**2. Physico-chemical properties of considered molecules**

PFCs and PBDEs include molecules characterized by a similar chemical formula but also by very different physico-chemical properties. As consequence of the structural dissimilarities, differences concerning environmental distribution dynamics, and levels in abiotic and bio‐ logical matrices are observed among PFCs and PBDEs congeners. Furthermore, the ecotoxi‐ cological risk associated to the diffusion of these persistent organic pollutants could be notably dissimilar. In fact, physico-chemical properties of molecules influence possible ad‐ verse effects on non-target biological communities. In addition, observed toxicity is notably affected by the interaction among considered chemicals and environmental matrices caused by the photo-chemical deterioration and the production of metabolites during microbial bio‐ degradation phenomena.

#### **2.1. Perfluorinated organic compounds (PFCs)**

compounds making the mixture and latitude/altitude of the geographical area considered [14]. Unluckily the effects induced by pure compounds on non-target species are frequently unknown at the time of their commercialization as well as possible by-products which are produced by the interaction with the environment. Usually, undesirable consequences of new synthesized chemicals are discovered many years later their distribution in commerce, often dramatically. This is the well-known case of the pesticide dichloro-diphenyl-trichloro‐ ethane (DDT) largely used to control malaria diffusion and publicized before 1970' as "the

Persistent organic pollutants (POPs) are characterized by molecular stability, high persistence due to the resistance to natural degradation processes derived by physical (i.e. temperature or photo-degradation), chemical (i.e. redox and acid-basic reactions, chemical interactions), and biological (i.e. metabolic or microbial deteriorations) aggressions. As reported by the Europe‐ an Community [15], to be classified as "persistent", chemicals must evidence a half-life in water

POPs concentrate in environment for a very long time and, due to their vapor pressure <1000 Pa and a half-life >2 days in atmosphere, evidence long range transport reaching, also, remote areas [16]. These chemicals usually are low water soluble but evidence a great affinity towards lipids and tend to accumulate in sedimentary organic matter and biological tissues affecting the trophic web along which tend to biomagnificate [17]. Chemicals characterized by logKow >5 and by a bio-concentration factor (BEF) >5,000 are considered "bioaccumulable" [15]. POPs are not biologically inert, on the contrary, they actively interact with physiological biochemistry of

Among POPs, perfluorinated organic compounds (PFCs) and polybrominated diphenyl ethers (PBDEs) are known as "emergent pollutants". PFCs and PBDEs are recently commercialized chemicals of particular ecotoxicological concern which are relatively little described by the lit‐ erature [18]. PFCs and PBDEs increased levels during the latest decades both in environments and wildlife. Several studies have assessed them in a wide range of organisms [19], including humans [20; 21], from low latitude regions to remote areas, suggesting atmospheric transport

**•** sources, distribution dynamics, and environmental levels (in air, soil, water, sediment)

**•** levels in wildlife tissues focusing evidences of bioaccumulation throughout the trophic web. Studies reporting levels both in red-list included species and foods at the basis of the

**•** international normative and guidelines developed to control considered chemicals

of volatile precursor compounds and/or transport in ocean currents [22; 23; 24].

superior than two months and in sediments/soils superior than six months.

species inducing toxicity on wildlife species and humans.

This chapter will focuses:

**•** general physico-chemical properties,

with a particular attention on aquatic ecosystem;

human diet will be considered and included;

**•** evidences on toxicity based on results of ecotoxicological tests;

**•** phenomena of contamination in humans;

best friend of housewives in controlling pests".

112 Organic Pollutants - Monitoring, Risk and Treatment

Concerning chemicals of ecotoxicological interest, perfluorinated organic compounds (PFCs) are of particular emerging interest due their documented presence both in wildlife's tissues and human blood PFCs [25].

PFCs are anionic, and fluorine-containing surfactants (both soluble in water and oil) and are applied for a large industrial and commercial employment to produce surfactants, lubri‐ cants, paints, polishes, food packaging, and fire-fighting, foams propellants, agrochemicals, adhesives, refrigerants, fire retardants, and medicines [26; 27].

