RADIOECOLOGICAL IMPACTS OF DIRECT APPLICATION OF PHOSPHATE ROCK (DAPR) Prof. ASHRAF KHATER PHYSICS DEPT.- KING SAUD UNI. SAUDI ARABIA

Conclusions DAPR and U in phosphate industries are;

Radioecolgical aspects of PI

Radioecolgical aspects PI

Natural Radionuclides ( 238 U series, 232 Th series and 40 K) NORM Occupational Exposure Public Exposure  Products, by- products,  Tailing, wastes,..  waste water  dust Environmental Impacts

Source Processing Application Disposal Original conc. Enhanced Conc. Increase exposure Environ. Impact Avoid at source Change process precaution or avoid Condition or remediation IAEA- TRS-419

ENVIRONMENAL IMPACTS

Behaviour of radionuclides in terrestrial ecosystems

ExternalExposure From the plume From ground InternalExposure Inhalation (contaminated Foodstuffs) Exposure pathways

DAPR Phosphorus (P) is an essential for plant growth and increase production yield. Phosphate industries are one of the most consistent sources for hazardous materials (e.g. stable and radioactive trace elements) accumulation in the environment. Agricultural direct application of phosphate rock (DAPR) to tropical acid soils is an alternative well known practice to chemical P fertilizers (FP).

Phosphate ore Phosphate rock is the starting raw material for all phosphate products. Phosphate deposits contain calcium and phosphorus, essentially as tri- calcium phosphate, Ca 3 (PO 4 ) 2 ; (i) Sedimentary marine deposits; (ii) Igneous (magmatic) deposits; (iii) Metamorphic deposits; (iv) Biogenic deposits, mainly accumulations of bird and bat guano; (v) Deposits caused by weathering.

Phosphate ore Total global phosphate deposits are estimated to be 67 billion t. Most of these deposits are of sedimentary origin. Annual worldwide production is 210 Mt (2012); – –71% of all phosphate rock produced is processed into phosphoric acid, The annual production of P 2 O 5 in the form of phosphoric acid is more than 30 million tone and about 120 phosphogypsum. – –24% is processed directly into fertilizer, – –5% is converted directly into various other products, – –Elemental phosphorus by reduction in an electric arc furnace in a process known as the ‘thermal process’, relatively small amount

Most of the phosphoric acid ( %), (55–60% of total rock ) is convert to fertilizer. The fertilizer products so derived from phosphoric acid Most of the phosphoric acid ( %), (55–60% of total rock ) is convert to fertilizer. The fertilizer products so derived from phosphoric acid The remaining,10–25%, is processed equally into animal feed supplements and into a variety of other products.

The major source of phosphorus is PR (a finite and non-renewable resource). Phosphate rock is the primary raw material for producing soluble P fertilizers. It can be applied directly and can solubilize in the soil, making the P available to crops depending on the type of rock, soil properties, climatic conditions, crops/cropping systems, and nutrient management practices.

the suitability of DAPR: – – Type/source of apatite and solubility characteristics – –Soil properties – –Crop species – –Management practices – –Socio-economic conditions

Phosphate mining in SA Phosphate project, at Hazm Al-Jalamid- Northern east region of Saudi Arabia, is the biggest phosphate mining projects in the Middle East with run of mine (ROM) ore of about 12 M tone per year (Mtpy) and about 4.5 Mtpy phosphate concentrate. The Wa’ad Al Shammal project will have a capacity of about 3.5 million tonnes a year and start in the late 2016.

The concentration of 238 U and its decay products tend to be elevated in phosphate deposits of sedimentary origin. The 238 U concentrations in phosphate rock originating from sedimentary deposits generally fall within the range 0.2–2.5 Bq/g 238 U and 232 Th decay chains appear to be in approximate radioactive equilibrium. In most cases, the 238 U and 232 Th decay chains appear to be in approximate radioactive equilibrium. Phosphate ore

Due to the similarity in ionic size between U 4+ (0.99A˚ ) and Ca (0.89A˚ ), the tetravalent uranium can readily enter the apatite structure. Uranyl (U 6+ ) is much larger, it can only be fixed in the exterior part of the structure by various adsorption processes. The presence of tetravalent uranium implies strongly reducing organic mud in which apatite is formed. Hexavalent uranium exists under more oxidizing post-sedimentary conditions that occur generally during emergence Phosphate ore

U and some trace element in PR P2O5%P2O5%PbCdAsUOre Abu-Tartor-I Abu-Tartor-II Hamrawain Ave Traif (SA) Evaluation the radioecological impacts of DAPR!!!!

