Byne's disease
Encyclopedia
Byne's disease, more accurately known as Bynesian decay, is a peculiar and permanently damaging condition (resulting from an on-going chemical reaction
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...

) which often attacks mollusk shells that are in storage or on display
Display case
A display case is a cabinet with one or often more transparent glass sides and/or top, used to display objects for viewing, for example in an exhibition, museum, house, in retail, or a restaurant. Often labels are included with the displayed objects, providing information...

 for long periods of time.

Bynesian decay is a form of efflorescence
Efflorescence
In chemistry, efflorescence is the loss of water of crystallization from a hydrated or solvated salt to the atmosphere on exposure to air.-Examples:...

 of salts formed by the reaction of acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

ic vapors with the basic
Base (chemistry)
For the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...

 shell surface. The efflorescence can sometimes superficially resemble a growth of mold
Mold
Molds are fungi that grow in the form of multicellular filaments called hyphae. Molds are not considered to be microbes but microscopic fungi that grow as single cells called yeasts...

. Although first described in the early 19th century, Bynesian decay was not well understood until almost a hundred years later. The condition is named after the man (L. Byne) who is best known for describing it in the late 19th century, even though he was not the first person to describe it in print. In addition, Byne mistakenly assumed that the condition was caused by bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

, and thus the condition came to be referred to as a "disease".

In addition to mollusk shells, various other natural history
Natural history
Natural history is the scientific research of plants or animals, leaning more towards observational rather than experimental methods of study, and encompasses more research published in magazines than in academic journals. Grouped among the natural sciences, natural history is the systematic study...

 specimen
Specimen
A specimen is a portion/quantity of material for use in testing, examination, or study.BiologyA laboratory specimen is an individual animal, part of an animal, a plant, part of a plant, or a microorganism, used as a representative to study the properties of the whole population of that species or...

s are susceptible to this form of decay, including eggshell
Eggshell
An eggshell is the outer covering of a hard-shelled egg and of some forms of eggs with soft outer coats.- Insect eggs :Insects and other arthropods lay a variety of styles and shapes of eggs. Some have gelatinous or skin-like coverings, others have hard eggshells. Softer shells are mostly protein....

s and some fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s and mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...

 samples that are composed of calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...

. This condition is of concern for museum
Museum
A museum is an institution that cares for a collection of artifacts and other objects of scientific, artistic, cultural, or historical importance and makes them available for public viewing through exhibits that may be permanent or temporary. Most large museums are located in major cities...

 scientists, and also for anyone who has a private collection of specimens of these kinds.

Appearance

Byne's disease can appear as a powdery white coating on a shell. It also often looks as if a shell has been "infected" with mold
Mold
Molds are fungi that grow in the form of multicellular filaments called hyphae. Molds are not considered to be microbes but microscopic fungi that grow as single cells called yeasts...

; however, under magnification the mold-like appearance is revealed to be a crystalline growth of salts.
first appeared in jordan in the 7th century
Jordan
Jordan , officially the Hashemite Kingdom of Jordan , Al-Mamlaka al-Urduniyya al-Hashemiyya) is a kingdom on the East Bank of the River Jordan. The country borders Saudi Arabia to the east and south-east, Iraq to the north-east, Syria to the north and the West Bank and Israel to the west, sharing...


History

In 1839, the British
British people
The British are citizens of the United Kingdom, of the Isle of Man, any of the Channel Islands, or of any of the British overseas territories, and their descendants...

 naturalist
Naturalist
Naturalist may refer to:* Practitioner of natural history* Conservationist* Advocate of naturalism * Naturalist , autobiography-See also:* The American Naturalist, periodical* Naturalism...

 and malacologist Thomas Brown
Thomas Brown (naturalist)
Captain Thomas Brown was a British naturalist and malacologist.Born in Perth, Scotland, he was educated at the Edinburgh High School. At the age of twenty, he joined the Forfar and Kincardine Militia, raising to the rank of captain in 1811. When he was quartered in Manchester, he became...

