Summary of Initial Risk Assessment Report Zinc Compounds (Water

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Summary of Initial Risk Assessment Report

Zinc compounds (water-soluble) This substance is assessed based on Guideline for Initial Risk Assessment Version 2.0

>> Introduction << Zinc compounds (water-soluble) are the subject of this assessment report. Inorganic compounds exist as diverse chemical species which can change in the environment. These chemical species have different hazardous properties. However, very few measured environmental concentrations are available for each species. Taking that into consideration, risk assessments of inorganic compounds are conducted using slightly different procedures from those of organic compounds. Refer to the Guideline for more detail. In this report, units of concentrations and intake (e.g., mg/L, mg/kg-Bodyweight/day) refer to the concentration or amount of pure material (Zn).

1. General Information 1.1 Physico-chemical properties

PRTR No. of Japan 1

Name (typical Zinc chloride Zinc sulfate Zinc nitrate substance)

ZnSO4 (anhydrous) Zn(NO3)2 (anhydrous) Chemical formula ZnCl2 ZnSO47H2O (heptahydrate) Zn(NO3)26H2O (hexahydrate) CAS No. 7646-85-7 7733-02-0 7779-88-6

White solid (anhydrous) Appearance White solid Colorless solid Colorless solid (hexahydrate) degradated at 680degC 36.4degC (hexahydrate) Melting point 290degC (anhydrous), anhydrated at 131degC 100degC(heptahydrate) Anhydrated at Boiling point 732degC No data 280degC(heptahydrate) 4,320g/kg 577g/kg(25degC)(anhydrous), 1,200g/kg(25degC) Water solubility (25degC) 540g/L(20degC)( heptahydrate) (hexahydrate)

1.2 Environmental fate Zinc oxide: Not highly bioaccumulative, Bioconcentration factor (BCF): <172-217 (0.25 Znmg/L) Zinc sulfide: Not highly bioaccumulative, BCF: ,95-217 (0.30mgZn/L) Zinc chloride: Non or not highly bioaccumulative, BCF: (230)-457 (0.05mgZn/L) Bioaccumulation Zinc sulfate: Non or not highly bioaccumulative, BCF: 94-242 (0.1mgZn/L) Zinc nitrate hexahydrate: Not highly bioaccumulative, BCF: <210 (1.0mgZn/L) Biomagnification of zinc has not been reported

Biodegradation --

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(In soil) In the environment, zinc exists mainly in sedimentary rocks such as shale, igneous rocks such as basalt. Zinc which shifted to soil by the weathering of a base rock and erosion sticks to the soil water or soil particles. Zinc forms complexes with organic ligands and sticks to the clay minerals. (In air) Zinc discharged into the atmosphere mainly exists as oxide particles, and it is considered that the size of particles depends on the source of discharge. The zinc particles in the atmosphere shift to soil and a water component by a descent by gravity or Stability and fate in rain. the environment (In water) Zinc which shifted to the water component by a decent in atmosphere or exudation from soil and rock, exists as a hydrate ion mainly, and also as a complex with an organic matter or an inorganic substance. Zinc is adsorbed to iron hydroxide, a sulfide, silica and clay in water. Since zinc is an amphoteric element, zinc metal, zinc oxide is soluble in acidic and basic aqueous solutions. Hydrate is produced in less than pH9, and is solved forming zincate anion. Zinc in solutions precipitates as zinc hydroxide in the pH range of 9 to 10.5 Biological methylation of zinc has not been confirmed.

2. Sources of release to the environment 2.1 Annual domestic supply in 2003 (ton/year, as pure zinc)

Substance Zinc metal Zinc oxide Zinc chloride

Domestic supply 621,391 74,617 4,767

2.2 Uses Zinc metal: galvanized iron, zinc oxide: vulcanization accelerator aids of rubber, zinc chloride: flux of hot dip zincing, Zinc sulfate: agricultural chemical, fertilizer, feed

2.3 Release from the industries within the scope of PRTR system (2003, as pure zinc)

Release sources Air (ton) Waters (ton) Soil (ton) Remarks

Reported release 66 625 <0.5

Release outside Listed 2 14 <0.5 industries notification

Release outside notification from Release to rivers: 432 tons 0 0 23 non listed industry Households ------

Mobile sources ------

Total 68 639 24

2.4 Releases from other sources Approximately 45,000 tons of zinc is released per year through natural processes such as soil entrained into the air by wind, volcanic activity, forest fires and biological activity. In the case of anthropogenic zinc emissions, 2,570 - 19,630 tons/ year and 532 - 3,786 tons/ year were released by combustion of petroleum and coal, respectively. In 1983, 2,950 - 3,786 tons was emitted annually from garbage combustors

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worldwide.

2.5 Main release route The main release routes of zinc include both natural emissions and anthropogenic emissions. Sources of anthropogenic emission of water soluble zinc include waste water from chemical industries, nonferrous metal industries, metal and other manufactures and emissions from sewage treatment facilities. Galvanized products are corroded by sulfur oxides, producing water soluble zinc compounds. The compounds drain into environmental water. Releases to the atmosphere include the emissions from manufacturing industries, manufacturing metal products and nonferrous metals, combustion of fossil fuels and abrasion of rubber tire.

