NOVA Science Publishers Inc. , New York, 2022
Phthalates are esters of phthalic acid that are group of chemicals used in mainly production of plastics. Phthalates are also called plasticizers that make solid plastics flexible and soft. Besides plastics, phthalates are also used as raw materials and/or auxiliary chemicals in many industrial activities.
Phthalates are classified as low molecular weight (C1-C6) and high molecular weight (C7-more) phthalates according to the carbon chain length of the subgroup in their chemical structure. Low molecular weight phthalates are used as raw materials or auxiliary chemicals in the production of cosmetics, detergents, shampoo, soap, paper, automotive, building materials, medical materials and paint. Diethylphthalate (DEP), one of the low molecular weight phthalates, is used in cellulosic films as well as a stabilizer and carrier in perfumes and fragrances. High molecular weight phthalates are generally used as vinyl plasticizers in the production of polyvinylchloride (PVC).
Phthalates are lipophilic substances in terms of their chemical structure and their solubility in water decreases inversely with the length of the subgroup carbon chain. Phthalates do not covalently bond to the plastics and release into their environment slowly over time. Because of their widespread use, phthalates are very common in nature and are classified as non-persistent pollutants. Their harmful effects have started to be shown by studies conducted in the last 20-30 years and revealed that phthalates have endocrine disrupting effects. For this reason, phthalates have begun to be classified as Endocrine Disruptive Chemicals. In addition, the use of certain phthalates has been restricted by the European Union and the United States at first. Diethylhexyl phthalate (DEHP), which is widely used phthalate in production of plastics, was the first phthalate to be restricted within the scope of the European Union REACH regulation in 1999 due to its effects on human health, especially infants and children. According to the restriction, DEHP should be less than 0.1% by mass in the manufacture of toys and materials related to children. Subsequently, Dibutyl phthlalate (DBP), Butylbenzyl phthalate (BBP), Di-iso-nonyl phthalate (DINP), Di-iso-decyl phthalate (DIDP), Dioctyl phthalate (DOP) and Di-iso-butyl phthlalate (DIBP) were added to the restricted phthalates.
Phthalates has been determined that they exert endocrine disrupting effects by changing the actions of some hormones in the body. Phthalates affect the endocrine system by mimicking or inhibiting endogenous hormones, interfering with hormone receptors, or inhibiting the synthesis of hormones. The effects of phthalates do not reflect the classical dose-response curve. Their harmful effects vary with dose, and they have a non-monotonic dose-response curve. In addition, harmful effects of phthalates are observed even at very low doses. Exposure to phthalates during developmental stages has been shown to cause greater effects. Therefore, it is necessary to monitor the exposure of these substances effectively in terms of human health. It is important to determine the concentrations of phthalates accurately and precisely, whose use is restricted, in various materials. As stated in Chapter I, proper preparation and extraction of the samples are also an important issue that needs attention in order to determine the phthalate concentrations in the materials. Analysis of many phthalates is carried out by chromatographic methods. High-performance liquid chromatography (HPLC), gas chromatography–mass spectrometry, liquid chromatography-tandem mass spectrometry and gas chromatography-tandem mass spectrometry are the most used analytical methods in phthalate analysis.
Exposure of human and natural life to phthalates occurs through inhalation, dietary and dermal routes. After phthalates are taken into the human body, they are metabolized by going through various detoxification stages. The primary and secondary metabolites of phthalates after detoxification stages are removed from the body by the kidneys. However, the metabolites of phthalates may exert more harmful effects than the parent chemical. Although phthalates have a short half-life in the body, they are, they tend to accumulate in tissues such as adipose tissue, kidney and lung, due to their lipophilic properties. Especially during the developmental periods, the harmful effects of these accumulated phthalates may increase even more. Phthalates accumulated in the adipose tissue are released as energy needs of the body increases during pregnancy, and cause adverse effects for both mother and child. Therefore phthalates, which are known to pass through the placenta, impair the development of fetus, especially the reproductive organs. Depending on the areas of usage, the effects of these substances may increase. DEHP, which is used especially in medical products, especially in tubes, serum and blood bags, causes more exposure of patients.