The Pollution Load of Phthalates in the Effluent of Plastic Recycling Units in the Coastal Areas of the Southern Caspian Sea

Abstract

Population growth followed by the increase in plastic consumption and excessive production of plastic waste has caused many concerns for mankind. At present, human is taking action to deal with the plastic pollution crisis through mechanical recycling and returning it to the production cycle. Therefore, in the recycling process when plastics are crushed and washed, phthalic acid esters, which are one of their components, are easily separated from plastics due to their weakness and lack of covalent bond in their structure and enter the water and finally through the effluent enters the environment. This study aims to investigate the pollution load of diethyl phthalate (DEP), isobutyl phthalate (IBP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), bis(2-ethylhexyl) phthalate (BEHP), di n-octyl-phthalate (DOP) and Di methyl phthalate (DMP) in the effluent of plastic recycling units. Sampling of the effluent from 32 plastic recycling workshops in the cities of the three southern coastal provinces of the Caspian Sea in Iran was carried out. Laboratory analysis was performed by gas chromatography-mass spectrometer method after phthalates extraction with hexane. According to the specificity of each workshop in terms of the type of plastic they grind and wash, and data analysis using SPSS software, the average total concentration of phthalates as ppb was determined for DMP (0.27), DEP (8.02), IBP (20.97), DBP (3.41), BBP (8.18), BEHP (23.26) and DOP (0.04). The average total concentration of BEHP in all three PET, HDPE and LDPE recycling units was higher than other phthalates and the highest value was 41.94 ppb belonging to the PET recycling unit. LDPEs did not have DMP and except for DEP and DBP which had the highest concentration in HDPE form, other phthalates had the highest concentration in PET form and there was a significant relationship between different types of plastic with the type and amount of phthalates (p < 0.05). Also the risk assessment of phthalates in the effluent of the plastic recycling workshops in the southern coastal areas of the Caspian Sea showed that BEHP has the potential adverse effects in living organisms and has a very high risk and the cumulative risk assessment (CRA) of the measured phthalates showed a serious threat to health (HI > 100).

Graphical Abstract