Their structure consisting of a fluorine atom with which all hydrogen atoms from the linearalkyl chain, which is a hydrophobic group, are replaced. Physico-chemical properties of PFCs favour the occurrence of long-range transport dynamics, as they are more volatile than chlorine or bromine analogues.

Among PFCs, perfluorooctanoic acid (PFOA) and perfluoroctanesulfonic acid (PFOS) repre‐ sents the principal compounds of environmental concern.

Salts of perfluorooctanoic acid (PFOA, C8HF15O2) have been used as surfactants and process‐ ing aids in the production of fluoropolymers, and these salts are considered critical to the production of certain fluoropolymers and fluoroelastomers [28]. The functional chemical structure is C7F15COOH and for this reason tends to behavior like an acid dissociating as fol‐ lows: C7F15COO- + H+ .

Perfluorooctane sulfonate (PFOS; C8HF17O3S even in this case it dissociates as follows: C7F17SO3 - + H+ ) evidences an excellent chemical and thermal stability and is a chemical pre‐ cursor for the synthesis of other molecules [26] such as fluorinated surfactants and pesti‐ cides (Abe and Nagase*.,* 1982 in [29]). Perfluoroalkanesulfonate salts and perfluorocarboxylates are reported to be present in fire-fighting foam formulations, includ‐ ing aqueous film forming foams which are fire-fighting materials largely used by military bases and airports to face hydrocarbon fuel fires or to prevent the potential risk of fire [30; 31]. Moody and colleagues [32] reported for the 2001, an estimated PFOS annual production quantity in United States of America of 2,943,769 kg.

**2.2. Polybrominated Diphenyl Ethers (PBDEs)**

added to improve fire safety [35].

ica, while in Europe only 12% [37].

Polybrominated diphenyl ethers (PBDEs) are a class of organohalogen compounds used worldwide over the past three decades as chemical additives to reduce the flammability of common use products [34]. These chemicals were first introduced to the market in the 1960s and their global demand has increased rapidly since the end of the 1970s, due to the grow‐ ing popularity of personal computers and other electronic equipment, to which they were

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Since '70 PBDEs were used as flame retardants in a wide range of common use such as cloths, foam cushions, polyurethane sponges, carpet pads, chairs, couches, electronic instru‐

In 2000, the industrial production of these chemicals has been esteemed to be around the 64,000 cubic tons per year. The 50% of this annual production was commercialized in Amer‐

Because of toxicity and persistence of PBDEs, these chemicals are included in the persistent organic pollutants (POPs) Reviewing Committee (www.pops.int) and their industrial pro‐

Polybrominated diphenyl ethers are, apart from the oxygen atom between the phenyl rings, structurally similar to PCBs, consisting of two halogenated aromatic rings linked by an ether group. PBDEs chemical synthesis is performed by the diphenyl-ethers bromination in pres‐ ence of dibromomethane as solvent. Diphenyl-ethers have 10 hydrogen atoms and each of them can be replaced by an atom of bromine. This reaction could produce 209 possible con‐ geners, numbered from 1 to 209 in relation to the number of bromine atoms substituting hy‐

In the United States, PBDEs are marketed with trade names: DE-60F, DE-61, DE-62, and DE-71 applied to penta-BDE mixtures; DE-79 applied to octa-BDE mixtures; DE 83R and

The available commercial PBDE products are not single compounds or even single conge‐ ners but rather a mixture of congeners. Nevertheless, commercial mixtures are constituted by a little part of the 209 possible congeners due to the instability of a large part of them [39]

Three technical mixtures are available and commercialized and differ related to the bromi‐

