Evaluation of the total Cr-levels in the ambient air in Belgium

As a part of the general network for the monitoring of heavy metals in the ambient air in Belgium, total Cr-levels were measured at 14 stations distributed over the country from April 1982 until March 1985. The most important statistical results are summarized and discussed. In two regions, Liège and Genk, with important ferrous industries, elevated chromium pollution with important peak values has been detected. In the last five years, a marked increase has been noted for the Liège region, while at the other sites only small changes occurred. The relationship between chromium and the other metals measured in the ambient air is examined and discussed. On the basis of pollution data an attempt of source identification is presented.     

Elemental content of lichens of the Point Reyes Peninsula, northern California

The Point Reyes peninsula in northern California is about 45 km northwest of San Francisco and occasionally receives air masses from the city contributing to haze and lowered visibility. Although gaseous pollutants are not a problem, fine particulates containing carbon and other elements are measurable at the park. In this study, five lichen species were sampled along a 40-km linear transect from southeast to northwest from the town of Bolinas at the southern end of the peninsula. Elevated levels of Na and S and the Na/S ratio at localities nearer the ocean confirmed there is a definite marine aerosol influence on lichen elemental content. Elevated potassium and mercury concentrations were also found at high elevation sites that intercept fog. However, arsenic and lead were found to decrease with distance from Bolinas along the transect, suggesting these two elements originate in the fine particulate haze that enters the park from San Francisco. Concentrations of elements were not at enriched levels for other lichen species. A possible local influence of roads on element content needs further study.     

Effects derived from long-term low-level chromium exposure in ferro-alloy metallurgy. Study of absorption and renal function in workers

Ferro-chromium production is based on the use of chromium oxide (III) and it is generally accepted that chromium in this form is not able to cross biological barriers. However, the data on the toxic and carcinogenic effects of hexavalent chromium in man are now firmly established. Some studies have questioned these data, calling for a clarification as to whether exposure to trivalent chromium can also produce human effects, perhaps with different latency time. A study was carried out on the exposure conditions (type and degree) in a ferro-chromium foundry that had been in operation since 1972. The absorption levels in the working population of the foundry, and the possible toxic effects on the kidney have been investigated. A total of 236 workers (142 employed in production departments, 33 office workers and 61 sub-contractor employees) were examined with measurement of the indicators of dose (urinary-chromium) and of effect on the kidney (albumin, retinol binding protein, and renal tubular epithelium antigens in the urine). Environmental hygiene measurements showed relatively low values of total chromium in the air (always less than 0.160 mg/m3). Hexavalent chromium was absent or, if present, at levels below the sensitivity of the analytical method used (0.001 mg/m3). The values of urinary chromium measured at the beginning and at the end of the working day and at the end of the work shift were always less than 5 micrograms/g creatinine, which has been proposed as a biological limit in chromium exposure. However, differences were observed between groups of subjects employed on different jobs, which is indicative of an absorption process varying according to the degree of exposure. The indicators of effect did not reveal any renal impairment, even early, that could be attributed to the toxic action of chromium.     

狭长线形公共空间的扩展——西哈雷姆码头公园

西哈雷姆码头公园位于一片狭长的线形区域,这一公共空间的诞生使哈雷姆社区与哈得孙河得以重新连接在一起,原本是一座面积仅为6410m^2的停车场,现已扩建为占地面积达9804m^2的公园,以一种极富意味的方式重新诠释了这座城市与河流,     

Occupational exposure to trihalomethanes in indoor swimming pools

The study evaluated occupational exposure to trihalomethanes (THMs) in indoor swimming pools. Thirty-two subjects, representing the whole workforce employed in the five public indoor swimming pools in the city of Modena (Northern Italy) were enrolled. Both environmental and biological monitoring of THMs exposure were performed. Environmental concentrations of THMs in different areas inside the swimming pools (at the poolside, in the reception area and in the engine-room) were measured as external exposure index, while individual exposure of swimming pool employees was estimated by THMs concentration in alveolar air. The levels of THMs observed in swimming pool water ranged from 17.8 to 70.8 microg/l; the mean levels of THMs in ambient air were 25.6+/-24.5 microg/m3 in the engine room, 26.1+/-24.3 microg/m3 in the reception area and 58.0+/-22.1 microg/m3 at the poolside. Among THMs, only chloroform and bromodichloromethane were always measured in ambient air, while dibromochloromethane was detected in ambient air rarely and bromoform only once. Biological monitoring results showed a THMs mean value of 20.9+/-15.6 microg/m3. Statistically significant differences were observed according to the main job activity: in pool attendants, THMs alveolar air were approximately double those observed in employees working in other areas of the swimming pools (25.1+/-16.5 microg/m3 vs. 14.8+/-12.3 microg/m3, P < 0.01). THMs in alveolar air samples were significantly correlated with THMs concentrations in ambient air (r = 0.57; P < 0.001). Indoor swimming pool employees are exposed to THMs at ambient air levels higher than the general population. The different environmental exposure inside the swimming pool can induce a different internal dose in exposed workers. The correlation found between ambient and alveolar air samples confirms that breath analysis is a good biological index of occupational exposure to these substances at low environmental levels.     

