摘要:

The University of Wisconsin‐Madison generates approximately 16,000 gallons of radioactive and non‐radioactive waste solvents per year. This study was conducted to characterize the waste stream and identify managecent options. Water, chloroform, acetone and hexane constitute the primary compounds of the waste stream. Management options include on‐site incineration, shipment and incineration elsewhere, and reclamation. Source separation of chlorinated and non‐chlorinated waste is an easy and effective procedure in facilitating further disposal options.

ISSN:0360-1226    

DOI:10.1080/10934528409375193

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Simulants for the CW agents HD, GB and VX, deposited as thin films on stainless steel surfaces, were exposed to UV (254 and 185 nm), O3(0–2 wt% in air) and O3+ UV at 0 and 100% relative humidity. The extents of the simulants decomposition were determined. The simulant for HD was found to be most reactive and its half life under easily achievable experimented conditions was estimated at ⋍7 seconds.

ISSN:0360-1226    

DOI:10.1080/10934528409375194

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Fried beef and commercial beef extract contain Ames/Salmonellaframeshift mutagens that require microsomal (S‐9) activation. To ascertain which fraction(s) of beef muscle contain(s) the essential precursors, aqueous (1:1) homogenates of lean round steak were centrifuged to give an insoluble residue1(R1) and a soluble supernatant1(S1). S1was then boiled for 30 min and again centrifuged, yielding a residue2(R2) and a soluble supernatant2(S2). S2represents only 5% of the meat dry wt and it contains only 10* of the H2O‐soluble protein, but it contributes all of the S‐9 dependentSalmonellaTA1538 mutagenic activity in boiled homogenates. Mutagen formation from S2boiled for 0–30 h at a constant volume increases exponentially with time and displays sharp pH optima at 4.0 and 9.0. By molecular ultrafiltration the pH 4.0 mutagen precursors in S2have molecular wts < 500. They are also stable to lyophilization. These observations and the disappearance of certain amino acids upon boiling at pH 4.0 suggest that select amino acids may be reactants for low‐temperature mutagen formation.

ISSN:0360-1226    

DOI:10.1080/10934528409375195

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Fried beef and commercial beef extracts contain Ames/Salmonellaframeshift mutagens that form at relatively low temperatures (100–200°C). To investigate the types of natural components in beef muscle that give rise to frameshift mutagenic activity, we previously devised a model boiling system and demonstrated that all of theSalmonellaTA1538 activity is formed from H2O‐soluble, < 500 molecular wt compounds that are present in round steak supernatant fractions (S1and S2). S2is derived from S1, the soluble fraction of homogenized beef, by a brief 30 min boil and centrifugation. We now report that proteolysis of beef S1with papain, trypsin, or chymotrypsin (± carboxypeptidase A) increases the mutagenic activity of boiled S2by 1.8–4.5 fold over the baseline range of 90–100 TA1538 revertants/108bacteria/g dry beef/14 h at pH 4.0. Sequential treatment of beef S1with chymotrypsin followed by carboxypeptidase A is the most efficient mutagen enhancing digestion (415 revertants/g dry beef or7.7revertants/mg of S2soluble protein). Fourteen h boiled, proteolytic digests of round steak insoluble‐protein fraction (R1), soybean protein, bovine serum albumin, and bovine α‐lactalbumin contain much less TA1538 activity/mg of soluble protein than beef S2(0.01–1.5 versus7.4revertants/108bacteria). For comparison, S2fractions prepared from chicken (light meat), chicken (dark meat), pork chops, turkey (light meat), beef liver, fish (sole), and whole eggs yield 89, 60, 71, 67, 58, 36, and < 1 TA1538 revertants/108bacteria/g of initial dry wt. Despite their low TA1538 activity yields, S2‐like fractions from proteolyzed beef R1, soybean protein, and the two pure albumins, and S2fractions from sole and eggs were comparable to our standard beef S1or S2in their amino acid compositions. Collectively, these mutagenicity and amino acid composition data indicate that select amino acids and/or small peptides plus some essential non‐amino acid compounds are the mutagen precursors in beef muscle.

ISSN:0360-1226    

DOI:10.1080/10934528409375196

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The early life stage effects of urban runoff (rain and snowmelt) on hatching, growth and survival of the fathead minnow(Pimephales promelas)was assessed in static and flow‐through systems. The data indicate a Maximum Allowable Toxicant Concentration (MATC) and a reduction of growth to 50% of controls at 28% and 60% runoff, respectively. Hatchability and average lengths were not as sensitive indicators of stress as millimeters produced per treatment. The data indicate a maximum toxicity in the fall which coincided with the reported drop in macroinvertebrate diversity during the same period, when untreated runoff events can contribute up to 1/4 of the river flow.

ISSN:0360-1226    

DOI:10.1080/10934528409375197

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0360-1226    

DOI:10.1080/10934528409375192

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor