Lead in glasgow street dirt and soul

The levels of lead in city street dirt and in soil from various locations in Glasgow were investigated during spring 1976. Lead concentrations in street dirt ranged from 150–2300 ppm, mean 960 ppm, and were significantly elevated with respect to the observed “natural” level of 78 ppm. Lead derived from anti-knock compounds in petrol and introduced to the environment via automobile exhausts was clearly implicated as the main source of lead pollution in a series of soil lead measurements at the centre and periphery of eight Glasgow parks.Various chemical leaching techniques were employed and compared. Less than 5% of street dirt and soil lead was found to be associated with the organic phase.     

Cigarette characteristics,smoker characteristics,and the relationship to cigarette fires

Data were collected from eight cities on a wide range of cigarette and smoker characteristics for a sample of smokers. Of these, 564 smokers had had fires and were identified through fire department response to those fires, while the other 1,611 smokers had not had fires and were identified through a telephone sample survey of the communities. The characteristics analyzed included those that had shown evidence of a relationship to the risk of a cigarette-initiated fire, either in laboratory studies or in previous statistical analyses of fire experience.The smoker characteristics analyzed were household income, education, age, gender, and race. The cigarette characteristics analyzed were filter, tobacco column length, filter length, circumference, density, amount of tobacco, menthol, citrate, porosity, and pack type. In addition, a variable was used to control for the smoker's city.After controlling for all smoker characteristics and city, logistic regression modeling showed four cigarette characteristics to be significant: filter, filter length, porosity, and type of pack. Filter, filter length, and porosity all affect air intake, which, therefore, appears to be an important physical element in the combustion process associated with risk. Analysis limited to filtered cigarettes only showed the same characteristics to be significant, plus tobacco column length. Extension of the analysis to two-way interaction terms did not change any of the conclusions on which cigarette characteristics are important, but it did indicate that the role of pack type was different for men and women.Sensitivity analyses, shown in the appendix, supported the main conclusions that cigarette characteristics are significant after controlling for smoker characteristics and that the four specific cigarette characteristics—filter, filter length, porosity, and pack—are the ones that are significant. These analyses checked the impact of cluster sampling, sensitivity to missing data on smoker characteristics, and sensitivity to nonfire smoker cases with responses by people other than the smokers themselves.All this means that there are already cigarettes commercially available that exhibit a reduced propensity for ignition when one controls for smoker characteristics.This report was originally written as the final report in June 1993 as part of CPSC-P-91-1147 Contract Cigarette Fire Incident Study that the National Fire Protection Association conducted for the U.S. Consumer Product Safety Commission.Harwood, formerly with the Consumer Product Safety Commission, is retired.     

Assessment of nitrification in groundwater filters for drinking water production by qPCR and activity measurement

In groundwater treatment for drinking water production, the causes of nitrification problems and the effectiveness of process optimization in rapid sand filters are often not clear. To assess both issues, the performance of a full-scale groundwater filter with nitrification problems and another filter with complete nitrification and pretreatment by subsurface aeration was monitored over nine months. Quantitative real-time polymerase chain reaction (qPCR) targeting the amoA gene of bacteria and archaea and activity measurements of ammonia oxidation were used to regularly evaluate water and filter sand samples. Results demonstrated that subsurface aeration stimulated the growth of ammonia-oxidizing prokaryotes (AOP) in the aquifer. Cell balances, using qPCR counts of AOP for each filter, showed that the inoculated AOP numbers from the aquifer were marginal compared with AOP numbers detected in the filter. Excessive washout of AOP was not observed and did not cause the nitrification problems. Ammonia-oxidizing archaea grew in both filters, but only in low numbers compared to bacteria. The cell-specific nitrification rate in the sand and backwash water samples was high for the subsurface aerated filter, but systematically much lower for the filter with nitrification problems. From this, we conclude that incomplete nitrification was caused by nutrient limitation.     

Spatial and temporal evolution of trihalomethanes in three water distribution systems

Spatial and seasonal changes in trihalomethane (THM) concentrations were investigated in three distribution systems of Quebec (Canada) which are supplied by different surface waters and which use a variety of physicochemical treatment strategies. The investigation was based on an intensive 25-week sampling programme, undertaken at a time of year when the temperature of southern Quebec surface waters exceeds 4 degrees C (April-November). THMs and other water quality and operational parameters were monitored at points along the distribution system--between the treatment plant and the system extremities--which represented variable residence times of water. Results showed that THM concentrations vary significantly (from 1.5 to 2 times, depending on the utility) between finished waters as they leave the plant and water at the system extremities. When water temperature exceeds 15 degrees C, spatial THM variations are particularly high (from 2 to 4 times, depending on the utility). The development of multivariate regression models showed that water temperature was a better predictor of THM seasonal variability than chlorine dose, surrogates of natural organic matter and pH. Also, initial THM formation (in finished waters leaving the plant) was a good predictor of THM levels at distribution system extremities.     

