Chemical fingerprinting of naphthenic acids and oil sands process waters-A review of analytical methods for environmental samples.

This article provides a review of the routine methods currently utilized for total naphthenic acid analyses. There is a growing need to develop chemical methods that can selectively distinguish compounds found within industrially derived oil sands process affected waters (OSPW) from those derived from the natural weathering of oil sands deposits. Attention is thus given to the characterization of other OSPW components such as oil sands polar organic compounds, PAHs, and heavy metals along with characterization of chemical additives such as polyacrylamide polymers and trace levels of boron species. Environmental samples discussed cover the following matrices: OSPW containments, on-lease interceptor well systems, on- and off-lease groundwater, and river and lake surface waters. There are diverse ranges of methods available for analyses of total naphthenic acids. However, there is a need for inter-laboratory studies to compare their accuracy and precision for routine analyses. Recent advances in high- and medium-resolution mass spectrometry, concomitant with comprehensive mass spectrometry techniques following multi-dimensional chromatography or ion-mobility separations, have allowed for the speciation of monocarboxylic naphthenic acids along with a wide range of other species including humics. The distributions of oil sands polar organic compounds, particularly the sulphur containing species (i.e., OxS and OxS2) may allow for distinguishing sources of OSPW. The ratios of oxygen- (i.e., Ox) and nitrogen-containing species (i.e., NOx, and N2Ox) are useful for differentiating organic components derived from OSPW from natural components found within receiving waters. Synchronous fluorescence spectroscopy also provides a powerful screening technique capable of quickly detecting the presence of aromatic organic acids contained within oil sands naphthenic acid mixtures. Synchronous fluorescence spectroscopy provides diagnostic profiles for OSPW and potentially impacted groundwater that can be compared against reference groundwater and surface water samples. Novel applications of X-ray absorption near edge spectroscopy (XANES) are emerging for speciation of sulphur-containing species (both organic and inorganic components) as well as industrially derived boron-containing species. There is strong potential for an environmental forensics application of XANES for chemical fingerprinting of weathered sulphur-containing species and industrial additives in OSPW.

Estimating the growth potential of the soil protozoan community.

We have developed a method for determining the potential abundance of free-living protozoa in soil. The method permits enumeration of four major functional groups (flagellates, naked amoebae, testate amoebae, and ciliates) and it overcomes some limitations and problems of the usual 'direct' and 'most probable number' methods. Potential abundance is determined using light microscopy, at specific time intervals, after quantitative re-wetting of air-dried soil with rain water. No exogenous carbon substrates or mineral nutrients are employed, so the protozoan community that develops is a function of the resources and inhibitors present in the original field sample. The method was applied to 100 soil samples (25 plots x 4 seasons) from an upland grassland (Sourhope, Southern Scotland) in the UK. Median abundances for all four functional groups lie close to those derived from the literature on protozoa living in diverse soil types. Flagellates are the most abundant group in soil, followed by the naked amoebae, then the testate amoebae and ciliates. This order is inversely related to typical organism size in each group. Moreover, preliminary evidence indicates that each functional group contains roughly the same number of species. All of these observations would be consistent with soil having fractal structure across the size-scale perceived by protozoa. The method described will be useful for comparing the effects on the soil protozoan community of different soil treatments (e.g. liming and biocides).

The survival story of a child with Ondine's curse in Northland.

The case of a six year old European male with congenital central hypoventilation is reported to illustrate that survival and positive developmental outcome is possible in a remote town in the Northland. Initial and ongoing problems include persistent ventilatory requirement, medical, developmental and psychosocial issues. Positive parental attitude, meticulous care to activities of daily living, medical and psychosocial surveillance and continuing support contribute to the success in management. Various treatment options are also discussed. Primary failure of respiratory regulation, also known as congenital central hypoventilation or Ondine's curse, has been infrequently reported in children. Survival and positive developmental outcome is possible but requires intensive support and positive parental attitude, as well as parental education and ongoing medical and psychosocial surveillance. We report this case to illustrate that this could be achieved even in a remote country town.

