Tetracycline: production, waste treatment and environmental impact assessment

The frequent occurrence of pharmaceuticals in the aquatic environment requires an assessment of their environmental impact and their negative effects in humans. Among the drugs with high harmful potential to the environment are the antibiotics that reach the environment not only, as may be expected, through the effluents from chemical and pharmaceutical industries, but mainly through the sewage and livestock; because around 25 to 75% of the ingested drugs are excreted in unchanged form after the passage through the Gastro-Intestinal Tract. Tetracycline has high world consumption, representing a human consumption of about 23 kg/day in Brazil in 2007. At the moment, researches are being made to develop new tetracycline that incorporate heavy metals (Hg, Cd, Re, Pt, Pd) to their structures in order to increase their bactericidal effect. The conventional wastewater treatment plants are not able to degrade complex organic molecules to reduce their toxicity and improve their biodegradability. For this reason new technologies, i.e., the advanced oxidation processes, are being developed to handle this demand. The objectives of this study are to review the literature on the processes of obtaining tetracycline, presenting its waste treatment methods and evaluation of their environmental impact

Effects of waste engine oil spillage on soil physico-chemical and microbiological properties

Changes in physic-chemical and microbial properties of soils contaminated with waste motor oil were monitored over a 24 week period. Oil application to soils resulted in a decrease in moisture content but brought about increase in organic matter, total nitrogen and available phosphorus contents. There was an initial decrease in microbial counts followed by a subsequent increase in population levels after four weeks. Microbial species diversity was however reduced in oil-contaminated sites relative to the control sites. Hydrocarbon-utilizing bacteria isolated from the experimental sites were identified as Pseudomonas, Acinetobacter, Alcaligenes, Flavobacterium and Corynebacterium. The organisms grew on long-chain n-alkanes, crude oil and fresh engine oil while a few species grew on aromatic hydrocarbons. Laboratory biodegradation studies of fresh engine oil using strains of Pseudomonas, Acinetobacter, and Corynebacterium showed a progressive decrease in oil concentration and pH of the medium due to the production of acidic metabolites

Occurrence and Distribution of Sulphate-Reducing Bacteria in a Polluted Lagoon

The presence and distribution of sulphate-reducing bacteria (SRB) in the sediment and water from four strategic points on the Lagos Lagoon were assessed using the most probable number technique. All the samples were positive for the dissimilatory sulphate reducers. The relative occurrence varied markedly with the site and pollution status. The least polluted end of the lagoon recorded the lowest number of SRB in both sediment (4.23x102 SRB/ml) and water (28 SRB/ml) while the most polluted site receiving sewage and domestic wastes harboured numbers as high as 5.71x103 and 7.6x104 SRB/ml for water and sediment sasmples, respectively. The occurrence of sulphate-reducing bacteria in such numbers indicated that this environment favoured biocorrosion of buried and immersed metals. The active involvement of these organisms in the syngenesis of sulphur, metallic sulphides and the general biodegradation of pollutants in this ecosystem is discussed