**•** Mixture penta-BDE (24-38% tetra-BDE, 50-60% penta-BDE, 4-8% esa-BDE). In these mix‐ tures, most abundant congeners are constituted by tetra-BDE 2,2',4,4' (IUPAC n. 47), penta-BDE 2,2',4,4',5 (IUPAC n. 99) and penta-BDE 2,2',4,4',6 (IUPAC n. 100), esa-BDE 2,2',4,4',5,5' (IUPAC n. 153) and esa-BDE 2,2',4,4',5,6' (IUPAC n. 154). These mixtures are viscose liquids principally used in industrial fabrication of clothes, foams, resins, polyurethane foam prod‐ ucts such as furniture and upholstery in domestic furnishing, and in the automotive and avi‐

ation industries. The European Union banned the use of this mixture in August 2004.

ments including computer castings, and insulating materials [36].

duction is to be eliminated under the Stockholm Convention.

drogen ones and their relative position within the molecule [38].

Saytex 102E applied to deca-BDE mixtures.

which tend to quickly debrominate.

nation levels:

The general chemical formula for PBDE family is C12H(10−x)BrxO (where x= 1,..., 10).

Principal PFOA and PFOS chemical properties are summarized in Table 1.


**Table 1.** Substance identification (extended names and international classification numbers), principal molecular properties, and related risks of PFOA (perfluorooctanoic acid) and PFOS (perfluoroctanesulfonic acid) are summarized in table. Specific references: record of PFOA were extracted from the GESTIS Substance Database from the IFA (last access on 5th November, 2008).

### **2.2. Polybrominated Diphenyl Ethers (PBDEs)**

perfluorocarboxylates are reported to be present in fire-fighting foam formulations, includ‐ ing aqueous film forming foams which are fire-fighting materials largely used by military bases and airports to face hydrocarbon fuel fires or to prevent the potential risk of fire [30; 31]. Moody and colleagues [32] reported for the 2001, an estimated PFOS annual production

quantity in United States of America of 2,943,769 kg.

114 Organic Pollutants - Monitoring, Risk and Treatment

Extended name Other names

Principal PFOA and PFOS chemical properties are summarized in Table 1.

Perfluorooctanoic acid Perfluorooctanoate Perfluorocaprylic acid

FC-143

CAS numb 335-67-1 1763-23-1 Pubchem 9554 74483 EC number 206-397-9 217-179-8

Molecular formula C8HF15O2 C8HF17O3S Molecular mass 414.07 gmol-1 500.13 gmol-1 Boiling point 189–192 °C 133 °C (6 torr) Appearance (25 C, 100 kPa) colorless liquid white powder

Melting point 40–50 °C >400 °C

*S-phrases* S36, S37, S39 S61

access on 5th November, 2008).

Vapor pressure 4.2 Pa (25 °C) 3.31 × 10-4 Pa (20 °C)

Solubility in water 3,400 mgL-1 519 mgL-1 (20 ± 0.5 °C)

Acidity (pKa) 2-3[23] calculated value of -3.27[33]

Solubility in other solvents polar organic solvents 56 mgL-1 (octanol)

F*-n-*octanoic acid

**PFOA PFOS**

**SUBSTANCE IDENTIFICATION**

**MOLECULAR PROPERTIES**

**RELATED RISKS**

*R-phrases* R22, R34, R52/53 R61, R20/21, R40, R48/25, R64, R51/53

**Table 1.** Substance identification (extended names and international classification numbers), principal molecular properties, and related risks of PFOA (perfluorooctanoic acid) and PFOS (perfluoroctanesulfonic acid) are summarized in table. Specific references: record of PFOA were extracted from the GESTIS Substance Database from the IFA (last

Perfluoroctanesulfonic acid 1-Perfluorooctanesulfonic acid Heptadecafluoro-1-octanesulfonic acid Perfluoro-n-octanesulfonic acid

680 mgL-1 (24 - 25 °C)

Polybrominated diphenyl ethers (PBDEs) are a class of organohalogen compounds used worldwide over the past three decades as chemical additives to reduce the flammability of common use products [34]. These chemicals were first introduced to the market in the 1960s and their global demand has increased rapidly since the end of the 1970s, due to the grow‐ ing popularity of personal computers and other electronic equipment, to which they were added to improve fire safety [35].