美国公园体系规划管理的特点与启示

城市公园运动以来,美国公园体系为改善自然和人居环境作出了重要贡献。对美国各层级公园体系的分类、管理和规划进行系统研究发现,美国公园体系主要由"国家-州-都会区-城市/郡"4个层级组成。各层级有不同的公园分类方式和功能侧重,且管理模式有所差异。四层级公园各采取垂直式、集权为主式、双层式和协同式管理。层级之间存在2种典型的管理衔接合作模式:通过立法实现多方参与或分权管理;通过财政支持和鼓励计划建立层级间合作关系。最后从建立完善多层级公园体系、选择合适的公园体系管理方式、促进各公园层级管理衔接与合作三方面对构建和完善中国公园体系提出政策启示与建议。     

Effects of initial climatic conditions on growth and accumulation of fluoride and nitrogen in leaves of two tropical tree species exposed to industrial air pollution

Saplings of Tibouchina pulchra and Psidium guajava, cultivated under standardized soil conditions, were placed in two sites at Cubat?o (state of S?o Paulo, southeast Brazil) to study the effects of air pollution on growth, biomass allocation and foliar nitrogen and fluoride concentrations. Thirty-six potted plants were maintained over two periods of one year (Jul/00 to Jun/01; Dec/00 to Nov/01) at each of two experimental sites with distinct levels of air pollution: Pil?es River Valley (PV) with vegetation virtually unaffected by air pollution; and Mogi River Valley (MV) severely affected by pollutants released mainly by chemical, fertilizer, iron and steel industries. For both species, saplings growing at MV showed alterations of growth and biomass allocation, as well as increased leaf concentrations of nitrogen and fluoride. Comparing both experimental periods, the one starting in winter (the driest season in Southeastern Brazil) seemed to affect the saplings more severely, the differences of the measured parameters between MV and PV being higher than in the second period. Multivariate analysis revealed two groups of data: one representing the MV and the other the PV saplings. For both species, saplings growing at MV showed differences in chemical composition, growth and biomass allocation, compared with the PV saplings. The results suggested that seasonal conditions of the first months of sapling exposure (summer or winter) modulate the intensity of responses to pollution stress.     

Storm water quality of first flush urban runoff in relation to different traffic characteristics

Storm water quality was monitored at four sites in a middle-sized Swedish town. The objective was to compare storm water pollution in the first flush storm water runoff between sites with different traffic intensities within a town. Flow proportional storm water runoff samples were collected. The samples were analyzed for suspended solids, conductivity, total nitrogen, total phosphorus, oil index, lead, cadmium, copper, chromium, nickel, and zinc.

The results showed that the levels of heavy metals and total phosphorus in storm water were highest at the site with the highest traffic intensity (7000 vehicles/day). A strong linear dependence between suspended solids (SS) and total phosphorus and heavy metals was observed. SS was the dominant explanatory variable for these parameters and a suitable predictor. The observed correlation between SS, heavy metals, and total phosphorus means that reducing levels of suspended solids in storm water would contribute to a substantial decrease of particle-bound heavy metals and total phosphorus in storm water. No samples were taken during winter; however, results indicate that de-icing material used in winter may affect surface runoff quality during other seasons. The results can be used as a reference for storm water quality management for traffic-related sites in towns with similar land use and climatic characteristics.     

