The non-target organism Caenorhabditis elegans withstands the impact of sulfamethoxazole

The widespread usage of antibiotics in agriculture leads to releases into the environment, but there is insufficient knowledge of the side-effects on non-target organisms. Therefore, we investigated the effects of the sulfonamide-antibiotic sulfamethoxazole (SMX) on Caenorhabditis elegans at phenotypic, biochemical and molecular biological levels. Multiple endpoints, including life history traits, thermal stress resistance and lipid peroxidation, as well as gene expression profiles, were determined after exposure of the nematodes to SMX. In contrast to expectations, SMX prolonged the lifespan and increased both the body size and pharynx pumping rate. On the other hand, SMX delayed reproductive timing and caused lipid peroxidation. The total number of offspring and thermal stress resistance were unaffected. The up-regulation of hsp-16.1 indicated stress in general and the increased lipid peroxidation oxidative stress in particular. This oxidative stress indicated that mitohormesis was the likely cause of the longevity and that enhanced pumping frequency was probably the reason for the increased growth. The sole adverse effect was delayed initial reproduction. This delay, however, can be crucial for r-strategists, such as the bacterivorous model animal used, in sustaining their populations in the environment in the presence of predators. Bacterivorous animals, in turn, are essential to maintaining nutrient recycling via the microbial loop.     

Calculating Air Quality and Its Control

Air quality is shown as a function of averaging times of five minutes to one year for carbon monoxide, hydrocarbons, nitric oxide, nitrogen dioxide, nitrogen oxides, oxidant, and sulfur dioxide in Chicago, Cincinnati, Los Angeles, New Orleans, Philadelphia, San Francisco, and Washington, D. C. Concentrations are approximately lognormally distributed for all pollutants in all cities for all averaging times. Maximum concentration is inversely proportional to averaging time to an exponent. The exponent is a function of the standard geometric deviation. General air quality and control parameters are derived and shown for one example, nitrogen oxides in Washington, D. C. These values are compared to one air quality standard.     

The chemical stability of formulations of some hydrolyzable insecticides in aqueous mixtures with hydrolysis catalysts

Abstract

The active ingredients in commercial formulations of malathion, oxamyl, carbaryl, diazinon, and chlorpyrifos diluted to “spray tank”; concentrations with buffered distilled or natural water of pH 4–9 were stable for at least 24 hr. Formulations of trichlorfon were not stable at pH 7 or above but disappearance rates were slower than for the pure chemical in homogeneous solution. Cupric ion was observed to be an effective catalyst for the hydrolysis of a variety of pure organophosphorus insecticides but did not catalyze hydrolysis of the active ingredients of the formulations examined. Increasing the dilution of the formulation increased the susceptibility of malathion, oxamyl, and carbaryl to hydrolysis.     

ESP Performance with Atmospheric Fluidized-Bed Combustion

Electric utilities considering atmospheric fluidized-bed combustion (AFBC) as an economic way to reduce SO₂ and NO_x emissions at coal-fired power plants must evaluate the impact AFBC will have on existing or planned plant systems and components. Because fly ash in AFBC units can have characteristics significantly different from that generated in pulverized-coal-fired boilers, a particular concern in this regard is the performance of the plant's particulate control equipment.     

An Air Quality Data Analysis System for Interrelating Effects,Standards, and Needed Source Reductions: Part 6. Calculating Concentration Reductions Needed to Achieve the New National Ozone Standard

The new ozone National Ambient Air Quality Standard specifies that the expected number of days per calendar year that the 1 hour average ozone concentration can exceed 0.12 ppm must be equal to or less than 1. This paper describes a method to calculate design frequency, design concentration, and the percentage concentration reduction necessary to achieve this standard. The design frequency is once per year (1/365) if daily maximum hour ozone concentrations are available at a particular site for an equal number of days in summer (April through September) and winter (October through March). An equation is used to adjust design frequency as a function of the number of summer and winter samples available. The design concentration (the ambient concentration measured at the design frequency) needs to be reduced to 0.12 ppm. Graphical and digital methods for determining the design concentration are presented. Percentage concentration reductions needed to achieve the standard are calculated for each site which has ozone concentration data available in the National Aerometric Data Bank for at least half of the days in one summer of years 1975 through 1977. The degree of reduction calculated for the site with the highest concentrations in each county is indicated by shading on a map of the United States.     

Herbicide impact on Hormosira banksii gametes measured by fluorescence and germination bioassays

The innovative bioassay described here involves chlorophyll a fluorescence measurements of gametes from the macroalgae, Hormosira banksii, where gametes (eggs) were exposed to Diuron, Irgarol and Bromacil. Response was assessed as percent inhibition from control of effective quantum yield (DeltaF/Fm') of photosystem II, herein referred to as % PSII Inhibition. This was measured with the dual-channelled pulse amplitude modulated (PAM) fluorometer, ToxY-PAM. The fluorescence bioassay was run simultaneously with an established H. banksii germination bioassay to compare sensitivity, precision, and time-to-result. The fluorescence bioassay gave highly sensitive results evidenced by EC(50)s (% PSII Inhibition) for Diuron, Irgarol and Bromacil being three, four and three orders of magnitude (respectively) lower than EC50s generated from the germination bioassays. Precision of the fluorescence bioassay was demonstrated with low coefficient of variations (<30%) for all three toxicants. With regard to time, the fluorescence bioassay gave results within 6h, as opposed to more than 50h for the germination bioassay.     

