Risky health and safety habits related to perceived value of the future

Risk homeostasis theory postulates that people accept a specific level (target level) of risk in a given activity in return for benefits accruing from that activity. It follows that, if people expect a great deal from the future, the less likely they are to jeopardise it by taking risks in respect of their health and safety. One effective method for reducing target level of risk are incentives, and the available literature contains ample evidence of the effectiveness of incentives programmes in accident prevention. As incentives essentially imply an enhanced quality of life in the future, the question arises as to how expectations of the future may be related to health and safety habits. In order to explore the relationship between perceived value of the future and health and safety habits, an analysis of the psychological literature on individual differences in future time orientation/perspective is presented. Four factors are identified: (1) clear ideation of the future, (2) active planning for the future, (3) time pressure, and (4) optimistic expectations about events outside one's own control. It is hypothesised that factors (1) and (2) are associated with positive health and safety habits, while factors (3) and (4) may characterise individuals with relatively high target levels of physical risk. Research questions and procedures for the study of these relationships are discussed.     

Comparative feeding preference of Strongylocentrotus droebachiensis (Echinoidea) for the invasive seaweed Codium fragile ssp. tomentosoides (Chlorophyceae) and four other seaweeds

Laboratory experiments conducted during 1987 on Appledore Island, Maine, USA, tested whether feeding preference or the absence of an attractant was the cause for the occurrence of beds of Codium fragile ssp. tomentosoides (herein referred to as Codium fragile) within rocky barrens grazed clear of kelp by the sea urchin Strongylocentrotus droebachiensis. Consumption of C. fragile in single-diet experiments (1 seaweed/sea urchin) was highly variable and was not significantly different from that for several other seaweeds (Agarum cribrosum, Ascophyllum nodosum, Chondrus crispus, and Laminana saccharina) important in the field diet of the green sea urchin. In multiple-diet experiments (5 seaweeds/sea urchin) significantly less Codium fragile was eaten than Chondrus crispus, but significantly more Codium fragile was eaten than A. cribrosum. Chemosensory experiments suggest that C. fragile does not attract the sea urchin. Sea urchins are unable to detect C. fragile but will eat it when they come in contact with it.     

Factors affecting trace-metal bioaccumulation in Finnish headwater lakes

Fourteen unpolluted Finnish headwater lakes with pH values varying from 4.8 to 7.0 were studied for trace-metal concentrations in water, sediment, aquatic plants (Nuphar luteum L., Sparganium sp.), aquatic insect larvae (Limnophilus sp., Phryganea sp.) and fish (Esox lucius L., Perca fluviatilis L., Coregonus sp., Salvelinus fontinalis L., Salmo trutta L.). Trace-metal deposition was estimated by analysing the snowpack. Non-parametric correlation analysis was carried out between trace metal concentrations in biota and pH, ANC, TOC, CA + Mg concentration in water and a given metal concentration in water and sediment. Bioaccumulation of several trace metals increased with increasing acidity and decreasing ANC in water. This was especially true for Pb and Cd. Aquatic plants were, in general, the best indicator group concerning differences in trace-metal bioaccumulation in lakes with different acidity. There was some evidence that a higher concentration of TOC in water may reduce bioaccumulation of Pb, Cd and Zn in aquatic plants and fish. The copper concentration in sediment was the only background variable explaining Cu concentration in aquatic insects. Multivariate analysis of the whole background data gave comparable preliminary results. Over 80% of the trace metal concentrations in biota of different lakes was explained by the background variables. In general, elevated concentrations of most of these trace metals can be expected to occur in the biota of acidified low calcareous lakes.     

