Ziram

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 February - March 2006

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

a solvent was used

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Version / remarks:

1997

Deviations:

yes

Remarks:

Feeding rate exceeds the OECD guideline of 0.1 - 0.2 mg C/daphnid/d, however an excess amount of feed was needed in order to maintain sufficient feed in the flow-through system to support acceptable reproduction rates.

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1300 (Daphnid Chronic Toxicity Test)

Version / remarks:

1996 (draft)

GLP compliance:

yes

Remarks:

Laboratories in the USA are not certified by any governmental agency, but are subject to official inspections.

Analytical monitoring:

yes

Remarks:

Liquid scintillation counting (LSC)

Details on sampling:

Water samples were collected from one test chamber of each treatment and control group two days prior to test initiation to confirm the operation of the diluter. Water samples were collected from alternating replicate test chambers of each treatment and control group on days 0, 7, 14 and 21 of the test to determine concentrations of the test substance in the test chambers. Additional samples were collected on day 17 to confirm concentrations after the initiation of aeration in the test chambers. All samples were collected at mid-depth in the test chambers, placed in glass scintillation vials and processed immediately for analysis.

Vehicle:

yes

Remarks:

dimethyl formamide

Details on test solutions:

Initial stock solutions were prepared combining an appropriate amount of 14C ziram stock solution prepared in DMF with non radiolabelled ziram stock solution. The dispensing solutions were then mixed with well water at a rate of 155 mL/min to achieve the desired test concentrations.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: laboratory culture
- Age at study initiation: < 24 h old
- Feeding during test: yes
- Food type: mixture of yeast, cereal grass media and trout chow (YCT) as well as a suspension of the freshwater green alga (Selenastrum capricornutum)
- Amount: 0.74 mL YCT and 1.5 mL of algae per test chamber
- Frequency: three times per day through day 7 of the test and two to four times per day until the last day of the test

ACCLIMATION
- Acclimation period: 15 days
- Acclimation conditions: freshwater
- Health during acclimation: good

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

132 - 144 mg/L as CaCO3

Test temperature:

Water bath at 20 ± 1°C
Measured temperature range: 19.6 to 19.9°C

pH:

7.9 to 8.2

Dissolved oxygen:

6.0 to 8.8 mg/L
> 60% saturation (60% saturation equals 5.4 mg/L at 20°C )

Conductivity:

290 - 325 µmhos/cm

Nominal and measured concentrations:

Nominal: 0 (negative and solvent control), 9.4, 19, 38, 75 and 150 µg/L
Measured: 0 (negative and solvent control), 9.3, 22, 39, 78 and 154 µg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: open
- The test chambers were 25 L Teflon®-lined stainless steel aquaria filled with approximately 22 L of test solution. The daphnids were held in two test compartments (300 mL glass beakers, approximately 6.5 cm in diameter and 12 cm in height) suspended in each of two test chambers. Depth of test water was 8.3 cm, while the depth of water in a representative test chamber was 28.9 cm.
- Aeration: Gentle aeration was added to each test chamber on day 16 to maintain dissolved oxygen concentrations above 60 % saturation.
- Type of flow-through: A continuous-flow diluter was used to deliver each concentration of the test substance and the controls. Syringe pumps (Harvard Apparatus) were used to deliver the five test substance stock solutions and dimethyl formamide (DMF) for the solvent control into mixing chambers. The flow of dilution water to the mixing chambers was controlled by rotameters. The flow of test water from each mixing chamber was split and allowed to flow into the replicate test chambers.
- Renewal rate of test solution: five volume additions of test water in each test chamber per day.
- No. of organisms per vessel: 10 (5 per compartment)
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- No. of vessels per vehicle control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: fresh water from a well approx. 40 meters deep located on the Wildlife International, Ltd. site. Well water was passed through a sand filter to remove particles greater than approx. 25µm and pumped into a 37,800 L storage tank where the water was aerated with spray nozzles. Prior to use, water was filtered to 0.45 µm to remove fine particles and was passed through a UV sterilizer.
- Hardness: 132 - 140 mg CaCO3/L
- Alkalinity: 180 - 182 mg CaCO3/L
- Specific conductance: 295 - 300 µmhos/cm
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light/8 hours darkness
- Light intensity: approx. 172 lux

EFFECT PARAMETERS MEASURED: Observations of each first-generation daphnid were made daily during the test. At these times, the numbers of dead and immobile daphnids were recorded along with any clinical sign of toxicity (eg., inability to maintain position in the water column, uncoordinated swimming or cessation of feeding). Immobility was defined as a lack of movement, except for minor spontaneous random movement of the appendages. The presence of eggs in the brood pouch, aborted eggs, males or ephippia also were recorded daily. With the onset of reproduction, neonates produced by the first generation daphnids were counted and then discarded every Monday, Wednesday and Friday during the test. The body length and the dry weight of each surviving first-generation daphnid were measured at the end ofthe test.

