ESTIMATION OF LONG-TERM DISCHARGE STATISTICS BY REGIONAL ADJUSTMENT1

ABSTRACT: A regional adjustment relationship was developed to estimate long-term (30-year) monthly median discharges from short term (three-year) records. This method differs from traditional approaches in that it is based on site-specific discharge data but does not require correlation of these data with discharges from a single hydrologically similar long-term gage. The method is shown to be statistically robust, and applicable to statistics other than the median.     

Metabolism of bis-methylthiotetrachlorobenzene in rats

Oral doses of bis-methylthiotetrachlorobenzene (bis-MTTCB) given to control rats and rats with cannulated bile ducts showed that at least 50% of the dose, although excreted mainly as bis-MTTCB in the feces, was metabolized. The metabolism involved replacement of one of the methylthio groups with glutathione, biliary excretion of the mercapturic acid pathway metabolites, and subsequent reformation of bis-MTTCB which is excreted with the feces.     

The metabolic fate of N-isopropyl-N-phenyloxamic acid in the rat and the milk goat.

Rats excreted the 14C from a single oral dose of N-isopropyl-N-[14C]phenyloxamic acid [I, a soil metabolite from 2-chloro-N-isopropylacetanilide (propachlor)] in approximately equal quantities in the urine (49.2%) and feces (48.2%). A milking goat given daily oral doses of [14C]-I (1 mg of I three times daily) excreted more 14C in the feces (56.6%) than it excreted in the urine. From both species, I accounted for 97 to 100% of the urinary 14C, and all of the 14C that was extractable from the feces (73 to 75% of the 14C in feces was extractable with methanol). Goat milk samples collected 16 hr after the last dose contained no detectable 14C. Tissue residues of 14C were determined.     

Metabolism of crufomate [(4-tert-butyl-2-chlorophenyl methyl methylphosphormidate)] by the rat.

Fifteen metabolites of crufomate (4-tert-butyl-2-chlorophenyl methyl methylphosphoramidate, I) were identified in the excreta from rats given single oral doses of I. Compound I was not detected in either the urine or the feces. The metabolic reactions observed were N-and O-demethylation, oxidations of the t-butyl moiety, replacement of the H-N-CH3 with an OH moiety, hydrolysis of the phosphoramidate moiety to yield the phenol, conjugation with glucuronic acid, and combinations of these reactions. No ring dehalogenation or ring substitution was observed.     

Application of the Lime/Limestone Flue Gas Desulfurization Process to Smelter Gases

In this presentation, adaptation of the lime/limestone process for flue gas desulfurization (FGD) is discussed and how this process can be adapted to applications in the nonferrous smelting industry such as fugitive gases, copper reverberatory furnace gases, lead sintering gases, molybdenum roasting plant tail gases, and other weak SO₂ smelter gases. Different methods for particulate removal are also discussed with emphasis on how the particulate removal process can be integrated with the desulfurization process.     

Organophosphates in aircraft cabin and cockpit air--method development and measurements of contaminants

Methods for measurements and the potential for occupational exposure to organophosphates (OPs) originating from turbine and hydraulic oils among flying personnel in the aviation industry are described. Different sampling methods were applied, including active within-day methods for OPs and VOCs, newly developed passive long-term sample methods (deposition of OPs to wipe surface areas and to activated charcoal cloths), and measurements of OPs in high-efficiency particulate air (HEPA) recirculation filters (n = 6). In total, 95 and 72 within-day OP and VOC samples, respectively, have been collected during 47 flights in six different models of turbine jet engine, propeller and helicopter aircrafts (n = 40). In general, the OP air levels from the within-day samples were low. The most relevant OP in this regard originating from turbine and engine oils, tricresyl phosphate (TCP), was detected in only 4% of the samples (min-max 相似文献   

Optimizing Filtration Parameters

The fundamental operating principle of the pulse-jet collector is explained with a series of performance curves. The effects of variables on the efficiency of the filters are also examined.