Fertility of female mice fed coumestrol and diethylstilbestrol

Coumestrol, a compound produced by various legumes which exerts estrogen-like activity in animals, and diethylstilbestrol (DES) were studied as chemical agents for controlling reproduction in mice. Female mice were fed control diets or diets containing 100 ppm coumestrol for eight days. Female mice were exposed to males and reproductive tracts examined 14 days later. Litter size was not affected by 100 ppm dietary coumestrol but feed consumption was reduced 17%. Similar trials were conducted with mice fed 1 ppm DES. Vaginal plugs were present in 50% of the females fed 1 ppm DES, but no fetal pups were present. Feed intake was reduced 37% by the DES. Levels of 0, .1, .25, .50, .75 and 1.0 ppm DES were compared in two strains of mice, Swiss and ICR. Reproduction in both strains was totally inhibited by all DES treatments. The use of DES to control rodent populations warrants further investigation.     

Sound Survey Designs Can Facilitate Integrating Stream Monitoring Data Across Multiple Programs1

Abstract: Multiple agencies in the Pacific Northwest monitor the condition of stream networks or their watersheds. Some agencies use a stream “network” perspective to report on the fraction or length of the network that either meets or violates particular criteria. Other agencies use a “watershed” perspective to report on the health or condition of watersheds. The agencies often use the same indicators and measurement protocols for data collection and often conduct monitoring in overlapping geographic regions. In these situations, agencies would like to combine data across different monitoring studies in a statistically sound manner to make regional estimates of condition. Three statistical survey design principles will facilitate combining such studies: (1) a clearly specified statistical target population of interest, including elements that comprise the population, (2) a consistent representation of that target population (such as a digital map of the stream network and watersheds), and (3) rules that incorporate randomization to guide the selection of the sample of sites on which measurements will be made. A case study illustrates the application of these design principles using two agency monitoring programs interested in combining stream channel data for different purposes: one for making network summaries and the other for evaluating watershed condition.     

Simulating property exchange in estuarine ecosystem models at ecologically appropriate scales

A computational scheme has been developed and tested to simulate property exchange by advection and dispersion in estuaries at time and space scales that are well suited to ecological and management simulations, but are coarse relative to the demands of physical hydrodynamic models. An implementation of the Regional Ocean Model System (ROMS) for the Providence River and Narragansett Bay (RI, USA) was used to determine property exchanges between the spatial elements of an ecological box model. The basis for the method is the statistical tabulation of numerical dye experiments done with the full ROMS physical model. The ROMS model domain was subdivided into fifteen coarse boxes, each with two vertical layers, defining 30 elements that were used for the box model simulations. Dye concentrations were set to arbitrary initial concentrations for all ROMS grids in the large elements, and the ROMS model was run for 24 h. The final distribution of the dye among the elements was used as a tracer for property exchange over that day and was used to develop an exchange matrix. Box model predictions of salinity over 77 days in each element compared favorably with ROMS simulated salinity averaged over the same spatial elements, although the disparity was greater in areas where large river inflows caused strong gradients in ROMS within elements assumed to be homogeneous in the box model. The 77-day simulation included periods of high and low river flow. Despite the large size of the spatial elements, dispersion artifacts were small, much less than the modeled daily exchanges. While others have taken a similar approach, we found a number of theoretical and practical considerations deserved careful attention for this approach to perform satisfactorily. Whereas the full ROMS model takes 9 days on a powerful computing cluster to compute the physics simulation for 77 days, the box model simulates physics and biology for the same interval in 5 s on a personal computer, and a full year in under 1 min. The exchange matrix mixing model is a fast, cost effective, and convenient way to simulate daily variation of complex estuarine physics in ecological modeling at appropriate scales of space and time.     

Fertility of female mice fed coumestrol and diethylstilbestrol

Abstract

Coumestrol, a compound produced by various legumes which exerts estrogen‐like activity in animals, and diethylstilbestrol (DES) were studied as chemical agents for controlling reproduction in mice. Female mice were fed control diets or diets containing 100 ppm coumestrol for eight days. Female mice were exposed to males and reproductive tracts examined 14 days later. Litter size was not affected by 100 ppm dietary coumestrol but feed consumption was reduced 17%. Similar trials were conducted with mice fed 1 ppm DES. Vaginal plugs were present in 50% of the females fed 1 ppm DES, but no fetal pups were present. Feed intake was reduced 37% by the DES. Levels of 0, .1, .25, .50, .75 and 1.0 ppm DES were compared in two strains of mice, Swiss and ICR. Reproduction in both strains was totally inhibited by all DES treatments. The use of DES to control rodent populations warrants further investigation.     

A modified risk assessment to establish molybdenum standards for land application of biosolids

The USEPA standards (40 CFR Part 503) for the use or disposal of sewage sludge (biosolids) derived risk-based numerical values for Mo for the biosolids --> land --> plant --> animal pathway (Pathway 6). Following legal challenge, most Mo numerical standards were withdrawn, pending additional field-generated data using modern biosolids (Mo concentrations <75 mg kg(-1) and a reassessment of this pathway. This paper presents a reevaluation of biosolids Mo data, refinement of the risk assessment algorithms, and a reassessment of Mo-induced hypocuprosis from land application of biosolids. Forage Mo uptake coefficients (UC) are derived from field studies, many of which used modern biosolids applied to numerous soil types, with varying soil pH values, and supporting various crops. Typical cattle diet scenarios are used to calculate a diet-weighted UC value that realistically represents forage Mo exposure to cattle. Recent biosolids use data are employed to estimate the fraction of animal forage (FC) likely to be affected by biosolids applications nationally. Field data are used to estimate long-term Mo leaching and a leaching correction factor (LC) is used to adjust cumulative biosolids application limits. The modified UC and new FC and LC factors are used in a new algorithm to calculate biosolids Mo Pathway 6 risk. The resulting numerical standards for Mo are cumulative limit (RPc)=40 kg Mo ha(-1), and alternate pollutant limit (APL) = 40 mg Mo kg(-1) We regard the modifications to algorithms and parameters and calculations as conservative, and believe that the risk of Mo-induced hypocuprosis from biosolids Mo is small. Providing adequate Cu mineral supplements, standard procedure in proper herd management, would augment the conservatism of the new risk assessment.