The ursid fossils collected from Saint Jacques include Pachycynodon tedfordi, new species, Amphicynodon sp., and Cephalogale sp. The distinctive features of Pachycynodon tedfordi are: short premolar series relative to molars, diastemata between c and p1 and among premolars very short or absent, distinct cingula on p1–p4, well-developed posterior accessory cuspids on p2–p4, long and narrow m1 with relatively high protoconid, metaconid lower than paraconid, and relatively long m2 without distinct paraconid. Four genera (Amphicticeps, Amphicynodon, Pachycynodon, and Cephalogale) representing two subfamilies (Amphicynodontinae and Hemicyoninae) have been discovered in the Oligocene of Asia. The last three are genera common to Asia and Europe, and indicate migration. Based on the ursid and other mammalian fossils, the deposits at Loc. 77046 near Saint Jacques are determined as Oligocene in age, and those at Loc. 77046.5 are late early Oligocene. Migration of ursids between Asia and Europe occurred in ...

Chapter 5: Notes on Early Oligocene Ursids (Carnivora, Mammalia) from Saint Jacques, Nei Mongol, China

Simultaneous transport of water and reacting solutes through multilayered soils under transient unsaturated flow conditions

A baseline groundwater quality survey of 120 household wells in an unsewered area at Yaldhurst, near Christchurch, was carried out between September and December, 1976. Ammonia‐N levels were below the detection limit (0.02 g m‐3) in all samples. Nitrate‐N, conductivity, and chloride levels tended to vary according to well depth and location, being lower in the deeper wells and in wells located in an area of shallow, stony soils. Approximately 33% of the wells contained coliform bacteria, faecal coliform bacteria or faecal streptococci. A subset of 25 wells was sampled fortnightly from January to August 1977. From January to June, mean nitrate‐N and conductivity levels remained stable at approximately 1.5 g m‐3 and 11.2 mS m‐1 respectively. An increase in these levels to 3.3 g m‐3 and 15.8 mS m‐1 in July‐August corresponded with a rise in the water table. Leaching losses from soils probably accounted for most of the nitrate entering the Yaldhurst aquifers, the contribution by septic tank systems b...

https://www.tandfonline.com/doi/pdf/10.1080/00288330.1982.9515975

A groundwater quality survey of an unsewered, semi‐rural area

A mathematical model was developed to simulate water movement, mass transport, and nitrogen transformations in soils during wastewater applications. The model is one-dimensional and based on the Galerkin finite-element method. The submodel of mass transport of nitrogen incorporates the convection-dispersion processes of ammonium and nitrate nitrogen, nitrification, denitrification, ammonium exchange and uptake of ammonium and nitrate ions. The accuracy and validity of the proposed model was examined by comparison with an explicit-implicit finite-difference model results. The model was used for simulation of water and nitrogen dynamics during wastewater application in homogeneous and multi-layered soils under different N concentration, rate, duration and scheduling of application.

Simulation of water and nitrogen dynamics in soils during wastewater applications by using a finite-element model

Drainage losses of nitrate and other nutrients were investigated at the Templeton effluent irrigation scheme (started in 1958), during the period June 1975 to May 1977. The average annual drainage was 900 mm for this period, compared with the effluent application of 840 mm and 760 mm rainfall. Losses of phosphorus in the drainage were very low, but percentage losses of all other nutrients were very high. The results indicated that after a few years' irrigation with sewage effluent no further removal of cations by the soil takes place, although at the present time sodium is displacing considerable quantities of calcium and magnesium from the soil, as a new equilibrium is established after cessation of liming in 1970. Annual losses of nitrogen in drainage were estimated to be 180 kg/ha, approximately 100 kg/ha of this being nitrogen leached from urine patches. If required, this nitrogen loss, which would give a maximum NO3-N concentration in the drainage of 20 ppm, could be greatly reduced by pastu...

II. Drainage losses of nitrate and other nutrients

Natural chemical and biological reactions will remove nitrogen from sewage effluent applied to soils if the wastewater is applied in a carefully managed treatment system. Only denitrification can remove the tremendous quantities of nitrogen applied in a high-rate land filtration system where nitrogen loads may be 10 to 30 times greater than those applied in irrigation systems. Columns packed in the laboratory with loamy sand removed 80% of the nitrogen applied at infiltration rates below 6 in./day (l5 cm/day). Percent nitrogen removal decreased exponentially as the infiltration rate increased from 6 in./day - 22 in./day (l5 cm to 55 cm/day). Nitrogen was also removed by the soil columns when high-nitrate water was collected, mixed with sewage, and recycled. Nitrogen may be removed by applying sewage to soils of low permeability and allowing it to trickle slowly down grassed slopes. Removal is probably due to a combination of plant uptake, denitrification, and immobilization in microbial tissue.

Fate of nitrogen in sewage effluent applied to soil

The removal of poliovirus type 1, coliforms, fecal coliforms and fecal streptococcus from treated sewage was compared in four sandy soils. In all soils, poliovirus removal was substantially greater than that observed for any of the bacterial indicator groups. These results suggest that in soils undergoing rapid infiltration of wastewater, indicator bacteria are conservative indicators of poliovirus removal.

J. Clarence Lance

Papers

Fate of nitrogen in sewage effluent applied to soil

Comparative removal of enteric bacteria and poliovirus by sandy soils