The ecological value of constructed wetlands for treating urban runoff.

The Sweetwater Authority's urban runoff diversion system (URDS) comprises constructed wetlands on a hillside between the town of Spring Valley and the Sweetwater Reservoir, California, USA. The URDS were designed to divert dry-weather and first-flush urban runoff flows from the Sweetwater reservoir. However, these constructed wetlands have developed into ecologically valuable habitat. This paper evaluates the following ecological questions related to the URDS: (1) the natural development of the species present and their growth pattern; (2) the biodiversity and pollutant stress on the plants and invertebrates; and (3) the question of habitat provided for endangered species. The URDS wetlands are comprised primarily of rush (Scirpus spp.) and cattails (Typha spp.). This vegetative cover ranged from 39-78% of the area of the individual wetland ponds. Current analyses of plant tissues and wetland sediment indicates the importance of sediment sorption for metals and plant uptake of nutrients. Analyses of URDS water following runoff events show the URDS wetlands do reduce the amount of nutrients and metals in the water column. Invertebrate surveys of the wetland ponds revealed lower habitat quality and environmental stress compared to unpolluted natural habitat. The value of the wetlands as wildlife habitat is constrained by low plant biodiversity and pollution stress from the runoff. Since the primary Sweetwater Authority goal is to maintain good water quality for drinking, any secondary utilization of URDS habitat by species (endangered or otherwise) is deemed an added benefit.

Trace metals in fish and invertebrates of three California coastal Wetlands.

Metal concentrations were measured in selected fish and invertebrate species from Mugu Lagoon, Malibu Lagoon and Ballona Wetlands in southern California in order to assess the extent of metal contamination in these three wetlands. Ranges of element concentrations (in microgram/g) found in biota were: Zn 12-650; Cu 1.9-440; Ni < 1-37; Cr < 1-55; Pb < 0.5-6.8; As < 1-8.5; Se < 1-3.8; Cd < 0.2-0.90; and Ag < 0.3-5.9. Relative to previous studies of California biota, the highest metal concentrations found were for chromium and nickel. The highest levels were in one of the two bottom-dwelling fish (juvenile Leptocottus armatus) (55 micrograms/g) and the two water-column fish sampled (Fundulus parvipinnis and Atherinops affinis) (30 and 24 micrograms/g). At Ballona Lagoon, elevated levels of copper and silver were found in the bivalve Tagelus californianus (440 and 5.9 micrograms/g). Chromium and nickel appeared to be most persistent in fish from Mugu (4.6-55 and 2.6-37 micrograms/g), the most northern site and an active military base, and Ballona (< 1-30 and < 1-16 micrograms/g), believed to be the most metal-contaminated site. Compared to previously measured metal concentrations in species of California coastal waters, these regions revealed higher levels of chromium, nickel, silver, arsenic, zinc, copper and, to a lesser extent, cadmium and selenium. Chromium and silver were present at high enough levels at all three sites to be considered environmental health hazards.

A comparison of techniques for preparing fish fillet for ICP-AES multielemental analysis and the microwave digestion of whole fish.

Four catfish fillet homogenate treatments before multielemental metal analysis by simultaneous inductively coupled plasma/atomic emission spectroscopy were compared in triplicate. These treatments were: nitric acid wet-ashing by Parr bomb digestion; nitric acid wet-ashing by microwave digestion; tetramethylammonium hydroxide/nitric acid wet digestion; and dry-ashing. The tetramethylammonium hydroxide/nitric acid method was imprecise (coefficients of variation > 20%). The dry-ashing method was fast and sensitive but had low recoveries of 50% for spiked Pb and Al and was not as precise as the Parr bomb or microwave treatments. The Parr bomb method was the most precise method but was less sensitive than the microwave method which had nearly the same precision. The microwave method was then adapted to homogenates of small whole fish < or = 3 cm in length. The whole fish homogenate required more vigorous digestion conditions, and addition of more acid after the evaporative step because of the presence of less oxidizable and acid-soluble components than fillet. The whole fish homogenate was also more heterogeneous than catfish fillet. A quality assurance protocol to demonstrate homogenate uniformity is essential. The use of a non-specialized microwave oven system allowed precise results for fillet and whole fish homogenates.

Rheumatoid arthritis patients and clinical drug trials. A case-control study.

In order to understand better why patients do or do not participate in clinical drug trials, we sent questionnaires to 100 patients with rheumatoid arthritis (RA) who participated in clinical drug trials at our center and to 100 RA patients with similar disease durations who did not participate in clinical drug trials at our center. We compared demographic, socioeconomic, and clinical characteristics of respondents. Those who participated and those who did not participate in clinical drug trials selected similar rank-order preferences of potential reasons for doing so. The most frequent reasons cited by participants and nonparticipants were physician recommendation (50% and 56%) and benefit to society (25% and 17%). Participants and nonparticipants were similar in reference to their age, sex, educational level, reported income per household, employment status, distance from the medical center, disease duration, number of tender joints, American Rheumatism Association functional class, and mean erythrocyte sedimentation rate variables. There were two differences between the groups: participants included a lower percentage of blacks and had a greater number of swollen joints. Even with those exceptions, we concluded that participants in clinical trials appear to be comparable to the general population of RA patients followed at our outpatient department.

Rheumatology algorithms for primary care physicians.

Primary care physicians were trained on three rheumatology topics to assess the effectiveness of an educational strategy for continuing medical education. Algorithm training was shown to be at least as effective as that based on standard prose monographs. Both training groups improved their knowledge of patient management skills but there were no statistically significant differences between groups in the amount learned. When algorithms were used to design text materials, the designed texts required less study time than did the annotated clinical algorithms alone. That difference was significant for the shoulder pain materials (P less than 0.05) but not for the osteoporosis materials. The ratio of knowledge gained to study time was significantly higher for the algorithm group on the low back pain topic (P less than 0.05) but not for the other topics. Taped interview problems tests were studied as a method for assessing patient management skills related to problem-specific indicator conditions and were found to produce interrater reliability greater than 0.80 on five of the six tests.

Construction of clinical algorithms for educational programs.

Clinical algorithms have been used successfully in a variety of health care settings to assist health care professionals in the diagnosis and management of medical problems. In addition to their clinical applications, algorithms also serve as an instructional resource by themselves and when used in conjunction with other educational methodologies. A recommended algorithm development process is described for cancer educators who wish to take advantage of the unique contribution clinical algorithms can offer for their educational programs. Algorithm design conventions are reviewed and specific writing suggestions are offered for the guidance of educators who want to design their own clinical algorithms. Objections to clinical algorithms can often be attributed to a misunderstanding of their proper role, which is to facilitate, not dictate, the decision process and guide the application of management logic. Clinical algorithms are a valuable instructional resource that can be used in a wide range of educational settings from self-instruction units to the design of lecture presentations.