Toxicity, accumulation and elimination studies of α-hexachlorocyclohexane (α-HCH) with freshwater organisms of different trophic levels

A short- and long-term toxicity study with α-hexachlorocyclohexane (α-HCH) was carried out with freshwater organisms of different trophic levels (algae, crustaceae and fishes). In this study mortality, immobilization, growth, reproduction, histopathologic changes and enzyme activities were chosen as criteria.Furthermore accumulation and elimination processes were investigated in separate organisms as well as the uptake of α-HCH by one organism and through a food-chain.Finally a tentative method for deriving an “ecological limit” for χ-HCH in surface water is described.     

The relative influence of wind,sunlight and temperature on user comfort in urban outdoor spaces

This paper presents the development of a comfort index that measures adaptivity in outdoor spaces. Over a 9-month period 649 people were surveyed in three locations, in temperatures between 10 and 28 °C. An exploratory factor analysis develops a 15-item scale of comfort that includes measures of adaptivity: clothing, exposure time and seating location. The scale is regressed on physical measures: average instantaneous wind speed; maximum wind speed; mean-exposed radiant temperature; mean-shaded radiant temperature and ambient temperature. The results model the relative contributions of the microclimatic factors for the comfort in the outdoor space. Analyses suggest gustiness and wind speed are most important in determining user satisfaction. There is strong support for the theory that people actively adapt to microclimatic conditions.     

景观建筑学

景观是我们生活的地区的基本结构，成熟的景观是文明社会发展最完善、最复杂的人工艺术，涵盖了相当数量的知识、经济和物质资源，它表达了人们对世界的期望，即使人在物质和精神方面都受益。对于一个成功的景观工程而言，统筹安排如何将道路、排水系统、资源和自然保护、野生动物栖息、社会空间以及建筑位置等进行控制协调是至关重要的。按照欧林事务所的经验，景观建筑师更容易具有整合各要素的能力。     

Lead,cadmium, and arsenic residues in animal tissues in relation to those in their surrounding habitat

The relationships of the residues of lead, cadmium, and arsenic in animal tissues to those in surrounding vegetation and soil were determined in a natural habitat representing a wide range of such residues. The samples studied were selected from 18 different locations. Analyses were performed on a total of 113 animals, 332 plant specimens (representing 33 species), and 408 soil samples (taken at different depths). For the purpose of evaluating relationships, the samples from each location were averaged and reported as parts per million on a dry weight basis. The average lead residues from different locations ranged from 1.4–9.2 ppm in the liver, 45–195 in bones, 4–283 in vegetation, and 15–1399 in soil samples. The cadmium contents ranged from 1–27 ppm in the liver, 3–77 in bones, 0.5–5 in vegetation, and 1–10 in soil. The arsenic contents in different components of the ecosystem varied with an average of 1–9 ppm in liver, 0.6–94 in vegetation, and 7–655 in soil samples. The soil residues varied considerably according to the depth of sampling. Little variation was noted in different species of vegetation or in soil and vegetation samples according to the time and year of sampling.Statistical analyses performed on the averages indicated a significant correlation between vegetation and soil residues for all three elements, and also between animal to vegetation and animal to soil cadmium residues. Multiple linear correlations for all elements in soil, vegetation, and animal tissues were determined. The results indicated a possibility of an increase in cadmium in animal tissues depending upon the increased residues of this metal in the environment.     

The depositional environment of zinc, lead and cadmium in reservoir sediments

Despite low water retention dams and intervening reservoirs, reservoirs located downstream from a lead-zinc mining and milling area contain relatively higher concentrations of zinc, lead and cadmium than reservoirs in other areas. These metals are also concentrated in reservoir bottom sediments relative to surrounding soils. The zinc and lead content closely correlates to depth of water, organic content and percentage of clay-sized sediments. Zinc is preferentially weathered and transported from its source relative to lead. A model is developed in which the zinc and lead are transported by ionic and/or organo-metallic solution into reservoirs. Because of the relatively long residency time of water in reservoirs, the zinc and lead in the water is removed by clay minerals. Most of the zinc and lead content of the sediments is shown to be associated with sediments of specific gravity between 2·0 and 2·9. The efficiency of these reservoirs as a sink for zinc and lead results in the removal of an average 0·3 ppm zinc and 0·04 ppm lead from waters passing through Fort Gibson Reservoir.     

The effect of temperature on the removal of non-ionic surfactants during small-scale activated-sludge sewage treatment—I. Comparison of alcohol ethoxylates with a branched-chain alkyl phenol ethoxylate

The degree of biodegradability of three non-ionic surfactants has been assessed using small-scale activated-sludge sewage treatment plants. The effect of temperature on biodegradability was studied by operation at 15°, 11° and 8°C.The two alcohol ethoxylate surfactants tested were well degraded at all three operating temperatures. The alkyl phenol ethoxylate surfactant tested was well degraded at 15°C but at lower temperatures the biodegradability was dependent on concentration. At 5 mg 1⁻¹, greater than 90 per cent removal was achieved but at 20 mg 1⁻¹ the degree of removal fluctuated between 40 and 95 per cent at 11°C and between 20 and 80 per cent at 8°C.The present results have been compared with those obtained using the same surfactants in community trials at a small sewage works employing biological filtration. Although a similar temperature effect was observed with the alkyl phenol ethoxylate, the biodegradabilities obtained in the laboratory were consistently greater than those obtained at the sewage works, perhaps because of the constant conditions of the laboratory test.