Sep 6, 2013

Phosphogypsum waste and the marine environment - science reports

Stockton Harbor's Kidder Point is host to industrial wastes from at least six fertilizer and chemical manufacturing companies that have operated there since the early 20th century.

The first five companies operated before  federal & state antipollution laws like the federal Clean Water Act and the Maine Site Location of Development Act were enacted in the 1970s. They collectively disposed of  tons of contaminated waste left over  from superphosphate fertilizer production. sulfuric acid production and alum production

PHOSPHOGYPSUM WASTE FROM  FERTILIZER PRODUCTION

VEGETATIVE COVER FOR PHOSPHOGYPSUM DUMPS: 
A ROMANIAN FIELD STUDY  "Metal uptake analyses (not presented here) showed higher concentrations of metals (up to 7 fold more) in plants grown on PG substrates, than in the same plants grown on normal soil. "Abstract The restoration of an uncontrolled phosphogypsum landfill was investigated for its effects on the
seasonal distribution of phytoplankton, ciliates, and copepods".  "Results showed drastic reduction of phosphate input and greater diversity of phytoplankton, ciliates, and copepods than before restoration. Pennate diatoms and new ciliates, considered bio-indicators of less-stressed marine ecosystems, proliferated in the A1 pond for the first time after restoration. Copepods appeared to feed on a wide range of prey."

IMPACT OF PHOSPHOGYPSUM AND OTHER FACTORY EFFLUENTS ON MEIOFAUNA COMMUNITIES OF BATROUN COASTAL REGION R. Mouawad 1, 2, G. Khalaf 1  and Y. Salameh 2 Meiofauna assemblages (nematodes) were sampled in summer 2007 and winter 2008 at ten stations along Batroun coastal region in North Lebanon, offshore from the fertilizer factory.

"A survey of the major meiofaunal taxa was made in order to study the impact of
chemical discharges (phosphogypsum) on meiofaunal population composition and density. There were significant changes in the community density and composition in the stations located in front of the plant (S5 to S8). Total meiofauna abundance was the lowest in the stations located in front of the plant."


Impacts of restoration of an uncontrolled phosphogypsum dumpsite on the seasonal distribution of abiotic variables, phytoplankton, copepods, and ciliates in a man-made solar saltern (Middle east). "Environmental Monitoring and Assessment 185 (2012) Accepted: 10 May 2012
"Abstract The restoration of an uncontrolled phosphogypsum landfill was investigated for its effects on the seasonal distribution of phytoplankton, ciliates, and copepods. Sampling was carried out monthly from September 2007 to August 2008 at four ponds of increasing salinity (A1, 41 psu; A5, 46 psu; A16, 67 psu; and C31, 77 psu) in the Sfax solar saltern (southeastern Tunisia). Physicochemical and biological analyses were carried out using standard methods.

Results showed drastic reduction of phosphate input and greater diversity of phytoplankton, ciliates, and copepods than before restoration. Pennate diatoms and
new ciliates, considered bio-indicators of less-stressed marine ecosystems, proliferated in the A1 pond for the first time after restoration. Copepods appeared to feed on a wide range of prey."

Assessment of phosphogypsum impact on the salt-marshes of the Tinto river (SW Spain): Role of natural attenuation processes by Aguasanta Miguel Sarmiento
About 120 Mton of phosphogypsum from the fertiliser industry were stack-piled on the salt-marshes of the Tinto river (Spain). This paper investigates the capacity of salt-marshes to attenuate contamination due to downward leaching from phosphogypsum. Solids and pore-waters were characterized at different depths of the pile to reach the marsh-ground. In superficial zones, metals were highly mobile, and no reduced sulphur was found. However, pollutant concentration decreased in the pore-water in deeper oxygen-restricted zones. Metal removal occurred by precipitation of newly formed sulphides, being this process main responsible for the contamination attenuation. Pyrite-S was the main sulphide component (up to 2528 mg/kg) and occurred as framboids, leading to high degrees of pyritization (up to 97%). The sulphidization reaction is Fe-limited; however, excess of acid-volatile sulphide over other metals cause precipitation of other sulphides, mainly of Cu and As. This decrease in metal mobility significantly minimises the impact of phosphogypsums on the salt-marshes.► Natural attenuation of contaminants occurs in phosphogypsums disposed on salt-marshes. ► Metals are highly mobile in superficial zones under oxidizing conditions. ► Mobility and toxicity strongly decrease in deep zones under oxygen-restricted conditions. ► Metal removal occurs by sulphate reduction and precipitation of metallic sulphides. ► Salt-marsh sulphate-reducing bacteria likely catalyse these natural processes. Publication Name: Marine Pollution Bulletin"

