ab s t r ac tIn the present experimental work, the degradation and detoxification of two commercially important products being widely used in the tannery industry as synthetic tannin (ST) and degreasing agent (EP) containing 0.1% of nonylphenol ethoxylate (NPE) as well as degreasing wastewater from re-tanning was investigated using Fenton (FO) and photo-Fenton (PFC) oxidation processes. FO and PFC oxidation experiments were performed in batch reactors for 30 min at pH 3 ± 0.2 and 40-45°C, considering the actual temperature and pH values of retanning bath effluents. For the FO experiments the effect of varying Fe 2+ and H 2 O 2 concentrations and UV-C light irradiation on oxidation measured by the parameters COD, UV 254 and UV 280 absorbancies was studied. Toxicity of untreated and FO, PFC-treated synthetic solutions to the freshwater cladoceran Daphnia magna was also tested. PFC provided appreciably high COD (> 80%) and UV 254 and UV 280 (> 90%) removals for ST. The toxicity could be drastically reduced in the PFC-treated ST samples. A maximum COD removal of 57% for FO and 77% for PFC was obtained for EP samples. However, the FO process resulted in 90% toxicity even after 30 min of oxidation, while the effluent of PFC exhibited 10% of immobilization to D. magna. FO carried out on degreasing wastewater allowed resulted in 72% COD removal as well as 86% and 77% of UV 254 and UV 280 removals, respectively.
Textile dyes and their residues gained growing attention worldwide. Textile industry is a strong water consumer potentially releasing xenobiotics from washing and rinsing procedures during finishing processes. On a decentralised basis, also final consumers generate textile waste streams. Thus, a procedure simulating home washing with tap water screened cotton textiles leachates (n = 28) considering physico-chemical (COD, BOD, and UV absorbance) and ecotoxicological data (Daphnia magna, Pseudokirchneriella subcapitata and Lepidium sativum). Results evidenced that: (i) leachates presented low biodegradability levels; (ii) toxicity in more than half leachates presented slight acute or acute effects; (iii) the remaining leachates presented "no effect" suggesting the use of green dyes/additives, and/or well established finishing processes; (iv) no specific correlations were found between traditional physico-chemical and ecotoxicological data. Further investigations will be necessary to identify textile residues, and their potential interactions with simulated human sweat in order to evidence potential adverse effects on human health.
Little is known about pharmaceutical and personal care products pollutants (PPCPs), but there is a growing interest in how they might impact the environment and microbial communities. The widespread use of Viagra (sildenafil citrate) has attracted great attention because of the high usage rate, the unpredictable disposal and the unknown potential effects on wildlife and the environment. Until now information regarding the impact of Viagra on microbial community in water environment has not been reported. In this research, for the first time, the genetic profile of the microbial community, developing in a Viagra polluted water environment, was evaluated by means of the 16S and 18S rRNA genes, for bacteria and fungi, respectively, amplified by polymerase chain reaction (PCR) and separated using the denaturing gradient gel electrophoresis (DGGE) technique. The DGGE results revealed a complex microbial community structure with most of the population persisting throughout the experimental period. DNA sequences from bands observed in the different denaturing gradient gel electrophoresis profiles exhibited the highest degree of identity to uncultured bacteria and fungi found previously mainly in polluted environmental and treating bioreactors. Biotransformation ability of sildenafil citrate by the microbial pool was studied and the capability of these microorganisms to detoxify a polluted water ecosystem was assessed. The bacterial and fungal population was able to degrade sildenafil citrate entirely. Additionally, assays conducted on Daphnia magna, algal growth inhibition assay and cell viability determination on HepG2 human cells showed that biotransformation products obtained from the bacterial growth was not toxic. The higher removal efficiency for sildenafil citrate and the lack of toxicity by the biotransformation products obtained showed that the microbial community identified here represented a composite population that might have biotechnological relevance to retrieve sildenafil citrate contaminated sites.
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