Evaluation of triclosan toxic effects on the methanogenic activity

BACKGROUND: Triclosan (TCS) is an antimicrobial agent widely used in health care and consumer products. This compound is present in sludge of wastewater treatment plants (WWTPs), and because of its bactericidal characteristics, it can inhibit the methanogenic activity in anaerobic digestion (AD) technology. The aim of this study was to evaluate the toxic effects of TCS on the methanogenic activity. RESULTS: Batch anaerobic reactors were used with TCS concentrations of 7.8, 15.7, 23.5, and 31.4 mg/L. These assays consisted in three successive feedings (I, II, and III), wherein the sludge was exposed to each TCS concentration and volatile fatty acid (VFA) substrate. For evaluation of the residual sludge activity during feeding III, only VFA was used. The results showed that the increase in TCS concentrations correlated with the reduction in methane (CH4) production. In this case, the minimum values were achieved for TCS concentration of 31.4 mg/L with CH4 levels between 101.9 and 245.3 during feedings I, II, and III. Regarding the effect of TCS on VFA consumption, an inhibitory effect was detected for TCS concentrations of 23.5 and 31.4 mg/L, with concentrations of acetic, butyric, and propionic acids at the end of the assay (37 d) between 153.6 and 206.8, 62.5 and 60.1, and 93.4 and 110 mg/L, respectively. Regarding the removal of TCS during AD, these values were above 47%. Conclusion: TCS is an inhibitor of methanogenic activity with a decrease between 63 and 70% during the different feedings. The CH4 production was not recovered during feeding III, with inhibition percentages of 21­72%.

Histological study of adult male rat seminiferous tubules following triclosan administation and the possible protective role of pomegranate juice

Triclosan [TCS] is an antimicrobial agent, widely incorporated in a variety of personal care products, household items, medical devices, and clinical settings. Recently, concern has been raised over TCS's potential for endocrine and reproductive disruption. The study aimed to elucidate the impact of TCS on the histological structure of the seminiferous tubules [STs] in adult male albino rats, as well as the possible protective role of pomegranate juice [PJ] coadministration. A total of 32 adult male albino rats [140-160 g] were randomly categorized into four equal groups. Group I [the control group]: rats in this group received PBS [1 ml/kg/day] orally. Group II: rats in this group received PJ orally at a dose of 10 ml/kg/day. Group III: rats in this group received TCS orally at a dose of 20 mg/kg/day. Group IV: rats in this group received TCS at the same dose as group III in conjunction with PJ daily. The experiment continued for 60 days. At the end of the experiment, blood samples were collected from the retro-orbital venous plexus of all rats for estimation of serum testosterone level. The animals were then euthanized. The testes of all rats were harvested for both light and transmission electron microscopic examination of the STs. The germinal epithelial height and the number of germ cells/high-power field [HPF] were estimated morphometrically in H and E-stained sections and statistically analyzed. The study revealed that PJ administration was safe as it did not alter serum testosterone levels as compared with the control group. Histologically, the STs of these animals exhibited normal appearance similar to that of the control group. TCS administration was associated with significantly lowered serum testosterone levels as compared with the control group. Histologically, the STs were lined with relatively few spermatogenic cells with deeply stained nuclei. Cytoplasmic vacuolation of the lining cells and exfoliation of germ cells in the tubular lumina were seen as well. Ultrastructurally, vacuolar degenerative changes involving all types of spermatogenic cells as well as Sertoli cells were revealed. Moreover, the germinal epithelial height and the number of germ cells/HPF were significantly reduced compared with the control group. Coadministration of PJ with TCS resulted in a significant increase in serum testosterone level as compared with the TCS group. Histologically, most of the STs retained normal appearance and epithelial stratification. Only some tubules revealed vacuolation of germ cells in the basal compartment with deeply stained nuclei. Mild ultrastructural alterations of germ cells were evidenced as well. These results were confirmed histomorphometrically by the significant increase in the germinal epithelial height and number of germ cells/HPF as compared with the TCS group. The study clearly indicates that TCS has the potential to adversely impact the testicular structure and function, and that PJ is able to ameliorate such adverse effects