Microbial transport into groundwater from irrigation: Comparison of two irrigation practices in New Zealand.

Unlabelled: Rising demand on food is leading to an increase in irrigation worldwide to improve productivity. Irrigation, for pastoral agriculture (beef, dairy and sheep), is the largest consumptive use of water in New Zealand. There is a potential risk of leaching of microbial contaminants from faecal matter through the vadose zone into groundwater.

Application of the re-circulating tracer well test method to determine nitrate reaction rates in shallow unconfined aquifers.

Five re-circulating tracer well tests (RCTWTs) have been conducted in a variety of aquifer settings, at four sites across New Zealand. The tests constitute the first practical assessment of the two-well RCTWT methodology described by Burbery and Wang (Journal of Hydrology, 2010; 382:163-173) and were aimed at evaluating nitrate reaction rates in situ. The performance of the RCTWTs differed significantly at the different sites.

Transport of Escherichia coli and F-RNA bacteriophages in a 5m column of saturated pea gravel.

The relative transport and attenuation of bacteria, bacteriophages, and bromide was determined in a 5m long x 0.3m diameter column of saturated pea gravel. The velocity (V), longitudinal dispersivity (alpha(x)) and total removal rate (lambda) were calculated from the breakthrough curves at 1m, 3m, and 5m, at a flow rate of 32Lh(-1).

Effects of pH, ionic strength, dissolved organic matter, and flow rate on the co-transport of MS2 bacteriophages with kaolinite in gravel aquifer media.

Viruses are often associated with colloids in wastewater and could be transported with colloids into groundwater from land disposal of human and animal effluent and sludge, causing contamination of groundwater. To investigate the role of colloids in the transport of viruses in groundwater, experiments were conducted using a 2m long column packed with heterogeneous gravel aquifer media. Bacteriophage MS2 was used as the model virus and kaolinite as the model colloid.

Impairments in pyridoxine-dependent sulphur amino acid metabolism are highly sensitive to the degree of vitamin B6 deficiency and repletion in the pig.

The objectives of the current study included the characterization of the temporal changes in indices of sulphur amino acid metabolism in piglets in response to vitamin B6 deficiency and repletion with graded levels of pyridoxine hydrochloride. In Experiment 1, 12 piglets (average initial weight = 5.3 kg; n = 6 per group) were fed a semi-purified diet containing either 0 (deficiency group) or 3 mg (control group) pyridoxine·HCl/kg diet, using a pair-feeding design, for 6 weeks.