6.8 Example: Risk Assessment of a Reactive Cotton Dye
149
and relevant calculations are presented separately for assessing the risk to human
health and the environment. The values provided here are based on typical values
for such reactive triazine dyes.
6.8.1 Hazard Identification (Step 1)
Through a review of existing toxicity data on this particular dye and on chemicals
within the same class, it was identified that:
• In preparing the dye liquor starting from powder, the sensitizing effect and
chronic toxicity of the dye can be a potential hazard to the health of the
employees.
• The dye may be toxic to the aquatic environment and may not be adequately
removed during wastewater treatment processes.
6.8.2 Exposure Assessment (Step 2)
Investigation of potential human exposure pathways results in the following observations about the dye:
• Used in open systems for dyeing and printing cotton.
• Used by employees in the form of a nonvolatile powder.
• No bioaccumulation is expected since log K ow ∼ = −4.
• Reported average concentrations of dye dusts in dyeing operations from an
earlier monitoring study at a similar factory are 0.1–0.3 mg/m 3 air.
• Average air volume inhaled by the employees during an 8-hr shift is 10 m 3 .
From this information, the predicted daily intake (PDI) via inhalation can be
calculated (with an assumed average body weight of 70 kg):
PDI =
0.3 mg/m 3 × 10 m 3 /d
70 kg
= 0.043 mg kg
−1
bw d −1
Investigation of potential environmental exposure pathways results in the following information:
• Mass of dyed material per day (textiles) (W 1 ) = 3000 kg/d
• Dye used per amount of dyed material (W 2 ) = 10 g/kg
• Fixation level of dye onto the cotton (F ) = 85%
• Amount of wastewater produced (Q) = 300 L/kg textiles
• Fraction of dye removed from the wastewater during treatment (P ) = 10%
• Dilution factor of the treated water upon release (V ) = approximately 100
The predicted environmental concentration from the release of the dye following
wastewater treatment (PEC local ) can then be calculated through Eq. 6.17. This
149
and relevant calculations are presented separately for assessing the risk to human
health and the environment. The values provided here are based on typical values
for such reactive triazine dyes.
6.8.1 Hazard Identification (Step 1)
Through a review of existing toxicity data on this particular dye and on chemicals
within the same class, it was identified that:
• In preparing the dye liquor starting from powder, the sensitizing effect and
chronic toxicity of the dye can be a potential hazard to the health of the
employees.
• The dye may be toxic to the aquatic environment and may not be adequately
removed during wastewater treatment processes.
6.8.2 Exposure Assessment (Step 2)
Investigation of potential human exposure pathways results in the following observations about the dye:
• Used in open systems for dyeing and printing cotton.
• Used by employees in the form of a nonvolatile powder.
• No bioaccumulation is expected since log K ow ∼ = −4.
• Reported average concentrations of dye dusts in dyeing operations from an
earlier monitoring study at a similar factory are 0.1–0.3 mg/m 3 air.
• Average air volume inhaled by the employees during an 8-hr shift is 10 m 3 .
From this information, the predicted daily intake (PDI) via inhalation can be
calculated (with an assumed average body weight of 70 kg):
PDI =
0.3 mg/m 3 × 10 m 3 /d
70 kg
= 0.043 mg kg
−1
bw d −1
Investigation of potential environmental exposure pathways results in the following information:
• Mass of dyed material per day (textiles) (W 1 ) = 3000 kg/d
• Dye used per amount of dyed material (W 2 ) = 10 g/kg
• Fixation level of dye onto the cotton (F ) = 85%
• Amount of wastewater produced (Q) = 300 L/kg textiles
• Fraction of dye removed from the wastewater during treatment (P ) = 10%
• Dilution factor of the treated water upon release (V ) = approximately 100
The predicted environmental concentration from the release of the dye following
wastewater treatment (PEC local ) can then be calculated through Eq. 6.17. This