Research Watch: Radionuclide uptake by zooplankton


Research Watch: Radionuclide uptake by zooplankton...

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Radionuclide uptake by zooplankton The susceptibility of zooplankton to radionuclide uptake is an indicator o environmental contamination. R. Jeffree and co-workers studied the uptake of radionuclides by zooplankton in the French Polynesian Pacific. Levels of Po-210 exhibited an unusual, inverse relationship with zooplankton biomass. Validated modelim of observed marine system behavior accounted for the rate of Po-210 input, ingestion, and removal by zooplankton. Results show that low densities of zooplankton can elevate concentrations of radionuclides in surrounding waters. These findings are consistent with recent observations of elevated Po-210 concentrations in fish taken from waters that surround the Marshall Islands. The authors say that these results point to vulnerability of marine systems to contamination following leakage of radionuclides from weapons test sites and waste repositories, (Environ. Sci. Technol., this issue, pp. 2584-88)

from the biofilm during the first three days of growth. P. putida then occurred at a constant 10% level in the active biomass biofilm. Results showed that P. putida degraded only about 11% of the total toluene; thus, changes in nutrient conditions affected the process. [Biotechnol. Bioeng. 1997, 54, 131-41)

GREEN CHEMISTRY Fish mince films Many natural polymers cannot be used for biodegradable packaging material because they lose strength and barrier properties as a result of changes in humidity and temperature. B. Cuq and co-workers characterized the properties of myofibrillar protein-based hydrophilic films used in several previous studies. The films were prepared from fish mince— gutted, headed, and deboned fish. During a temperature increase, the films showed sudden changes in their mechanical properties and specific heat, classically associated with a glass-rubber transition in amorphous materials. Increasing the wa-

ter content of the film involved a nonlinear decrease in the glass transition temperature. A hydrodynamic theory could not fully explain the plasticizing effect of water on the films using a thermodynamic theory. (Polymer 1997, 38, 2399-405)

HEALTH CO and hospitalizations Many recent epidemiological studies have reported links between ambient air pollution and hospitalizations. Most have emphasized particulate air pollution and cardiopulmonary disease; relatively few have evaluated cardiac diseases specifically. R. T. Burnett and colleagues investigated the association between ambient air pollution, including CO, and hospitalization due to congestive heart failure in 10 Canadian cities. The study found that several ambient air pollutants (CO, particulates, nitrogen dioxide, and sulfur dioxide) were associated with increased hospitalizations of elderly persons with congestive heart failure. The association with CO was the strongest and most consistent of all pollutants measured. {Epidemiology 1997, 8, 162-67)

Exhaust and lung function Motor vehicles are a major source of air pollution, yet few studies have examined the health of people living near roads with heavy traffic. B. Brunekreef and colleagues used lung function tests to assess the relationship in 877 children who lived within 1000 miles of a busy highway in The Netherlands. Particulates and nitrogen dioxide were measured in the children's schools, and separate traffic counts were taken for automobiles and trucks in residential zones where subjects lived. Lower levels of lung function were associated with truck, but not automobile, traffic density. This relationship was strongest for those children living within 300 miles of major roads. (Epidemiol. 1997, 8, 298-303)

VOC-free paints Health concerns led some manufacturers to produce paints with no VOCs. J. R. Beach and co-workers compared effects of the new VOCfree paint and conventional water-

3 9 6 A • VOL. 3 1 , NO. 9, 1997 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS

Modeling biosorption performance Biosorption holds promise as an economical method for removal of toxic heavy metals from industrial wastewaters. The complicated process, however, is not well understood. The ionic strength and pH of wastewater and the presence of lighter metals such as sodium and calcium can interfere with heavy metal binding to biosorbents. Until now, the influence of these alkaline (earth) metals on heavy metal biosorption has been neglected. S. Schiewer and B. Volesky report on a mathematical model they developed and used to account for the combined influence of these parameters on the uptake of cadmium by a brown alga (Sargassum). This model should be useful in the analysis of biosorption performance and the design of wastewater treatment processes. {Environ. Sci. Technol., this issue, pp. 2478-85)

based paint (which contains some VOCs) on people with asthma in England having known sensitivity to paint odor. In a double-blind crossover study, 17 asthmatics painted with VOC-free and conventional water-based interior paint. Lung function tests were done before, during, and after each 60-minute painting session. Reports of wheezing, breathlessness, and other symptoms increased during painting with conventional water-based paint, but not with VOC-free paint. The authors concluded that the use of VOC-free paints protects people sensitive to paint odor better than conventional water-based paints. (Eur. Respir. J. 1997, 10, 563-66)

MEASUREMENTS Rapid PAH water analysis A need exists for an inexpensive, simple, and sensitive analytical technique for PAHs in water to supplement complicated existing techniques. A-L. Nguyen and J. H. T Luong reported the development of a new procedure using solid-phase microextraction (SPME) and cyclodextrin-modified capillary electrophoresis. PAHs are extracted from a 0.1-mL sample by placing a poly-