AAL (kg/h) +EC (PL)TAV* (mg/kg) MAC* (mg/kg) ---U As Cd Pb * Kabata- Pendios, EC, 1986

PbCdU *AAL (kg/ha) Time (t), y + (3-10) * Based on Canadian limit of 23 mg/kg for agricultural soil + calculated based on application rate of 600 kg PR/ha.y

Phosphate beneficiation

Wet process sulphuric acid phosphorus extraction process

U and some trace element (ppm) fractionation in beneficiation processes %P2O5 %Pb CdAsU ROM Conc mm Mag Slim

Measurement of Pb-210 using different techniques

IFA, 2013 The use of DAPR has fallen because of environmental restrictions in the unloading of finely ground PR and the increasing availability of water soluble chemical PF.

It would be very practical to use PR for direct application as source of P after considering the PR characterization, soil properties and other parameter. The main advantages of DAPR and /or phosphate beneficiation by products are; The cost, Reducing the amount of PI wastes such as phosphogypsum produced, Recycling the by products due to beneficiation processes. It seems that the evaluation processes of the ecological impacts of phosphate industries are fuzzy confused.

URANIUM IN PHOSPHATE FERTILIZERS: CONCENTRATION AND ENVIRONMENTAL IMPACTS Prof. ASHRAF KHATER PHYSICS DEPT.- KING SAUD UNI. SAUDI ARABIA

Phosphate industries (PI) are one of the most consistent sources for some hazardous trace as well as radioactive elements that could be accumulated in the environment especially in cropland soil. Phosphate industries (PI) are one of the most consistent sources for some hazardous trace as well as radioactive elements that could be accumulated in the environment especially in cropland soil. Since the 1950s, the application of plant nutrients, including phosphate fertilizers, has increased substantially. The long-continued application of phosphate fertilizers can redistribute and elevate uranium and toxic heavy metals, such as As, Cd and Pb in soil profiles and consequently their transfer to the food chain, mainly in acid soils. It can also raise these elements concentration in irrigation runoff/drainage waters (da Conceicao and Bonotto 2006).

Uranium in world P-resources can feed the nuclear energy cycle for 350 years (World U resources actually: approx. for 50 more years) cleaner fertilizers cleaner soils cleaner waters cleaner atmosphere By: Prof. Ewald Schnug

Phosphate fertilizers Phosphate rock product streams

Wet process sulphuric acid phosphorus extraction process

Phosphogypsum Th-232Po-210Pb-210 U-238Ra USA- Fl Europe South Africa Australia IN PHOSPHOGYPSUM (Bq/kg)

It has been estimated that, by 2006, a total of 2.6–3.7 billion t of phosphogypsum had been accumulated in stacks worldwide A phosphogypsum stack in central Florida, USA It has been estimated that, by 2006, a total of 2.6–3.7 billion t of phosphogypsum had been accumulated in stacks worldwide,

Sampling and sample preparation Analytical techniques

Uranium concentrations in PF WSGIGL 0.26 ( )39 (14-31)174 (38-329)U (ppm) (20-52)17 (17-20)38 ( 23-52)P (%) U (ppm) in Local granule PF U concentrations in locally produced fertilizers are higher than that of imported fertilizers, which depend on their levels in phosphate rocks and chemical treatments (sulfuric or nitric acids chemical attack).

Radium-226/Uranium-238 activity ratios were ranged from to and from 0.2 to 0.8 in locally produced and imported samples, respectively. It is related to the chemical processing of phosphate rocks, either sulfuric or nitric acid chemical attack.

There is no limit or a regulation for U concentration in PF !!!!!! The rate of PF application depend on their P content. Most literature, if not all, express the uranium concentration per phosphate mass which are mainless. U concentration should be expressed per unit mass of P. The relation ship between U concentration and PF physical forms needs more research.

