mancozeb (ISO); manganese ethylenebis(dithiocarbamate) (polymeric) complex with zinc salt  

Sediment toxicity

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Reason / purpose for cross-reference:

reference to same study

Key result

Duration:

77 d

Dose descriptor:

NOEC

Effect conc.:

400 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

emergence rate

Remarks on result:

other: derived based on Chironomus emergence

Key result

Duration:

56 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 250 µg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: population dynamic

Remarks on result:

other: NOEC derived for Oligochaeta

Key result

Duration:

15 wk

Dose descriptor:

other: NOEAEC

Effect conc.:

< 10 µg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: population dynamic

Remarks on result:

other: based on effects of eight weekly short-lived pulses of Penncozeb 80 WP on zoo- and phytoplankton communities and macrozoobenthos

Key result

Duration:

15 wk

Dose descriptor:

NOEC

Effect conc.:

10 µg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: population dynamic

Remarks on result:

other: based on effects of eight weekly short-lived pulses of Penncozeb 80 WP on zoo- and phytoplankton communities and macrozoobenthos on community level

Details on results:

The NOEAEC for this study is set at < 10 μg a.s./L because:

- at the 10 μg a.s./L-treatment level, pronounced long-term reductions without recovery (Class 5B-effect) occurred in the most sensitive endpoint (i.e., the rotifer Hexarthra sp.).

- between the concentration of 3.2 μg a.s./L (Class 1-effects only) and 10 μg a.s./L (Class 5B-effects) no intermediate concentrations showing Class 3A-effects were available.

- at concentrations below 10 μg a.s./L (1.0 and 3.2 μg a.s./L), no effects were
observed.

- at the 10 μg a.s./L-treatment level, the impact on the most sensitive phytoplankton species (Volvox sp.) was short-term only.

- at 10 μg a.s./L direct effects within the most sensitive group (rotifers) were not observed, except for Hexarthra sp. which is one of the 11 rotifers monitored in the study.

Reference 2

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-02-04 to 2010-04-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 225 (Sediment-Water Lumbriculus Toxicity Test Using Spiked Sediment)

Version / remarks:

adopted 16 October 2007

Deviations:

yes

Remarks:

please refer to section "Principles of method if other than guideline".

Principles of method if other than guideline:

The study was conducted in accordance with OECD guidelines for the testing of chemicals, guideline 225-Sediment-water Lumbriculus Toxicity Test Using Spiked Sediment. However, the test method employed deviated from the guideline by using a spiked water system.

On three occasions, the maximum temperature of the media in auxiliary vessels used to monitor the test area was slightly above the recommended maximum (22ºC).

The temperature measured each week in each test vessel was within the acceptable range.

The pH of the media in four of the vessels on Day 21 and 16 of the vessels on Day 27 was slightly over the maximum specified in the protocol. Seven out of eight of the controls were also over this range.

On Day 0, the dissolved oxygen of vessel 30 was slightly below the minimum level (30%) recommended for the test. However, on all other measurement occasions the dissolved oxygen measurements were acceptable.

The organic carbon content (measured 4.1%) of the sediment used in the test system was higher than that recommended for this test type (2% ± 0.5%).

Since the test fulfilled the validity criteria for the increase in the number of worms in the control vessels and all other parameters in the test were considered acceptable, none of these deviations was considered to be significant or to have affected the integrity of the study.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

An aliquot (5 mL) of sample was transferred into a polypropylene tube (50 mL). The sample was fortified with the test substance at this stage if required. Aliquots of extraction solvent (5 mL), methanol (5 mL) and iodomethane (200 μL) were added and the sample was shaken well by hand and allowed to stand for approximately 30 minutes (the initial derivatised standard solution was also prepared at this stage). Following derivatisation, water (20 mL) followed by 2M CaCl2 (2 mL) was added to the sample extract.

