Phosphorus

Endpoint summary

Additional information

Toxicity to soil macroorganisms

Effects ofRed Phosphorus, untreated(Batch number: Fra 07-23) on mortality, biomass and the reproductive potential of the earthworm speciesEisenia fetida(Savigny) were determined according to the guidelines DIN ISO 11268-2 (1998), OECD 222 (2004) and BBA (1994) from February 26^thto April 26^th, 2010 with the definitive exposure phase from February 26^thto April 23^rd, 2010 atDr.U.Noack-Laboratorienin 31157 Sarstedt, Germany. The study was conducted under static conditions over 8 weeks with the test item concentrations of 62.5, 125, 250, 500 and 1000 mg test item/kg soil dry weight, which were mixed into artificial soil containing 10 % peat and a control using untreated artificial soil. 40 test organisms, with an individual weight of 0.30 to 0.60 g, were divided into 4 replicate groups with 10 test organisms per replicate.

After 28 days no evident mortality of adult earthworms was observed in the control and at all test item concentrations. No pathological symptoms or changes in the behaviour of adult earthworms were seen in the control as well as at 62.5, 125 and 250 mg test item/kg soil dry weight. However, at 500 and 1000 mg test item/kg soil dry weight biologically significant pathological symptoms of the adult earthworms occurred.The earthworm biomass increased in the control and at 62.5 and 125 mg test item/kg soil dry weight over 28 days without any statistically significant differences. At 250, 500 and 1000 mg test item/kg soil dry weight the biomass increase was statistically significantly reduced compared to the control.

After further four weeks the reproduction rate (average number of juveniles) was 280 in the control and ranged between 31 and 255 at the test item concentrations. Compared to the control, the reproduction rate was statistically significantly reduced at 250, 500 and 1000 mg test item/kg soil dry weight.The EC₅₀for reproduction was determined to be at 428 mg/kg soil dry weight. 

Overall, the NOEC of the test item concerning mortality, biomass and reproduction of earthworms was determined to be at125 mg test item/kg soil dry weight.

All validity criteria recommended by the test guidelines were fulfilled.

Summary of All Observed Effects in the Tested Doses

Effects	Red Phosphorus, untreated
[mg test item/kg soil dry weight]	62.5	125	250	500	1000
Mortality of adult earthworms	No	No	No	No	No
Reduction of body weight	No	No	Yes	Yes	Yes
Reduced reproduction rate  (Number of juveniles)	No	No	Yes	Yes	Yes
Summary of all effects	No	No	Yes	Yes	Yes

NOEC and LOEC for Reproduction, Mortality and Body Weight

Red Phosphorus, untreated
	Test item concentration
	[mg test item/kg soil dry weight]
NOECreproduction, body weight	125
LOECreproduction, body weight	250
NOECmortality	1000
LOECmortality	> 1000
EC50 of reproduction (95 % Confidence Interval)	428 (342 - 551)

The effects of the test itemRed Phosphorus, untreated(batch no.Fra 07-23)on the bacterivorous nematodeCaenorhabditis elegans in a sediment system were determined atDr.U.Noack-Laboratorien, Sarstedt, Germany, fromJune 9^thto June 22^nd, 2010with the definitive exposure phase from June 16^thto June 21^st, 2010. The study was carried out according to the Draft guideline ISO/DIS10872 (2008). Test duration was 96 hours after insertion of the test organisms.The study was performed by spiking the test item into the sediment with the limit test item concentration of 1000 mg test item/kg sediment dry weight.Six replicates per control and limit test item concentration were set up.

After four days of exposure to the limit test item concentration of 1000 mg test item/kg sediment dry weightRed Phosphorus, untreateddid not induce biologically significant mortality ofC. elegans. Also, adult nematode fertility as well as nematode reproduction was not affected at 1000 mg test item/kg sediment dry weight. Accordingly, no statistically significant reduction of adult nematode growth was observed at the limit test item concentration of 1000 mg test item/kg sediment dry weight after an exposure of 96 hours to Red Phosphorus untreated.

