Abstracts on Phosphate Fertilizers that cite effects or levels of fluoride
Part 2: 1990 - present
See also Part 1: 1954-1989
 
 

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The Phosphate Fertilizer Industry: An Environmental Overview

Photographs of the Phosphate Fertilizer Industry

This photo was taken by Michael Connett in Central Florida (the heart of the phosphate industry) in June 2001.

Full report available at Science Direct

Environmental Pollution - Volume 139, Issue 2 , January 2006, Pages 232-243

Radionuclides, heavy metals and fluorine incidence at Tapira phosphate rocks, Brazil, and their industrial (by) products

Fabiano Tomazini da Conceição (a), and Daniel Marcos Bonotto (b)

(a) Unidade Diferenciada Sorocaba/Iperó (UDSI), UNESP, Sorocaba, Iperó, Brazil
(b) Instituto de Geociências e Ciências Exatas (IGCE), UNESP, Rio Claro, Brazil

Abstract
Inorganic phosphate fertilizers may contain radionuclides, heavy metals and fluorine. This paper presents the possible environmental hazards from Tapira phosphate rocks and their (by) products (Brazil) utilized as phosphate fertilizers. The activity concentration of 238U, 234U, 226Ra and 40K in Tapira phosphate rocks is within the world range for these rock types. The 232Th activity concentration is higher than the mean reported in phosphate rocks. A value of 2184 nGy h-1 was obtained for the exposure dose rate in Tapira phosphate deposit area, which is indicative of a high background radiation area. The flotation-separation process causes the incorporation of no more than 9%, 11% and 24% of radionuclides, heavy metals and fluorine, respectively, into the phosphate concentrate. The radionuclides and heavy metals existing in phosphate fertilizers applied in Brazilian crops according to the recommended rates, do not raise their concentration in soils to harmful levels.

1. Introduction
... Phosphate fertilizers are manufactured from phosphate rocks and, according to their origin, may contain various heavy metal micronutrients (Co, Cu, Fe, Mn, Mo, Ni, Zn), fluorine and heavy metals considered toxic (As, Al, Cd, Pb and Hg) (Camelo et al., 1997 and Mirlean et al., 2001). The build up of toxic heavy metals and fluorine in soils as a result of continuous application of phosphate fertilizers has been evaluated in long term experiments carried out in many national and international studies (Allaway, 1968, Kabata-Pendias and Pendias, 1984, Adriano, 1986, Mortvedt, 1987, Mortvedt, 1991, Alloway, 1990, Bockman et al., 1990, Freitas, 1992, Charter et al., 1993, Kponblekou and Tabatabai, 1994, Malavolta, 1994, McLaughlin et al., 1996, Gimeno-García et al., 1996, Camelo et al., 1997 and Abdel-Haleem et al., 2001).

The phosphate rocks are also enriched in uranium, thorium and their daughters, deposited as calcium phosphate minerals by isomorphic substitution (Pfister et al., 1976), since the natural uranium can substitute calcium in the phosphate rock structure due to the similarity in ionic size between U4+ and Ca2+ (Guzman, 1992). The presence was first reported in 1908 (Ring, 1977) and the behaviour has been described worldwide (Menzel, 1968, Pfister et al., 1976, Ring, 1977, Guimond, 1978, Rothbaum et al., 1979, Mortvedt, 1986, Todorovsky and Kulev, 1993, Sam and Holm, 1995, Hull and Burnett, 1996, Alam et al., 1997, Ioannides et al., 1997, Ibrahim, 1998, Khan et al., 1998, Sam et al., 1999 and Khater et al., 2001). Various authors have also studied the behaviour of radionuclides in phosphogypsum (Bolívar et al., 1995, Rutherford et al., 1994 and Haridasan et al., 2002) and in phosphoric acid (Singh et al., 2001) that are by-products of the fertilizer industry. In Brazil, most of the studies have emphasized the presence of radionuclides in phosphate rocks and phosphogypsum (Paschoa et al., 1984, Pessenda et al., 1988, Godoy, 1989, Mazzilli and Saueia, 1997 and Mazzilli et al., 2000).

The long-continued application of phosphate fertilizers and their by-products can redistribute and elevate heavy metal and fluorine concentrations in soil profiles, and, consequently, their availability for plants and subsequent transfer to the human food chain, mainly in acid soils. Thus, it is important to know the proportion of such a transfer due to the implications for human and animal health (Malavolta, 1994). Additionally, the long-continued application of phosphate fertilizers can also raise the heavy metal and fluorine concentrations in irrigation runoff/drainage from fertilized lands, and, then, their application in agricultural soils constitute another source for workers and members of the public. Thus, the objective of this paper was to investigate possible environmental hazards caused by the presence of radionuclides, heavy metals and fluorine in Tapira phosphate rocks and their (by) products used as phosphate fertilizers. This is because they are used by the Brazilian agriculture system, mainly in the southeast region (São Paulo, Minas Gerais, Espírito Santo and Rio de Janeiro states) that concentrates the more modern and productive agricultural areas in Brazil (IBGE, 1998). Moreover, a contamination index has been applied to provide a basis for comparison of potential radionuclides, heavy metals and fluorine hazards...

5. Conclusion
The heavy metal concentration and 238U, 234U, 226Ra and 40K activity concentration in Tapira phosphate rocks is within the worldwide range for these rock types. The flotation-separation process used to produce commercial-grade fertilizer causes the incorporation of no more than 11% of heavy metals, 24% of fluorine and 9% of radionuclides into the phosphate concentrate. The addition of inorganic phosphate fertilizers to soils and crops has become a common practice in agriculture and the results show that the additional external radiation exposure for the farmers due to phosphate fertilizers is insignificant if compared to the average annual effective dose from other natural sources and, consequently, the possible increase of (a) radon flux from the soil, (b) uptake by plants and (c) natural alpha activity of food products must be minimal. The heavy metal environmental hazards to the population due to phosphate fertilizers are also negligible. On the other hand, the high input of fluorine may pollute 220 m3 of water with the tolerance limit of 1.4 mg L-1. Thus, among the analysed elements, fluorine may be of major concern since no allowable limit has been established by the Brazilian legislation for its addition into soils. Despite the fact that low agrichemical addition of heavy metals and radionuclides is expected during the use of phosphate fertilizers in Brazilian crops, other elements not often considered in mass-balance calculations must be properly evaluated to yield more realistic scenarios related to long term use.