Vehicle:

no

Details on sediment and application:

PREPARATION OF SPIKED SEDIMENT
- Details of spiking: In this study the test substance was applied to the overlying water as the test substance was known to be rapidly degraded in aqueous systems so the likely route of contamination is as spray drift. Consequently a spiked water system was considered to be a more realistic route of exposure than a spiked sediment.
- Equilibration time: Vessels were left to settle and acclimate under test conditions for three days before the addition of the worms.
- Equilibration conditions: same as test
- Controls: negative control (without test item), 8 replicates

Test organisms (species):

Lumbriculus variegatus

Details on test organisms:

TEST ORGANISM
- Common name: blackworm
- Strain/clone: not specified
- Source: commercial supplier
- Breeding conditions: Cultures were prepared by adding worms at a density of approximately 500 individuals per six to eight-litre culture. Each culture vessel typically contained a 2.5 to 5 cm depth of artificial substrate (shredded paper) and at least 10 to 12 cm of overlying water, (Elendt M4 medium), which is gently aerated with compressed air. The cultures were fed with a suspension of Tetramin® (20 mL of a 10 mg/mL suspension).
- Age of animals at beginning of exposure: adult worms (synchronized)
- Synchronization: fourteen days before the start of the test, worms to be used in the study were synchronised by isolating adult worms from stock cultures and bisecting them at the mid-point. The two halves were returned to two 3L beakers containing sediment and reconstituted water. This was to ensure that all worms used in testing were of a similar physiological state.
- Feeding during test: Feed was included in the vessels within the artificial sediment (0.5% nettle powder).

Study type:

laboratory study

Test type:

static

Water media type:

freshwater

Type of sediment:

artificial sediment

Remarks:

prepared in accordance with OECD guideline 219

Limit test:

no

Duration:

28 d

Exposure phase:

total exposure duration

Post exposure observation period:

None

Hardness:

306-458 mg CaCO3/L

Test temperature:

19.3°C - 21.9°C.

pH:

7.6 – 10.0

Dissolved oxygen:

46-111 % ASV

Salinity:

not applicable

Ammonia:

0.13 – 7.95 mg NH3-N/L

Conductivity:

not specified

Nominal and measured concentrations:

Nominal: 0 (control), 0.00800, 0.0230, 0.0750, 0.240, 0.780 and 2.50 mg/L
(which corresponds to 0.00644, 0.0185, 0.0604, 0.193, 0.628 and 2.01 mg a.s./L)

Measured: 0 (control), 0.00335, 0.00824, 0.0383, 0.186, 0.680, 1.83 mg/L (initial mean measured; 35% to 101% of nominal)

Details on test conditions:

TEST SYSTEM
- Test container: glass beakers (400 mL capacity)
- Sediment volume: approximately 1.5 cm
- Overlying water volume: 5 to 6 cm (300 mL in volume)
- Depth of sediment and overlying water: sediment of approximately 1.5 cm depth and 5 to 6 cm of overlying water (300 mL in volume) to give a sediment to water depth ratio of approximately 1:4.
- Aeration: yes (two days into the acclimation period, aeration was paused)
- Aeration frequency and intensity: Aeration was re-started after approximately 24 hours of settling and was provided through a narrow bore glass tube. All vessels were covered.
- Replacement of evaporated test water, if any: only after acclimatisation phase

EXPOSURE REGIME
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control / vehicle control: 8
- Feeding regime: fed continuously
- Type and preparation of food: nettle powder
- Amount of food: 0.5% of artificial sediment.

OVERLYING WATER CHARACTERISTCS
CaCl2.2H2O: 293.8 g/L
MgSO4.7H2O: 246.6 g/L
NaHCO3: 64.8 g/L
KCl: 58.0 g/L
All reagents were analytical grade.
The reconstituted water was then be aerated for approximately 30 minutes to achieve oxygen saturation. The sum of Ca and Mg ions in the reconstituted water was 2.5 mmol/L. The proportion of ions in the reconstituted water was Ca:Mg 4:1 and Na:K 10:1. The acid capacity (Ks4.3) of the reconstituted water was 0.8 mmol/L.

