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Classification & Labelling & PBT assessment

PBT assessment

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PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB
Justification:

Classification for Persistence

Sodium dichromate is an inorganic substance and so the issue of biodegradation does not apply. The substance dissociates rapidly to its constituent ions in the aqueous environment. As such sodium dichromate does not satisfy the criteria for classification as persistent.

Classification for Bioaccumulation

Chromium (VI) has been shown to be taken up by a wide range of organisms from water, sediment and soil. For fish, although uptake does occur, the bioconcentration factors for chromium (VI) are usually very low (~1 l/kg). In addiiton, chromium is usually present in the environment as Cr (III). Sodium dichromate is not considered to satisfy the criteria for classification as bioaccumulative.

Classification for Toxicity

Sodium dichromate is classified in Annex I of Directive 67/548/EEC (DSD) as Very Toxic (T+) with the risk phrases R45, R46, R60, R61, R8, R21, R25, R26, R34, R42/43, R48/23 and R50/53. The substance is also listed in Annex VI of the CLP Regulation (1272/2008) with classification H301 (Toxic if swallowed), H312 (Harmful in contact with skin), H314 (Causes severe skin burns and eye damage), H317 (May cause an allergic skin reaction), H330 (Fatal if inhaled), H334 (May cause allergy or asthma symptoms or breathing difficulties if inhaled), H340 (May cause genetic defects), H350 (May cause cancer), H360 (May damage fertility or the unborn child), H372 (Causes damage to organs through prolonged or repeated exposure) and H410 (Very toxic to aquatic life with long lasting effects). The criteria for ‘Toxic’ are therefore met.

Likely routes of exposure:

The most likely route of exposure is through inhalation and dermal exposure. The exposure to workers should be mimised by the use of appropriate personal protective equipment (gloves, RPE and protectives overalls) and enigineering controls (process enclosure, local exhaust ventilation).

Environmental exposure is minimal as an efficient waste water treatment ensures all Cr (VI) is reduced to Cr (III) prior to flocculation and precipitation and subsequent disposal of treated sludge to landfill.