Table 3.
Activity concentration of radionuclides and Raeq (Bq kg-1) in phosphate rocks from different countries
Country 238U 226Ra 232Th 40K Raeq Reference
Brazil (Araxá) 1849 Cullen and Paschoa (1978)
Brazil (Jacupiranga) 370 Lapido-Loureiro (1986)
URSS (Kola) 40 30 80 40 147 Guimond (1990)
Morocco 1700 1600 20 10 1629 Guimond (1990)
Sudan (Uro) 2598 2263 2.5 51.7 2270 Sam and Holm (1995)
Sudan (Kurun) 684 555 0.83 23 558 Sam and Holm (1995)
Egypt (Abu-Tartor) 408 287 23.7 21.4 323 Khater et al. (2001)
USA (North Florida) 474 648 Rossler et al. (1979)
Tanzania (Arusha) 4641 5022 717 286 6069 Makweba and Holm (1993)
Israel 1726 1852 11 4 1868 Olszewska-Wasiolek (1995)
Tunisia 580 821 29 32 865 Olszewska-Wasiolek (1995)
Algeria 1627 619 64 22 712 Olszewska-Wasiolek (1995)
Jordan 1837 1044 2 8 1048 Olszewska-Wasiolek (1995)

Bureau of Mines, Avondale, MD. Avondale Research Center. 1982.

Available from NTIS: Order Number: NTIS/PB82-176330, 23p

Fluorine and Uranium in Phosphate Rock Processing and Waste Materials

Haynes BW, Kramer GW, Jolly JA

Materials from phosphate rock mining and processing were analyzed for fluorine and uranium content as part of the Bureau of Mines program to more effectively recover resources from mining and mineral processing reject materials. The analysis of both feed and waste materials generated in the beneficiation and acidulation of phosphate rock was performed to obtain information on the disposition and concentration of these elements in phosphate rock processing streams. Fluorine was determined by a distillation-titration method and by ion chromatography. Uranium was determined by the dibenzoylmethane (DBM) method, the reliability being confirmed by roundrobin analysis of samples within Bureau of Mines research centers. National Bureau of Standards (NBS) Standard Reference Material (SRM) 120b-Phosphate Rock was also analyzed for fluorine and uranium to verify procedures and results. Fluorine values ranged from 0.3 wt-pct in gypsum filter cake to 3.7 wt-pct in phosphate rock concentrate.


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9393620&dopt=Abstract

Mutat Res 1997 Oct 24;393(3):283-8

Chromosomal aberrations and micronuclei in lymphocytes of workers at a phosphate fertilizer factory.

Meng Z, Zhang B.

Department of Life Sciences, Shanxi University, Taiyuan, China.

The frequencies of chromosomal aberrations (CA) and micronuclei (MN) in peripheral blood lymphocytes of 40 workers at a phosphate fertilizer factory in North China, were studied. HF and SiF4 are the main air pollutants and small amounts of dust containing fluoride, NH3 and SO2 were also present in the factory. It was shown that the chemicals caused an increase in both CA and MN. The mean frequencies per 100 metaphase of major CA type (chromosome rings, translocations, and dicentrics) of the workers and the non-exposed controls were 0.91 and 0.24 (p < 0.01), respectively. The average percentages of lymphocytes with MN of the workers and the controls were 1.55 +/- 0.71 and 0.62 +/- 0.54 (p < 0.01), respectively. Both CA frequency and MN frequency of the workers increased with length of the chemical exposure period up to 10 years.


PMID: 9393620 [PubMed - indexed for MEDLINE]


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Mutat Res 1995 Apr;334(2):243-6

Sister-chromatid exchanges in lymphocytes of workers at a phosphate fertilizer factory.

Meng Z, Meng H, Cao X.

Department of Environmental Science, Shanxi University, Taiyuan, People's Republic of China.

The frequencies of sister-chromatid exchange (SCE) in peripheral blood lymphocytes of 40 workers at a phosphate fertilizer factory in North China were studied. HF and SiF4 are main air pollutants in the factory, there is also some dust containing fluoride, phosphate fog, NH3 and SO2. It was shown that the chemicals caused an increase in SCE, and also induced cell mitotic delays. The mean SCEs/cell of the workers and the non-exposed controls were 7.47 +/- 0.31 and 4.94 +/- 0.14 (p < 0.01) respectively. SCEs/cell in 75% of 40 workers were higher than 6 while 40 controls all had values lower than 6. SCE frequencies of the workers increased with length of the chemical exposure period up to 10 years. Smoking enhanced the SCE frequencies induced by the chemicals.


PMID: 7885378 [PubMed - indexed for MEDLINE]


From Toxline at Toxnet

MUTAT RES 1991 DEC;253(3):278

INDUCTION OF MICRONUCLEI BY SODIUM FLUORIDE.

SUZUKI Y, LI J, SHIMIZU H

DEPARTMENT OF PUBLIC HEALTH, THE JIKEI UNIVERSITY SCHOOL OF MEDICINE, TOKYO, JAPAN.

More than 500 million people live in communities with artificially or naturally fluoridated drinking water that has been treated with 1 ppm or more of fluoride. Workers in aluminum plants, phosphate fertilizer plants and other fluoride-related factories are also exposed to high concentration of fluoride. It is reported that workers in aluminum plants suffer from an increased risk of leukemia. To date, information concerning the topic remains controversial. It is important to evaluate the genotoxic effects of fluoride by in vivo test systems because of its increasing usage. We tested the induction of mutagenic effects by in vivo and in vitro bone marrow micronnucleus tets. A significant increase in micronucleated polychromatic erythrocytes was observed 24 h after introperitoneal injection of sodium fluoride at a dose of 30 mg/kg body weight. In the in vitro micronucleus test, the frequency of micronucleated polychromatic erythrocytes was increased significantly at concentrations of 2 and 4 mm. These results indicate that the micronucleus test may be useful in evaluating the cancer risk of sodium fluoride.


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J Environ Biol 2002 Jul;23(3):265-9

Retarding fluoride accumulation in Amaranthes viridis through liming and implications of phosphorous treatment.

Stanley VA, Shaleesha A, Murthy PB, Pillai KS.

Department of Toxicology, Fredrick Institute of Plant Protection and Toxicology, Padappai 601 301, India.