CHARACTERIZATION OF SEDIMENT
- 4-5% sphagnum peat
- 20% kaolin clay
- 75-76% fine, acid-washed sand
- 3-6% calcium carbonate
- 0.5% nettle powder (Urtica sp)
The final pH of the sediment was adjusted ca. 7.0 ± 0.5 by the addition of calcium carbonate. The organic carbon content of the sediment was 4.1%
Artificial sediment (approximately 50 g) was added to each test vessel and then carefully mixed with reconstituted water to give a plastic consistency.

EFFECT PARAMETERS MEASURED:
During the definitive test, vessels were monitored for signs of growth, behaviour and development of the worms. At the end of the test (Day 28) the worms were removed from the sediment and the numbers in each replicate were counted. The dry biomass of worms from each replicate was determined. Sampling of mancozeb levels in the overlying media of the control and all test level vessels was performed on days 0, 7, and 28. Sampling of mancozeb levels in the overlaying media of the destructive vessels (only nominal test concentrations 0.008 and 2.50 mg Mancozeb 80 WP/L) was performed on days 0 and 7. Sampling of mancozeb in sediment was only performed at the end of the study period (Day 28) for the control, 0.008 and 2.50 mg Mancozeb 80 WP/L test level vessels. Sampling of mancozeb in the sediment of destructive vessels (only nominal test concentrations 0.008 and 2.50 mg Mancozeb 80 WP/L) was performed on Days 0, and 7.

TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations: Nominal product concentrations of 0.0100, 0.100, 1.00, 10.0 and 100 mg/L plus an untreated control were employed without replication.
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

no

Key result

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

0.04 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

biomass

Remarks on result:

other: 95% confidence interval: 0.004-0.399 mg/L

Remarks:

re-assessed by the European Food Safety Agency (EFSA)

Key result

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

0.109 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Remarks on result:

other: 95% confidence interval: 0.023-0.526 mg/L

Remarks:

re-assessed by the European Food Safety Agency (EFSA)

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

0.038 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

0.37 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

0.186 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

reproduction

Key result

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

0.69 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

0.46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 95% confidence interval: 0.220 to 0.970 mg/L)

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

0.24 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

0.85 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: 95% confidence interval: 0.450 to 1.60 mg/L

Details on results:

On Days 7 and 28, analysis of aqueous media showed that mancozeb was not detected in the samples (Limit of Quantitation, LOQ: 0.002 mg a.s./L. Limit of Detection, LOD: <0.0009 mg a.s./L). Sediment analysis only detected mancozeb in the 2.50 mg Mancozeb 80 WP/L nominal test concentration. Detected levels in the sediment did not exceed 0.701 mg (0.491 mg a.s./kg) of mancozeb, which was detected on day 0. Mancozeb was not detected in the sediment of the 0.008 mg Mancozeb 80 WP/L nominal test concentration (LOQ: 0.005 mg a.s./kg. LOD: <0.002 mg a.s./kg). These results indicate that the concentrations of the test substance could not be maintained under the conditions of this test. Additionally, measurements of recovery of the product at day 0 were not all within 80 and 120% of the nominal. Therefore, test results have been expressed in terms of initial mean measured values on Day 0. The temperatures measured in the test vessels each week did not stray outside of the acceptable range (20°C ± 2°C). The pH levels measured in the test vessels never fell short of the lower bound for pH (6), but exceeded the higher bound for pH (9) on several occasions within the day 21 and day 27 measurements (reaching a maximum of 10.0). Dissolved oxygen levels were mostly within the acceptable bounds, only dropping below 30% ASV on one occasion on day 0 (where %ASV was 28). Organic carbon content (measured 4.1%) of the sediment used in the test system was higher than that recommended for this test type (2% ±2%). Water hardness (mg CaCO3/L) was measured as 458 and 306 in the control on days 0 and 28 respectively, and 426 and 430 in the nominal 2.50 Mancozeb 80 WP concentration on days 0 and 28 respectively. These measurements exceed the acceptable boundaries for water hardness in a test of this type (90-300 mg CaCO3/L).