Axial rotation of lumbar intervertebral joints in forward flexion.

This paper examined the mobility of intervertebral joints in axial rotation in a neutral and in two flexed positions. Torsion tests were conducted in vitro on specimens of isolated intervertebral joints in a rig specifically designed to apply torsion without imposing a fixed axis. This permitted the specimens to rotate about their own mobile axis of axial rotation. In addition the specimens were flexed about previously defined physiological axes of sagittal flexion in order to simulate movements as close as possible to those seen in life. It was shown that some intervertebral joints do exhibit an increased ability to rotate when in some degree of sub-maximal flexion dependent on the morphology of the zygapophysial joints. In full flexion axial rotation is limited, most probably by tightening of the posterior ligaments and zygapophysial joint capsules. This study lends evidence to the argument that torsion alone is insufficient to damage the intervertebral disc but a combination of flexion and torsion will increase its vulnerability to injury.

Mechanical function of the human lumbar interspinous and supraspinous ligaments.

The mechanical function of the interspinous and supraspinous ligaments has been examined by simulating, on excised specimens, the deformation caused during forward flexion of the spine in real life. The load extension curves showed that during the first half of flexion the ligaments carried very little load but towards the end of the range of flexion they resisted up to 134N. When the supraspinous ligament was sectioned the interspinous ligament alone resisted 75% of this load. Testing at high strain rates showed an increase in load-carrying capacity of up to 30%. The maximum extension moment that can be produced by these ligaments was calculated to be approximately 7 Nm, or 5% of the moment the back muscles can produce across any intervertebral joint. Hence, during active lifting, these ligaments in isolation provide little mechanical assistance.

Three-dimensional kinematics of the human back.

This study examined the use of a new device, the 3space isotrak, to measure the kinematic behaviour of the backs of normal subjects and of patients from two orthopaedic practices. The device was shown to measure angles with a root mean square error of less than 0.2° and individuals showed a maximum standard deviation from the mean of movements repeated five times of less than 4°. Eighty normal subjects both male and female in four age ranges 20-29, 30-39, 40-49 and 50 years and over were measured. The three-dimensional kinematic patterns were similar for all groups, showing normals to have clearly identified patterns of movement. A general trend for decreasing mobility with age and some sex differences were also demonstrated. The clinical series showed widespread disruption to the primary and coupled movements of all the patients. When grouped together by clinical diagnosis the patient groups showed evidence of discrete and identifiable alterations from the normal kinematic patterns. However, further studies of homogeneous patient groups are required in order to demonstrate whether the measurements are of actual clinical use. The clinical studies also demonstrated that clinical subjective assessment of back mobility bore little relation to the true movements and therefore the clinical measurement of back movements should be reassessed. This study has shown the 3space isotrak to be an effective tool in the clinic for the three-dimensional kinematic measurement of low back mobility.

Rotational mobility of the human back in forward flexion.

This paper describes the measurement of the ability of the human back to twist when in flexed postures using a new electromagnetic measurement device. The mobility of the lumbar spine in 12 normal male subjects was investigated and it was demonstrated that increased rotation was possible when in a flexed posture. This suggests that the intervertebral disc may be vulnerable to torsion when twisting is combined with sub-maximal sagittal flexion.

Prevalence of hepatitis B in children in a high risk New Zealand community, and control using recombinant DNA vaccine.

Two hundred and sixty-six children aged 3-10 years were tested for hepatitis B virus (HBV) serologic markers. Thirty-eight were positive, including seven who were positive for hepatitis B surface antigen (HBsAg). Two hundred and fifteen healthy children were randomised to receive either 3 x 5 micrograms doses or 3 x 10 micrograms doses of Smith Kline Biologicals Engerix B recombinant DNA (rDNA) hepatitis B vaccine into the deltoid muscle at 0, 1 and 6 months. They were tested for seroconversion and levels of antibody to hepatitis B surface antigen (anti-HBs) one month after dose 3. Ninety-nine percent of children in each group seroconverted for anti-HBs. Geometric mean titres (GMT) or anti-HBs in IU/L were higher with 10 micrograms doses. Nevertheless, 3 x 5 micrograms is the appropriate regimen for protecting children in this age group, as long as cost of vaccine remains a major factor in immunisation programmes.

