canidentify which contaminants are present. The level of plantmortality depends on the composition of the soil, nitratelevels, organic content, for example. For animals, problemsarise when levels in cells or blood rise to toxic levels, having adirect effect on their health. Very little can be done to removemetal particulate matter from a stream.

The area around Prestongrange consists of coarse grass,consistent with that of a coastline, and there is therefore noreason to suspect any high concentration levels are present inthe subsoil. If problems were to occur with high metalconcentrations, then ‘specialist’ vegetation may be used toreclaim the area. Examples of such plants include the sweetclover (Festuca arundinacea) and tamarisk (Tamarix pentandra).

Brick, Tile and Glass

The historical production of bricks at Prestongrange is the bestpreserved industrial monument with the exception of theCornish beam engine. The remaining Hoffman Kiln and thefoundations of the ‘beehive’ kilns show the extent to whichthis industry grew at Prestongrange. The brick, tile andporcelain industry is not as widely known as coal mining forits contaminative effects, but the chemicals used in finishingproducts and the heat generated through firing can have adetrimental effect on the environment.

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Clay was not dug at Prestongrange, it lies too close to thecoast and the underlying rock is Carboniferous in age; it wasimported from the Upper Birslie Plantation.10 The site ofPrestongrange was used due to its coal resources and Morrison’sHaven, at that time a gateway for exporting numerousproducts from all over the Lothians. Later, the harbourbecame useful for importing china clay from the south ofEngland, a cheaper and higher quality of clay.11

The extracted natural clay from the area around UpperBirslie is known as ‘Fireclay’ and the formula is [in most cases]Al2O3.Si2O2.2H2O being a form of Kaolinite clay. It comprisesapproximately 40% aluminium oxide, 45% silicon oxide and15% water. Also included in the clay varying but smallconcentrations of iron, magnesium, titanium sodium,potassium and free silica.12

The metals contained in the clay may be released into theenvironment and cause their own problems but the main by-product is hydrogen fluoride (HF). This substance which canattack concrete, glass, cast iron and other products containingsilica. It is used to increase the porosity of ceramics, polishglass and enamelling which are all processes used in industriesthat have been located at Prestongrange. Hydrogen fluoride inplants can cause mutations of the roots13 which may lead todeath of the plant. At the Prestongrange brickworks thereappears to be no indication of any detrimental effect on thevegetation around the kilns. Where the concrete around theHoffman Kiln and beehive kilns is cracked, vegetation isattempting to break through from beneath the surfaceindicating the subsurface is in a reasonably healthy condition.

Aluminium and silica (originally in the form of an oxide)may be leached out of any waste deposited in spoil heaps, andis therefore a potential hazard to the surrounding environ-ment. Heavy metals have been dealt with, but aluminium isalso a concern as it may combine with water and oxygen toform hydroxides and acids which in high enough con-centrations kill plants.

Glass is also a product of silica and silicates. The productionof glass is reported to have taken place at Morrison’s Havenfrom 1697 but lasted only a few years.14 The process ofmaking glass involves mixing silica (in sand), potash, zinc, andmetals for colouring, for example, iron (green) and cobalt(blue). Once mixed, the mixture is heated to extremely hightemperatures up to 1600 degrees Centigrade. 15

Using chemical elements such as iron, cobalt and selenium

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in the production of glass leads to problems of heavy metalcontamination and thermal pollution in the soil beneath thesurface. If there is heavy contamination, as has been seen in StHelens, Lancashire, then it may be necessary to remove someor all of the contaminated material from the site, or treat itwith bioremediation techniques on the site in question.

The long history of the Prestongrange colliery site andMorrison’s Haven means that there has been much activity onthe site and the movement of the ground material means thatany contaminants are more than likely untraceable back toone particular industry.

Figure 8 Beehive Kiln

Sulphuric Acid

There are records of sulphuric acid (oil of vitriol) beingproduced in Prestonpans from 1749 when John Roebuck andSamuel Garbett opened a plant. The primary use of the acidwas for the bleaching of linen as experiments had found it tobe faster than any other product of its time.6

The production of sulphuric acid was hazardous and thehealth effects on the workforce and the surrounding areacould be very damaging. Advancements in methods since thedays of Garbett and Roebuck means that production is nowsafe and environmental concerns are addressed, but the

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environmental impact of production in the eighteenth andnineteenth century received little or no attention.

Sulphuric acid is produced via one the following equationsequences.