Worm reproduction:
The number of worms at test end ranged from 18 to 36 per vessel for the controls (mean 26.0). In the nominal treatment groups, at 0.00800, 0.0230 and 0.0750 mg Mancozeb 80 WP/L the mean number of worms was 21.5, 24.8 and 24.8 per vessel, respectively. The mean number of worms was not statistically significantly different to the control (p>0.05) in any of these test concentrations, displaying a similar reproductive rate. There was no dose-response relationship at these levels. At 0.240 and 0.780 mg Mancozeb 80 WP/L the mean number of worms decreased to 19.0 and 14.0 per vessel, respectively. At 2.50 mg Mancozeb 80 WP/L the mean number of worms per vessel further decreased to 4.8 (Table 8.2.5.4-X). There was a statistically significant reduction in the number of worms at 0.78 mg Mancozeb 80 WP/L (p=0.002) and 2.5 mg Mancozeb 80 WP/L (p<0.001) compared to the control. The p-value for the number of worms in the 0.075 mg Mancozeb 80 WP/L treatment compared to the control, was close to significant (p=0.07). There was a dose-response relationship for nominal concentrations above and inclusive of 0.78 mg Mancozeb 80 WP/L. EC50 for worm reproduction based on initial mean measured mancozeb concentrations was 0.69 mg Mancozeb 80 WP/L.

There was an observable reduction in worm reproduction compared to the mean at nominal 0.240 mg Mancozeb 80 WP/L, however this was not statistically significant at this testing concentration.

Worm biomass:
There was no statistically significant difference in mean worm dry biomass between the nominal test concentrations of 0.008, 0.023 and 0.075 mg Mancozeb 80 WP/L (26.55, 27.27, and 30.27 mg respectively) and the control (33.79 mg). There was no dose-response relationship at these levels. The mean dry biomass at levels 0.240, 0.78, and 2.5 mg Mancozeb 80 WP/L were 19.80, 12.30, and 2.99 mg respectively. Dry biomass of the 0.240 mg Mancozeb 80 WP/L group was significantly lower than the control (p=0.008), as was the biomass of the 0.78 and 2.5 mg Mancozeb 80 WP/L groups (both p<0.001). Mancozeb 80 WP shows a dose-response relationship with mean biomass weight above and inclusive of 0.78 mg Mancozeb 80 WP/L. EC50 for worm biomass based on initial mean measured mancozeb concentrations was 0.370 mg Mancozeb 80 WP/L.

Worm behaviour:
Worm behaviour in the test concentrations were judged in relation to control worm behaviour. Between nominal product concentrations of 0.008 and 0.075 mg Mancozeb 80 WP/L, the worms appeared mostly normal and active, with little abnormal behaviour. Most worms behaving abnormally compared to the control were observed displaying lethargy. Few abnormalities were observed during the first 7 days of the study period, but after thisabnormalities became more frequently observed and more severe, with observations including extreme lethargy, pale colouration, abnormal movement, and death. The qualitative nature of this observation data makes it unsuitable for statistical analysis.

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

The data was compiled in an Excel spreadsheet then analysed using SAS 9.1 (SAS Institute 2002) and Quasar 1.1 (Quasar 1.1 2009). Nominal product concentrations and mean measured concentrations of applied test substance concentration (on Day 0) were used in the statistical analysis and test results are reported in terms of these concentrations. p -values calculated are for the comparison with the control using Williams’ test. For worm number the standard non-linear regression procedure was terminated without achieving convergence due to mathematical problems. The lowest NOEC from this study was based on biomass of worms (0.03 mg a.s./L). The lowest EC10 was calculated from the same parameter (0.04 mg a.s./L).

Validity criteria fulfilled:

yes

Remarks:

The study was assessed by the European Food Safety Agency and found to be valid.