Since '70 PBDEs were used as flame retardants in a wide range of common use such as cloths, foam cushions, polyurethane sponges, carpet pads, chairs, couches, electronic instru‐ ments including computer castings, and insulating materials [36].

In 2000, the industrial production of these chemicals has been esteemed to be around the 64,000 cubic tons per year. The 50% of this annual production was commercialized in Amer‐ ica, while in Europe only 12% [37].

Because of toxicity and persistence of PBDEs, these chemicals are included in the persistent organic pollutants (POPs) Reviewing Committee (www.pops.int) and their industrial pro‐ duction is to be eliminated under the Stockholm Convention.

Polybrominated diphenyl ethers are, apart from the oxygen atom between the phenyl rings, structurally similar to PCBs, consisting of two halogenated aromatic rings linked by an ether group. PBDEs chemical synthesis is performed by the diphenyl-ethers bromination in pres‐ ence of dibromomethane as solvent. Diphenyl-ethers have 10 hydrogen atoms and each of them can be replaced by an atom of bromine. This reaction could produce 209 possible con‐ geners, numbered from 1 to 209 in relation to the number of bromine atoms substituting hy‐ drogen ones and their relative position within the molecule [38].

The general chemical formula for PBDE family is C12H(10−x)BrxO (where x= 1,..., 10).

In the United States, PBDEs are marketed with trade names: DE-60F, DE-61, DE-62, and DE-71 applied to penta-BDE mixtures; DE-79 applied to octa-BDE mixtures; DE 83R and Saytex 102E applied to deca-BDE mixtures.

The available commercial PBDE products are not single compounds or even single conge‐ ners but rather a mixture of congeners. Nevertheless, commercial mixtures are constituted by a little part of the 209 possible congeners due to the instability of a large part of them [39] which tend to quickly debrominate.

Three technical mixtures are available and commercialized and differ related to the bromi‐ nation levels:

**•** Mixture penta-BDE (24-38% tetra-BDE, 50-60% penta-BDE, 4-8% esa-BDE). In these mix‐ tures, most abundant congeners are constituted by tetra-BDE 2,2',4,4' (IUPAC n. 47), penta-BDE 2,2',4,4',5 (IUPAC n. 99) and penta-BDE 2,2',4,4',6 (IUPAC n. 100), esa-BDE 2,2',4,4',5,5' (IUPAC n. 153) and esa-BDE 2,2',4,4',5,6' (IUPAC n. 154). These mixtures are viscose liquids principally used in industrial fabrication of clothes, foams, resins, polyurethane foam prod‐ ucts such as furniture and upholstery in domestic furnishing, and in the automotive and avi‐ ation industries. The European Union banned the use of this mixture in August 2004.

**•** Mixture octa-BDE (10-12% esa-BDE, 44% epta-BDE, 31-35% octa-BDE, 10-11% nona-BDE, <1% deca-BDE). In these mixtures, most abundant congeners are epta-BDE 2,2',4,4',5',6 (IUPAC n. 183), and esa-BDE 2,2',4,4',5,5' (IUPAC n. 153). These mixtures are white dusts and are commonly used in little objects for house and office purposes made by plastic products, such as housings for computers, automobile trims, telephone handsets and kitchen appliance casings.

**3. Sources, distribution dynamics, and environmental levels**

ces, superficial and groundwater [31].

flame-retardants factories [40].

usually measured in mg/kg or ng/g.

geneity in data acquisition procedures.

