Barium

Monitoring data

Administrative data

Endpoint:

monitoring data

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Monitoring data (ambient and background) that were generated in National and International Monitoring surveys were analysed and relevant PEC-values were derived in line with the principles given in ECHA-Guidance documents

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: ECHA (European Chemicals Agency), 2008. RIP 3.2: Guidance on information requirements and chemical safety assessment. Chapter R.16: Environmental Exposure Estimation.

GLP compliance:

not specified

Type of measurement:

other: ambient and background concentrations

Media:

sediment

Results and discussion

Any other information on results incl. tables

A French dataset with measurements around the Rhone Mediterranean in 2006 was evaluated. Measurements from the SWAD database were investigated for relevance. French monitoring data from the Rhone mediterranée area, dated back to 2006, were retrieved. Ten measurements were identified, representing several locations in 2006.

Table: Overview of available barium-related monitoring data in the French Seine database

Fraction No. of data points 25th and 75th percentile Measured values (mg/kg)

                                                           Min Max

Ba       10                     236.5 – 307 mg/kg                      152 392

French stream sediment values are much higher than the baseline value that was derived for France. No other ambient stream water sediment monitoring data were identified; hence, no proper RWC-ambient PEC could be derived directly for this environmental compartment.

However, assuming equilibrium between the surface water and sediment compartment, a RWC-ambient PEC can be derived, using the RWC-ambient PEC for freshwater and the barium Kd-value for sediment (equilibrium partitioning method). A Kd,sediment of 3,478 L/kg (Log Kd: 3.54) has been determined for szediment. In a first step the units have to be converted from L/kg to m3/m3 using the formula below.

Kd,sediment (m3/m3) = 0.8 + [ 0.2 x (Kd,sediment (L/kg) x 2,500) / 1,000 ]

This results in a Kd,sediment of 1,739.8 m3/m3. This value can be entered in the equation below to calculate the RWC-ambient PECsediment:

RWC-ambient PECsediment = ( Kd, sediment/ RHOsediment ) x PECaquatic x 1,000

With the PECaquatic expressed as mg/L (0.0389 mg/L), RHOsediment representing the bulk density of wet sediment (1,300 kg/m3) and Kd,sediment is 1,739.8 m3/m3, a RWC-ambient PECsediment of 52.1 expressed as mg/kg wet weight is derived. This value can be converted to a dry weight-based PEC, using a conversion factor of 2.6 kg wet weight/ kg dry weight.

This results in a RWC-ambient PECsediment of 135.4 mg Ba/kg dry wt.

An overview of all typical, country-specific background levels in European sediments is given below

Country	Median background (mg/kg dw)	Country	Median background (mg/kg dw)
Austria	61.2	Latvia	52.1
Belgium	127.2	Lithuania	79.9
Czech Republic	148.1	Netherlands	35.3
Denmark	53.1	Norway	51.4
Estonia	43.4	Poland	52.4
Finland	61.2	Portugal	122.3
France	82.4	Slovakia	139.7
Germany	101.3	Slovenia	58.0
Greece	82.5	Spain	88.0
Hungary	74.0	Sweden	60.2
Ireland	151.9	United Kingdom	146.9
Italy	102.4

Applicant's summary and conclusion

Conclusions:

Data can be used for exposure assesment and risk characterisation purposes of barium in the sediment compartment