Conclusions:

Based on initial mean measured values of product on Day 0, the NOEC value for reproduction (number of worms) was 0.186 mg product/L. The NOEC value for development rate (dry biomass of worms) was 0.0383 mg product/L. EC50 values (95% confidence interval) for reproduction and development rate were 0.68 (0.37 – 1.30) and 0.37 (0.17 – 0.81) mg Mancozeb 80 WP/L, respectively. The EC values were calculated by the EFSA. The EC10 based the worm number was determined to be 0.109 mg a.s./L, based on weight (biomass) to be 0.040 mg a.s./L and based on individual weight to be 0.466 mg a.s./L. The EC50 based the worm number was determined to be 0.670 mg a.s./L, based on weight (biomass) to be 0.407 mg a.s./L and based on individual weight to be 1.499 mg a.s./L.

Executive summary:

A study was performed to assess the toxicity of Mancozeb 80 WP to the sediment-dwelling oligochaete Lumbriculus variegatus, using a static test system with application of the test substance to the water phase. The study was conducted in accordance with OECD guideline 225: Sediment-water Lumbriculus toxicity test using spiked sediment. However in this study the test substance was applied to the overlying water as the test substance was known to be rapidly degraded in aqueous systems so the likely route of contamination is as spray drift. The study was initiated with synchronised adult Lumbriculus variegatus worms. The parameters measured were growth (biomass) and the increase in numbers (reproduction) of the worms. Four replicates of (nominally) 10 adult worms per vessel were exposed for 28 days to Mancozeb 80 WP at nominal concentrations (as product) of 0.00800, 0.0230, 0.0750, 0.240, 0.780 and 2.50 mg/L. Initial mean measured concentrations of Mancozeb 80 WP applied to the media at the start of the test were 0.00335, 0.00824, 0.0383, 0.186, 0.680 and 1.83 mg/L respectively (52%, 45%, 63%, 96%, 108% and 91% of nominal). On Days 7 and 28, analysis of aqueous media showed that Mancozeb 80 WP was not detected in the samples. These results indicate that the concentrations of the test substance could not be maintained under the conditions of this test. Therefore, test results have been expressed in terms of initial mean measured values on Day 0 and nominal concentrations of product. Estimations of reproduction (increase in worm numbers) and dry biomass (growth) gave the following results: the 28-day EC50, and NOEC based on reproduction (increase in worm numbers) was determined to be 0.690 mg/L and 0.186 mg/L, respectively. Based on dry biomass (growth) the 28-day EC50 and NOEC was found to be 0.370 mg/L and 0.0383 mg/L, respectively. These results were re-calculated by the European Food Safety Agency (EFSA) to determine the EC50 and EC10 corresponding to the active substance content. The EC10 based the worm number was re-assessed to be 0.109 mg a.s./L, based on weight (biomass) to be 0.040 mg a.s./L and based on individual weight to be 0.466 mg a.s./L. The EC50 based the worm number was determined to be 0.670 mg a.s./L, based on weight (biomass) to be 0.407 mg a.s./L and based on individual weight to be 1.499 mg a.s./L.

Description of key information

In a study according to OECD TG 225 with Lumbriculus variegatus the NOEC (28 d, development) was determined to be 30 µg a.s./L (init). The EC10 was re-assessed by the European Food Safety Agency to be 40 µg a.s./L (init).

Additional information

Two valid guideline studies on long-term toxicity to sediment organisms are available. In addition, results of an aquatic mesocosm study are presented below.

 

Key study

 

Mancozeb 80 WP - Toxicity to the sediment-dwelling endobenthic aquatic oligochaete Lumbriculus variegatus (Dickinson 2011b (Doc. No. 828-002, cross reference to Risk Assessment Report according to Regulation (EU) No 1107/2009: 8.2.5.4/01))

