Natural attenuation potential of downwelling streams for perfluorochemicals and other emerging contaminants.

Stream augmentation with tertiary treated municipal wastewater-i.e., recycled water-is increasingly considered as an ecologically beneficial way to utilize recycled water, especially in semi-arid regions of the American Southwest. There is concern that emerging contaminants, i.e. unregulated but biologically active organic compounds, may be present in recycled water and will impact on the aquatic environment and the underlying groundwater. Emerging contaminants include a wide variety of chemically disparate compounds, including pharmaceuticals, endocrine disruptors, and residues of perfluorochemical surfactants (PFCs). This paper presents background data on the occurrence and transport of PFC in Upper Silver Creek (USC) and Coyote Creek, in San Jose, California. USC feeds into Coyote Creek, which discharges into San Francisco Bay. Augmenting the natural flow of Coyote Creek with highly treated recycled water is currently being considered as a means to provide more freshwater to the river ecosystem. The reach of interest is approximately 1,000 m where USC flows on alluvial fan deposits. Data indicate that some PFCs are refractory.

Mercury concentrations in gonad, liver, and muscle of white sturgeon Acipenser transmontanus in the lower Columbia River.

This study determined the partitioning of total mercury in liver, gonad, and cheek muscle of white sturgeon (Acipenser transmonatus) in the lower Columbia River. The relationship between tissue mercury concentrations and various physiologic parameters was assessed. White sturgeon were captured in commercial fisheries in the estuary and Bonneville, The Dalles, and John Day Reservoirs. Condition factor (CF), relative weight (Wr), and gonadosomatic index (GSI) were determined for each fish (n = 57). Gonadal tissue was examined histologically to determine sex and stage of maturity. Liver (n = 49), gonad (n = 49), and cheek muscle (n = 57) were analyzed for total mercury using cold-vapor atomic fluorescence spectrophotometry. Tissue protein concentrations were measured by ultraviolet-visible spectroscopy. Plasma was analyzed for testosterone (T), 11-ketotestosterone (KT), and 17ss-estradiol (E2) using radioimmunoassay. Mean tissue mercury concentrations were higher in muscle compared with liver and gonad at all sampling locations, except Bonneville Reservoir where mean liver mercury content was the highest tissue concentration observed in the study. Significant negative correlations between plasma androgens (T and KT) and muscle mercury content and plasma E2 and liver mercury content were found. A significant positive linear relationship between white sturgeon age and liver mercury concentrations was evident. Significant negative correlations between CF and relative weight and gonad and liver mercury content were found. In addition, immature male sturgeon with increased gonad mercury content had decreased GSIs. These results suggest that mercury, in the form of methylmercury, may have an effect on the reproductive potential of white sturgeon.

Efficacy of thiopeptin as a growth promotant for growing barrows and gilts--a cooperative study.

A cooperative study involving 280 crossbred pigs was conducted at three experiment stations (Illinois, Indiana and Kentucky) to evaluate the efficacy of the antibiotic, thiopeptin, as a growth promotant for growing pigs. At each station, two replications of barrows and two replications of gilts (four or five/pen), initially averaging 9.3 kg, were fed a fortified corn-soybean meal basal diet with 0, 5.5, 11, 22 or 44 ppm thiopeptin. The pigs averaged 41.4 kg at the end of the 56- to 57-d experimental period. Daily gain increased quandratically (505, 550, 565, 585, 590 g/d; P less than .001) and feed required per unit of gain decreased quadratically (2.32, 2.26, 2.29, 2.22, 2.22; P less than .15) with increasing levels of thiopeptin. Breakpoint analysis indicated that rate and efficiency of growth were maximized at the 14- and 22-ppm levels of thiopeptin, respectively. Averaged across all levels of thiopeptin, gain was increased by 13.4% and feed/gain by 3.2% in pigs fed the antibiotic. Responses to dietary treatment were similar at each station, with no evidence of a treatment X station interaction for gain (P = .35) or feed/gain (P = .80). Barrows and gilts performed similarly (558 vs 560 g/d, 2.26 vs 2.26 feed/gain) and there was no evidence of a sex X treatment interaction. From the results of this experiment, we conclude that thiopeptin is an effective growth promoting agent for growing swine.

A comparative study of iodine and potassium perchlorate metabolism in the laying hen. 2. Uptake, distribution, and excretion of potassium perchlorate.

The concentrations of 36Cl-labeled potassium perchlorate (K36CiO4) and previously reported iodide (131I) in the ova, thyroid gland, and blood of the laying hen were compared in this investigation. Radioperchlorate concentration and deposition properties showed a remarkable resemblance to those of iodide (131I). The topographic distribution of radioperchlorate in ova followed a peripheral and concentric ring deposition identical to that observed in the 131I investigation. The studies of the distribution of radioperchlorate showed that about 10.3, 2.0, and 1.4% of a single intramuscular injection of K36CiO4 was retained in the body at 3, 24, and 48 hours, respectively. The largest total concentration in the 3-hour group was found in the blood (2.9%), followed by muscles (2.4%), internal organs (1.1%), and the 10 largest ova (1.0%). The 24 and 48-hour hens' ova showed the largest concentrations with values of 1.5 and 1.2% of the dose, respectively. This represented 76.9 and 81.3% of the total activity retained in the body at these times. The excreta in the 3 and 24-hour experiments accounted for most of the radioperchlorate dose.

A comparative study of iodine and potassium perchlorate metabolism in the laying hen. 1. incorporation of I-131 in chicken ova.

The uptake of 131-I in chicken ova was studied for 3 hours after a single intramuscular dose. There was uptake as early as 10 minutes and it continued throughout the 3 hours in spite of a rapid decrease in blood activity. The fast growing ova, weightin 0.5 to 2.0 grams, were the most efficient in the uptake of 131-I per unit weight. Autoradiograms of the topographic distribution of 131-I showed a peripheral deposition. When multiple doses were given, concentric rings in the growing ovocytes were seen.