Modification of an Ambient Air Quality Model for Assessment of U. S. Naval Aviation Emittants

Previous studies have indicated that the EPA-HIWAY model significantly overestimates the pollutant concentrations for stable atmospheric conditions, especially under parallel wind-road orientation angles with low wind speed. This overestimation is due to the fact that the model's dispersion parameters do not properly account for the traffic-induced turbulence near roadways. In this paper, the Pasquill- Gifford dispersion curves used by the model are modified based on the recent studies that have quantified the nature of the trafficinduced turbulence and its influence on the pollutant dispersion in the near-field. The results show that the model performance is significantly improved when these new dispersion curves in conjunction with an aerodynamic drag factor, which in a rough way accounts for the change in the mean wind field due to the moving vehicles, are used in the HIWAY model.     

Engineeringand MaintainingIn-Plant Air Pollution Control

Informative Report No. 7 on the inedible rendering industry is one of a series of survey reports prepared by APCA’ TI-2 Committee on air pollution problems and control methods encountered in the chemical industry today.     

The Oxidation of Hydrocarbons on Simple Oxide Catalysts

A simple practical scheme for prediction and control of short duration air pollution maxima from a single source is demonstrated for a particular source-site geometry. The method makes use of a number of traditional semi-empirical atmospheric turbulence and diffusion relations in a different application. The concepts stressed in the current example are: (1) the incorporation of interactions of high frequency turbulence and low frequency meandering of the wind into a concentration forecast and (2) the use of source-site geometry to simplify the practical problem as much as possible.     

Benthic macrofaunal assemblages of the San Francisco Estuary and Delta, USA

The spatial and temporal distribution of macrobenthic assemblages in the San Francisco Estuary and Sacramento–San Joaquin River Delta were identified using hierarchical cluster analysis of 501 samples collected between 1994 and 2008. Five benthic assemblages were identified that were distributed primarily along the salinity gradient: (1) a polyhaline assemblage that inhabits the Central Bay, (2) a mesohaline assemblage that inhabits South Bay and San Pablo Bay, (3) a low-diversity oligohaline assemblage primarily in Suisun Bay, (4) a low-diversity sand assemblage that occurs at various locations throughout the Estuary, and (5) a tidal freshwater assemblage in the Delta. Most sites were classified within the same assemblage in different seasons and years, but a few sites switched assemblage designations in response to seasonal changes in salinity from freshwater inflows.     

Nitrogen uptake kinetics in three year-classes of Laminaria groenlandica (Laminariales: Phaeophyta)

Nitrate and ammonium uptake rates were measured for three year-classes of the perennial macrophyte Laminaria groenlandica Rosenvinge, collected from nitrogen-depleted waters in Barkley Sound, British Columbia, Canada, in summer 1981. A time course of uptake rate revealed that ammonium uptake was high during the first hour and then decreased for all three year-classes; the opposite pattern was exhibited for the time course of nitrate uptake rate. Nitrate uptake rate increased linearly with nitrate concentration up to the highest level tested (60 M). The nitrate uptake rate of first-year plants was three times higher than second- and third-year plants; ammonium uptake rates showed similar patterns to those for nitrate. The interaction between nitrate and ammonium was examined for first-year plants. Nitrate and ammonium were taken up simultaneously and uptake rates were identical and equal to uptake rates when only nitrate or ammonium was present in the medium. Therefore, first-year plants are able to take up twice as much inorganic nitrogen per unit time when both nitrate and ammonium are present. First-year plants showed significant diel periodicity in ammonium uptake rates, whereas second- and third-year plants showed no periodicity in nitrate or ammonium uptake rates.     

Sulphur dioxide in Greater London, 1931-1985

Annual mean sulphur dioxide concentrations measured at County Hall in central London between 1931 and 1985 showed no clear trend until 1963/64, when a steady decline set in. Results for a number of sites across London for the period 1964/65 to 1984/85 have been divided into three geographic zones: the City of London, a central zone and an outer zone. A steady downward trend is evident in each zone, but is most pronounced in the City of London, especially after 1970. This could reflect the successful introduction of a 1% limit on the sulphur content of oil used within the City, but not elsewhere in London. Annual mean sulphur dioxide concentrations are now around 40 microg m(-3) in all three zones. Highest daily sulphur dioxide levels in both summer and winter have also declined steadily during the period 1964/65 to 1984/85, while at the same time the seasonal pattern of higher winter peaks in daily maxima, which was strong at the beginning of the period, has been virtually eliminated.     

VENTILATORY RESPONSES OF BLUEGILL SUNFISH TO SUBLETHAL,FLUCTUATING EXPOSURES TO HEAVY METALS (Zn++ and Cu++)1

ABSTRACT Minicomputer interfaced, continuous, noncontact sensing of the ventilatory behavior of the bluegill (Lepomis macrochirus) was used to investigate the response to exposure to solutions of copper and zinc under various modes of application. The results of these studies indicate that fish respond to sublethal concentrations of these toxicants by increasing the average ventilatory rate as well as decreasing the amplitude of the ventilatory signal. Appropriate statistics for the analysis of these data are also described.     

Prenatal exclusion of duchenne muscular dystrophy by fetal muscle biopsy

A fetal thigh muscle biopsy was performed at 18 weeks and 6 days' gestation using an automatic 18-gauge biopsy needle. A positive immunoreaction with antisera to the amino- and carboxy-terminals of dystrophin excluded Duchenne muscular dystrophy from this at-risk male.     

Cystic hygroma simulating an encephalocele

An ultrasound examination at 17 weeks gestation on a woman with a family history of spina bifida suggested that the fetus had a closed encephalocele. Amniotic fluid alphafetoprotein, rapidly adhering cells and acetylcholinesterase gel electrophoresis were normal. The pregnancy was terminated and the fetus was found to have a large cystic hygroma. It is suggested that in counselling parents of an infant or fetus with a cystic hygroma and with a normal chromosome constitution, ultrasound examination in future pregnancies is advisable, because of the possibility of autosomal recessive inheritance.     

Phthalates and the aquatic environment: Part II The bioconcentration and depuration of di-2-ethylhexyl phthalate (DEHP) and di-isodecyl phthalate (DIDP) in mussels (Mytilus edulis)

Mussels ($\text{Mytilus edulis}$) were exposed to di-2-ethylhexyl phthalate (DEHP) and to di-isodecyl phthalate (DIDP) over a period of 28 days. The bioconcentration factor (BCF) as measured by ¹⁴C analysis, reached estimated plateau levels corresponding to mean BCF values of approximately 2500 and 3500 for the DEHP and DIDP respectively. The mussels were then held in clean seawater for a further 14 days and ¹⁴C analysis showed a depuration half-life of approximately 3.5 days for both phthalates. During the whole 42 days of the experiment general observations on the health of the animals showed no evidence of any adverse effects.