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

39 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

growth

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

78 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

78 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

mortality

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

144 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

mortality

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

121 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Details on results:

- No. of offspring produced per day per female: Daphnids in the 9.3, 22, 39, 78 and 154 µg/L treatment groups produced an average of 11.97, 11.71, 14.82, 10.90 and 4.29 live young per reproductive day, respectively.
- Type and number of behavioural abnormalities: inability of maintain positionin the water column, uncoordinated swimming or cessation of feeding
- Number of males and females (parental): 10 per replicate (sex not specificied)

The mean measured concentrations, over the whole test period, in the test chambers ranged from 95 to 125 % of nominal concentrations.

There was a slight, yet statistically significant difference in reproduction between the negative and solvent control groups. Therefore, the treatment data were compared to the solvent control.

Table 1: Validity criteria for OECD 211

Criterion from the guideline	Outcome	Validity criterion fulfilled
The mortality of the parent animals in the control (femaleDaphnia) does not exceed 20% at the end of the test.	Immobility in the negative and solvent control groups was 0 and 5 %	yes
The mean number of living offspring produced per parent animalsurvivingat the end of the test is ≥ 60 in the control.	Negative control: 143.3 Solvent control: 200.9	yes

Validity criteria fulfilled:

yes

Remarks:

For details please refer to field "any other information on results incl. tables"

Executive summary:

Materials and methods:The chronic toxicity of ziram to Daphnia magna was investigated. A group of twenty daphnids were exposed for up to 21 days under flow-through conditions to one of five concentrations of test substance, a solvent control, and a dilution water control.Nominal concentrations of the active ingredient were: 0 (control and solvent control), 9.4, 19, 38, 75, and 150 mg/L ziram. Mean measured concentrations were: LOQ ( 1.37 µg/L); control and solvent control, 9.3, 22, 39, 78, and 154 µg/L ziram. The recovery ranged from 99 to 116 %. First-generation daphnids were observed daily during the test for mortality, the onset of reproduction, and signs of toxicity. Following the onset of reproduction, the numbers of second-generation daphnids were counted three times per week.

Results and discussion: Mean measured concentrations were used for all calculations. Water quality parameters were within acceptable limits throughout the testing period.

There were statistically significant effects on survival and reproduction at the highest concentration of 154 µg/L and there was a statistically significant decrease in growth (length) at 78 and 154 µg/L. Consequently, the NOEC for this study was 39 µg/L and the LOEC was 78 µg/L. The calculated MATC was 55 µg/L. The 21-day EC50 value for adult mortality/immobility was 144 µg/L and the 21-day EC50 value for reproduction was 121 µg/L.

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

3 October 2000 - 20 August 2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

GLP study, there is no official test guideline available for a 10 week toxicity test with populations of Daphnia magna; procedure meets basic scientific principles

Qualifier:

no guideline available

Principles of method if other than guideline:

Test species is recommended by the OECD Guideline 211, chronic test over ten weeks

GLP compliance:

yes (incl. QA statement)

Remarks:

The Swiss GLP Monitoring Authorities

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

- A concentrated stock solution of nominal 33 mg/L ZIRAM 76 WG was freshly prepared by homogeneously dispersing 33 mg of the test item in 1000 mL test water by ultrasonic treatment for 15 minutes and stirring for 10 minutes at room temperature. An application solution was then prepared for each test concentration by diluting a requisite volume of the stock solution with test water
- The test item was applied inta the test water at the start of the study and in weekly intervals on Days 7, 14 and 21, respectively
- 10 mL of the application solutions were dosed into the water column in each test beaker by means of a pipette. Immediately after application, the water column was gently mixed with a glass rod to ensure homogeneous distribution of the test item, without affecting the daphnids. To the control beakers 10 mL test water without test item were applled and mixed into the test media in the same way as at the treated test beakers.