Twisting of the human back in forward flexion.

This paper addresses the role of torsion in the production of spinal injury and in particular the possibility of injury resulting from torsion combined with flexion. The back movement of 16 normal male subjects was measured using a non-invasive, three-dimensional measurement system for assessing spinal mobility, the opto-electronic CODA-3 scanner. Measurements were made of the ability to twist the back while standing upright and in two flexed postures. Rotational ability was shown, in general, to be increased in a flexed posture, presumed to be due to an opening of the lumbar zygapophysial joints. This suggests that twisting in a flexed posture could be a mechanism for intervertebral disc injury.

New method for the non-invasive three-dimensional measurement of human back movement.

A new method for the non-invasive three-dimensional measurement of human lumbar movement is described. The electro-magnetic 3space Isotrak system was found to be accurate and reliable, having a total r.m.s. error for rotations of less than o·2°. The system was able to produce consistent plots of subjects' movement patterns and it is proposed that this system should be evaluated in respect of its discriminatory and predictive potential in clinical studies of low back disorders. It may then become a useful tool in the routine clinical assessment of patients with spinal disorders, providing a complete quantification of back kinematics quickly and efficiently.

Determination of N-nitrosodipropylamine in trifluralin emulsifiable concentrates using minicolumn cleanup and gas chromatography with thermal energy analyzer.

A quick method for determining N-nitrosodipropylamine (NDPA) levels in trifluralin emulsifiable concentrate formulations is described. At least 18 samples can be analyzed at one time in a minimum of fumehood space, with up to 90% savings on solvents and materials. A sample aliquot is mixed with a solution containing nitrosamine recovery standards, and nitrosamines are separated by minicolumn cleanup. Internal standard is added directly to the eluate containing the nitrosamines, and levels are determined by gas chromatography with thermal energy analyzer. Recoveries of spiked nitrosamines ranged from 98 to 102%. Coefficients of variation for samples containing less than 0.5 ppm NDPA are less than 13%. Minimum detectable limit, calculated as 3 times the noise, is 0.06 ppm. Comparison with the method formerly used by this laboratory shows no significant difference in the analytical results at 95% confidence limits, and control experiments were performed to ensure that there was no artifact formation of NDPA.

On the abundance and distribution of protozoa and their food in a productive freshwater pond.

We have examined and quantified the protozoa living in a productive freshwater pond during a 2-day period in June 1987. Over 90 species were recognised. The planktonic and benthic communities were dominated by ciliates and heterotrophic flagellates although the large amoeba Pelomyxa palustris was abundant (102 ml(-1)) in anaerobic sediments. Picoplankton averaged 1.4 × 10(7) ml(-1), phototrophic nanoplankton 0.8 × 10(5) ml(-1), heterotrophic nanoplankton 0.9 × 10(5) ml(-1) and planktonic ciliates 1.3 × 10(2) ml(-1). Numbers were about two orders of magnitude higher in the sediment. Protozoan biomass ranged from 3% to 61% of the total plankton biomass. Heterotrophic flagellates were the principal grazers of the picoplankton. Planktonic ciliates fed mainly on phototrophic nanoplankton but they probably also ingested heterotrophic flagellates. Benthic ciliates were predominantly bactivorous. Competition between ciliate species was minimised by both spatial and food niche separation. Ten species of planktonic ciliates appeared to contain algal symbionts: one species (Strombidium viride) contained structures resembling sequestered chloroplasts. These findings concerning the diversity and abundance of protozoa in a freshwater pond are consistent with the consensus opinion expressed in the marine literature that protozoa play a fundamental role in microbial food webs within aquatic ecosystems.