Cadmium nitrate

PBT assessment

PBT assessment: overall result

PBT status:

PBT assessment does not apply

Justification:

According to regulation (EC) 1907/2006 (REACH) a PBT and vPvB assessment shall usually be conducted as foreseen in Article 14 (3) (d) in conjunction with Annex I Section 4 and according to the criteria laid down in Annex XIII. However, according to Annex XIII a PBT and vPvB assessment shall not be conducted for inorganic substances.Cd(NO₃)₂ is an inorganic substance, thus a PBT and vPvB assessment is not required.

Still, the points below are raised:

Persistence

Cadmium is an element and as such, the criterion “persistence” is not applicable to Cd and Cd-compounds.

As an alternative for persistency (for organic substances), the concept of “removal from the water column” has been developed for inorganic elements.

In section 4.6 (of the CSR), the rapid removal of cadmium from the water column is documented. So, cadmium can be considered as equivalent to “degradable” and, consequently, does not match in chronic toxicity terms with the criterion “persistent”.

 

Bio-accumulation

Data on bioaccumulation of cadmium are presented and discussed under section 4.3. From this analysis, the following was concluded:

There is a number of data available on the possible accumulation of cadmium in aquatic organisms.

BCF in fish (whole body data) are generally below the criterion for considering a substance bioaccumulative.

Higher BCF /BAF factors are observed in the lower levels of the food chain (algae notably). However, there are some uncertainties with the data: the high BCF/BAF factors observed in the algae are (at least partly) due to external absorption, not to uptake. In general, algae data are not considered in a context of bioaccumulation. The higher levels in invertebrates may be related to lack of gut clearance of the organisms studied.

In terms of hazard identification/classification, several considerations speak further against considering Cd as bioaccumulative substance:

-the BCF/BAF values observed with Cd consistently decrease with increasing exposure, which clearly shows some level of physiological regulation of uptake. One of the key theoretical conditions of the BCF model in terms of its relevance for chronic toxicity and applicability to the hazard identification/classification of chemicals is that the BCF/BAF should be independent of exposure. BCF/BAF values should in other words remain fairly constant over a range of exposures, which is clearly not the case for Cd.

-Evidence related to biomagnification in the aquatic food chain consistently shows that Cd is not biomagnifying.

The data on terrestrial organisms show that cadmium is not bioaccumulating in terrestrial organisms. Based on an extensive review of evidence on a wide variability of taxonomic groups, McGeer et al (2003) concluded that the BCF/BAF criteria, as conceived for organic substances, are inappropriate for the hazard identification and classification of metals, including Cd. They highlighted the inconsistency between BCF/BAF values and toxicological data, as BCF values are highest (suggesting hazard) at low exposure concentrations and are lowest (indicating no hazard) at the highest exposure concentrations, were toxicity is likely.

Considering the elements mentioned above, cadmium and its compounds are considered as not bioaccumulative. 

Related to secondary poisoning, the following was concluded from the analysis in section 4.4.:

In the freshwater compartment, the risk of secondary poisoning of fish eating birds by Cd is predicted to be smaller than the direct effects of Cd in the aquatic environment. The RA demonstrated, using BCF’s of fish (mentioned in section 4.3) that the Cd concentration in whole fish at the PNEC_waterof 0.19 µg Cd/l (section 7.) could be predicted to range between 0.0001 and 0.13 mg Cd/kg fresh weight using thewholerange of BCF’s (0.5-684 l/kg fresh weight). It was concluded that these Cd concentrations were below the PNEC_oralfor birds or birds+mammals (ECB 2007). 

In the terrestrial compartment, a PNEC for secondary poisoning was calculated from the lowest observed PNEC_oralfor mammals and birds, which was derived from feeding studies with Cd salt spiked diets. Nine feeding studies were selected (sub-chronic and chronic studies), four studies with birds and 5 studies with mammals. The PNEC_oralof 0.9 µg Cd/g DW soil was calculated from the lowest NOEC using an assessment factor (see section 7). It follows from the risk characterisation under section10.2.2. (Environment (combined for all emission sources), that the PNEC secondary poisoning is in general not reached in soil.

 

Toxicity

The reference values for aquatic toxicity following from section 7 are 18µg/l for acute toxicity, and 0.21 µg Cd/l for chronic aquatic toxicity.

Summary and overall conclusions on PBT or vPvB properties

According to Annex XIII of regulation (EC) 1907/2006 (REACH) a PBT and vPvB assessment shall not be conducted for inorganic substances. Cd is an inorganic substance, thus a PBT and vPvB assessment is not required. Still, based on the elements mentioned above, cadmium and its compounds are considered as non-bioaccumulative and non-peristent.