Test organisms (species):

Daphnia magna

Details on test organisms:

- The study was performed with the species Daphnia magna Straus. A clone of this species was originally supplied by the University of Sheffield, UK in 1992, defined from the supplier as clone 5. Since this date the clone was bred in the RCC laboratories under identical temperature and light conditions as in the study, and in the same kind of test water as used in the study.
Five and twelve days before start of the study young daphnids with an age of less than 24 hours and not from first progeny were isolated from the routine culture of Daphnia magna. These young daphnids were separately cultivated in the same kind of test water and under identical temperature and light conditions as in the study. The offspring of these pre-cultures were regularly discarded.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

10 wk

Test temperature:

20.4- 21.5°C

pH:

7.6-8.2

Dissolved oxygen:

>= 7 mg/L

Nominal and measured concentrations:

Nominal: 1.3, 4.2, 13, 42 and 132 ug/L
Nominal active ingredient: 1.0, 3.2, 10, 32 and 100 ug a.i./L
Measured: 82-106% nominal concentrations

Details on test conditions:

- At the start of the study (on Day 0, before the first test item application) a population of 18 daphnids with three different age classes was inserted into each test beaker: 8 offspring with an age of less than 24 hours, 5 females with an age of 5-6 days, and 5 females with an age of 12—13 days . The number of inserted test animals and their ages were identical in each test beaker. The test animals were randomly distributed to the test vessels.
- Five replicates (test beakers) were tested at each test concentration and the control. The test was performed in a temperature-controlled room.
The initial test medium volume was 2.5 liter per test beaker, corresponding to a water column of 19.5 cm height
- Vitamins of the test water were regularly added to the test media to keep the test animals healthy during this chronic study. Once a week 2.33-2.50 mL of a vitamin stock solution was dosed per test beaker. However, ultrastructural lesions of the antennae of the daphnids occurred at least in the control approximately four weeks after study start. Such antennal damage can be caused by selenium deficiency. Therefore, 500 ml of the old test media were replaced with fresh test water (without test item) in all test beakers at all test concentrations and the control on Day 29, 36, 43 and 50, respectively. This regular exchange of 1/5 of the total test medium volume per renewal date was necessary to provide the daphnia populations also for trace elements as selenium by the addition of fresh test water. In this way a further and increasing antennal damage could be avoided, and the test animal populations could be kept healthy
- A 16-hour light to 8-hour darkness photoperiod with a 30 minute transition period between Iight and darkness was applied. Light intensity at light period within the range of about 580—720 Lux (measured approximately at water surface)
- During the whole study the test media were gently aerated with compressed air through a glass Pasteur pipette

Duration:

10 wk

Dose descriptor:

NOEC

Effect conc.:

10 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

other: population development, average population density

Duration:

10 wk

Dose descriptor:

LOEC

Effect conc.:

32 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks:

and delayed population development

Description of key information

NOEC (21 d) = 39 µg/L (mean measured, based on growth of Daphnia magna, OECD 211)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

NOEC

Effect concentration:

39 µg/L

Additional information

The chronic toxicity of zinc bis dimethyldithiocarbamate (CAS No. 137-30-4) to Daphnia magna was investigated in a study (2006) according to the OECD Guideline No. 211, EPA Guideline OPPTS 850.1300 and GLP. Daphnids were exposed for 21 days, in a flow-through test system to nominal test item concentrations of 9.4, 19, 38, 75, and 150 µg/L (corresponding to mean measured concentrations of 9.3, 22, 39, 78, and 154 µg/L). Dimethyl formamide was used as a vehicle. A 14-C radio-labelled test item was used for the test and was analytically monitored via liquid scintillation counting (LSC). Adverse effects on growth, survival and reproductive performance were recorded, resulting in a mean measured NOEC (21 d) of 39 µg/L (based on growth). This study was chosen as key study due to its high methodological reliability and the higher purity of the test substance.

An additional study (2001) investigating the chronic effects of the formulation Ziram 76 WG on population densities ofDaphnia magnafor ten weeks is available. This test was conducted under GLP conditions but no guideline was followed. Test organisms were exposed for 10 weeks to a four-fold application of the test item (at days 0, 7, 14 and 21). A NOEC (10 wk) of 10 µg a.i/L was determined in this study. However, the study was performed with a product and was therefore used as supporting information.