Metal pollution of soils and vegetation in an area with petrochemical industry

The aim of this study was to determine the concentrations of arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), manganese (Mn), lead (Pb), and vanadium (V) in soil and chard samples collected in various industrial sites of Tarragona County (Spain), an area with an important number of petrochemical industries. Samples were also collected in urban (Tarragona downtown) and presumably unpolluted (blank samples) sites. Human health risks derived from metal inhalation and ingestion of soils were also assessed. With the exception of an increase in the levels of Cd and V, significant differences in soil samples from the industrial and the unpolluted zone were not found. In chard samples, significant differences between collection sites were only noted for V concentrations. For non-carcinogenic risks, the current levels of metals in the industrial area were lower than those considered as safe for the general population. In relation to carcinogenic risks, only As ingestion and Cr inhalation in the industrial zone might potentially cause an increase of the cases of cancer. A Kohonen self-organized map (an Artificial Neural Network) showed differences in metal concentrations according to the zone of origin of the samples. The current results suggest that although in general terms the petrochemical complex is not a relevant metal pollution source for the area, attention should be paid to As, Cr and V.     

Reductions in air conditioning energy caused by a nearby park

Field observations were carried out to determine the influence of a park on the urban summer climate in the nearby areas. The possibilities of reduction in air conditioning energy were investigated. Air temperature, relative humidity and other meteorological factors were measured at many locations inside a park and in the surrounding areas in the Tama New Town, a city in the west of the Tokyo Metropolitan Area, Japan. The observations indicated that vegetation could significantly alter the climate in the town. At noon, the highest temperature of the ground surface of the grass field in the park was 40.3 °C, which was 19 °C lower than that of the asphalt surface or 15 °C lower than that of the concrete surface in the parking or commercial areas. At the same time, air temperature measured at 1.2 m above the ground at the grass field inside the park was more than 2 °C lower than that measured at the same height in the surrounding commercial and parking areas. Soon after sunset, the temperature of the ground surface at the grass field in the park became lower than that of the air, and the park became a cool island whereas paved asphalt or concrete surfaces in the town remained hotter than the overlying air even late at night. With a size of about 0.6 km², at noon, the park can reduce by up to 1.5 °C the air temperature in a busy commercial area 1 km downwind. This can lead to a significant decrease of in air conditioning energy in the commercial area.     

Back-trajectory analyses of fine particulate matter measured at Big Bend National Park in the historical database and the 1996 scoping study

Analyses of the sources of fine particles associated with visibility reduction at Big Bend National Park during a 10-year period from 1989-1998 and from a regional visibility scoping study conducted during September and October 1996 at 19 sites in Texas and Mexico are summarized and compared. Fine sulfate particles are the largest fraction of the fine mass, and scattering by sulfates is estimated to be nearly half of the non-Rayleigh light extinction at Big Bend. Fine particulate sulfur concentrations are seasonal, with the highest values occurring during the summer and fall when back trajectory analyses show that air masses are most likely to arrive at Big Bend from the southeast after passing over Mexico or from areas to the northeast including east Texas. Episodically, high concentrations of fine mass and high light extinction values can be due to other species such as fine organic carbon or blowing soil dust. Organic carbon concentrations are often extremely high during the spring, especially during May. A combination of back trajectory analyses and the coincidence of high organic carbon and high non-soil potassium concentrations leads to the hypothesis that these concentrations are due to fires, primarily seasonal agricultural burning in Mexico and Central America. Fine soil concentrations often reach values that are twice the annual mean during July. These concentrations also frequently have high Al/Ca ratios, indicative of Saharan dust. Back trajectories associated with these events show air masses arriving from the southeast and are consistent with the hypothesis of transport of air masses from Africa during July. There is a high frequency of transport of air masses from Mexico to Big Bend, especially during the summer when fine mass concentrations and light extinction are highest. Therefore, sources and potential sources of sulfates and other fine particles in Mexico, particularly in areas southeast of the park have a high likelihood of contributing to visibility degradation at the park. Source areas to the northeast of the park, in east Texas and farther upwind also contribute to high fine sulfate concentrations.     

Field study on the indoor thermal environment and carbon monoxide levels in a large underground car park

Results of an indoor environment survey in a large underground car park in Hong Kong are reported in this paper. Field measurements were divided into three parts: (1) assessment of the thermal environment; (2) measurement of the carbon monoxide concentration; and (3) a survey on thermal comfort. The indoor air temperature, relative humidity, instantaneous airspeeds, turbulence intensity, and carbon monoxide concentration at different locations in the car park were measured. Design and operation of the installed ventilation systems were studied and the number of cars staying at the car park was investigated. Correlation relationships between the mean carbon monoxide and the mean air speed, the turbulence intensity, and the number of cars entering or leaving the car park were derived. Field studies of this kind are very important for providing ventilation system design data.     