With an objective to retard fluoride being taken up by the plants from soil, a study was carried out on Amaranthes viridis. Four groups of treatment were carried out vis-a-vis fluoride alone, fluoride and calcium, fluoride and phosphorous and fluoride, calcium and phosphorous together at three different concentration levels vis-a-vis 1, 10 and 25 mg/kg soil of each. Sampling was carried out first on day 45 and at the end of reproductive phase on leaf and seed for accumulation of fluoride in the plants. It was observed that fluoride accumulation in plants could be averted through soil amendment by calcium treatment in the form of calcium carbonate thereby reducing the risk of human and livestock exposure to abnormal levels of fluoride through food chain other than protecting plants from getting affected. At the same time, fertilizing the soil contaminated with fluoride by superphosphate would aggravate fluoride accumulation and exacerbate fluorosis problem in human and livestock through food chain. Therefore it is recommended to use acid water-soluble orthophosphate or anhydrous dicalcium phosphate or soluble pyrophosphate fertilizers as an alternative.


Table 2. Fluoride concentration of a range of phosphate rocks and fertilisers that have been used in New Zealand.

Material

F concentration (%)

Reference

Phosphate rocks

Arad (Israel)

4.0

Syersetal. (1986)

Christmas Island -A

2.2

Evans et al. (1971)

Chatham Rise phosphorite

3.0

Syersetal. (1986)

Gafsa (Tunisia)

4.1

Syersetal. (1986)

Jordan

3.8

Syersetal. (1986)

Makatea Island

3.2

Syersetal. (1986)

Mexican

4.1

Syersetal. (1986)

Khouribga (Morocco)

4.0

Anon. (1990)

Nauru Island

3.0

Syersetal. (1986)

North Carolina

3.5

Syersetal. (1986)

North Florida

4.0

Syersetal. (1986)

Sechura (Peru)

3.4

Syersetal. (1986)

Fertilisers

Single superphosphate

1.08-1.84

Evans et al. (1971); P. Loganathan et al. unpubl. data; McLaughlin et al. (1997)

Triple superphosphate

1.3-2.4

Mordvedt & Sikora (1992); Evans et al. (1971)

Monoammonium phosphate

1.6-2.2

Mordvedt & Sikora (1992); Evans et al. (1971)

Diammonium phosphate

1.2-3.0

Mordvedt & Sikora (1992); Manoharan et al. (1996)

Ref: New Zealand Journal of Agricultural Research, 2000, Vol 43: 295-321
Fluoride: A review of its fate, bioavailability, and risks of fluorosis in grazed-pasture systems in New Zealand
by S. J. CRONIN, V. MANOHARAN, M. J. HEDLEY, P. LOGANATHAN.
Online at http://www.rsnz.org/publish/nzjar/2000/29.pdf
Keywords cattle; fluoride; pasture; fluoride bioavailability; fluorosis; phosphate fertilisers; sheep; soil ingestion; volcanic ash


The Concern Over Fluorides by Raymond Sheldrake, Jr. Professor Emeritus, Cornell University.

... We used a mix of 50-50 peat and perlite (volume) and used rates of dolomitic limestone of 0,10, 20, and 30 pounds per cubic yard. We direct seeded three crops in 6-inch pots of these mixes (lettuce, spinach, and ryegrass). The peat had a pH of 3.5 and the perlite 7.5. To a cubic yard of the peat-perlite were added 1 pound of granular super-phosphate (0-20-0), 1.5 pounds of calcium nitrate, 1 pound of slow release nitrogen (31-0-0) and 1.5 ounces of FTE 503. Potash was added in the liquid feed as KNO3 at 1 pound per 100 gallons.

What happened? Well, we got a lot of data and published a paper in the Journal of the American Society for Horticultural Science, Vol. 103(2). March 1978.* Since few growers may have seen this, I will popularize the findings here.

As expected, when we increased the limestone the pH went up and the fluoride in the "soil" solution went down. We analyzed the leaves and the fluoride pick up went down.

I will list the pertinent data below and will use only the leaf analysis data for spinach because it is known to be a good accumulator of fluoride.

The Effect of Limestone Additions to Peat and Perlite Mix
Limestone lbs/yd3
pH
Fluoride in Media Solution, PPM
Fluoride in Leaves, PPM
0
5.0
44.1
30.8
10
7.5
7.4
10.2
20
7.3
5.1
7.2
30
7.2
3.8
5.7

In an attempt to ascertain where fluoride might come from in a peat-perlite mix we analyzed many components and some of the levels are presented.

Releasable Fluoride and pH of Individual Constituents of Growing Media
Constituent
pH
Fluoride, PPM
Sphagnum peat moss
3.5
1.4
Perlite
7.5
9.1
Superphosphate
3.2
1254.0
Calcium Nitrate
5.6
19.0
Slow release 31-0-0
7.5
0.4
FTE 503
9.1
91.2
Limestone
9.3
2.9
Activated Charcol
9.9
0.1

* Sheldrake, Raymond, George E. Doss, Leigh E. St. John, Jr., and Donald J. Lisk
Lime and Charcoal Amendments Reduce Fluoride Absorption by Plants Cultured in a Perlite-peat Medium. J. Amer. Soc. Hort. Sci. 103(2): 268-270,1978.

See also: Fluoride levels in Perlite and various fertilizers and substrate components. A report from The Schundler Company.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=17288010&query_hl=1&itool=pubmed_DocSum

Environ Geochem Health. 2007 Feb 8; [Epub ahead of print]

Fluoride distribution in the environment along the gradient of a phosphate-fertilizer production emission (southern Brazil).

Mirlean N, Roisenberg A.

Department of Geosciences, FURG, Av. Italia, km-08, Campus Carreiros, Rio Grande, 96201-900, RS, Brazil, nmirlean@log.furg.br.

Airborne fluoride was determined in the rainwater, surface soil and groundwater along a gradient of emission of a phosphate fertilizer factory in Rio Grande, southern Brazil. Concentrations of fluoride in rainwater and groundwater achieved 3 mg l(-1) and 5 mg l(-1), respectively, and were dependent on pH. The fluoride deposited from emissions accumulated in a superficial horizon of soil in quantities comparable to those in the manufactured end-products-up to 23,000 mg kg(-1). Fluoride distribution in the environment is controlled by physical-chemical parameters of emission, rain intensity and soil properties. The highest fluoride concentrations were registered at a close distance of up to 2 km from the factory. The distribution of fluoride in groundwater resembled the same distribution in rainwater due to the high permeability of the local soils. Fluoride penetration to the groundwater also depended on the type of vegetation cover. The groundwater in woodland areas was less affected by contamination of fluoride than in the grassland areas, most probably because of the influence of eucalyptus throughfall, which increases the pH of wet precipitates.

