## 3 Results and Discussions  
### Phytotoxic Assessment  
Instead of the number of germinated seeds, root length was taken as an endpoint for analysis, an approach consistent with the previous study for organic contaminants [12,23]. Table 2 lists the EC\({}_{50}\) values of the VAs tested on lettuce, carrot, and pepper seeds after the seed germination test. Carrot seeds were found to be the most susceptible to VAs and had the lowest EC\({}_{50}\) value of 7.49 mg kg\({}^{-1}\) for SDZ antibiotics. On the other hand, pepper seeds presented the least susceptibility to the VAs. STR antibiotics were the least toxic compound, especially towards pepper seeds with EC\({}_{50}\) value \(>\) 300 mg kg\({}^{-1}\) (306.84 mg kg\({}^{-1}\)). Comparatively, SDZ, and OTC antibiotics were more toxic with EC\({}_{50}\) values \(<\) 100 mg kg\({}^{-1}\). From the seed germination test, it was evident that the effect of VAs on plant seed germination varied depending on both the type of VAs and the plant species used. Among the three-plant species studied, carrot was the most susceptible to the VAs depending upon the antibiotic type. SDZ antibiotics were most toxic to plant seed germination whereas; STR antibiotic was the least toxic. Based on the plant growth tests in soil, only SDZ antibiotics affected the growth of plants significantly, EC\({}_{50}\) value less than 100 mg kg\({}^{-1}\) (Table 3). SDZ was the most toxic and visible plant growth observed at concentrations of 300 mg kg\({}^{-1}\) and above. Similar observations have been seen by [PERSON] et al. 1998, where sulphamethoxine at 300 mg kg\({}^{-1}\) depressed the growth of _Hordeum dichticum_ both in vitro and in soil [24]. In contrast to the seed germination test, which showed significant inhibitory effects, the EC\({}_{50}\) values of OTC were near or more than 200 mg kg\({}^{-1}\) for plant growth in soil. STR antibiotics showed no evident growth inhibition to the test plants. \begin{table}
\begin{tabular}{c c c c} \hline \multirow{2}{*}{**Veterinary Antibiotics**} & \multirow{2}{*}{**Endpoint**} & \multicolumn{3}{c}{**EC\({}_{50}\) (mg kg\({}^{-1}\))**} \\ \cline{3-4}  & & **Lettuce** & **Carrot** & **Pepper** \\ \hline Sulfadimethoxine & 10.89 & 7.49 & 11.76 \\ Oxytetracycline & 13.15 & 9.11 & 28.06 \\ Streptomycin & 60.24 & 36.89 & 306.84 \\ \hline \end{tabular}
\end{table} 
Table 2: Toxicity data from seed germination tests for lettuce, carrot, and pepper (filter paper test). \begin{table}
\begin{tabular}{c c c c c} \hline \multirow{2}{*}{**Veterinary Antibiotics**} & \multirow{2}{*}{**Endpoint**} & \multicolumn{3}{c}{**EC\({}_{50}\) (mg kg\({}^{-1}\))**} \\ \cline{3-5}  & & **Lettuce** & **Carrot** & **Pepper** \\ \hline \multirow{2}{*}{Oxytetracycline} & Plant height & 167.103 & 155.608 & 325.307 \\  & Root length & 97.825 & 61.662 & 113.06 \\ \hline \multirow{2}{*}{Sulfadimethoxine} & Plant height & 55.201 & 40.835 & 152.142 \\  & Root length & 14.983 & 16.919 & 47.7 \\ \hline \multirow{2}{*}{Streptomycin} & Plant height & 484.38 & 306.995 & 893.606 \\  & Root length & 197.44 & 153.72 & 377.77p \\ \hline \end{tabular}
\end{table} 
Table 3: Toxicity data from plant growth tests in soil for lettuce, carrot, and pepper plants. Through this study, we established species variability to VAs toxicity. As found through the seed germination test, pepper was the least sensitive to the VAs, which was translated in the plant growth tests in the soil as well (Table 3). On the other hand, carrot plants were the most sensitive to VAs administration. The negative effect of VAs in lettuce plants, sampled after 30 days of growth in soil, was evident. The increasing concentration of SDZ in the soil-manure mixture hampered both root length and foliar development. On the other hand, in comparison with control, root length, instead of foliar development, was more compromised with OTC and STR treatments. Previous studies have reported species variability to VAs treatment [5; 12].