Levels of heavy metals in outdoor and indoor dusts in Muscat,Oman

The concentrations of lead, copper, nickel, zinc and chromium in outdoor and indoor dusts collected from different sites in Muscat, Oman, were determined by flame atomic absorption. Results showed a wide range of concentrations, the means in the outdoor dust being, 65?±?50, 124?±?316, 47?±?45, 930?±?666 and 64?±?26 mg kg^??1 for lead, zinc, copper, nickel and chromium, respectively. The 2001 Omani phasing out of leaded fuel resulted in low levels of lead in outdoor dust compared to those reported in the literature. Outstanding was the high nickel concentration in outdoor dust when compared to that in the literature, the reason being natural soil pollution due to the local geology of the northern parts of Oman. The concentrations of chromium, copper and zinc are lower than or comparable to these in other cities around the world. The results also showed that the industrial activities in Muscat do not contribute significantly to metal pollution in street dusts.

On the other hand, the mean concentrations of lead, zinc, copper, nickel and chromium in indoor dust were 108?±?65, 753?±?1162, 108?±?91, 130?±?125 and 34?±?14 mg kg^??1, respectively. In general, zinc and nickel levels are higher than those reported in the literature while lead, copper and chromium levels are lower or comparable.

When outdoor and indoor dusts were correlated, the ratios between indoor–outdoor mean concentrations revealed that lead, zinc, and copper were generated internally, while nickel and chromium were from external sources.     

Characterization of an episode with elevated ozone concentrations.

A detailed analysis has been made of a seven day period in 1973, during which elevated ozone levels were observed at Ottawa. In addition to the ozone data, results are also presented for oxides of nitrogen, carbon monoxide, methane, total hydrocarbons and particulate matter. The particulates were analyzed for seven constituents, including the cations ammonium, calcium, sodium, potassium and lead and the anions sulfate and nitrate. Also measured were several other properties of the particulates, including the size distribution. It was found that none of the other gaseous pollutants showed any increase in concentration when high ozone levels were present. In contrast, the particulate matter did increase and several constituents, notably ammonium and sulfate, showed a dramatic rise. A comparison with ozone data from Toronto and upper New York state showed that the high ozone concentrations were widespread. A meteorological analysis showed that elevated ozone levels were associated with a Tropical air mass with a moderate southwesterly flow of air. Trajectory calculations were carried out to show the origin of the air over Ottawa before, during and after the period of increased ozone.     

Eye trigeminal sensitivity, tear film stability and conjunctival epithelium damage in 182 non-allergic, non-smoking Danes

The population distributions of CO(2)-induced irritation sensitivity in the eyes (COI), tear film stability (break-up time, BUT), and epithelium damage (ED) and the relation of these to basic potential confounders were assessed in an age- and gender-stratified random sample of citizens in Aarhus County, Denmark. One hundred eighty-two non-allergic, non-smoking persons participated. A general health questionnaire and an indoor air questionnaire was filled out before the measurements. The BUT was non-normally distributed, as was COI at 16% CO(2) and single ED-scores. However, COI average for all levels was normally distributed and the total score for ED was only marginally deviating. BUT decreased, the threshold to CO(2) increased, and irritation intensity at CO(2) eye exposure decreased with increasing age. ED was increased among women. There were no internal relations between the three measures, but reduced BUT was seen among subjects rating high levels of exposure to dust, electrostatic fields, and dry air. ED decreased by perceived unpleasant odors and increased with experiences of high temperatures. CO(2) sensitivity increased by perceived draught, dry air, and noise exposure prior to measurements. Selection bias cannot be excluded and the results may therefore not be truly representative of the general population. However, the results may be used as reference data for future use of measurements of break-up time, epithelium defects, and CO(2) sensitivity of the eyes in the indoor air. PRACTICAL IMPLICATIONS: The most direct implication is that results can be used as reference level for measurements in problem buildings and for individual measurements. The reference can also be used in research and the other results as basis for future hypotheses and for support of existing hypotheses.     

