**2.8.1 Non-cancer toxic effects (Hazard Quotient)**

For agents that cause non-cancer effects, a Hazard Quotient (H.Q) was calculated, comparing the expected exposure to the agent to an exposure that is assumed not to be associated with toxic effects.

For oral or dermal exposures, the Average Daily Dose (ADD) was compare to a Reference Dose (RfD):

$$\text{H. Q.} = \text{Average Daily Dose /Reference Dose} \tag{7}$$

Any Hazard Quotient less than 1 is considered to be safe for a lifetime exposure.

#### **2.8.2 Cancer risk**

For chemicals that may cause cancer if ingested, risk is calculated as a function of Oral Slope Factor and can was calculated by using the formula:Risk = Oral Slope Factor \* Lifetime Average Daily Dose (8)

#### **2.8.3 Cross-media transfer equations used to generate exposure estimates**

The formulae used to generate the contaminant exposure concentration in water were those described by the US-EPA (1990) for water to fish; vegetables; dairy and meat concentrations. The formula for the consumption of recreationally caught fish and shellfish-water to edible tissue is presented in equations below:

$$\mathcal{L}(f) = BCF \* \left(\frac{fat}{3}\right) \* \mathcal{L}(\mathcal{w}) \tag{9}$$

$$\text{BCF} = [0.79 \ast \log \text{ (Kow)}] - 0.40 \tag{10}$$

Health Risk Assessment of Plasticizer in Wastewater Effluents and Receiving Freshwater Systems 201

The dose estimates in this assessment, as well as the risk estimates derived from them, refers only to the specific exposures that have been described in Table 3. The average daily dose was calculated taking into account the concentration of the chemicals in water, sediment, for a 70 Kg adult, assuming an intake of 0.054 kg fish on a daily basis (equivalent to 378 g per week). A range of risks is presented making use of average and 95th percentile concentrations of chemicals detected in water, calculated to represent concentrations expected in fish. The 95th percentile represents the "reasonable maximum"

C(w) = Concentration in water chemical Specific

BCF = Bioconcentration factor for tissue fat chemical specific

Kow = Octanol-water partition coefficient of the compound chemical Specific

**2.8.7 Exposure parameters used to calculate exposure estimates** 

Exposure parameter Amount

Events per year 350 Kg fish per day 0.054 Kg dairy 0.4 Kg meat per day 0.1 L water per day 2

Body weight 70 kg Exposure duration 30 years

Table 3. Exposure parameters used to generate exposure estimates.

The LOD of each compound for the analytes was determined as three times the standard deviation of seven independent replicate analyses. LOQs were determined as 3.3 times of LODs. Instrument detection limits ranged from 0.6 µgl-1 (DEHP) to 3.16 µgl-1 (4-NP) and the LOQs varied from 1.9 µgl-1 (DEHP) to 10.44 µgl-1 (4-NP) as presented in Table 4. The LODs and LOQs values are adequate for environmental monitoring of the target compounds and low enough compared to previous work on the analytes of interest (Fatoki and Noma, 2002; Yuan *et al*., 2002; Cortazar *et al*., 2005; Zhou *et al*., 2005; Kayali *et al*., 2006; Ling *et al*., 2007) taking into account the complexity of the samples and the low sample amounts used. For wastewater and river samples, the LODs achieved in the present work were at similar levels or lower than those obtained in previous studies with GC–MS (Yuan *et al*., 2002; Cortazar *et al*., 2005; Kayali *et al*., 2006). The chromatogram of the derivatized phenols and phthalate

**3. Result and discussion** 

esters congeners are presented in Figure 3.

F = Fat content in tissue (dairy) 4.00 % F = Fat content in tissue (Meat) 14.00 %

risk.

Where:C (*f*) = concentration in fishC (w) = concentration in waterC(sd) = Concentration in Sediment

DN = Sediment Density (Relative to Water Density of 1.0 kgl-1) (1.90) OC = Organic Carbon Fraction of Sediment (4.00 %) Koc = Octanol-Carbon Partition Coefficient of the Compound Kow = Octanol - Water coefficient of the compound

BCF = Bioconcentration factor