PMID: 17288010 [PubMed - as supplied by publisher]


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J Occup Environ Hyg. 2007 Jan;4(1):17-25.

Chemical characteristics of aerosol mists in phosphate fertilizer manufacturing facilities.

Hsu YM, Wu CY, Lundgren DA, Nall JW, Birky BK.

Department of Environmental Engineering Sciences, University of Florida, Gainesville, Florida 32611, USA.

Of the carcinogens listed by the National Toxicology Program (NTP), strong inorganic mists containing sulfuric acid were identified as a known human carcinogen. In this study, aerosol sampling was conducted at 24 locations in eight Florida phosphoric acid and concentrated fertilizer manufacturing plants and two locations as background in Winter Haven and Gainesville, Florida, using dichotomous samplers. The locations were selected where sulfuric acid mist may potentially exist, including sulfuric acid pump tank areas, belt or rotating table phosphoric acid filter floors, sulfuric acid truck loading/unloading stations, phosphoric acid production reactors (attack tanks), and a concentrated fertilizer granulator during scrubbing with a weak sulfuric acid mixture. An ion chromatography system was used to analyze sulfate and other water soluble ion species. In general, sulfate, fluoride, ammonium, and phosphate were the major species in the fertilizer facilities. For the rotating table/belt phosphoric acid filter floor, phosphate and fluoride were the dominant species for PM10, and the maximum concentrations were 170 and 106 microg/m3, respectively. For the attack tank, fluoride was the dominant species for PM10, and the maximum concentration was 462 microg/m3. At the sulfuric acid pump tank, sulfate was the dominant species, and the maximum PM10 sulfate concentration was 181 microg/m3. The concentration of PM10 sulfate including ammonium sulfate, calcium sulfate, and sulfuric acid were lower than 0.2 mg/m3 at all locations. The aerosols at the filter floor and the attack tank were acidic. The coarse mode aerosol at the sulfuric acid pump tank (an outdoor location) was acidic, whereas the fine mode aerosol was neutral to basic.

PMID: 17162477 [PubMed - indexed for MEDLINE]


http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=17386441&query_hl=1&itool=pubmed_DocSum

Anal Chim Acta. 2007 Jan 2;581(1):168-73. Epub 2006 Aug 7.

On-line flow injection solid sample introduction, leaching and potentiometric determination of fluoride in phosphate rock.

Sweileh JA.

Department of Chemistry, The Hashemite University, P.O. Box 150459, Postal Code 13115, Zarka, Jordan. jsweileh@hotmail.com <jsweileh@hotmail.com>

A flow injection method with on-line solid sample dissolution was developed for the determination of fluoride in phosphate rock. The fluoride was selectively leached (98-102.4 % recovery) from a 50-mg powdered phosphate rock sample with 0.50 M citric acid. Using the zone sampling technique the fluoride in the buffered leachate was determined by injecting 87 muL into the carrier stream using a fluoride ion-selective electrode detector. The sensing element of the electrode was housed in a home-made sleeve-type flow-through cell. On-line solid sample digestion with 0.50 M citric acid at 55 degrees C resulted in minimum dissolution of interfering iron and aluminum ions with improved accuracy and calibration linearity. The incorporation of relatively high level of fluoride in the carrier stream (40 microg mL(-1)) facilitated the determination of high levels of fluoride in phosphate rock (up to 4.1%) with out the need for excessive on-line dilution. The optimized flow system was applied for the determination of fluoride in phosphate rocks samples and a reference material at a rate of nine samples per hour with a relative standard deviation (n=5) of 2.95-4.0 %. Comparison of the proposed flow injection method with the standard method, which involves steam distillation from sulfuric acid solution and manual titration with thorium nitrate, showed no evidence of bias at the 95% confidence level.

PMID: 17386441 [PubMed - in process]


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Huan Jing Ke Xue. 2006 Nov;27(11):2279-82.

[Sequential extraction experiments applied to study chemical mobility of fluorine in rocks]

[Article in Chinese]

Xu LR, Liang HD, Luo KL, Feng FJ, Tan JA.

Key Laboratory of Coal Resources, Ministry of Education, China University of Mining and Technology, Beijing 100083, China.

Sequential extraction experiments were used to study the chemical mobility of fluorine in rocks. The results show that there are quite big differences in chemical mobility of fluorine in rocks of different types. Fluorine in carbonate rock is very active, in which the proportion of leachable fluorine is generally more than 75%. Fluorine in black rocks of Lower Cambrian is closely related to their different metamorphosed grades, in which fluorine in black carbonaceous slate with higher metamorphosed grade mostly has lower leachability than black shale and black siliceous rock. Generally speaking, the leachable percentage of fluorine is high in phosphorite rocks and low in phyllite. The leachable fluorine in diabase is in direct proportion to its fluorine concentration. There are some differences in chemical mobility of fluorine in stone coal of different ages. Fluorine in stone coal of Silurian has higher leachability than stone coal of Cambrian.

PMID: 17326440 [PubMed - in process]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12602633&dopt=Abstract

Environ Monit Assess 2003 Mar;82(3):311-20

Spatial patterns of nitrate, chloride, sulfate, and fluoride concentrations in the Woodbine Aquifer of north-central Texas.

Hudak PF, Sanmanee S.

Department of Geography and Environmental Science Program, University of North Texas, Denton, Texas, USA. hudak@unt.edu

A geographic information system was used to map and analyze nitrate, chloride, sulfate, and fluoride concentrations in 110 wells tapping the Woodbine Aquifer. The study area, covering nine counties in north-central Texas, includes large percentages of both urban and agricultural land uses. Land use maps were compared with solute concentration data, and statistics were applied to detect associations between solutes, well depth, and land use. Anthropogenic sources such as fertilizer applications and natural sources such as gypsum, lignite, and clay deposits controlled nitrate, chloride, and sulfate concentrations, each inversely correlated with well depth. However, only one nitrate observation--from a shallow well in the aquifer's outcrop zone--surpassed the maximum contaminant level (MCL) of 44.3 mg L(-1). By comparison, nearly half of the sulfate and several of the chloride observations surpassed the MCL of 250 mg L(-1) for each of those ions. Volcanic ash deposits influenced fluoride concentrations, which directly correlated with well depth. There were no statistically significant associations between solute concentrations and land use. Low recharge rates and confining layers have mitigated anthropogenic impacts on solute levels in the aquifer.