Chromium carcinogenicity: California strategies

Hexavalent chromium was identified by California as a toxic air contaminant (TAC) in January 1986. The California Department of Health Services (CDHS) concurred with the findings of the International Agency for Research on Cancer that there is sufficient evidence to demonstrate the carcinogenicity of chromium in both animals and humans. CDHS did not find any compelling evidence demonstrating the existence of a threshold with respect to chromium carcinogenesis. Experimental data was judged inadequate to assess potential human reproductive risks from ambient exposures. Other health effects were not expected to occur at ambient levels. The theoretically increased lifetime carcinogenic risk from a continuous lifetime exposure to hexavalent chromium fell within the range 12-146 cancer cases per nanogram hexavalent chromium per cubic meter of air per million people exposed, depending on the potency estimate used. The primary sources found to contribute significantly to the risk of exposure were chrome platers, chromic acid anodizing facilities and cooling towers utilizing hexavalent chromium as a corrosion inhibitor. Evaluation of genotoxicity data, animal studies and epidemiological studies indicates that further consideration should be given to the potential carcinogenicity of hexavalent chromium via the oral route.     

Chromium in urine, serum and red blood cells in the biological monitoring of workers exposed to different chromium valency states

Using personal air sampling exposure to hexavalent and trivalent chromium was measured in 22 workers mainly exposed to Cr(VI) and in 15 workers mainly exposed to Cr(III) as basic chromium sulphate. Determination of Cr(VI) in the urine of all the subjects using a selective technique by ETA-AAS and liquid anion exchangers failed to show detectable amounts of the hexavalent form, the detection limit of the technique being 0.05 micrograms/L. A clear relationship between exposure and postshift urinary total chromium was found in subjects exposed to Cr(VI), while urinary levels in workers exposed to chromic sulphate high concentration proved lower. Determination of total chromium in serum and red blood cells showed a significant increase of chromium levels in erythrocytes of workers exposed to Cr(VI) while in subjects mainly exposed to Cr(III) an increase of the serum fraction was observed. The results demonstrate that Cr(III) is absorbed through the respiratory tract, but its kinetics and distribution in the body are not the same as for Cr(VI), and are not adequately monitored by short-term urinary determinations. Oxidation states of chromium largely influence uptake, mechanism of absorption, transport and organ distribution as well as toxicity of chromium-containing compounds. In particular, hexavalent derivatives are known to induce adverse effects, both acute and chronic, in occupationally exposed subjects, while there is little conclusive evidence for toxic effects caused by trivalent chromium compounds. Biological monitoring of exposure to chromium(VI) has usually been performed by determining total chromium levels in urine, whereas biological monitoring data in subjects occupationally exposed to Cr(III) are still scanty.(ABSTRACT TRUNCATED AT 250 WORDS)     

Urinary chromium levels in subjects living in two north Italy regions

The concentration of total urinary chromium (Cr-U) in two different groups of healthy occupationally non-exposed subjects living in the Italian regions of Lombardia and Veneto has been determined using an ETA-AAS direct method. The age, sex, residence and smoking habits were correlated with CrU excretion. The mean CrU value found in subjects living in Lombardia (n = 310, males 170 and females 140) was 0.59 + 0.26 microgram/l (range 0.08 - 2.10); in Veneto subjects (n = 238, males 187 and females 51) the mean value was 0.52 +/- 0.31 microgram/l (range 0.05 - 1.90). A significative difference between male and female values and a decrease of CrU levels with age increasing have been evidenced in both groups. Smoking habits seem to influence metal urinary levels while, on the other hand, no influence of living sites was observed. Some analytical problems of ETA-AAS Cr determination systems are discussed and "normal" CrU values measured in this study are compared with data reported in the literature.     

The Illinois Forest Preserve District Act of 1913 and the emergence of metropolitan park system planning in the USA

In 1913, the Illinois Legislature enacted the Forest Preserve District Act. After adoption of the Act by voters in Cook County, the Chicago metropolitan area became among the first in the USA to establish a park system with an outer ring of nature preserves. This article chronicles the story of how the Cook County Forest Preserve District was established, its historical context and its influence on planning practice. It contends that although Chicago was not the originator of the idea of outer parks, it added significantly to development of the concept of comprehensive park system planning. The article contends that the paradigm of park management changed from conservation of the native landscape to multiple use management during the 20‐year struggle to establish the district, and that passage of the Act was largely the result of the efforts of two individuals – Dwight Perkins and Jens Jensen.