3. Exposure Assessment 3.1 Measured environmental concentration

No. of points No. of samples Year of detected / detected / Detection 95th Detection Media 1) investigation, No. of points No. of samples range percentile limit institution measured measured

Air 0.027- 2002 8/8 90/90 0.16 0.000095 (microg/m3) 0.20 Osaka prefecture

2000 River water 896/ 896/ nd- 120 1-500 Ministry of (microg/L) 1,981 1,981 1,600 Environment

2003 Drinking water 1,185/ -- / nd-420 50 10-400 Japan Water Works (microg/L) 5,435 13,825 Association

The Ministry of Health, Labor and Welfare surveyed the zinc intake from food of the general Japanese population in 2002. The survey was conducted by each age group, and maximum intake Food was shown in the 18-29 age group. The ninety fifth percentile of intake of this group was 16,300microg/person/ day.

1) nd: not detected For calculation of the 95th percentile, data less than the detection limit are replaced with a value equal to 1/2 of the detection limit.

3.2 Estimated environmental concentration

Estimation by mathematical model was not conducted, because it was difficult to make assumptions on the effects on environmental concentration considering natural emission and dynamism in the environment.

3.3 Estimated environmental concentration in water (EEC) for risk assessment

120

EEC(microg/L) The ninety fifth percentile of measured concentrations in rivers was used, since no estimation was conducted.1)

3.4 Estimated human intake 3 R0150

Concentrations used for Estimated intake Estimated intake Intake route estimation of intake (microg/ person/ day) (microg /kg-Bodyweight (BW) / day)

Air micro 3 3.2 0.064 0.16 ( g/m )

The ninety-fifth percentile of measured concentrations in air was used for the risk assessment, since

estimation was not conducted. Inhalation

Drinking 50 (microg/L) 100 2.0 water The ninety-fifth percentile of measured concentrations in treated water at water purification plants

was used for the risk assessment.

Food - 16,300 330 Oral

The ninety-fifth percentile of intake of Japanese 18-29 ages group was used for the risk assessment.

Subtotal 16,400 330

Total route 16,400 330

1) This substance is assessed based on the Guideline for Initial Risk Assessment Version2.0. Under Version 2.0, a measured concentration and an estimated concentration (calculated by mathematical model) are compared and the larger of two concentrations is used for risk assessment.

4. Hazard assessment 4.1 Environmental organisms toxicity

Acute or Chronic Species Endpoint Concentration

Algae 96 hours EC Acute Nitzschia closteium 50 0.065 (mg/L) (zinc chloride) Growth inhibition

Crustacea 21 days EC50 Chronic Daphnia magna 0.102 (mg/L) (zinc chloride) Reproduction

Fish 100 days NOEC Chronic Jordanella floridae 0.026 (mg/L) (zinc sulfate) Growth (female)

Key study Data of fish was chosen for the key study because effects were observed at the lowest concentration in the hazard assessment.

4.2 Human health toxicity

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NOAEL or Exposure Dose term/ dose species Toxic effects LOAEL route method (converted)

Inhalation No appropriate study was available for the risk assessment. Repeated dose toxicity Tolerable Upper Intake Level specified in Dietary Reference Intakes posed by Ministry of Health, 0.60 Oral Human Labor and Welfare in Japan as 30 mg-Zn/person/ mg/ kgBW/ day day was used for NOAEL.

Dermal - - - -

Reproductive and developmental No appropriate study was available for the risk assessment. - toxicity

Carcinogenicity Evaluation by IARC : Zinc and its compounds are not assessed by IARC

Genotoxicity Unable to determine genotoxicity

5. Risk Assessment 5.1 Environmental organisms

Product of EEC NOEC MOE uncertainty Conclusion (microg/L) (mg/L) (NOEC / EEC) Risk factors character- 120 NOEC: 0.026 0.22 50 Substance of concern ization Product of uncertainty factors (UF): Duration of test (10) * Extrapolation from chronic toxicity data on two trophic level (5) = 50

Recommendation The substance is considered to be of concern and further investigation, analysis and assessment are necessary

5.2 Human health 5.2.1 Repeated dose toxicity

Risk characterization

Exposure Intake NOAEL Product of route (microg/kgBW/day) (mg/kgBW/day) MOE uncertainty Conclusion factors

Inhalation 0.064 No adequate study was available for the risk assessment.

Oral 330 NOAEL: 0.60 1.8 1 No immediate concern

Product of uncertainty factors (UF): = 1

5.2.2 Reproductive and developmental toxicity

Risk assessment was not conducted, since NOAEL could not be determined

5.2.3 Recommendation for Human Health

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In terms of oral exposure, the substance is considered to be of no immediate concern for the moment, and a low priority of further work. As for inhalation exposure, a risk assessment was not conducted due to a lack of toxicity data.

6. Supplement

1) Zinc is essential metal element for human, Ministry of Health, Labor and Welfare of Japan pose presumed necessary daily average intake level as 8mg/day for male and 6mg/day for female. 2) Although diverse zinc compounds occur in the environment, this environmental risk assessment was conducted using the toxic data for zinc sulfate because it exhibited the lowest NOEC amongst the zinc compounds examined for this assessment. As a result, the assessment may be conservative.