 (1785–1862) briefly mentioned this form of deterioration in his book A Conchologist's Text-Book. Agnes Kenyon also described the condition in 1896, suggesting that "saline particles in the atmosphere
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...

 [were] evidently exerting a corrosive
Corrosive
A corrosive substance is one that will destroy or irreversibly damage another surface or substance with which it comes into contact. The main hazards to people include damage to the eyes, the skin, and the tissue under the skin; inhalation or ingestion of a corrosive substance can damage the...

 effect".

Origin of the name

In 1899, the British amateur conchologist
Conchology
Conchology is the scientific or amateur study of mollusc shells. Conchology is one aspect of malacology, the study of molluscs, however malacology studies molluscs as whole organisms, not just their shells. Conchology pre-dated malacology as a field of study. It includes the study of land and...

 and naturalist
Naturalist
Naturalist may refer to:* Practitioner of natural history* Conservationist* Advocate of naturalism * Naturalist , autobiography-See also:* The American Naturalist, periodical* Naturalism...

 Loftus St. George Byne (1872–1947) described this condition, in a presentation to the Conchological Society of Great Britain in Ireland, and did so again in another presentation in June of that same year.
Byne was convinced that butyric acid
Butyric acid
Butyric acid , also known under the systematic name butanoic acid, is a carboxylic acid with the structural formula CH3CH2CH2-COOH. Salts and esters of butyric acid are known as butyrates or butanoates...

 was present together with calcium acetate
Calcium acetate
The chemical compound calcium acetate is the calcium salt of acetic acid. It has the formula Ca2. Its standard name is calcium acetate, while calcium ethanoate is the systematic IUPAC name. An older name is acetate of lime...

 in the affected shells, although he never really described the methods he used in the so-called "extensive chemical tests" he claimed to have applied to these specimen
Specimen
A specimen is a portion/quantity of material for use in testing, examination, or study.BiologyA laboratory specimen is an individual animal, part of an animal, a plant, part of a plant, or a microorganism, used as a representative to study the properties of the whole population of that species or...

s. Among other conclusions, he assumed that the butyric acid originated from bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

l activity. He also concluded that the decaying effect 'travelled from shell to shell and drawer to drawer', and thus the condition came to be called a "disease".

Clarification and resolution

The true nature of the "disease" was partially clarified in 1934, when the British government chemist
Chemist
A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...

 John Ralph Nicholls explained that oak cabinets at the Natural History Museum
Natural History Museum
The Natural History Museum is one of three large museums on Exhibition Road, South Kensington, London, England . Its main frontage is on Cromwell Road...

 in London were giving off acetic acid fumes, which were attacking the shells stored in them.

In 1985, almost 150 years after the Byne's disease was first mentioned in the literature, Norman H. Tennent and Thomas Baird published an extensive study on the subject. Their deep analysis, involving many complex and sophisticated techniques such as X-Ray diffraction, infrared spectroscopy
Infrared spectroscopy
Infrared spectroscopy is the spectroscopy that deals with the infrared region of the electromagnetic spectrum, that is light with a longer wavelength and lower frequency than visible light. It covers a range of techniques, mostly based on absorption spectroscopy. As with all spectroscopic...

, thermogravimetric analysis
Thermogravimetric analysis
Thermogravimetric analysis or thermal gravimetric analysis is a type of testing performed on samples that determines changes in weight in relation to change in temperature. Such analysis relies on a high degree of precision in three measurements: weight, temperature, and temperature change...

 and nuclear magnetic resonance spectroscopy, finally revealed the true nature of the decaying process. They identified the substances involved (the calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

 salts), as well as the chemical reaction
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...

s that originated them. They concluded that Byne's disease is not actually a disease, and is in fact caused by simple chemical reactions which occur in the presence of acidic vapors originated from the very environment the specimens were stored in.