PMID: 12602633 [PubMed - in process


Full report available at: http://www.inchem.org/documents/ehc/ehc/ehc227.htm

2002 - World Health Organization, Geneva.

FLUORIDES. Environmental Health Criteria 227.

This 224 page report was released on August 8, 2002.

Excerpt: The concentration of fluoride in food products is not significantly increased by the addition of superphosphate fertilizers, which contain significant concentrations of fluoride (1-3%) as impurities, to agricultural soil, due to the generally low transfer coefficient from soil to plant material. However, a recent study suggests that, given the right soil conditions and application of sufficient fluoride as an impurity in phosphate fertilizers to soils, plant uptake of fluoride can be increased... Aluminium smelters, brickworks, phosphorus plants and fertilizer and fibreglass plants have all been shown to be sources of fluoride that are correlated with damage to local plant communities... there is a potential risk from fluoride-contaminated pasture and soil ingestion due to the long-term use of phosphate fertilizers containing fluoride as an impurity.


Full report available at: http://www.fluorideaction.org/pesticides/canada.2001.inorganic.f.pdf

August 2001 - Scientific Supporting Document. Ecosystem Health: Science-based Solutions Report No. 1-1. National Guidelines and Standards Office, Environmental Quality Branch. Environment Canada. Ottawa. Cat. no. Enl-34/3-2001E. August, 2001.

Canadian Water Quality Guidelines for the Protection of Aquatic Life: Inorganic Fluorides.

Excerpts:

Inorganic fluorides act as enzyme inhibitors and have wide-ranging effects. Adverse effects observed in aquatic organisms include: changes in blood composition; reduced size and growth; slowed embryonic and developmental life stage; impaired reproduction; and abnormal or impaired behavior (e.g., fish migration). Inorganic fluorides are also neurotoxic, causing adverse effects on the central nervous system. Inorganic fluoride toxicity is negatively correlated with water hardness (calcium) and positively corelated with temperature...

Anthropogenic Sources. In Canada, the primary anthropogenic emission sources of inorganic fluorides are phosphate fertiliser production (34.6%), and aluminum smelting operations (35.2%). Other important emission sources include coal burning facilities, oil refining, steel production, chemical producers, primary copper and nickel production, clay production, magnesium smelting, lead and zinc smelting, glass and enamel making, brick and ceramic manufacturing, production of glues and adhesives, fluoridation of drinking water, fluoride-containing pesticides, waste from sewage sludge, and the production of uranium trifluoriide (UF3) and uranium hexafluoride (UF6) for the nuclear electric industry (page 9).


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Environ Pollut 2001;115(2):275-82

Fluoride accumulation in pasture forages and soils following long-term applications of phosphorus fertilisers.

Loganathan P, Hedley MJ, Wallace GC, Roberts AH.

Fertilizer and Lime Research Center, Institute of Natural Resources, Massey University, Palmerston North, New Zealand. p.loganathan@massey.ac.nz

Ingestion of soils with high fluoride (F) concentration may cause chronic fluorosis in grazing animals. Analysis of New Zealand pasture soils with long-term phosphorus (P) fertilisation histories showed that total surface soil (0-75 mm depth) F concentration increased up to 217-454 mg kg-1 with P fertiliser application. One-third to two-thirds of F applied in fertilisers resides in the top 75 mm soil depth. Pasture forage accumulation of F was low, and therefore, F intake by grazing animals through pasture consumption is expected to be much lower than F intake by soil ingestion. Ten annual applications of single superphosphate (30 and 60 kg P ha-1 year-1) to a Pallic Soil (Aeric Fragiaqualf) significantly increased total F and labile F (0.01 M CaCl2 extract) concentrations to 200 and 120 mm depths, respectively, of the 300 mm depth investigated. The mobility of F in the soil profile was similar to two other elements, P and cadmium derived from the fertiliser.


PMID: 11706800 [PubMed - indexed for MEDLINE]


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Environ Pollut 2001;112(3):321-7

Effects of alkaline dust deposits from phosphate fertilizer production on microbial biomass and enzyme activities in grassland soils.

Langer U, Gunther T.

Biologisch-Pharmazeutische Fakultat, Institut fur Mikrobiologie, Friedrich-Schiller-Universitat Jena, Philosophenweg 12, D-07743 Jena, Germany. uwe.langer@uni-jena.de

Microbial biomass carbon (Cmic) and soil enzyme activities were measured at 12 sites along a gradient of former emissions of phosphate fertilizer production. Seven years after close down of operation, still moderate to high total concentrations of the dust constituents cadmium (up to 33 mg kg-1 dw), fluoride (5300 mg kg-1 dw) and phosphorous (120,000 mg kg-1 dw) were found in topsoils of contaminated sites. Accumulation of partially decomposed plant matter, soil respiration and dehydrogenase activity paralleled the increase of dust deposits, whereas microbial biomass decreased along the gradient. A significant negative correlation was obtained between the Cmic-to-Corg-ratio and the concentration of contaminants. In contrast, the Cmic-specific respiration (qCO2) and the dehydrogenase activity-to-Cmic-ratio were positively correlated. The low Cmic-values and the enhanced activities in the contaminated soils are suggested as a response of microbial communities to environmental stress or ecosystem disturbances. The apparently missing detrimental effects of the alkaline deposits on soil microbial activities are probably due to the low bioavailability of contaminants in the calcareous soil.


PMID: 11291438 [PubMed - indexed for MEDLINE]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10843338&dopt=Abstract

Sci Total Environ 2000 May 15;253(1-3):145-50

Industrial fluorosis in cattle and buffalo around Udaipur, India.

Patra RC, Dwivedi SK, Bhardwaj B, Swarup D.

Division of Medicine, Indian Veterinary Research Institute, Izatnagar, U.P.

