Iranian Journal of

Background and Objective: As pharmaceutically active compounds (particularly antibiotics) are known emerging contaminants (EC), their occurrence in the environment has high health risks for the living organisms and the public. The effluent of wastewater treatment plants (WWTPs) is the most important source of residues of these compounds in the environment. The urban wastewater of Bandar Abbas is discharged into the marine environment of the Persian Gulf at the rate of 500 to 700 L/s, which could be a potential source of pharmaceutical contamination for the marine ecosystem.
Materials and Methods: In this research, two main wastewater discharge stations at Gursuzan and Suru were sampled during three phases between December 2020 to February 2021. The concentration of Erythromycin residues, as the first antibiotic clinically used to treat human infections, was assessed by high performance liquid chromatography (HPLC) method.
Results: Data analysis showed that mean (± 95% CI) concentration of Erythromycin in Suru and Gorsuzan stations were 16 ± 1.53 and 19 ± 5.86 μg/L, respectively; which their differences did not differ significantly (p>0.05). Pooled data also indicated that the wastewater discharge contained 13.2 to 23.50 μg/L of Erythromycin (α=0.05). Considering the discharge of high volume of Bandar Abbas wastewater effluent into the Persian Gulf (500-700 L/s) as well as the data obtained from this study, the results of the simulation model showed that 5184×10⁴ L Bandar Abbas municipal wastewater is discharged into the Persian Gulf marine ecosystem daily. This volume contains 0.877×10³-1.02×10³ g active residues of Erythromycin antibiotic (α=0.05).
Conclusion: The present study is the first report of contamination of residues of medicinal compounds into the Marine Environment of the Persian Gulf by urban wastewater. Regarding the high volume of wastewater discharged, which calls for immediate actions to be taken.

Background and Objective: Microplastics enter the food chain of aquatic animals; they cause damage to the digestive system, disruption of the reproductive cycle, and finally their death. The present study was conducted to investigate the microplastic pollution in the digestive system of Vanami shrimps cultivated in some shrimp farms in Bushehr, Khuzestan, and Hormozgan provinces.
Materials and Methods: Sampling was done from two shrimp farms in each port including Bandar Rig in Bushehr province, Bandar Choebdeh in Khuzestan province, and South Tiab located in Hormozgan province. 90 shrimp samples were randomly collected from each breeding farm from June to October 2019. The identification method of microplastics was done by FT-IR spectrophotometer.
Results: The highest frequency of microplastics related to farmed shrimps was 41.11% in the fields of Khuzestan province, and a lower amount of microplastic pollution was observed in Hormozgan and Bushehr provinces with 28.88% and 17.70%, respectively. According to one-way ANOVA, the mean of microplastics in the digestive tract of shrimp had a significant difference in the studied stations (p<0.05). The most type and colors of microplastics in the digestive system of shrimps in the farms of all provinces belonged to fiber and black color. Polypropylene and polystyrene were detected in microplastics found in the digestive system of shrimps.
Conclusion: Microplastics were observed in some of digestive tracts of the shrimps of the breeding farms examined in this research in all three provinces of Bushehr, Khuzestan, and Hormozgan. The highest frequency of microplastics in the digestive tract of shrimps is related to the breeding farms of Khuzestan province, and Hormozgan and Bushehr respectively have a lower amount.

Background and Objective: Occurrence of the pharmaceutical active residues (particularly antibiotics) threatens the health of the environment and human society. Therefore, this research aimed to investigate the impacts of the Amoxicillin (AMX) residues on resistance to environmental stress and biochemical compositions of the body in Penaeus vannamei.
Materials and Methods: Six-hundred specimens with a mean (±SD) weight and total length of 9.23±1.77 g and 9.28±0.73 cm were randomly experimented in four triplicate treatments, namely T₁(control): without AMX residues in a rearing environment, T₂: 100 μg/L AMX residues concentration in water, T₃: 300 μg/L and T₄: 500 μg/L for 60 days. At the end of the experimental trial, five specimens for biochemical body composition analyses were separately sampled. Ten shrimps from each treatment were also randomly selected and exposed to 50 ppt salinity stress for 48 hours, and then survival rates were computed.
Results: Body composition analyses showed that moisture and protein not differed among the treatments (p>0.05), while fat in T₂ (28.29±5.50) was significantly more than in others (p<0.05). The lowest values of ash were obtained in T₁ and T₄, and they differed with T₂ and T₃ (p<0.05). The highest survival rate of shrimps exposed to salinity stress (50 ppt in 48 h) was observed in T₂ and T₃, in contrast, the lowest value was recorded for T₄ (p<0.01).
Conclusion: Findings of the present research indicate that the occurrence of high doses of AMX residues pollution in the rearing water affects the stress resistance of P. vannamei which can be due to disruption of protein and fat metabolisms in the shrimp body.