Publications

Plastic film have been used by fishery workers as barriers to subdivide experimental ponds in order to assess the value of some chemical treatment, and as test vessels to contain dilute solutions or suspensions of toxic chemicals in experiments conducted to establish tolerance levels of these chemicals for fish.

The introduction of artifacts from vessels, materials, and chemicals is a serious problem in the study of pesticide residues. It is therefore of interest to record findings that polyethylene wash bottles contain substances soluble in organic solvents and reactive with the silver nitrate chromogenic spray commonly employed in the paper chromatographic analysis of chlorinated organic...

Carboxylic esters and lactones react with alkaline hydroxylamine to yield hydroxamates; these in acidic solution form colored iron(III) complexes. A photometric determination of such esters and lactones is thus permitted and has been extensively applied ( I-6). Hestrin ( 3) utilized this method for the microdetermination of acetylcholine and his procedure is much used for the in vitro...

The fate of toxaphene, applied in three treatments at a total calculated concentration of 0.05 p.p.m. to Clayton Lake, New Mexico, was followed over a 1.5-year period. A detailed description of the chromatographic method of analysis is given. Water concentrations of toxaphene were higher in leeshore samples than in windward samples for 2 weeks after the application; toxaphene levels then...

No abstract available.

The growing impetus of studies on fish and pesticides focuses attention on the need for standardized reporting procedures. Good methods have been developed for laboratory and field procedures in testing programs and in statistical features of assay experiments; and improvements are being made on methods of collecting and preserving fish, invertebrates, and other materials exposed to...

Clayton County includes 784 square miles in northeastern Iowa and in 1960 had a population of 21, 962. For the most part, the county is a dissected upland that is drained mainly by the southeastward flowing Turkey River and its principal tributary, the Volga River. The Turkey River empties into the Mississippi River, which flows southward along the eastern border of the county. The...

The effects of pesticides on fish have become improtant to fish conservation since World War II, when DDT first came into common use. With the development of other potent insecticides and the increasing use of massive dosages in more recent years, the threat to fish and fish foods has increased. Fishery biologists have conducted some studies on the effects of insecticides, but it has...

Study of the occurrence of low flow on interior Iowa streams and the Big Sioux River.

The drainage area of a stream at a specified location ordinarily may be defined as that area, measured in a horizontal plane, which is enclosed by a topographic divide such that direct surface runoff from precipitation would drain by gravity into the river basin above the specified point. One of the most important factors in the hydrologic computation for the design of structures on or...

Webster County, comprising an area of 718 square miles just northwest of the center of Iowa, had a population of 44,241 in 1950, with 25,115 in Fort Dodge, the principal city. Some 94.4 percent of the county is in farm land; corn is the principal crop and is used in the raising of hogs and cattle, an important occupation in this part of the country. Mineral products include gypsum, clay...

The State and Federal cooperative program for the systematic collection of stream-flow records in Iowa was initiated in L914, although a few records were obtained by special arrangements during an earlier period. Since the beginning of the cooperative program measurements of stage or discharge have been obtained at about 100 stations on Iowa streams and lakes for periods of various...