# Assessment of Dietary Exposure and Risk of DDT Concerning Freshwater Fish Aquaculture
## 2 Materials and Methods
### Evaluation Procedures of Non-Genotoxic Carcinogenic Chemical Substances  
Based on the cluster analysis, two evaluation methods distinguishing between non-carcinogenic and long-term carcinogenic effects were performed for the consumer groups of extreme consumers, regarding the frequency and the amount of carp consumption. The comparison of the dietary exposure and the definite safety goal--the acceptable daily intake (ADI)--was carried out based on the following approach [23; 24]. In the case of DDT, there is a risk of longer-term, chronic health effects. Therefore, the value of ADI should be considered instead of the acute reference dose (ARfD) in the evaluation [25]. According to literature data, the ADI is 0.01 mg/kg bw/day for DDT and DDT metabolites [26]. Regarding the exposure assessment, the estimation of the total dietary intake for DDT contamination was conducted, considering the dietary intake data within each food category. The assessed exposure, the so-called estimated daily intake (EDI) is formulated as [24]:  
\[EDI=\frac{H\times C}{Bw}, \tag{1}\]  
where \(H\) is the concentration of the certain chemical [mg/kg], \(C\) is the amount of the consumed food (kg/day), \(Bw\) is the body weight (the average body weight in each cluster) (kg). The frequency of consumption of each food category was asked in the questionnaire survey, considering the consumption habits of the previous year. The consumed amount of the different food types was calculated based on the serving size recommendations by \"_safef_ood\" and Bupa organizations [27; 28]. The evaluation of the ratio of tolerable (the \(ADI\)) and the estimated dietary intake (the \(EDI\)) for DDT was based on the \(HQ\) (hazard quotient)--a metric, which is used for chemicals with a threshold [24; 29]. The ratio between 1 and 10 refers to moderate risk, while a value above 10 could be linked to increased risk [29]. The \(HQ\) is calculated as:  
\[HQ=\frac{EDI}{ADI} \tag{2}\]  
A chemical risk assessment for DDT was also performed for carcinogenic effects according to the following outline:  
1. Calculation of chronic daily intake (CDI--mg/kg of body weight per day)--also known as intake rate (I)--according to the following formula [30]: \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & \multicolumn{4}{c}{**Gender**} \\ \hline Female & & & & Male & \\
33.37\% & & & & & 66.63\% & \\ \hline \multicolumn{8}{c}{**Age**} \\ \hline
18–29 years old & 30–39 years old & 40–59 years old & 60+ years old & 13.85\% & 13.94\% & 13.94\% & 13.94\% & 13.94\% \\ \hline \multicolumn{8}{c}{**Regions**} \\ \hline Central & Central & Western & Southern & Northern & Northern & Southern \\ Hungary & Transdanubia & Transdanubia & Transdanubia & Hungary & Great Plain & Great Plain \\
28.98\% & 14.05\% & 9.26\% & 5.38\% & 3.89\% & 16.83\% & 21.61\% \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Demographic data of the survey on extreme fish consumers. \[CDI=C*\frac{CR*EF*ED}{BW*AT}, \tag{3}\]  
where C: average concentration of the studied contaminant (average DDT concentration in carp based on laboratory tests. The detailed description of the laboratory analysis can be found in Supplementary Materials S1); average value in other food categories based on previous international research results (mg/mg). CR: contact rate (the amount of the studied compound ingested daily) (mg/day). EF: exposure frequency (the number of days when the contaminated food was consumed in a year) (day/year). ED: exposure duration (over the lifetime--estimated at 70 years) (years). BW: body weight (the average body weight in each cluster) (kg). AT: the studied exposure period (over the lifetime--estimated at 70 years) (days). 2. Risk characterization  
The product of chronic daily intake and the slope factor of the studied chemical contaminant characterize the identified risk for certain consumer groups. The slope factor is a value applied for the estimation of carcinogenicity. The slope factor of ingestion DDT is 0.34 [31].