Concerning PFCs, principal environmental sources are represented by the direct diffusion of surfactants, lubricants, paints, polishes, foams propellants, agrochemicals, adhesives, refrig‐ erants, fire retardants, and medicines containing these chemicals. Indirect releases could oc‐ curs from food packaging and painted manufacturing when discharged and exposed to rain and bad weather conditions. Nevertheless, the large use of fire-fighting materials containing PFCs both when a critical fire occurs and to prevent accidents in high risk procedure (i.e. military or firemen exercitations, routine activities, airports activities), represents the princi‐ pal direct diffusion of these chemicals on the ground able to affect wide geographical surfa‐

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As regard as PBDEs, environmental releases could occurs during manufacturing lifetimes. Releasing mechanism are not completely cleared, however, it is believed that PBDEs are re‐ leased to the air when objects are manufactured and during object's life span. Their disposal and waste could produce releases too [42]. In the last years recycling of end products con‐ taining PBDE is becoming the principal source of release of these chemicals in the environ‐ ment [43]. Burning of plastics, waste electronic goods, and oil shale may provide an additional PBDEs loads both in atmosphere and soil. Also, productive processes represents an important source, high levels are measured in environmental matrices closed to the

Monitoring PFCs and PBDEs in environmental matrices evidenced first of all the needing to develop accurate sampling strategies to collect representative samples from heteroge‐ neous and quickly variable matrices such as air and water are. On the contrary, soils and sediments even if much more stable present structural heterogeneity (i.e. organic matter content and composition, grain-size structure, redox conditions) which could interfere with quantifications and data interpretation. Concerning biota the matter (if it is possi‐ ble!) is quite more complex. Measured levels could be affected by a lot of different fac‐ tors as well as age, sex, phase of animal life-stage, lipid content, water content in tissues, part of the animal excised for the analyses and much more other factors. Another point is represented by the sampling treatments and the detecting method adopted to perform laboratory analyses. Different methods are associated to different detection limits, preci‐ sion and accuracy. Low polluted matrices such as air and water required methods able to detect levels of chemicals at concentrations measured in pg/L, whereas biological tis‐ sues allowed the adoption of quite less sensible methods as well as concentrations are

Hereby levels reported by the literature in different environmental matrices are reported or‐ ganizing them per matrix. When possible information about the sampling strategies adopt‐ ed are reported (i.e. depth of sampling for water and soils or sediments, geographical areas, type of tissues), nevertheless a complete data selection related to the sampling strategies, sampling treatments, and detecting methods has not been possible due to the wide hetero‐

**•** Mixture deca-BDE (<3% nona-BDE, >97% deca-BDE (IUPAC n. 209). These mixtures are white dusts. In 2003 they represent above the 80% of the annual production of PBDE and they are, currently, the only PBDE product in production. Deca-BDE are commonly used in the following applications: thermoplastic, elastomeric, and thermo set polymer sys‐ tems, including high impact polystyrene (HIPS), polybutylene terephthalate (PBT), nylon, polypropylene, low-density polyethene (LDPE), ethylene-propylene-diene rubber and ethylene-propylene terpolymer (EPDM), unsaturated polyester, epoxy. Are used for wire and cable insulation, coatings and adhesive systems, including back-coatings for fabrics, and electronic instruments [36; 38].

PBDEs are semi volatile compounds characterized by a low vapor pressure and a scarce wa‐ ter solubility. These properties tends to decrease with the level of substitutions by bromine atoms in the molecular structure whereas hydrophobic properties increase. Octanol/water distribution coefficients (Kow) are variable with substitutions and are included within: 5.9-6.2 for tetra-BDE, 6.5-7.0 for penta-BDE, 8.4-8.9 for octa-BDE, and 10.0 for deca-BDE. PBDEs half-life in air are extimated to be about two days, while in water longer times are modeled (two months) whereas in soils and sediments average half-lives are six months [40].


**Table 2.** Substance identification and principal molecular properties of PBDEs (polybrominated diphenyl ethers) are summarized. The number of isomers, the molecular formula, molecular mass, % of bromine, vapor pressure, octanol/ water distribution coefficients, and solubility in water are reported. Data collected by the European Food Safety Authority [41].