Thus, the Lowest Observed Effect Concentration (LOEC) concerning all test parameters was set at > 1000 mg test item/kg sediment dry weight. The Overall No Observed Effect Concentration (NOEC) was determined to be 1000 mg test item/kg sediment dry weight. All effect levels given are based on the nominal concentration ofRed Phosphorus, untreated.

 

 

Table1:          Summary of all Effectsand resulting LOEC, NOECbased on nominal concentrations

Effects	Red Phosphorus, untreated
	[mg test item/kg sediment dry weight]
Mortality	> 1000
Fertility	> 1000
Reproduction	> 1000
Growth	> 1000
LOEC (Mortality, Fertility, Reproduction, Growth)	> 1000
NOEC (Mortality, Fertility, Reproduction, Growth)	1000

Toxicity to soil microorganisms

The effects of Red Phosphorus, untreated  (Batch no. Fra 07-23) on the metabolic activity of soil micro-organisms were determined according to OECD Guideline 216 (2000) atDr.U.Noack-Laboratorien, 31157 , , from April 26^thto May 26^th, 2010. The test item was applied with the test item concentrations 62.5 - 125 - 250 - 500 - 1000 mg/kg soil dry weight. Untreated standard silty sand soil was tested as control under the same test conditions as the test item concentrations. Plastic boxes (volume 1.0 L) with perforated tops to enable gas exchange and filled with 450 g soil dry weight, moistened to nominally 55 % of its maximal water holding capacity, were used.

The treated soils were incubated for 28 days at 52.4 - 54.5 % (measured) of the maximum water holding capacity and a pH-value between 6.28 and 7.12. The effects of the test item on nitrate transformation were determined on the day of treatment (day 0) and after 8, 14 and 28 days.The values were compared to the untreated control.

After 8 days of exposure, Red Phosphorus, untreated stimulated the nitrate formation rate throughout all test item concentrations from 26 to 95 % compared to the control. This stimulation was abolished after 14 days of exposure with no evident ( 25 %) nitrate formation inhibition or stimulation at all test item concentrations. Accordingly, no inhibition or stimulation≥ 25 % was observed after 28 days of exposure to Red Phosphorus, untreated at all test item concentrations.

Throughout the entire study inhibitions or stimulations of the nitrate transformation did not show a dose response effect. Presumably, the soil microflora is only directly affected at the particle surface but not at other soil parts. Anyhow, no evident effects of Red Phosphorus, untreated appeared after 14 and 28 days of exposure.  

The NOEC for nitrate transformation in soil on day 8 was determined to be 62.5 mg/kg soil dry weight. The NOEC for nitrate transformation in soil on day 14 and 28 was set at 1000 mg/kg soil dry weight. Thus, Red Phosphorus, untreatedis not expected to cause any long term detrimental effects on nitrogen turnover in soil under normal conditions.

Toxicity to terrstrial arthropodes, Toxicity to terrestrial plant, Toxicity to birds

Based on the available terrestrial toxicity data it is obvious that phosphorus red has a low terrestrial toxicity: A chronic 56d Earthworm reproduction test is available with a NOEC reproduction; mortality and biomass of 125 mg/kg dw and the EC50 for reproduction was determined to be at 428 mg/kg dry weight. In addition a long-term toxicity study with the nematode caenorhabditis elegans and a soil microorganism study shows a NOEC at 1000 mg/kg which supports a very low toxicity. A chronic 28d sediment-water test with Lumbriculus variegates is available with a NOEC reproduction, mortality, behaviour and biomass of 1000 mg/kg sediment dry weight. This means that exposure to agricultural soil via application of sewage sludge is very low. Also direct exposure via air is unlikely due to the very low vapour pressure and very low volatility of red phosphorus. When considering these facts it can be stated that a toxicity test to terrestrial arthopods is not warranted.

The statement given above is in line with the specific rule in 1907/2006/EC Annex IX, Column 2, 9.4: Longterm toxicity testing be proposed by the registrant if the chemical safety assessment according to Annex I indicates the need to investigate further the effects on terrestrial organisms. The choice of the appropriate tests depends on the result of the chemical safety assessment.