Manganese

Toxicity to terrestrial arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to terrestrial arthropods: long-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: peer reviewed journal

Justification for type of information:

Data is from peer reviewed journal.

Qualifier:

according to guideline

Guideline:

ISO 11267 (Inhibition of Reproduction of Collembola by Soil Pollutants)

GLP compliance:

not specified

Application method:

soil

Analytical monitoring:

yes

Test organisms (species):

other: Enchytraeus crypticus

Animal group:

other: Haplotaxida

Details on test organisms:

TEST ORGANISM
- Common name: Enchytraeids
- Feeding during test: twice a week
- Food type: oats

Study type:

laboratory study

Total exposure duration:

18 wk

Test temperature:

22± 1°C

pH (if soil or dung study):

5

Details on test conditions:

TEST SYSTEM

- Test medium: 4.3-L clear plastic boxes

- Material, size, headspace, fill volume:
34 x 20 x l 0 cm filled with
2 kg (dry mass) SSL soil.

- Aeration: Soil in the breeding culture was aerated by carefully mixing it once per week.


- No. of vessels per control (replicates): Four replicates

TEST MEDIUM
- Test medium: A natural soil, Sassafras sandy loam [Fine-loamy, siliceous, mesic Typic
Hapludult] (SSL)

- Source/preparation of dilution water
Source : collected from an open
grassland field on the property of the U.S. Army Aberdeen Proving Ground

Nominal and measured concentrations:

100, 500, 1000, 5000 and 10000 mg/kg

Reference substance (positive control):

yes

Remarks:

30 mg/ kg 4-Nitrophenol

Key result

Duration:

18 wk

Dose descriptor:

NOEC

Effect conc.:

191 mg/kg soil ww

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

18 wk

Dose descriptor:

LOEC

Effect conc.:

267 mg/kg soil ww

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Details on results:

The 18 weeks NOEC and LOEC value was determined to be 191 mg/kg and 267 mg/kg respectively.

Reported statistics and error estimates:

Analysis of Variance (ANOVA)

Table-1: Physical and chemical characteristics of Sassafras sandy loam soil analyzed by the Cooperative Extension Service, University of Maryland Soil Testing Laboratory, College Park, MD.

Soil parameters	Sassafras Sandy Loam
Sand%	71
Silt%	18
Clay%	11
Texture%	Sandy loam
CEC cmol kg-1	4.27
Organic matter %	1.2

 

Table- 2: Nominal manganese concentrations selected for definitive toxicity studies withE. crypticus,as determined from range finding tests.

Chemical	Mn
First positive concentration tested:
1	10
2	18
3	31
4	54
5	94
6	164
7	287
8	503

 

Table- 3: Nominal and measured concentrations of metals in soil following a three-week aging/weathering procedure for total manganese amended individually in SSL soil. Measured concentrations were determined using USEPA Method 200.8 and inductively coupled plasma mass spectrometry (ICP-MS).

 

Nominal (mg/kg)	Measured (mg/kg)	Recovery (%)
0	94
10	99	50**
18	110	89
31	119	80
54	157	117
94	191	103
167	267	105
287	386	102
503	644	109

 

Table- 4: Ecotoxicological parameters (mg/ kg) for juvenile production determined in aged/weathered SSL soil independently amended with manganese using Enchytraeid Reproduction Test; parenthetical values are 95% confidence intervals.

Endpoint	Manganese
NOEC	157
LOEC	191
EC20	116(56-176)
EC50	192 (147-238)

 

Validity criteria fulfilled:

not specified

Conclusions:

The 18 weeks NOEC and LOEC value was determined to be 191 mg/kg and 267 mg/kg respectively.

Executive summary:

 

Study was conducted to determine toxicity of test chemical to terrestrial arthropods in accordance with ISO 11267 (Inhibition of Reproduction of Collembola by Soil Pollutants) guideline at temperature of 22± 1°C and 5.0 pH. The study was performed on Enchytraeuscrypticus for 18 weeks. A natural soil, Sassafras sandy loam [Fine-loamy, siliceous, mesic typic Hapludult] (SSL) was used in this study to determine toxicity of test chemical.The SSL soil was collected from an open grassland field on the property of the U.S. Army Aberdeen Proving Ground.The soil was sieved through a 5mm²mesh screen and air-dried for at least 72h and mixed periodically to ensure uniform drying then passed through a 2-mm sieve and stored at room temperature before use in testing. Range finding test was performed at different nominal concentrations of 100, 500, 1000, 5000 and 10000 mg/ kg test chemical.30 mg/ kg of 4-Nitrophenol was used as positive control substance. Four replicates were used for each treatment concentration and controls.