Effects of metals on condition and reproductive output of the smooth toadfish in Sydney estuaries, south-eastern Australia

This study determined the condition and reproductive output of a common estuarine toadfish, Tetractenos glaber, in two metal contaminated and two reference estuaries near Sydney, Australia. Female toadfish from metal contaminated estuaries were smaller and younger than in reference estuaries; however, it could not be resolved whether these differences were due to direct effects of metal contamination or differences in nutritional value of prey. Lipid content in liver and gonad tissues was inversely related with levels of As, Pb, Cd and Co in sediment. In contrast, protein content in liver, gonad and muscle tissues was positively related to sediment levels of Ni and Co. Increased levels of Pb in gonads were associated with decreased oocyte diameter and density. This suggests a reduction in egg size and fecundity, which ultimately may lead to a decline in female reproductive output. Changes in fish health and reproduction caused by chemical pollutants may alter fish population and community structure.     

Differences in stress tolerance and brood size between a non-indigenous and an indigenous gammarid in the northern Baltic Sea

Differences in stress tolerance and reproductive traits may drive the competitive hierarchy between non-indigenous and indigenous species and turn the former ones into successful invaders. In the northern Baltic Sea, the non-indigenous Gammarus tigrinus is a recent invader of littoral ecosystems and now occupies comparable ecological niches as the indigenous G. zaddachi. In laboratory experiments on specimens collected between June and August 2009 around Tvärminne in southern Finland (59°50′N/23°15′E), the tolerances towards heat stress and hypoxia were determined for the two species using lethal time, LT₅₀, as response variable. The brood size of the two species was also studied and some observations were made on maturation of juveniles. Gammarus tigrinus was more resistant to hypoxia and survived at higher temperatures than G. zaddachi. Brood size was also greater in G. tigrinus than in G. zaddachi and G. tigrinus matured at a smaller size and earlier than G. zaddachi. Hence, there are clear competitive advantages for the non-indigenous G. tigrinus compared to the indigenous G. zaddachi, and these may be further strengthened through ongoing environmental changes related to increased eutrophication and a warming climate in the Baltic Sea region.     

Persistence of testosterone and 17beta-estradiol in soils receiving swine manure or municipal biosolids

Natural and synthetic steroidal hormones can be carried to agricultural soil through fertilization with municipal biosolids, livestock manure, or poultry manure. The persistence and pathways of dissipation of [4-(14)C]-testosterone and of [4-(14)C]-17beta-estradiol in organic-amended soils were investigated using laboratory microcosms. Testosterone dissipation was investigated over a range of amendment concentrations, temperatures, and soil types. Under all conditions the parent compound and transformation products were dissipated within a few days. Addition of swine manure slurry to soil hastened the transformation of testosterone and 17beta-estradiol to the corresponding less hormonally active ketones, 4-androstene-3,17-dione and estrone. Two other testosterone transformation products, 5alpha-androstan-3,17-dione and 1,4-androstadiene-3,17-dione, were also detected. Experiments with sterilized soil and sterilized swine manure slurry suggested that the transformation of (14)C-labeled hormonal parent compounds was mainly caused by microorganisms in manure slurry, while mineralization of the hormones to (14)CO(2) required viable soil microorganisms. Organic amendments transiently inhibited the mineralization of [4-(14)C]-testosterone, perhaps by inhibiting soil microorganisms, or by enhancing sorption and reducing the bioavailability of testosterone or transformation products. Overall, organic amendments influenced the pathways and kinetics of testosterone and estradiol dissipation, but did not increase their persistence.     

PATTERN OF GROUND-WATER LEVEL DECLINE IN THE HIGH PLAINS AQUIFER NEBRASKA1

ABSTRACT: Ground-water level decline patterns in parts of Nebraska conform to the circular island concept of Bredehoeft et al. (1982), which indicates how water is derived by wells developed in a circular island. If elongated, the center of the island corresponds to a regional ground-water divide while the shoreline corresponds to a regional river. In both versions, ground-water table elevation is a function of recharge and transmissivity. A dynamic equilibrium exists such that the gradient of the water table will convey all recharge to discharge areas. Withdrawals of ground water result initially in mining, with a new equilibrium attained when pumping equals capture. During early development, capture is an important source of water in discharge areas, while mining is more significant in recharge areas. The pattern observed in many areas shows the greatest ground-water level decline in the vicinity of ground-water divides and the steepest gradient near regional rivers. A similar pattern has been observed adjacent to the Arkansas River in south-central Kansas. Similar decline patterns can be modeled for a hypothetical ground-water basin. This is of major importance to water-resource managers because it dictates that management programs be applied to the entire hydrologic system.