Limit Values (BLV

Table 11. Chromium case study scenarios for provisional OBL* derivation

Chromium scenario

precautionary

balanced

relaxed NOAEL* /LOAEL*. reference

LOAEL* inhalation 0.002 mg Cr/m3 , (Lindberg and Hedenstierna, 1983) inhalation exposure,for nasal irritation, mucosal atrophy, impaired lung function in 104 workers , median exposure 4.5 years

NOAEL* inhalation 0.01 mg Cr/m3 , (Derelanko et al., 1999) increased lung weight in rats after 13 weeks exposure 0.38 µg/kg/d 15.2 µg/L

LOAEL* inhalation 4.3 mg Cr/m3(Nettesheim and Szakal, 1972) mice had epithelial necrosis after 18 months inhalation exposure study 10.975 µg/kg/d 439 µg/L

Mode of action relevant endpoint DNEL* oral POBL*

0.019 µg/kg/d 0.76 µg/L  37

Relevance of POD*

Partially yes for lung function, but carcinogenicity is missing

Partially yes for lung function, but carcinogenicity is missing No, too late effects with risk missing other adverse endpoints

The relevance assessment of available data is of high importance in deriving POBL*, as it helps in prioritizing the identified occupational toxicological risks. The minimum relevance POBL* requirement is a link between the POD* and known toxicity endpoint, and was established for most case study substances (DEHP*, HDI*, and Aluminium). For Chromium, the lung cancer risk POD* was only indirectly linked with impaired lung function. We recommend using all potential reliable studies identified as relevant and leading to adverse effects. This can reduce expert judgement discussions, and the risk of missing available evidence in a crucial primary risk identification step.

3.3.4. Sensitivity comparison of POBL with refined OBL and other occupational Biomonitoring Limit Values (BLV)

Available BLVs* were compiled by several experts in the refined OBL* subtask. A systematic data collection approach was ensured by using templates and after discussion of these templates by all experts. The BLVs* were compared in a case study sensitivity comparison (see Table 11) with POBL* derivations from the urinary mass balance approach (derivations in Tables 8-11). A further normalization to creatinine levels is recommended before the application of POBLs, but this was not necessary for comparison purposes.

Table 11. Case study sensitivity comparison of Provisional Occupational Biomonitoring Levels (POBLs*) with refined Occupational Biomonitoring Levels (OBLs*) and available Biomonitoring Limit Values (BLVs)

Case study POBL* Refined OBL* or

BLV*

DEHP* 0.15 - 1.44 mg/L 4.52 mg/L #

(S5-oxo and 5-OH MEHP) (SMEHP, 5-OH-MEHP, 5-oxoMEHP and 5-cx-MEPP)

Ratios between refined OBL* and POBL*

3-30

OCCUPATIONAL BIOMONITORING GUIDANCE DOCUMENT © OECD 2022