Chemistry

Bynesian decay usually starts when specimens are stored or displayed for considerable periods of time in an enclosed space. The storage method itself can directly cause this problem, when containers, cabinets or display case
Display case
A display case is a cabinet with one or often more transparent glass sides and/or top, used to display objects for viewing, for example in an exhibition, museum, house, in retail, or a restaurant. Often labels are included with the displayed objects, providing information...

s are entirely or partially made of wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

, plywood
Plywood
Plywood is a type of manufactured timber made from thin sheets of wood veneer. It is one of the most widely used wood products. It is flexible, inexpensive, workable, re-usable, and can usually be locally manufactured...

 or other wood products such as Masonite
Masonite
Masonite is a type of hardboard invented by William H. Mason.-History:Masonite was invented in 1924 in Laurel, Mississippi, by William H. Mason. Mass production started in 1929. In the 1930s and 1940s Masonite was used for many applications including doors, roofing, walls, desktops, and canoes...

, or when the specimens are surrounded by, or in contact with, various other kinds of materials that are cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....

-based and can turn water vapor acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

ic.

Other potentially damaging materials include non-archival quality cardboard
Paperboard
Paperboard is a thick paper based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker than paper. According to ISO standards, paperboard is a paper with a basis weight above 224 g/m2, but there are exceptions. Paperboard can be single...

, card, paper
Paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....

, cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....

 and cork, all of which give off acidic vapors over time. PVC
PVC
Polyvinyl chloride is a plastic.PVC may also refer to:*Param Vir Chakra, India's highest military honor*Peripheral venous catheter, a small, flexible tube placed into a peripheral vein in order to administer medication or fluids...

 and polyurethane
Polyurethane
A polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are...

 plastics are also a problem, as they degrade and give off acidic vapors with time. High humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...

 of the air is a significant contributing factor, as is lack of ventilation of the specimens. High ambient temperatures can increase the rapidity of the decay.

Generally, in cabinets or display cases entirely or partially made of wood, the hydrolysis
Hydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...

 of acetyl
Acetyl
In organic chemistry, acetyl is a functional group, the acyl with chemical formula COCH3. It is sometimes represented by the symbol Ac . The acetyl group contains a methyl group single-bonded to a carbonyl...

 groups in the wood hemicellulose
Hemicellulose
A hemicellulose is any of several heteropolymers , such as arabinoxylans, present along with cellulose in almost all plant cell walls. While cellulose is crystalline, strong, and resistant to hydrolysis, hemicellulose has a random, amorphous structure with little strength...

s creates acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...

, in a rate that is proportional to the concentration of esters in the wood, the humidity, the temperature, and the overall acidity of the environment. Formaldehyde
Formaldehyde
Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...

 can also occur in wood, being formed by a degradation reaction of lignin
Lignin
Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae. The term was introduced in 1819 by de Candolle and is derived from the Latin word lignum, meaning wood...

. It can also stem from ubiquitous formaldehyde
Formaldehyde
Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...

 resins (commonly urea-formaldehyde resins).
In the first case, acetic acid reacts with the calcium carbonate (one of the main components of freshwater and marine shells, birds' eggs and other such specimens) producing calcium acetate
Calcium acetate
The chemical compound calcium acetate is the calcium salt of acetic acid. It has the formula Ca2. Its standard name is calcium acetate, while calcium ethanoate is the systematic IUPAC name. An older name is acetate of lime...

, a salt. Formaldehyde
Formaldehyde
Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...

 can be oxidized by the oxygen in air to create formic acid
Formic acid
Formic acid is the simplest carboxylic acid. Its chemical formula is HCOOH or HCO2H. It is an important intermediate in chemical synthesis and occurs naturally, most notably in the venom of bee and ant stings. In fact, its name comes from the Latin word for ant, formica, referring to its early...

, which then has basically the same effects as acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...

, reacting with calcium carbonate to produce a salt. The salts (calcium acetate
Calcium acetate
The chemical compound calcium acetate is the calcium salt of acetic acid. It has the formula Ca2. Its standard name is calcium acetate, while calcium ethanoate is the systematic IUPAC name. An older name is acetate of lime...

 and calcium formate
Calcium formate
Calcium formate, Ca2, is the calcium salt of formic acid, HCOOH. It is also known as food additive E238 in food industry. The mineral form is very rare and called formicaite. It is known from a few boron deposits. It may be produced synthetically by reacting calcium oxide or calcium hydroxide with...