P fertilizers There is no MAC for natural radionuclides in FP. –The federal German authority for environmental protection is going to recommend mg U/ kg P 2 O 5. – the recommended Canadian Soil Quality Guidelines for the protection of environmental and human health are 23 mg/kg for agricultural land & residential/parkland land use, 33 mg/kg for commercial land use, and 300 mg/kg for industrial land use (due to off-site migration check).

# Long-term impacts of P fertilization # Long-term impacts of P fertilization The mobilization and accumulation behavior of U in soil plays a key role in risk assessment studies

Twenty eight soil samples were collected from 14 location in 25 year old farm, where one cultivated (in) and another uncultivated soil (out) from each location. Fourteen water sample were collected from 14 underground water wells, as shown (map) All soil samples were dried, crushed, homogenized and sieved through 2 mm sieve

All soil samples were leached using Aqua Rigia and completely dissolved using mineral acid (HF, HNO 3, HCl) Uranium in soil and water samples were measured using Perkin Elmmer ICP-MS model ELAN-9000 at ALS Chemex – Canada. Soil physical and chemical properties (pH, EC, organic matter %, CaCo 3 %, soluble anions and soluble cations) and soil texture (clay%, silt% and sand %) were determined using standard method (Omran 1987)

Uranium activity concentration in Bq/kg

Average uranium concentration, mg/kg (Bq/kg) in different countries soil MeanRangeCountry 1.9 (24) S.A 1.22 (15) Canada 3.7 (46) 2.5 (31) < 0.01 – 45 U.S.A Europe Kabata- Pendias, 2001 & Salminen 2005

Leachable U in Soil

 Interaction of radionuclides with OM leads to formation of mineral-organic complexes and chelates, which is more important than metals hydroxo complex.  OM is extremely heterogeneous. There are a large number of possible reaction and interaction of radionuclides with OM.  The stability of these complexes depends on the pH of the soil, the cation concentration in the soil, the functional gp and the degree of saturation of the potential sorption site  Interaction of radionuclides with OM leads to formation of mineral-organic complexes and chelates, which is more important than metals hydroxo complex.  OM is extremely heterogeneous. There are a large number of possible reaction and interaction of radionuclides with OM.  The stability of these complexes depends on the pH of the soil, the cation concentration in the soil, the functional gp and the degree of saturation of the potential sorption site

Uranium in water

Going on projects # Industrial radioecology of Al-Jalamid phosphate mining, Saudi Arabia (NPST) : Characterize the radiological and elemental features of phosphate mining and beneficiation materials, Establishment an environmental baseline assessments (EBAs), Evaluation of the radio-ecological impacts of phosphate mining processes, Evaluation and management of radiation exposure due to phosphate mining processes, Mining wastes and by-products characterization, management and recycling

# Radioecological impacts and risk assessment of phosphate fertilizers - Saudi Arabia (NPST) : Radiological and chemical characterization of TENORM and selected heavy metals in various phosphate fertilizers Radioecological impacts of PFs industry. Radioecological impacts of long term soil fertilization. Risk assessment for TENORM and selected heavy metals in PFs life cycle

Relationship between phosphate fertilizers quality and their physical forms. Application of biopolymers for heavy metals and natural radionuclides removal. Removal of heavy for heavy metals and natural radionuclides using meso-porous nano-materials.

Conclusions

Radioecolgical aspects of PI

Radioecolgical aspects PI

Time WastesWastes Achieve safe disposal and recycle Best Practice Risks to Worker or Public & environment environment

Thank you for your attention!

Thank you for your attention

Conclusions Some chemical industries produce a huge amount of wastes….. NORM is extremely high in some wastes Their radio-ecological impacts should be investigate deeply to ensure the environ-mental and health safety. Toxic heavy element impacts should be considered as associated risk with NORM, Wastes could be considered as a mixed hazardous materials Environmental impacts should be more studied RP regulations for NORM in chemical industries (except uranium and oil/gas) are not really exist. RP regulations for NORM in chemical industries (except uranium and oil/gas) are not really exist.