Signs of dental discolouration, difficulty in mastication, bony lesions, lameness, debility and mortality in domesticated animals, reared around superphosphate fertiliser plants located approximately 15 km north of Udaipur, Rajasthan prompted us to investigate for the occurrence of fluorosis. Out of 166 animals clinically examined, the prevalence rate was 17.4% (4/23) in calves below 1 year of age, 37.2% (16/43) in cattle between 1 and 3 years, 61.3% (46/75) in cattle above 3 years and 72% (18/25) in buffalo above 1 year. Dental fluorosis was common in buffalo compared to cattle of all the age groups. Fluoride levels in fodder and water, consumed by the animals were much higher than the recommended permissible limit. Mean fluoride concentrations in serum and urine were 1.53 +/- 1.27 and 26.4 +/- 6.17 mg l(-1) in calves below 1 year of age, 0.56 +/- 0.17 and 26.2 +/- 3.86 mg l(-1) in cattle of 1-3 years, 0.49 +/- 1.13 and 27.5 +/- 4.63 mg l(-1) in cattle above 3 years and 0.60 +/- 0.07 and 28.6 +/- 4.73 mg l(-1) in buffalo over 1 year, respectively. The values were significantly (P < 0.01) higher than those of control animals kept over a 15-km distance from the factories. Fluoride concentrations in the environmental sample collected from the affected locality were 534.4 +/- 74.9 mg kg(-1) in fodder, 1.19 +/- 0.29 mg l(-1) in pond water and 0.479 +/- 0.351 mg l(-1) in tube well water. It was concluded that the consumption of fodder and water contaminated by the fumes and dusts emitting from superphosphate fertiliser plants resulted in the development of chronic fluorotic lesions in cattle and buffalo.


PMID: 10843338 [PubMed - indexed for MEDLINE]


Full report available at: http://www.acresusa.com/toolbox/reprints/phosphate-fluoride%20link_jun00.pdf

June 2000 - Acres USA. Vol. 30, No. 6 - Page 17

The Phosphate-Fluoride Link. An analysis of substance abuse in conventional agriculture.


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10702345&dopt=Abstract

Ecotoxicol Environ Saf 2000 Mar;45(3):260-5

Cellular method for evaluation of noxiousness of inorganic pollutants in industrial wastes: calculation of a safety index for monitoring sludge discharge.

Delmas F, Villaescusa I, Woo NY, Soleilhavoup JP, Murat JC.

Laboratoire de Biologie Cellulaire et Pollution, Faculte de Medecine, Universite Paul Sabatier, 37 allees Jules Guesde, Toulouse, 31073, France.

This article deals with a biological test of safety applicable to industrial wastes. The test is based on the measurement of the growth rate of cultured human cells exposed to waste samples with different dilutions. As a first approach, 15 chemicals in which discharge concentrations are submitted to sanitary regulations were tested one by one. For Zn, Cu, Ni, Cd, Ag, Co, Mg, sulfates, and fluorides, it was possible to detect concentrations that are below the allowed limit. For Hg, Al, As(V), Cr(III), Fe, and Pb, the concentrations that affect cell growth are higher than the allowed limit. Tests were also performed using actual samples (liquid effluent from a laundry and sludge from waste-water treatment plants). Results indicate that, in contrast to chemical analyses, the current biological test has the advantage of providing an indication of global toxicity, integrating all substances and factors that can be harmful to life processes. From the sludge data and the observed threshold of concentration that does not affect cell growth, a numeric safety index has been calculated which indicates the amount of sludge that could be dispersed, as a fertilizer, per hectare of agricultural soil. Such an index could be conveniently used for designing sewage sludge disposal strategies. Copyright 2000 Academic Press.


PMID: 10702345 [PubMed - indexed for MEDLINE]


Full report available at: http://www.epa.gov/opptintr/fertilizer.pdf

January 1999. Report No. EPA 747-R-98-003. 393 pages.

BACKGROUND REPORT ON FERTILIZER USE, CONTAMINANTS AND REGULATIONS

Prepared by BATTELLE for the National Program Chemicals Division Office of Pollution Prevention and Toxics U.S. Environmental Protection Agency Washington, D.C. 20460. Contract No. 68-D5-0008


 

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9827892&dopt=Abstract

Int Arch Occup Environ Health 1998 Sep;71 Suppl:S97-100

Assessment of the working-environment harmful factors and health risk of workers in a nitrogen fertilizer plant.

Zlatev Z, Todorova K, Anastasova N, Chuturkova R, Yaneva A, Sabeva Y.

Varna Branch of National Center of Hygiene Medical Ecology and Nutrition, HEI Varna, Bulgaria.

The authors examined the influence of harmful factors of the working environment such as: microclimate, dust, noise, vibrations, and chemical noxes such as: ammonia, nitric oxides, hydrogen fluoride and gaseous fluorides, on the health status of workers involved in the production of fertilizers and ammonia in a nitrogen fertilizer plant. Various biochemical examinations of 158 workers were carried out. The morbidity rate for 1993-1995 was also studied. The biochemical monitoring indicated a statistically significant dependence of the abnormalities of the biochemical parameters on the professional exposure. The metabolic disturbances were proved by serum creatinine and urea elevations and rising urinary ammonia concentrations, by disturbances of the liver function consisting in an enhanced transaminase activity, and by disorders of the mineral metabolism presented with an increased urinary phosphorus excretion at a low serum phosphorus level as well as with increased serum and urinary fluorine concentrations. The temporarily registered morbidity rate showed a tendency towards an increase in diseases of the respiratory, gastrointestinal and cardiovascular system.


PMID: 9827892 [PubMed - indexed for MEDLINE]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9741727&dopt=Abstract

Aust Vet J 1998 Aug;76(8):565-9

Chronic gypsum fertiliser ingestion as a significant contributor to a multifactorial cattle mortality.

Bourke CA, Ottaway SJ.

NSW Agriculture, Orange Agricultural Institute, New South Wales.