) crystallize through the specimen's outer surface, destroying its fine detail and exposing more areas for further reaction. As the condition progresses, the salt crystals build up over the specimen's surface, which becomes increasingly eroded.

The calcium carbonate and acetic acid chemical reaction occurs as follows:

CaCO3
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...

 + 2CH3COOH
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...

 → Ca(CH3COO)2
Calcium acetate
The chemical compound calcium acetate is the calcium salt of acetic acid. It has the formula Ca2. Its standard name is calcium acetate, while calcium ethanoate is the systematic IUPAC name. An older name is acetate of lime...

 + H2O
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 + CO2
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...



Calcium carbonate and formic acid chemical reaction occurs as follows:

CaCO3
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...

 + 2CH2O2
Formic acid
Formic acid is the simplest carboxylic acid. Its chemical formula is HCOOH or HCO2H. It is an important intermediate in chemical synthesis and occurs naturally, most notably in the venom of bee and ant stings. In fact, its name comes from the Latin word for ant, formica, referring to its early...

 → Ca(HCOO)2
Calcium sulfate
Calcium sulfate is a common laboratory and industrial chemical. In the form of γ-anhydrite , it is used as a desiccant. It is also used as a coagulant in products like tofu. In the natural state, unrefined calcium sulfate is a translucent, crystalline white rock...

 + H2O
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 + CO2
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...



Calcium carbonate and sulfuric acid chemical reaction occurs as follows:

CaCO3
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...

 + H2SO4
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...

 → CaSO4
Calcium sulfate
Calcium sulfate is a common laboratory and industrial chemical. In the form of γ-anhydrite , it is used as a desiccant. It is also used as a coagulant in products like tofu. In the natural state, unrefined calcium sulfate is a translucent, crystalline white rock...

 + H2O
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

 + CO2
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...



In this last reaction, calcium carbonate reacts with sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...

 and produce calcium sulfate, water and carbon dioxide.

Prevention

When specimens are to be placed in any size of container for long-term storage or display, the consistent use of only archival-quality materials prevents the development of Byne's disease. Thus, materials such as metal cabinets and display cases, archival quality paper labels and card trays are used in museum collections of specimens that might be vulnerable to this reaction.

It is also worth mentioning that sea shells, after collecting, need to be washed thoroughly in freshwater to remove the salt that is on and in the shell, and then dried thoroughly before they are stored. Salt attracts moisture and makes shells more vulnerable to Bynesian decay.

The following is a chart that shows non-archival materials and their archival equivalents:
Traditional non-archival materials Archival materials without acidic fumes
wood, plywood, masonite metal
paper acid-free paper
Acid-free paper
Acid-free paper is paper that has a neutral or basic pH . It can be made from any cellulose fiber as long as the active acid pulp is eliminated during processing. It is also lignin and sulfur free...

card and cardboard acid-free card
cotton (in the UK cotton wool) polyester fiberfill
cork polyester fiberfill
ethylene vinyl acetate, colored plastic foam ethafoam: white polyethylene
Polyethylene
Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...

 foam
ballpoint pen ink, other everyday inks carbon ink (or pencil)
ordinary glue archival glue
ordinary cellulose tape archival cellulose tape
ordinary (polyetheylene) zipper storage bags archival (polypropylene
Polypropylene
Polypropylene , also known as polypropene, is a thermoplastic polymer used in a wide variety of applications including packaging, textiles , stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes...