EPA about Phosphogypsum The United States Environmental Protection Agency has banned most applications of phosphogypsum "with a radium-226 concentration of greater than 10 picocurie/gram (0.4 Bq/g)."  "Due to the operational processes, which included the necessity to make sulfuric on site and the need for vast amounts of lead-lined chambers and vats to contain the corrosive acid, the sites left behind significant problems most notably with lead and arsenic contamination of soil and groundwater."


South Carolina Historic Superphosphate Fertilizer Industry.


Florida CHAPTER 62-673 PHOSPHOGYPSUM MANAGEMENT

Guidelines for  Management and Handling of Phosphogypsum Generated from Phosphoric Acid Plants [IN INDIA](Final Draft) CENTRAL POLLUTION CONTROL BOARD (Ministry of Environment & Forests) Parivesh Bhawan, East Arjun Nagar  DELHI -110 032 Website: www.cpcb.nic.in

European strategy for  use of phosphorus related chemicals (phosphogypsum)
"Phosphogypsum from the sulphuric acid dissolution should be re-used to the extent possible. If this is not practicable it has to be disposed of in a disposal facility appropriately equipped. A discharge into waters does not comply with BAT..."

A new approach to determine the phosphogypsum spread from the deposition site into the environment
Abstract
Phosphogypsum (PG), a waste product in phosphate fertilizer production, is characterized by technically enhanced natural radioactivity. The presented investigation was performed on a PG deposition site in Croatia. A new approach in the determination of the spread of PG particles from the deposition site into the environment based on the PG particle radioactivity measurements is suggested and explained. The stationary diffusion model was assumed and employed to describe long term PG particle transfer into the surroundings. The advantage of this method is that it requires a minimal number of measurement locations and offers a realistic and reliable distribution of PG particles. The mass concentration of PG particles decreased to the distance of about 3 m, at most up to 10 m from the deposition site edge. The results indicate that a unique mechanism of particle transport exists and the migration of PG particles by surface water is the dominant way of their spread. The particle current deduced from the measurements was very low, approximately 4.05 × 10−2 kg/h, and the migration coefficient was approximately 1.69 × 10−5 m2/h. The obtained results confirmed the initial hypothesis of the stationarity of the migration process, reached within about 6 years."

Investigation of the radiological impact on the coastal environment surrounding a fertilizer plant. J Environ Radioact. 2013 Jun 13.
Abstract
This investigation was carried out in order to assess the marine environmental radioactive pollution and the radiological impact caused by a large production plant of phosphate fertilizer, located in the Lebanese coastal zone. Natural radionuclides (238U, 235U, 232Th, 226Ra, 210Po, 210Pb, 40K) and anthropogenic 137Cs were measured by alpha and gamma spectrometry in seawater, sediment, biota and coastal soil samples collected from the area impacted by this industry. The limited environmental monitoring program within 2 km of the plant indicates localized contamination with radionuclides of the uranium decay chain mainly due to the transport, the storage of raw materials and the free release of phosphogypsum waste.

Environmental impact and management of phosphogypsum 

Abstract
The production of phosphoric acid from natural phosphate rock by the wet process gives rise to an industrial by-product called phosphogypsum (PG). About 5 tons of PG are generated per ton of phosphoric acid production, and worldwide PG generation is estimated to be around 100–280 Mt per year. This by-product is mostly disposed of without any treatment, usually by dumping in large stockpiles. These are generally located in coastal areas close to phosphoric acid plants, where they occupy large land areas and cause serious environmental damage. PG is mainly composed of gypsum but also contains a high level of impurities such as phosphates, fluorides and sulphates, naturally occurring radionuclides, heavy metals, and other trace elements. All of this adds up to a negative environmental impact and many restrictions on PG applications. Up to 15% of world PG production is used to make building materials, as a soil amendment and as a set controller in the manufacture of Portland cement; uses that have been banned in most countries. The USEPA has classified PG as a “Technologically Enhanced Naturally Occurring Radioactive Material” (TENORM).
This work reviews the different environmental impacts associated with PG storage and disposal.


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