About POPS

Eng: pentachlorophenol

CAS Number: 87-86-5 (salts and esters have different CAS Numbers)

Formula: C6HCl5O

Molecular weight: 266.34 g/mol

Density: 1.99 g/cm3

Melting point: 191 °C

Water solubility at 20 °C: 1000 mg/l

Pentachlorophenol (PCP) is a white, gray crystalline solid. It is a highly toxic poisonous compound. It enters the body through the skin, respiratory tract and gastrointestinal tract (irritating to the skin and mucous membranes).

Pentachlorophenol was used as a continuous herbicide and also as herbicide. It is also used to control annual weeds in corn, sugar beet, cotton, legumes.

Eng: naphthalene polychlorinated

CAS Number: 70776-03-3 (naphthalenes in different pesticides have different CAS Numbers)

General chemical formula: C₁₀H_8−(m+n)Cl_(m+n)

Polychlorinated naphthalenes are oil or waxy solid, depending on the degree of chlorination. When they enter mammalian organisms, PCNs affect the liver, lungs, gastrointestinal tract, and disrupt metabolism.

Polychlorinated naphthalenes (PCNs) are industrial chemicals and a by-product. The use of PCNs is based on their chemical inertness, low flammability, their electrical insulating properties and resistance. Mainly, the properties and applications are similar to PCBs (polychlorinated biphenyls): resistance to biodegradation as well as biocidal properties.

PCNs were used in wood preservatives, as an additive to paints and motor oils, and to insulate cables and capacitors. Although the use of PCNs has been phased out, they are also present in PCBs and are unintentionally formed during incineration and industrial plants.

Eng: decabromodiphenyl oxide

CAS Number: 1163-19-5

Formula: C12Br10O

Molecular weight: 959.17 g/mol

Density: 3 g/cm3

Boiling point: 425 °C

Water solubility at 20 °C: insoluble

Decabromodiphenyl oxide can be toxic to reproductive system; it is also an endocrine disruptor and is carcinogenic. Decabromodiphenyl oxide and other polybrominated antipyrenes are stable in the environment and can accumulate in fish, meat and plant products. Polybrominated antipyrenes are found in breast milk.

Decabromodiphenyl oxide performs the function of a fire retardant agent in the product, slows down the ignition and combustion of the product (antipyrene). This substance is used as antipyrene in electrical and electronic equipment. It is widely present in electronic waste and, when incinerated, produces brominated dioxins and furans.

Eng: short-chain chlorinated paraffins (SCCPs)

CAS Number: 85535‑84‑8

Formula: CxH(2x-y+2)Cly (where x = 10-13; y=3-12), example – C10H17Cl5

Molecular weight: 959.17 g/mol

Density: 3 g/cm3

Boiling point: 425 °C

Water solubility at 20 °C: insoluble

SCCPs meet the deposit persistence criterion. They are also characterized by sufficient persistence in the atmosphere, which determines their ability to be transported over long distances, and have the ability to bioaccumulate. They may accumulate in food ingested by fish. The accumulation in food depends on the chain length and the chlorine content.

The main application and source of SCCPs emissions was metalworking. Other applications include paints, adhesives and sealing materials, tanners for leather, plastics and rubbers, fire retardants, textiles and polymers.

Eng: p,p'-DDT (1,1'-(2,2,2-trichloroethylidene)bis[4-chlorobenzene])

CAS Number: 50-29-3

Formula: C14H9Cl5

Molecular weight: 354.49 g/mol

Density: 0.99 g/cm3

Melting point: 109 °C

Boiling point: 185 °C

Water solubility at 20 °C: 0.006 mg/l

DDT is a white crystalline substance. It is a highly toxic compound. DDT inevitably enters the food chain, after which it does not decompose, but accumulates in the living organisms. Disorders of development, reproductive function, cardiovascular system, as well as neurological changes occur. Aquatic microorganisms are most sensitive to DDT.