) zipper storage bags


If possible, the use of wood and cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....

 derivatives should be avoided entirely. Many varnish
Varnish
Varnish is a transparent, hard, protective finish or film primarily used in wood finishing but also for other materials. Varnish is traditionally a combination of a drying oil, a resin, and a thinner or solvent. Varnish finishes are usually glossy but may be designed to produce satin or semi-gloss...

es and paint
Paint
Paint is any liquid, liquefiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film. One may also consider the digital mimicry thereof...

s are well known emitters of volatile organic compounds (VOCs), some of which may be acidic, and thus have the potential to damage calcium carbonate specimens. Because of this, these coating
Coating
Coating is a covering that is applied to the surface of an object, usually referred to as the substrate. In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wetability, corrosion resistance, wear resistance, and scratch resistance...

s should also be avoided; water-based varnishes and paints are considered less harmful, and should be preferred.

Because the reactions involved in Bynesian decay require a certain quantity of moisture
Moisture
Humidity is the amount of moisture the air can hold before it rains. Moisture refers to the presence of a liquid, especially water, often in trace amounts...

 in the air in order for them to take place, keeping the air somewhat dry, i.e. keeping the environmental relative humidity
Relative humidity
Relative humidity is a term used to describe the amount of water vapor in a mixture of air and water vapor. It is defined as the partial pressure of water vapor in the air-water mixture, given as a percentage of the saturated vapor pressure under those conditions...

 under control is beneficial. This is achieved by careful monitoring of the relative humidity (using instruments such as a hygrometer
Hygrometer
A hygrometer is an instrument used for measuring the moisture content in the environmental air, or humidity. Most measurement devices usually rely on measurements of some other quantity such as temperature, pressure, mass or a mechanical or electrical change in a substance as moisture is absorbed...

), and applying dehumidifiers when necessary; sometimes, simple air conditioning
Air conditioning
An air conditioner is a home appliance, system, or mechanism designed to dehumidify and extract heat from an area. The cooling is done using a simple refrigeration cycle...

 systems may suffice. Extremely low humidity can damage some specimens, so caution is recommended. Usually, a relative humidity maintained around 50% is considered to be adequate. Applying sorbent
Sorbent
A sorbent is a material used to absorb liquids or gases. Examples include:*A material similar to molecular sieve material. It has a large internal surface area and good thermal conductivity. It is typically supplied in pellets of 1 mm to 2 mm diameter and roughly 5 mm length or as...

s containing a strong base, such as potassium hydroxide
Potassium hydroxide
Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...

, inside the storage environment to protect the specimens against degradation is also possible. Copy paper or KOH-impregnated filter paper
Filter paper
Filter paper is a semi-permeable paper barrier placed perpendicular to a liquid or air flow. It is used to separate fine solids from liquids or air.-Properties:Filter paper comes in various porosities and grades depending on the applications it is meant for...

 are some low cost examples of sorbents which can be used. These strong bases have a preference to react with acid, thus they compete successfully with the calcium carbonate specimens for any acidic vapors that may be present. The bases also help reduce the overall acid concentration
Concentration
In chemistry, concentration is defined as the abundance of a constituent divided by the total volume of a mixture. Four types can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration...

 inside the enclosed space.

Management

The damage to specimens is unfortunately not reversible; however, the decay can be arrested by washing or soaking the specimens in water, followed by a very thorough drying. The specimens must then be placed in an environment that consists of only archival materials, in a completely archival setting.

Pyrite disease

In collections which contain fossils, high humidity can also affect pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...

 (or its more reactive polymorph marcasite
Marcasite
The mineral marcasite, sometimes called white iron pyrite, is iron sulfide with orthorhombic crystal structure. It is physically and crystallographically distinct from pyrite, which is iron sulfide with cubic crystal structure. Both structures do have in common that they contain the disulfide...

) (iron sulphide) fossils in a somewhat similar condition, which is known as pyrite disease. The iron sulfide
Iron sulfide
Iron sulfide or Iron sulphide refers to a chemical compound of iron and sulfur with a wide range of stoechiometric formulae and different crystalline structures.-Natural minerals:By increasing order of stability:...

 can react with water and oxygen to form iron sulfate
Iron sulfate
Iron sulfate may refer to:*Ferrous sulphate, Iron sulfate, FeSO4*Ferric sulphate, Iron sulfate, Fe23...

s and sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...

, which then can produce Bynesian decay.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK