Investigation of 235U, 226Ra, 232Th, 40K, 137Cs, and heavy metal concentrations in Anzali international wetland using high-resolution gamma-ray spectrometry and atomic absorption spectroscopy

Zare, Mohammad Reza; Kamālī, Mahdī; Fallahi Kapourchali, Maryam; Bagheri, Hashem; Khoram Bagheri, Mahdi; Abedini, Ali; Pakzad, Hamid Reza

Investigation of 235U, 226Ra, 232Th, 40K, 137Cs, and heavy metal concentrations in Anzali international wetland using high-resolution gamma-ray spectrometry and atomic absorption spectroscopy

2016

Measurements of natural radioactivity levels and heavy metals in sediment and soil samples of the Anzali international wetland were carried out by two HPGe-gamma ray spectrometry and atomic absorption spectroscopy techniques. The concentrations of ²³⁵U, ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs in sediment samples ranged between 1.05 ± 0.51–5.81 ± 0.61, 18.06 ± 0.63–33.36 ± .0.34, 17.57 ± 0.38–45.84 ± 6.23, 371.88 ± 6.36–652.28 ± 11.60, and 0.43 ± 0.06–63.35 ± 0.94 Bq/kg, while in the soil samples they vary between 2.36–5.97, 22.71–38.37, 29.27–42.89, 472.66–533, and 1.05–9.60 Bq/kg for ²³⁵U, ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs, respectively. Present results are compared with the available literature data and also with the world average values. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. Heavy metal concentrations were found to decrease in order as Fe > Mn > Sr > Zn > Cu > Cr > Ni > Pb > Co > Cd. These measurements will serve as background reference levels for the Anzali wetland.

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