● Sulphur burns in oxygen (air) to form sulphur dioxide

S + O2 ⇒ SO2

The gaseous acid is then put into solution, where it reacts withwater to form sulphurous acid:

SO2 + H2O ⇒ H2SO3

Using further oxygen, the sulphurous acid is then oxidised toform sulphuric acid:

H2SO3 + O ⇒ H2SO4

● Dissolving sodium trioxide in water

2S + 3O2 ⇒ 2 SO3

SO3 + H2O ⇒ H2SO4

Neither of these procedures are one hundred per centefficient and therefore gases escape into the environmenthaving health effects on both humans and vegetation. Theeffects of sulphuric acid on humans are extreme. Small dropsinternally are usually fatal and inhaling the vapour may causeserious lung damage.16

Further to this, combined with the production of salt, otherharmful chemicals are produced. Sodium chloride (foundnaturally in seawater), when mixed with sulphuric acid formssodium bisulphate and hydrochloric acid.17

NaCl + H2SO4 ⇒ NaHSO4 + HCl

If sulphuric acid enters a watercourse it will most likely kill allspecies even at low concentrations and remains in waterafterwards as a sulphate.18 This is also true of hydrochloricacid.

The effect of acid rain is well documented and sulphuricacid is one of its components. Much research has beenundertaken into methods of remediating areas affected by acidrain and is available through numerous sources. However, it isnot likely to have been relevant at Prestongrange as the localsulphuric acid industry has not been recorded as being presentat the Prestongrange site and the production of salt is unlikely

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GEOLOGY AND THE ENVIRONMENT

to have produced quantities of acid sufficient to causeenvironmental harm.

Thermal Pollution

Thermal pollution is not a widely known type of pollution butit can cause change in ecosystems and effect ecology. Heatgenerated from the brick kilns, and to a lesser extent salt pans,created temperatures up to 1600 degrees Centigrade.

There are no natural watercourses adjacent to where thebrick kilns stood, only groundwater. This however will stillhave an impact on the ecology. Warmer water, and thereforesoil, leads to a decrease in dissolved oxygen levels, a decreasein photosynthesis rates and the death of some organisms leadsto a higher biochemical oxygen demand.19 The heat generatedwould evaporate all water out of the ground within the topfew centimetres making life very difficult for shallow rootedplants, mosses and lichens close to the kilns.

Ash from Cockenzie Power Station

When coal is burned to produce electricity, the residual ash leftis known as pulverised fuel ash. This substance is grey incolour and has been dumped (legally) along the shoreline fromthe power station west to the lagoons located to the west ofPrestongrange Industrial Museum. (Way-leave along thebaronial lands on the foreshore has been given for an ashslurry pipe that is covered over and provides an excellentscenic walkway.) The ash can be found around Morrison’sHaven, on the open coastline and also around the area wherepreviously there were railway lines between the beehive kilnsand the beam engine – it has indeed been used to level the areanow pleasingly covered with grass.

Pulverised fuel ash has much the same properties as coalspoil as it is just the residue after coal has been burned andtherefore contains similar contaminants including chlorine,sodium and heavy metals. The ash, however, is relatively inertand in its stable state, as at Prestongrange, is unlikely to causeany environmental problems.

The Local Industrial Railways

Prestoungrange at the time when the colliery, brickworks andMorrison’s Haven were fully operational, had railway linesrunning across the works and to the Haven. Railway land canbe highly contaminative, but risks to humans and plants are

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less than contaminants from other industries. Oil leaked byengines may have contributed hydrocarbon contamination tothe ground but the volumes of any oil dropped around theworks are likely to be relatively small and in their liquid phase.The oils will most likely have been saturated by soil or ballast.

If oil were to penetrate the soil there would be a detrimentaleffect on organisms within the soil and for the soil itself. Theeffects of oils on the environment have been well documentedand information is available from the Scottish and EnglishEnvironment Agencies20, 21. Oil coats the surface of waterbodies, thereby reducing the light penetrating the water. Thismeans that algae and plants cannot photosynthesise aseffectively and reducing the oxygen level of the water. Thiscombined with the direct action of coating animals and fishmay kill whole communities. If the oil releases vapours andlarge volumes are allowed to build up then there may be riskof explosions, but only if concentrations reach 1% by volume.

Due to the large scale of development at the Prestongrangesite, many areas would have been covered with made surfacespreventing oil reaching the natural sub-soil. The lack offreshwater lakes or streams also means that there will havebeen little or no adverse effect to wildlife. Also, the nature ofindustry located there contributed contaminants far worsethan oil dropped by railway vehicles.