OBJECTIVE: To assess the validity of claims that heavy metal contamination from an open-cut mine caused the death of 226 cattle on a nearby farm over a period of 18 months, and to investigate other possible contributing factors.
PROCEDURE: A retrospective assessment of previous investigations combined with additional chemical analyses.
RESULTS: Extensive chemical analyses produced no evidence of heavy metal contamination associated with the mine. Analysis of bones indicated exposure to fluoride in greater than normal amounts. The main source of fluoride seems to have been gypsum that was included in a feed supplement and also ingested from fertiliser dumps on paddocks. The gypsum itself may have contributed significantly to the ill health. Other factors probably affected some classes of animals, notably the young calves.
CONCLUSIONS: What originally seemed to be a disease problem of single aetiology probably was an expression of interacting multifactorial causes. This investigation has highlighted the potential toxicity of gypsum to livestock and the need for further studies to establish its basis.


PMID: 9741727 [PubMed - indexed for MEDLINE]


From Toxline at Toxnet

CANADIAN JOURNAL OF SOIL SCIENCE; 78 (2). 1998. 351-357.

Attenuation of cadmium, fluoride and uranium in phosphogypsum process water by calcareous soil.

POULSEN L, DUDAS MJ

Dep. Renewable Resources, Univ. Alberta, Edmonton, AB T6G 2E3, Canada.

Concerns about contaminant migration from phosphogypsum (PG) repositories prompted the present study. A sequential batch procedure, in which acidic process water (PW) from a phosphate fertilizer plant was reacted with samples of a calcareous till, was employed to determine the attenuation of environmentally sensitive elements by reaction with typical subsoils at PG waste repositories. PW leachates were monitored for total soluble fluoride (F) and pH during the experiment. Soil samples were analyzed for pH, F, cadmium (Cd), uranium (U), and calcium carbonate (CaCO3) equivalent at the end of the study. Leachate pH increased from <2 to 5.5 where it stabilized; soil pH stabilized at 6.5. Fluoride solution concentrations were reduced within regulatory limits. Soils accumulated Cd, F, and U in excess of background concentrations (up to 99x, 83x, and 12.5x, respectively). Soil carbonates persisted after leachate was buffered near pH 4.5, and played a major role in Cd attenu [abstract truncated]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9352334&dopt=Abstract

Int Arch Occup Environ Health 1997;70(5):314-20

Respiratory impairment among children living in the vicinity of a fertilizer plant.

Gomzi M, Saric M.

Institute for Medical Research and Occupational Health, Zagreb, Croatia.

The study included 162 second-grade children (85 boys and 77 girls) aged 8-9 years, attending two schools in an area with a fertilizer production plant, and 59 second-graders of the same age (32 boys and 27 girls) from a small neighbouring town located 20 km west of the plant, without any particular source of pollution. During the period from December 1990 to May 1991 the incidence of acute respiratory diseases was surveyed in children and their family members, and forced expiratory volumes were measured in selected second-graders in December 1990 and April 1991. In the area with the fertilizer plant as well as in the compared area ammonia, hydrogen fluoride, nitrogen dioxide, total suspended particulate matter and smoke were measured daily in ambient air and inside the school buildings. The mean concentrations of pollutants during the study period were below the recommended limits, with only a few exceptions, but daily fluctuations, particularly of ammonia and hydrogen fluoride in the area around the plant happened to exceed these values. The observed differences in the levels of air pollution correlated to some extent with the health parameters followed up during the study period. The incidence of acute respiratory diseases corresponded to the registered differences in the exposure to measured pollutants. Forced expiratory volume values in the compared groups of children did not consistently reflect the differences in exposure levels.


PMID: 9352334 [PubMed - indexed for MEDLINE]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9273664&dopt=Abstract

Rocz Panstw Zakl Hig 1997;48(1):53-8

[Exposure of Poznan inhabitants to fluorides. II. Fluorides in urine and hair of school children]

[Article in Polish]

Oporowska-Moszyk K, Senczuk W.

Zaklad Toksykologii, Akademia Medyczna w Poznaniu.

In view of the plans of fresh water fluoridation in Poznan the necessity arose of obtaining of information about the exposure to fluoride compounds. The reported study was carried out in Poznan and environs. Urine and hair samples of children were obtained. The determinations were done with a ion- selective electrode. The mean fluoride concentrations in urine were between 0.3 and 0.9 mg F-/dm3. The concentration in hair was 2.2 mg F-/g in Poznan and 3.3 mg F-/g in Lubon. These values were, however, not exceeding the acceptable ones. In Lubon the concentrations of fluorides in hair was 50% higher than in Poznan. The authors believe that the possible cause was Fertilizer Chemical Works in that location.

Publication Types: Clinical Trial

PMID: 9273664 [PubMed - indexed for MEDLINE]


Aust J Soil Res 1996 34: 154

Review: the behaviour and environmental impact of contaminants in fertilizers.

McLaughlin MJ, Tiller KG, Naidu R, & Stevens DP


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8244868&dopt=Abstract

J Am Vet Med Assoc 1993 Oct 15;203(8):1176-7

Accidental superphosphate fertilizer poisoning in pregnant ewes.

East NE.

Department of Medicine, School of Veterinary Medicine, University of California, Davis 95616.

Consumption of superphosphate fertilizer by 200 pregnant ewes resulted in signs of toxicosis in 41 ewes, 14 of which died. Predominant clinical signs were marked teeth grinding, voluminous diarrhea, CNS depression, apparent blindness, and a stiff-legged atactic gait. Biochemical abnormalities were hypocalcemia, hypoglycemia, and a high anion gap. The primary toxic principal in superphosphate fertilizers is the fluorine contaminant; however, calcium pyrophosphate and calcium orthophosphate also contribute to toxicosis, which results in acute proximal renal tubular necrosis. Voluntary consumption of superphosphate fertilizer in well-fed livestock is not expected, and was believed to be related to the lack of availability of salt.

PMID: 8244868 [PubMed - indexed for MEDLINE]


From Toxnet

SOIL SCI SOC AM J; 56 (3). 1992. 961-966.

Corn growth as affected by suspension fertilizers containing fluorosilicic acid.

SIKORA FJ, COPELAND JP, DILLARD EF, BURNELL JR

Agric. Res. Dep., Natl. Fertilizer Environmental Res. Cent., Tenn. Valley Auth., Muscle Shoals, Ala. 35660-1010.

