325
polluted gases and their residues in the air and also through direct skin contact.
EDCs transfer can also occur through placenta and breast milk from the pregnant
woman to the developing fetus and to the young child, respectively.
Different mechanisms are involved which interfere functions of the endocrine
system either by direct binding to hormonal receptors causing stimulation or inhibition of downstream cellular pathway of target cells or indirectly by increasing or
decreasing endogenous hormone(s) concentration. Therefore, this results in the
stimulation or inhibition of their bio-availability or degradation [2, 3]. Although
there are a lot of potent and most available classes of environmental chemicals
which are been studied but here in this chapter we have focused only on those which
are polycyclic aromatic hydrocarbons in nature.
Polycyclic Aromatic Hydrocarbons (PAHs)
Organic compounds which are composed of aromatic rings (two or more) arranged
in various configurations are termed as polycyclic aromatic hydrocarbons [4],
mostly white, colorless, or pale yellow solids. Generally, structural angularity,
hydrophobicity, resistance to biodegradation, electrochemical stability, persistency
and carcinogenic index of PAHs is directly proportional to the number of aromatic
rings, while volatility of PAHs has inverse proportionality with that of molecular
weight [5].
Sources of Polycyclic Aromatic Hydrocarbons
PAHs are universal environmental contaminants/pollutants produced primarily as a
result of incomplete combustion of organic substances such as coal, oil, and petrol.
Predominantly, PAHs are released from anthropogenic activities; however, some
originates from natural sources in the environment including open air burning, seepage or natural losses of coal/petroleum deposits, and volcanic bursts [6, 7]. Majority
of PAHs anthropogenic sources include domestic heating system, carbon black, liquefying factories, coal gasification and tar, tarmac, aluminum and coke production,
catalytic cracking posts and connected activities in petroleum processing plants and
automobile exhaust. In the enclosed air, PAHs are found in gaseous stage and as ice
to vaporizers. Partitioning PAHs environmental compounds (in between the gaseous
and particulate phase) intensely affects their nature and movement in the environment and also by the way they get entered into the human body. PAHs removal from
the environment can be made via wet and dry sedimentation processes which are
intensely influenced by their gas/particle partitioning.
19 Role of Polycyclic Aromatic Hydrocarbons as EDCs in Metabolic Disorders
polluted gases and their residues in the air and also through direct skin contact.
EDCs transfer can also occur through placenta and breast milk from the pregnant
woman to the developing fetus and to the young child, respectively.
Different mechanisms are involved which interfere functions of the endocrine
system either by direct binding to hormonal receptors causing stimulation or inhibition of downstream cellular pathway of target cells or indirectly by increasing or
decreasing endogenous hormone(s) concentration. Therefore, this results in the
stimulation or inhibition of their bio-availability or degradation [2, 3]. Although
there are a lot of potent and most available classes of environmental chemicals
which are been studied but here in this chapter we have focused only on those which
are polycyclic aromatic hydrocarbons in nature.
Polycyclic Aromatic Hydrocarbons (PAHs)
Organic compounds which are composed of aromatic rings (two or more) arranged
in various configurations are termed as polycyclic aromatic hydrocarbons [4],
mostly white, colorless, or pale yellow solids. Generally, structural angularity,
hydrophobicity, resistance to biodegradation, electrochemical stability, persistency
and carcinogenic index of PAHs is directly proportional to the number of aromatic
rings, while volatility of PAHs has inverse proportionality with that of molecular
weight [5].
Sources of Polycyclic Aromatic Hydrocarbons
PAHs are universal environmental contaminants/pollutants produced primarily as a
result of incomplete combustion of organic substances such as coal, oil, and petrol.
Predominantly, PAHs are released from anthropogenic activities; however, some
originates from natural sources in the environment including open air burning, seepage or natural losses of coal/petroleum deposits, and volcanic bursts [6, 7]. Majority
of PAHs anthropogenic sources include domestic heating system, carbon black, liquefying factories, coal gasification and tar, tarmac, aluminum and coke production,
catalytic cracking posts and connected activities in petroleum processing plants and
automobile exhaust. In the enclosed air, PAHs are found in gaseous stage and as ice
to vaporizers. Partitioning PAHs environmental compounds (in between the gaseous
and particulate phase) intensely affects their nature and movement in the environment and also by the way they get entered into the human body. PAHs removal from
the environment can be made via wet and dry sedimentation processes which are
intensely influenced by their gas/particle partitioning.
19 Role of Polycyclic Aromatic Hydrocarbons as EDCs in Metabolic Disorders