Evidence for microfloral succession on allochthonous plant litter in Apalachicola Bay,Florida, USA

Changes in hydrolytic, respiratory,catabolic and lipid biosynthetic activities depend at least in part on successional changes in the microfloral populations of allochthonous plant litter incubated in a semi-tropical estuary. Initial colonization is by populations which have a high content of muramic acid relative to the adenosine triphosphate (ATP) and which are progressively displaced by a microflora with a lower ratio of muramic acid to ATP. Scanning electron micrography of the plant-litter microflora shows a succession of forms, with an initial bacterial colonization and its progressive displacement by more complex forms. Estimates of the microbial mass and the rates of phospholipid synthesis suggest that the detrital microflora has a relatively slow growth rate compared to its growth potential.     

A survey of drinking water supplies in the Province of Ontario for dioxins and furans

A survey of drinking water supplies in the Province of Ontario was initiated in 1983 to determine the extent of their contamination by polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). This drinking water survey arose from concerns regarding the discovery of PCDDs and PCDFs in sport fish from western Lake Ontario in the early 1980's.A total of 49 water supplies throughout all Regions of Ontario have been examined to date. Water supplies in the vicinity of chemical industries and pulp and paper mills were sampled more frequently; as many as 20 times. Detection limits were in the low parts per quadrillion (ppq) range for all tetra- to octachlorinated PCDDs and PCDFs.As of February 1989, 4, 347 results were received for 399 raw and treated water samples. Only 37 positive results were reported, constituting less than 1 percent of the total number of results. The O₈CDD congener accounted for 36 of the 37 positive results. The 2,3,7,8- TCDD isomer was not detected in any sample.     

Comparison of instrumental methods for chlorinated dibenzo-p-dioxin (CDD) determination - interim results of a round-robin study involving GC-MS, MS-MS, and high resolution MS

A study was designed to determine the feasibility of using GC-MS-MS techniques for the determination of chlorinated dibenzo-p-dioxins (CDD) and dibenzofurans (CDF) in difficult environmental samples with reduced cleanup. Three fish and three sediment extracts were provided to six different laboratories with GC-MS-MS capability for analysis. In addition, extracts were analysed by GC-low reduction MS (LRMS) and GC-high resolution MS (HRMS). At the time of this report, all participating GC-MS-MS laboratories had not completed their analysis of the supplied samples. All reporting laboratories found the analysis of these very complex samples difficult without extensive cleanup. GC-HRMS determination of some samples was possible with reduced cleanup compared to GC-LRMS.