Fluorosilicic acid (H2SiF6) is a suggested additive to suspension fertilizers produced from monoammonium phosphate (MAP) to prevent gelling of the suspension. A greenhouse study was conducted to determine if F added to soil via P suspension fertilizers was detrimental to corn (Zea mays L.) growth. The F sources consisted of reagent-grade NH4F, NH4SiF6, and three P suspension fertilizers. Equilibria constants and measurements with a F- ion selective electrode (ISE) indicated SiF62- dissociates to component in soils. At an initial soil pH of 5.8, an 11% dry-matter weight decrease was observed when a suspension fertilizer with 89 g F kg-1 was added to soil to supply a rate of 170 mg F kg-1 soil. An adequate level of F in P suspension fertilizers is between 16 and 23 g kg-1 and this level did not affect corn dry-matter weight with application rates | 32 mg F kg-1 soil. At high soil F-applications rates from 30 to 170 mg F kg-1 soil, F was not suspected to be the phytotoxic a [abstract truncated]


http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15092167

Environ Pollut. 1991;69(1):17-23.
 
Studies on the progeny of rice plants grown at an unpolluted and polluted site.

Anbazhagan M, Bhagwat KA.

Plant Physiology Laboratory, Department of Botany, M.S. University of Baroda, Baroda 390 002, India.

Oryza sativa L. cv. GR3 was grown near to a fertilizer plant and the growth of its seed progeny was evaluated at sites near to, and distant from, the fertilizer plant. The grain yield was reduced in plants grown at the polluted site, with reduced panicle length and increased sterility index. This decrease in grain yield was higher in the progeny plants than in the normal polluted plants. The polluted progeny grown at a control site showed a normal yield, but an increased sterility index. Accumulation of total sulphur and fluoride was higher in the leaves of polluted rice plants. It was evident that tolerance to air pollution was reduced in the progeny plants due to an additional dosage of sulphur and fluoride pollutants and to unfavourable climatic factors. Further, pollution effects were not carried over in progeny plants when grown in an unpolluted environment.

PMID: 15092167 [PubMed]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1655585&dopt=Abstract

Gig Tr Prof Zabol 1991;(6):19-22

[Working conditions and health-related measures in the processing of waste products of phosphorus-containing mineral fertilizers]

[Article in Russian]

Rumiantsev GI, Khodykina TM, Arkhangel'skii VI, Nesterenko LN.

In the processing of the waste products of phosphorus containing fertilizer production, several major health-related factors were identified depending on the industrial site's peculiarities: unfavourable microclimate conditions (both cold and heat), relative temperature differences, noise and vibration caused by the equipment, semi-product's, additives' and finished product's dusts, fluorine- and phosphorus-containing substances' affects and poor illumination. The proposed data were used for health-related improvements in the occupational conditions.


PMID: 1655585 [PubMed - indexed for MEDLINE]


http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1966560&dopt=Abstract

Czas Stomatol 1990 Nov-Dec;43(11-12):651-3

[Dental surfaces in workers exposed to fluorides]

[Article in Polish]

Szajewska-Jarzynka W, Kosmider K, Smilgin Z.

Imprint preparations were taken by Eifinger's method from the labial surfaces of upper incisors from 65 workers working at least since 10 years at the production of phosphate fertilizers, and from 33 subjects without occupational exposure to any industrial harmful agents, at least in the last 10 years. Differences were noted in the dental imprints in subjects exposed to fluorides in relation to controls in microscopic examinations.


PMID: 1966560 [PubMed - indexed for MEDLINE]


From Toxline at Toxnet

Br J Ind Med 1990 May;47(5):349-51

Fluoride in the urine, hair, and nails of phosphate fertiliser workers.

Czarnowski W, Krechniak J.

Department of Toxicology, Medical Academy in Gdansk, Poland.

This study evaluated the exposure of fertilizer manufacturing workers employed on different posts and exposed to fluorine (7782414) compounds. Exposure was divided into high (mean hydrogen-fluoride (7664393) (HF) concentration ranged from 0.5 to 3.0mg/m3), medium (mean HF concentrations were below 0.5 mg/m3), and low exposure. Fluoride concentrations were determined in the urine, hair, and nails of 106 employees (88 men and 28 women). The fluoride content examined for workers in the highest exposure group employed in a phosphate fertilizer facility were higher than comparisons with the highest increase in fluoride content found in hair. In highly exposed workers the results exceeded even more than a hundred fold the normal value. Positive correlations were found between group means for fluoride concentrations between urine and hair, hair and nails, as well as urine and nails. Individual values in the total population gave a positive correlation only for concentrations in urine and nails. No correlation was found between the period of employment and the fluoride content in indicator media.


From Toxline at Toxnet

FLUORIDE; 23 (3). 1990. 129-136.

Exposure to fluorides in the French phosphate fertilizer industry.

HERY M, DIEBOLD F, HUBERT G, GERBER JM, LIMASSET JC

Inst. Natl. Recherche Securite, BP 27, 54501 Vandoeuvre-les-Nancy, Fr.

Exposure to fluorides was assessed in seven French fertilizer-production plants. Results show that the short-term limit value of hydrogen fluoride is often exceeded and that long-term values are generally respected, except in the case of superphosphate production, where almost fifty percent of sampling results are over limit values.


From Toxline at Toxnet

NORW J AGRIC SCI; 4 (3). 1990. 239-250.

Cadmium and fluoride uptake by oats and rape from phosphate fertilizers in two different soils: Cadmium and fluoride uptake by plants from phosphorus fertilizers.

SINGH BR

Agricultural University Norway, Dep. Soil Sciences, P.O. Box 28, N-1432 As-NLH, Norw.

The effects of rates and sources of phosphate fertilizers on the uptake of cadmium (Cd) and fluoride (F) by oats (Avena sativa L.) and rape (Brassica napus L.) grown in loam and peat soils were investigated in a greenhouse experiment. NPK fertilizers containing low (2.6 mg kg-1) and high (40 mg kg-1) Cd and single superphosphate (SSP) containing 15 mg Cd kg-1 at rates ranging from 30 to 180 mg P kg-1 soil were used as P fertilizers. While grain and straw yields of both oats and rape were generally unaffected by P fertilization, the P concentration in grain and straw tended to increase with increased rates of P fertilization. At higher rates of high Cd NPK and SSP, the concentration of Cd in the grain and straw of oats and rape was generally increased, and more so in the peat soil than in the loam soil. In the peat soil, Cd in the grain increased from 0.8 mg kg-1 in the control to 0.21 mg kg-1 at the highest rate of SSP in the first year. The corresponding values in the [abstract truncated]


 
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