Evidence for exposure to selenium by breeding interior snowy plovers (Charadrius nivosus) in saline systems of the Southern Great Plains.

Interior snowy plover (Charadrius nivosus) population declines and deteriorating conditions throughout the Southern Great Plains (SGP) of Texas, New Mexico, and Oklahoma may be linked to environmental contaminants. Concentrations of V, As, Cd, Pb, and Se were quantified in breeding snowy plover blood, feathers (5th primary; P5), and potential prey (tiger beetles [Cicindela circumpicta and C. togata]). Se was (a) most commonly detected relative to other quantified elements and (b) frequently quantified at levels exceeding background or toxicity thresholds. Of samples greater than instrumentation detection limits, 98% of snowy plover blood and 22% of feather samples were greater than Se toxicity thresholds of 1 ppm ww for blood and 5 ppm dw for feathers (blood quantifiable range: 0.83-15.12 ppm; feathers quantifiable range: 1.90-27.47 ppm). Almost all tiger beetle Se concentrations were below reported invertebrate thresholds of 30 ppm dw (quantifiable range: 0.54-45.84 ppm). Snowy plover blood Se concentrations were related to sex, individual body condition, and local tiger beetle Se concentrations, while plover P5 Se concentrations were related to state, sex, and presence of body molt. Tiger beetle Se concentrations were related to individual study sites in Texas. These results provide some of the first evidence of Se exposure risk for interior snowy plovers nesting in saline lake and alkali flat environments of the SGP. Future efforts should focus upon specific Se uptake pathways during breeding and nonbreeding seasons, as snowy plovers breeding in the SGP appear to be exposed to Se throughout their annual cycle.

A study of the dietary fluoride supplementation prescribing pattern of south Glamorgan dentists.

Following the inclusion of dietary fluoride supplements in the Dental Practitioners Formulary on 1st January 1993, the aims of this study were to observe the fluoride supplementation prescribing pattern of South Glamorgan general dental practitioners and relate it to the latest caries prevalence data. The analysis was carried out on the prescribers and recipients of the prescriptions using post codes to locate all members of both groups into one of 26 dental planning areas (DPA) within the district. As the age of a minority of recipients could not be substantiated, an assumption that they were all 14 years or under was used to calculate a prescription to population ratio for each DPA. These ratios were correlated against the latest available caries prevalence data for each DPA to ascertain any relationship between the level of fluoride supplement prescription and the caries prevalence within South Glamorgan. Data were collected via the Prescription Pricing Division of Welsh Health Common Services Authority for the six month period, 1st January to 30th June 1993. Of 623 prescriptions dispensed within South Glamorgan, 581 were issued by dentists working in the District for patients living in the District. Of the 163 dentists registered within South Glamorgan FHSA, (boundary coterminous with the DHA) 49 made one or more prescription. Of these, 10 dentists wrote 20 prescriptions or more, totalling 401, during the study period, i.e. 6 per cent of the dentists made 69 per cent of the prescriptions. The correlation of the number of prescriptions issued per DPA (according to the dentists' location) with whole time equivalents in that DPA was 0.58 (P < 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)