Test organism were bred in 4.3-L clear plastic boxes of 34 x 20 x l 0 cm in length filled with 2 kg (dry mass) SSL soil.The culture was kept in an incubator at 22± l °C with continuous light. Aeration was achieved by careful mixing of soil once per week.Test organisms were fed approximately twice a week with a proper amount of ground oats spread on the soil surface. Test containers were placed randomly on trays and incubated at 21±1°C with continuous light cycle. The natural manganese concentration determined in the negative control treatment was 94 mg kg-1. Inductively coupled plasma mass spectrometry (ICP-MS) was used to identification and detection of test chemical. Analyses of test chemical concentrations were conducted using a Perkin-Elmer 5100 PC Atomic Absorption Spectrophotometer equipped with an AS-90 auto-sampler. Test substance was extracted from soil using0.05MCaCl₂with agitation on a reciprocating shaker for 24h. Analysis of Variance (ANOVA) was used to determine the bounded No Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration (LOEC) values for test organism. The 18 weeks NOEC and LOEC value was determined to be 191 mg/kg and 267 mg/kg respectively.

 

  

 

Description of key information

The 18 weeks NOEC and LOEC value was determined to be 191 mg/kg and 267 mg/kg respectively.

Additional information

Following different studies includes experimental study for the target chemical to observe the toxicity of test chemical to terrestrial arthropods as follows:

First study was conducted to determine toxicity of test chemical to terrestrial arthropods in accordance with ISO 11267 (Inhibition of Reproduction of Collembola by Soil Pollutants) guideline at temperature of 22± 1°C and 5.0 pH. The study was performed on Enchytraeuscrypticus for 18 weeks. A natural soil, Sassafras sandy loam [Fine-loamy, siliceous, mesic typic Hapludult] (SSL) was used in this study to determine toxicity of test chemical.The SSL soil was collected from an open grassland field on the property of the U.S. Army Aberdeen Proving Ground.The soil was sieved through a 5mm²mesh screen and air-dried for at least 72h and mixed periodically to ensure uniform drying then passed through a 2-mm sieve and stored at room temperature before use in testing. Range finding test was performed at different nominal concentrations of 100, 500, 1000, 5000 and 10000 mg/ kg test chemical.30 mg/ kg of 4-Nitrophenol was used as positive control substance. Four replicates were used for each treatment concentration and controls.

Test organism were bred in 4.3-L clear plastic boxes of 34 x 20 x l 0 cm in length filled with 2 kg (dry mass) SSL soil. The culture was kept in an incubator at 22± l °C with continuous light. Aeration was achieved by careful mixing of soil once per week. Test organisms were fed approximately twice a week with a proper amount of ground oats spread on the soil surface. Test containers were placed randomly on trays and incubated at 21±1°C with continuous light cycle. The natural manganese concentration determined in the negative control treatment was 94 mg kg-1. Inductively coupled plasma mass spectrometry (ICP-MS) was used to identification and detection of test chemical. Analyses of test chemical concentrations were conducted using a Perkin-Elmer 5100 PC Atomic Absorption Spectrophotometer equipped with an AS-90 auto-sampler. Test substance was extracted from soil using0.05MCaCl₂with agitation on a reciprocating shaker for 24h. Analysis of Variance (ANOVA) was used to determine the bounded No Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration (LOEC) values for test organism. The 18 weeks NOEC and LOEC value was determined to be 191 mg/kg and 267 mg/kg respectively.

Second study was conducted to determined the effect of test chemical on the mortality ofFolsomia candida (soil micro-organism).Test was conducted for 4 week. A natural soil, Sassafras sandy loamwas used in this study to assess the toxicity of test chemicals to F. candida.The soil was sieved through a 5mm2 Mesh screen, air-dried for at least 72 h and mixed periodically to ensure uniform drying, passed through a 2-mm sieve, and stored at room temperature before use in testing. This soil was 71 % sand, 18% silt, 11 % clay, a CEC of 4.27 crnol/kg, pH of 5.0 and an organic matter content of 1.2% The culture of micro-organism was maintained in culture jars on a mixture of charcoal and plaster of Paris in the dark at 20°C and fed withcattle manure spiked with Mn at 151.7 mg/kg. The positive control used in these studies was Prentox carbarnate(0.05 mg/kg) and the Concentrations for Mn were 100, 500, 1000, 5000 and 10000 mg kg-1.Five replicates were used for each treatment concentration and controls. Nominal Mn treatment concentrations included 0, 10, 18, 31, 54, 94, 164, 287, and 503 mg kg" 1. Ten-to-twelve day-old juveniles are exposed to a range of concentrations of the test chemical added to soil. Inductively coupled plasma mass spectrometry (ICP-MS) was used to identification and detection of test chemical. Analyses of test chemical concentrations were conducted using a Perkin-Elmer 5100 PC Atomic Absorption Spectrophotometer equipped with an AS-90 auto-sampler. Test substance was extracted from soil using0.05MCaCl₂with agitation on a reciprocating shaker for 24h. Analysis of Variance (ANOVA) was used to determine the bounded No Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration (LOEC) values for test organism. Manganese did not affect adult springtail survival at the 1667 mg/kg concentration (NOEC). Adult survival was significantly reduced at 2444 mg/kg (LOEC).The bounded NOEC for juvenile production was 1067 mg/kg and the bounded LOEC for juvenile production was 1100 mg/kg.