Assessment of the occupational exposure at a fertiliser industry in the northern part of Greece

Abstract

In the northern part of Greece, close to the city of Kavala, a phosphoric acid production industry has operated since 1965. The raw material used is the phosphate rock imported from the foreign countries. During industrial processes, naturally occurring radioactive materials (NORM) deposits exist in many facilities in the industry, causing increased levels of radiation exposure. Additionally, increased levels of NORM concentrations are also detected in the waste material of the production process, the phosphogypsum. According to the Greek Regulations for Radiation Protection (no. 216B, 5/3/2001), which is in accordance with the 96/29/EURATOM 31/5/1996, the action levels concerning the effective dose to workers at workplaces due to natural radiation sources are 1 mSv y(-1). Work activities where the corresponding doses exceed 6 mSv y(-1) are under the control of the Greek Atomic Energy Commission (GAEC). The mean yearly radon concentration action level at workplaces is 400 Bq m(-3), while the corresponding concentration limit is 3000 Bq m(-3), respectively. GAEC, according to its constitutional law, is the responsible organisation to enforce and to implement the law by means of in situ surveys and laboratory measurements. The first inspection of the area was performed in 2002 and the first measures were proposed. Periodic inspections were performed every 2 y in order to extend the operation licensing of the industry. In this work a dose assessment of the workers based on in situ and laboratory measurements is presented. In order to assess the doses to the workers the external and the internal doses are estimated.

Sustainable Chemistry: Solubilization of Phosphorus from Insoluble Phosphate Material Hydroxyapatite with Ozonized Biochar

“…The wet route typically requires the use of strong industrial acids such as sulfuric acid, nitric acid, and/or hydrochloric acid to solubilize phosphate from phosphate rock materials. − The thermal route is represented by thermophosphate. , Both routes are quite energy-intensive. The use of strong industrial acids in the wet route is also not very environmentally friendly, in that they can be hazardous to the health of the people handling them. − Any environmentally friendly technology that could solubilize phosphorus from insoluble phosphate materials such as hydroxyapatite without requiring the use of strong industrial acids (e.g., hydrochloric acid) would be valuable to address the phosphorus sustainability issue for long-term agricultural and environmental sustainability.…”

Fast determination of phosphorus concentration in phosphogypsum waste using calibration-free LIBS in air and helium

“…Phosphate fertilizers' life cycle starts with phosphate ore (mainly of sedimentary or ingenious origin) that is chemically treated with sulphuric acid to produce phosphoric acid and phosphogypsum (PG) (CaSO 4 ) as a by-product waste. PG waste has considerable concentrations of radioactive materials ( 238 U, 226 Ra, 210 Pb, 232 Th, and others), phosphorus pentoxide (P 2 O 5 ), and some trace elements such as chromium, uoride, zinc, antimony, arsenic, lead, cadmium, and copper (Calin et al 2015;Cuadri et al 2014;Potiriadis et al 2011). So, a precise determination of phosphate content in fertilizers and PG is needed for agricultural good-practice and environmental protection.…”

“…Phosphogypsum (PG) is a by-product waste of phosphoric acid (H 3 PO 4 )/phosphate fertilizers manufacture where phosphate ore attacked by sulfuric acid (H 2 SO 4 ) as shown in the following reaction equation (Calin et al 2015;Cuadri et al 2014;Potiriadis et al 2011); Ca 5 (PO 4 ) 3 F + 5H 2 SO 4 + 10H 2 O 3H 3 PO 4 + 5(CaSO 4 .2H 2 O) + HF (Fluorapatite) (PG) Although there are various useful applications (such as agricultural and building materials), only about 15% of some billion tons of PG produced worldwide are recycled due to its impurities and contaminants (Nizevičienė et al 2018;Pacheco-Torgal et al 2012).…”

Fast Determination of Phosphorus Concentration in Phosphogypsum Waste Using Calibration-Free LIBS in Air and Helium

“…So, a precise determination of phosphate content in fertilizers and PG is needed for agricultural good-practice and environmental protection. Phosphogypsum (PG) is a by-product waste of phosphoric acid (H 3 PO 4 )/phosphate fertilizers manufacture where phosphate ore attacked by sulfuric acid (H 2 SO 4 ) as shown in the following reaction equation (Calin et al 2015;Cuadri et al 2014;Potiriadis et al 2011 Although there are various useful applications (such as agricultural and building materials), only about 15% of some billion tons of PG produced worldwide are recycled due to its impurities and contaminants (Nizevičienė et al 2018;Pacheco-Torgal et al 2012).…”