Ecotoxicological evaluation of the biocidal agents sodium o-phenylphenol, sodium o-benzyl-p-chlorophenol, and sodium p-tertiary amylphenol.

The ecotoxicological effects of three biocidal agents frequently employed as active ingredients in phenolic-based disinfectants were evaluated using a test battery comprising of organisms representing three aquatic trophic levels. Phenolic-based disinfectants are commonly used by mushroom growers to disinfect spent mushroom compost. In general, the most sensitive assay used in this study was the Microtox test. In the case of the fish lethality assay, sodium o-benzyl-p-chlorophenol was found to be slightly more sensitive than the bacterial test system. The freshwater alga and invertebrate tests were also among the most sensitive test species employed. The active ingredient, sodium o-benzyl-p-chlorophenol (with the exception of the Microtox assay), was the most toxic chemical tested on each species. The majority of ecotoxicity data obtained in this research has not been previously reported and may therefore assist in the management and planning decisions regarding the application of pesticides and utilisation of SMC.

A test battery for the ecotoxicological evaluation of the agri-chemical Environ.

The ecotoxicological effects of the agri-chemical Environ were evaluated using a test battery comprising organisms representing three trophic levels of the aquatic ecosystem. The sensitivities of the test species to Environ were as follows: Microtox > Daphnia magna > Pseudokirchneriella subcapitata = Thamnocephalus platyurus = Oncorhynchus mykiss > Artemia salina > Tetrahymena thermophilia. An order of magnitude sensitivity between the test species was observed which emphasizes the importance of a test battery approach in the assessment of possible ecological consequences of agri-chemicals. In addition, the aquatic bioassays were found to be more sensitive (e.g., greater than three orders of magnitude for D. magna) than previously reported mammalian toxicity data for Environ. Toxicity of Environ was also investigated using fish (RTG-2) and human fibroblast cell lines (HepG2 cells) and juvenile O. mykiss. Environ was shown to have greater toxicity in the acute lethality test than with the fish cell line. However, in vivo/in vitro comparisons in this instance we feel would be premature and imprecise owing to valid concerns regarding fish loading rates for the in vivo test, and exposure duration with the in vitro test.

Microbiological degradation of the herbicide dicamba.

Pseudomonas paucimobilis was isolated from a consortium which was capable of degrading dicamba (3,6-dichloro-2-methoxybenzoic acid) as the sole source of carbon. The degradation of dicamba by P. paucimobilis and the consortium was examined over a range of substrate concentration, temperature, and pH. In the concentration range of 100-2000 mg dicamba L-1 (0.5-9.0 mM), the degradation was accompanied by a stoichiometric release of 2 mol of Cl- per mol of dicamba degraded. The cultures had an optimum pH 6.5-7.0 for dicamba degradation. Growth studies at 10 degrees C, 20 degrees C, and 30 degrees C yielded activation energy values in the range of 19-36 kcal mol-1 and an average of Q10 value of 4.0. Compared with the pure culture P. paucimobilis, the consortium was more active at the lower temperature.

Microbiological degradation of pesticides in yard waste composting.

Changes in public opinion and legislation have led to the general recognition that solid waste treatment practices must be changed. Solid-waste disposal by landfill is becoming increasingly expensive and regulated and no longer represents a long-term option in view of limited land space and environmental problems. Yard waste, a significant component of municipal solid waste, has previously not been separated from the municipal solid-waste stream. The treatment of municipal solid waste including yard waste must urgently be addressed because disposal via landfill will be prohibited by legislation. Separation of yard waste from municipal solid waste will be mandated in many localities, thus stressing the importance of scrutinizing current composting practices in treating grass clippings, leaves, and other yard residues. Yard waste poses a potential environmental health problem as a result of the widespread use of pesticides in lawn and tree care and the persistence of the residues of these chemicals in plant tissue. Yard waste containing pesticides may present a problem due to the recalcitrant and toxic nature of the pesticide molecules. Current composting processes are based on various modifications of either window systems or in-vessel systems. Both types of processes are ultimately dependent on microbial bioconversions of organic material to innocuous end products. The critical stage of the composting process is the thermophilic phase. The fate and mechanism of removal of pesticides in composting processes is largely unknown and in need of comprehensive analysis.

Angioscopy. New developments in vascular surgery.

Angioscopy is not a new procedure, but it is one that has undergone recent changes as the effects of technological improvement are adapted to the surgical environment. Recent advances allow the use of angioscopy to change the way some surgeries are performed and has altered others to a great degree. If the procedure is done infrequently, it can take several months and more than a few cases to master the procedure and setup. Having a small team of six vascular nurses for four full-time vascular surgeons has helped speed this process in our institution. In some institutions, the role of the nurse described in this article is performed by the surgical resident or fellow. As we gained experience, breakdown time was reduced and setup was more efficient.