DDT is an insecticide. It is one of the most famous POPs. It was widely used as a means of protection against malaria, typhoid and other insect-borne diseases. The widespread household name for DDT is "dust" (this is a preparative form, not the active substance itself). It continues to be used in some countries. The use of DDT in agriculture in many countries is prohibited or severely restricted due to its high persistence and strong cumulative properties.

Eng: Perfluorooctane sulfonic acid (PFOS), its salts and perfluorooctane sulfonyl fluoride (PFOSF)

CAS Number: perfluorooctane sulfonic acid (CAS: 1763-23-1) and its salts of perfluorooctane sulfonyl fluoride (CAS: 307-35-7)

Formula: perfluorooctane sulfonic acid (C8HF17O3S) and its salts of perfluorooctane sulfonyl fluoride (C8F18O2S)

Molecular weight: perfluorooctane sulfonic acid – 500.13 g/mol and its salts of perfluorooctane sulfonyl fluoride – 502.12 g/mol

Density: perfluorooctane sulfonic acid – 1.25 g/cm3 and its salts of perfluorooctane sulfonyl fluoride – 1.82 g/cm3

Boiling point: perfluorooctane sulfonic acid – 260 °C and its salts of perfluorooctane sulfonyl fluoride – 155 °C

PFOS is released into the environment during production, use, and in disposal sites. It can be transported over long distances in the environment. PFOS is highly resistant to chemical and biological changes, and it is capable of bioaccumulating in various food chains. PFOS is toxic in low concentrations. Perfluorooctanesulfonate is a carcinogenic substance. It stimulates tumors and has effect on reproductive system.

Industrial substance. PFOS was used to make clothes and shoes water and dirt repellent, in the production of: fire foam, carpets, leather clothing, textiles, upholstery fabrics, paper and packaging, paints and varnishes, cleaning products for industrial and home use, pesticides and other insecticides, photographic industry, photolithography and semiconductor manufacturing, hydraulic fluids and electroplating coatings.

Eng: polychlorinated dibenzo-p-dioxins (PCDD) and polchlorinated dibenzofurans (PCDF)

Polychlorinated dibenzo-p-dioxins (PCDDs) are a large group of heterocyclic polychlorinated compounds based on two aromatic rings linked by two oxygen bridges; polychlorinated dibenzofurans (PCDFs) are compounds with one oxygen bridge.

There are 75 PCDD congeners and 135 PCDF congeners in total. Brominated analogs of these compounds are less common and their toxicity is less well understood, although for some of them the toxicity data are as high as for chlorinated derivatives. The most toxic is 2,3,7,8-tetrachlorodibenzo-p-dioxin (C12H4Cl4O2, CAS Number 1746-01-6).

PCDDs and PCDFs are not intentionally produced in any industry. The natural formation of these compounds in the environment has not been established either.

Most PCDDs and PCDFs are colorless crystalline substances with high adsorption capacity, the melting point of which depends on the degree of chlorination. They are adsorbed on particles of soot, ash, dust, bottom sediments, which contributes to their accumulation and migration in the environment, as well as their release into air, water and food products. Dioxins have high chemical and thermal stability. The half-life of dioxins exceeds 10 years in soil, and it can reach several decades in water and bottom sediments. For humans, the danger of dioxins lies not so much in acute toxicity as in the cumulative capacity and long-term effects of prolonged exposure to immunity.

The main industrial sources of unintentional production of dioxins and their release into the environment are:

• production of cellulose using elemental chlorine for bleaching or chemicals that form elemental chlorine;
• thermal processes in the metals industry: secondary production of copper, aluminum, zinc, etc.;
• incineration of waste, including municipal solid waste, dry sludge from wastewater treatment, hazardous industrial and medical waste;
• cement kilns with associated combustion of hazardous waste;
• a number of chemical industries.

Unintentional production and release of dioxins are also possible through open incineration of waste (including incineration of landfills), combustion of fossil fuels and wood, the production of certain chlorine-containing chemicals, gas emissions from vehicles, car recycling and used oils.