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GEOLOGY AND THE ENVIRONMENT

Figure 9 Eastward view of Morrison’s Haven, Prestonpans showing landreclamation process

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GEOLOGY AND THE ENVIRONMENT

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Conclusion

The long past of the Prestongrange Colliery and brickworksand other associated industries had the potential to leaveecological problems for the following decades, even centuries.However, the lack of intensity, arising from a ceasing ofactivity before the onset of the late twentieth century, hasmeant that the site remains in a relatively clean state. Workhas been carried out to level the site and remove the railwaylines and there is the obvious demolition of the beehive kilns,which is an archaeological tragedy. The infilling of Morrison’sHaven in 195718 was also a tragedy, the Haven being a potentsymbol of the site’s rich industrial past. Covering of the areawith ash from Cockenzie power station has meant that manytraces of local industry have disappeared.

The revegetation of the area to the south of the beam enginehas undoubtedly helped the site recover from the industrialprocesses and the site is now undergoing natural processes ofreclamation to bring the areas of contamination by coal backto life.

References1 Goodman, G. T. & Chadwick, M. J. (1978): Environmental

Management of Mineral Waste. Sijthhoff & Noordhoff, Holland2 Acid Mine Drainage In Pennsylvania Streams: “Ironing Out”

The Problem (Carrie H. Reinhardt).3 Staffordshire Multimedia Archive – http://archive.sln.org.uk4 The Coal Authority – www.coal.gov.uk5 Hester, R. E. and Harrison, R. M.: Contaminated Land and its

Reclamation (1997), Thomas Telford6 Anderson, David: Sourcing Brickmaking Salting and Chemicals

at Prestongrange, Prestoungrange University Press, 20007 Cheetham Salt – www.cheethamsalt.com.au8 www.papercamp.com/sci29.htm 9 United States Salinity Laboratory

10 Bonnar, Jane: Decorative Pottery at Prestongrange, Prestoun-grange University Press, 2000

11 Gone to Pot, East Lothian Council, 200012 Lee, P. William.: Ceramics (1961), Reinhold Publishing Corp-

oration13 United States Environmental Protection Agency: Chemical

Profile 7664-39-314 Aitken, Julie: Morrison’s Haven: What came and went and

how? Prestoungrange University Press, 200015 Iron and Glass – www.ironandglass.com

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16 United States Environmental Protection Agency: ChemicalProfile 7664-39-9

17 Sulphuric Acid, University College, Cork, 2000, Donal O’Leary18 European Fertilizer Manufacturers Association19 Earthforce – www.earthforce.org20 Scottish Environment Agency – www.sepa.org.uk21 The Environment Agency – www.environment-agency.gov.uk

Other SourcesFluoride Action Network: Cytogenetic Effects of Gaseous Fluorides

on Grain Crops, Fluoride, Vol. 26 No.1 23-32 1993 www.fluoridealert.org/grain.htm

Gibson, J.: Coal and the Environment, Northwood Science Reviews,1984.

5. CONCLUSIONS

The Prestongrange works have been fully industrialised for thepast 500 years and has the potential to be a highly con-taminated site. The environmental impact of industrialactivity, however, appears to very small in comparison to whatmight have been. The areas around the brick kilns and thecolliery equipment and the area to the south of works havebeen layered with colliery spoil and pulverised fuel ash. Toreclaim that it was necessary to cover the area with cleantopsoil and revegetate it, achieved with alder, birch and grass.Other species have appeared which is a benefit to the areashowing the reclamation work carried has clearly beensuccessful and the shallow sub-soil is reasonably healthy.

Overall, the Prestongrange site and the area aroundMorrison’s Haven is in good condition. There is little knownabout what exactly has been used to fill the Haven. Bricksfrom the demolition of the beehive kilns and ash from thepower station are obvious sources. Whatever has occurred inthe past will not be remembered for the pollution caused butfor the monuments that remain such as the Cornish beamengine and Morrison’s Haven as well as for the history toldout in the studies of which this is the tenth.

These historical and analytical studies are already providingthe basis for Schools’ educational visits to the Museum and forartists to create murals and to reproduce Prestonpans potteryand brickworks artefacts in the years ahead. As the hoped forincrease in tourism materialises visitors will find a cleanenvironment in which to enjoy themselves and to appreciatethe industrial history of Prestoungrange.

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