Dickinson (2011b) performed a study to assess the toxicity of Mancozeb 80 WP to the sediment-dwelling oligochaete Lumbriculus variegatus, using a static test system with application of the test substance to the water phase. The study was conducted in accordance with OECD guideline 225: "Sediment-water Lumbriculus toxicity test using spiked sediment". However in this study the test substance was applied to the overlying water as the test substance was known to be rapidly degraded in aqueous systems so the likely route of contamination of the sediment compartment is via the aqueous phase. The study was initiated with synchronised adult Lumbriculus variegatus worms. The parameters measured were growth (biomass) and the increase in numbers (reproduction) of the worms. Four replicates of (nominally) 10 adult worms per vessel were exposed for 28 days to Mancozeb 80 WP at nominal concentrations (as product) of 0.00800, 0.0230, 0.0750, 0.240, 0.780 and 2.50 mg/L. Initial mean measured concentrations of Mancozeb 80 WP applied to the media at the start of the test were 0.00335, 0.00824, 0.0383, 0.186, 0.680 and 1.83 mg/L respectively. On Days 7 and 28, analysis of aqueous media showed that Mancozeb 80 WP was not detected in the samples. These results indicate that the concentrations of the test substance could not be maintained under the conditions of this test. Therefore, test results have been expressed in terms of initial mean measured values on Day 0 and nominal concentrations of product. Estimations of reproduction (increase in worm numbers) and dry biomass (growth) gave the following results: the 28-day EC50, and NOEC based on reproduction (increase in worm numbers) was determined to be 0.690 mg/L and 0.186 mg/L, respectively. Based on dry biomass (growth) the 28-day EC50 and NOEC was found to be 0.370 mg/L and 0.0383 mg/L, respectively. These results were re-calculated by the European Food Safety Agency (EFSA) to determine the EC50 and EC10 corresponding to the active substance content. The EC10 based the worm number was re-assessed to be 0.109 mg a.s./L, based on weight (biomass) to be 0.040 mg a.s./L and based on individual weight to be 0.466 mg a.s./L. The EC50 based the worm number was determined to be 0.670 mg a.s./L, based on weight (biomass) to be 0.407 mg a.s./L and based on individual weight to be 1.499 mg a.s./L. The 28-day NOEC of 30 µg a.s./L (init) and the 28-day EC10 of 40 µg a.s./L (init) are considered as key values for the risk assessment.

 

 

Supporting information

 

Mancozeb 80 WP - Toxicity to the sediment-dwelling phase of the midge Chironomus riparius (Dickinson 2011a (Doc. No. 828-001, cross reference to Risk Assessment Report according to Regulation (EU) No 1107/2009: 8.2.5.3/01))

In a supporting study by Dickinson (2011a) the toxicity of Mancozeb 80 WP to the sediment-dwelling larvae of the non-biting midge Chironomus riparius was evaluated, using a static test system with application of the test substance to the water phase. The study was conducted in accordance with GLP principles and OECD TG 219: "Sediment-water Chironomid toxicity test using spiked water". This method was chosen since spray drift is considered to be the most relevant entry path to surface waters and, consequently, to the sediment compartment. The study was initiated with first instar C. riparius. Observations which included the general condition of the larvae, emergence and the female : male ratio of adults, were recorded for each vessel. The larvae were fed with a TetraMin® fish food suspension. Four replicates of (nominally) 20 chironomid larvae per vessel were exposed for 28 days to Mancozeb 80 WP at nominal concentrations of 0.256, 0.640, 1.60, 4.00 and 10.0 mg/L (as product). Initial mean measured concentrations applied to the media were 0.150, 0.430, 1.09, 2.80 and 6.56 mg/L respectively (73%, 84%, 91%, 87% and 82% of nominal). As the test substance was shown to be unstable, test results have been expressed in terms of measured values on Day 0 and the nominal product concentrations. Mancozeb 80 WP significantly reduced the emergence success of C. riparius at nominal test substance concentrations of 1.60 mg/L (1.09 mg/L measured) and above. The calculated EC50 for emergence success was nominally >10.0 mg/L (7.16 mg/L measured). The no observed effect concentration (NOEC) for emergence success was nominally 0.640 mg/L (0.430 mg/L measured). Mancozeb 80 WP significantly reduced the mean development rate of C. riparius at nominal concentrations of 4.00 mg/L and above. The NOEC for mean development rate was nominally 1.60 mg/L (1.09 mg/L measured) Mancozeb 80 WP did not affect the sex ratio of C. riparius under the conditions of this test. The NOEC for this parameter was 10.0 mg/L (nominal) or 6.56 mg/L (measured). The results were re-assessed by the European Food Safety Agency (EFSA): a 28-day EC10 of 3.755 mg a.s./L (measured) was determined based on the development rate (males/females). The 28-day EC10 based on cumulative emergence (males/females) was calculated to be 1.594 mg a.s./L (measured).