A review of the likely causal pathways relating the reduced density of breeding dippers Cinclus cinclus to the acidification of upland streams

Previous work has shown that the breeding density of a bird characteristic of upland streams, the dipper Cinclus cinclus, is markedly reduced at low pH in both Wales and Scotland. Populations also declined when streams became more acidic. Evidence of causal explanation for these relationships is that: (1) Food quantity is reduced in acidic streams, and important prey, including those rich in calcium, are scarce; (2) Blood chemistry in pre-breeding birds differs between acid and circumneutral streams, with plasma calcium reduced in those breeding at low pH. Skeletal sources of calcium are probably limited; (3) The time spent foraging by pre-breeding birds on acidic streams is markedly increased, even though overall energy costs on acidic and circumneutral streams are similar. Body condition is inferior to birds on circumneutral streams; (4) Egg laying is significantly delayed on acidic streams irrespective of an effect on laying of altitude, and clutch and brood sizes are significantly reduced; (5) Eggs are lighter and shells thinner at low pH; (6) Chick growth is reduced at low pH; (7) Contamination by heavy metals and persistent organochlorines is low in the populations on acidic streams and cannot explain the impaired breeding performance. None of these features can exclude the possibilities that acidic streams either hold populations of poor quality birds, which show the above features, or that acidity affects the breeding ecology of all dippers that attempt to breed at low pH. The qualitative outcome of these two alternatives is identical.     

Disappearance of bromopropylate residues in artichokes, strawberries and beans

Residues of Bromopropylate were determine in artichokes, strawberries and beans after foliar spray of acaricide at two rates. The rates used were 1 g/l formulated product (normal recommended) and 1.5 g/l. The residue levels of bromopropylate in the three crops after 14 days were lower than 0.7 ppm and did not exceed the Maximum Residual Level (MRL) recommended by FAO. In the artichokes and strawberries, the total concentration of residues decreased by 50% of the initial level after 2-3 days. Only trace levels of the bromopropylate residues (less than 0.01 ppm) were detected in the "hearts" of the artichokes. Bromopropylate residues in the green beans were also less than 0.8 ppm after the first day of foliar spraying. The kinetic of degradation occurred in two different steps. In the first step (4-6 days) the dissipation of bromopropylate was faster whereas in the second step (7-14 days) the loss of residues was much slower.     

Soil sampling and analysis for volatile organic compounds

Concerns over data quality have raised many questions related to sampling soils for volatile organic compounds (VOCs). This paper was prepared in response to some of these questions and concerns expressed by Remedial Project Managers (RPMs) and On-Scene Coordinators (OSCs). The following questions are frequently asked:

1. Is there a specific device suggested for sampling soils for VOCs?
2. Are there significant losses of VOCs when transferring a soil sample from a sampling device (e.g., split spoon) into the sample container?
3. What is the best method for getting the sample from the split spoon (or other device) into the sample container?
4. Are there smaller devices such as subcore samplers available for collecting aliquots from the larger core and efficiently transferring the sample into the sample container?
5. Are certain containers better than others for shipping and storing soil samples for VOC analysis?
6. Are there any reliable preservation procedures for reducing VOC losses from soil samples and for extending holding times?

Guidance is provided for selecting the most effective sampling device for collecting samples from soil matrices. The techniques for sample collection, sample handling, containerizing, shipment, and storage described in this paper reduce VOC losses and generally provide more representative samples for volatile organic analyses (VOA) than techniques in current use. For a discussion on the proper use of sampling equipment the reader should refer to other sources (Acker, 1974; U.S. EPA, 1983; U.S. EPA, 1986a). Soil, as referred to in this report, encompasses the mass (surface and subsurface) of unconsolidated mantle of weathered rock and loose material lying above solid rock. Further, a distinction must be made as to what fraction of the unconsolidated material is soil and what fraction is not. The soil component here is defined as all mineral and naturally occurring organic material that is 2 mm or less in size. This is the size normally used to differentiate between soils (consisting of sands, silts, and clays) and gravels. Although numerous sampling situations may be encountered, this paper focuses on three broad categories of sites that might be sampled for VOCs:

1. Open test pit or trench.
2. Surface soils (<5 ft in depth).
3. Subsurface soils (>5 ft in depth).

     

The importance of temperature in assessing iron pipe corrosion in water distribution systems

Temperature is expected to play a significant role in the corrosion of iron pipes in drinking water distribution systems. Temperature impacts many parameters that are critical to pipe corrosion including biological activity, physical properties of the solution, thermodynamic and physical properties of corrosion scale, and chemical rates. Moreover, variations in temperature and temperature gradients may give rise to new corrosion phenomena worthy of consideration by water treatment personnel.