This supporting study is not documented in an individual IUCLID Endpoint Study Record. However, a summary is given in the Renewal Assessment Report for Mancozeb prepared according to the Commission Regulation (EU) No 1107/2009 of 2019.

Additional information on the toxicity of Mancozeb to sediment organisms was evaluated in an aquatic outdoor mesocosm study by Memmert (1999). This study was re-assessed by van Wijngaard (2013) and is considered to be reliable with restrictions (Klimisch 2). The focus of the semi-field was on sediment organisms and planktonic organisms. Effect concentrations were derived based on population dynamic. As a result, a consistent 77-day NOEC for Chironomus emergence of 400 µg a.s./L was determined. For Oligochaeta a 77-day NOEC of >= 1000 µg/L is considered.  Further, a NOEAEC of < 10 μg a.s./L (< 12.5 μg/L Penncozeb 80 WP) was derived for this study. On the basis of the effect evaluation procedure, a NOEC_population of 3.2 μg a.s./L was determined. The NOEC_community was 10 μg a.s./L. However, the NOEC for the populational and community level were triggered by results for the zooplankton community level, not by results for the sediment organisms. Therefore, the 77-day NOEC of 400 µg a.s./L based on Chironomus emergence is regarded most relevant and conservative regarding the toxicity of Mancozeb to sediment organisms.

 

Remark: In accordance with Regulation (EU) No 1107/2009 both the key study and the supporting study by Dickinson (2011a) were peer reviewed by rapporteur member states and have been proven by the EFSA to be valid.

 

For details on test conditions and findings please also refer to the disseminated EFSA Conclusion on the active substance Mancozep (Peer review of the pesticide risk assessment of the active substance mancozeb; European Food Safety Authority (EFSA), approved 12 June 2019, doi:10.2903/ j.efsa.2019.5755).

Conclusion

Two valid and GLP-compliant guideline studies on long-term toxicity of the preparation Mancozeb 80 WP (containing 80.5% of the active substance Mancozeb) to sediment organisms and one mesocosm study are available. Thus, short-term toxicity tests are regarded scientifically not necessary and additional studies are considered unjustified.

In a study according to OECD TG 225 with Lumbriculus variegatus by Dickinson (2011b) the NOEC (28 d, development) was determined to be 30 µg a.s./L (measured). The EC10 was re-assessed by the European Food Safety Agency to be 40 µg a.s./L (measured). This values is considered to be conservative as in an aquatic semi-field study by Memmert (1999, re-evaluated by van Wijngaard, 2013) a 77-day NOEC of >= 1000 µg/L was derived. Moreover, in this study a 77-day NOEC for Chironomus emergence of 400 µg a.s./L was determined demonstrating less toxic potential of Mancozeb to sediment organisms under environmental conditions. These effect values are supported by the results of a study with sediment-dwelling larvae of the non-biting midge Chironomus riparius according to OECD TG 2019 (Dickinson, 2011a). In this test the EC10 based on development rate and cumulative emergence was determined to be 3.755 mg a.s./L (measured) and 1.594 mg a.s./L (measured), respectively. Regarding the available data it seems that Lumbriculus is more sensitive than Chironomus riparius by a factor of 39.85. Following a worst case approach the study by Dickinson (2011b) with Lumbriculus variegatus is considered as key information and the 28-day NOEC of 30 µg a.s./L (measured) as well as the 28-day EC10 of 40 µg a.s./L (measured) are taken into account for the risk assessment. The provided information is regarded reliable and sufficient to cover the data requirements according to REACH Annex X, section 9.5.1.