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PubMed1983

Rational establishment of air quality standards.

This paper attempts to apply two principles of rationality--efficiency and equity--to the establishment of air quality standards for total suspended particulates in the USA. It is argued that standard setting should embrace either the use of some cost-benefit-risk criterion, or some concept of equity whereby risks are not reduced below levels judged to be acceptable elsewhere. There is often a trade-off to be made between these principles of efficiency and equity and that both cannot be pursued in tandem. In other words, the cost of fairness is more deaths in total than there need be at a particular level of expenditure. The concept of the "margin of safety" is also discussed, and we conclude that, as currently defined, it is of doubtful relevance in either the context of efficiency or of equity. Finally, and using evidence from other studies, we conclude that there are much more cost-effective ways of using scarce resources to save lives (e.g., in health care and in road safety) than pursuing the primary standards for TSP laid down by the United States Environmental Protection Agency in light of the U.S. Clean Air Act Amendments of 1970 and 1977.

Air Pollution↗
PubMed1995

Developmental effects of dioxins.

The potent developmental toxicity of dioxin in multiple species has been known for a number of years. However, recent studies have indicated that dioxin also induces functional developmental defects, many of which are delayed. Subtle structural deficits, not detectable at birth, have also been described in multiple species and in both sexes. Certain defects have been reported not only in animals but also in children prenatally exposed to complex mixtures containing dioxinlike compounds. None of the effects can be attributed to modulation of any one endocrine system. For example, dioxin does not bind to the estrogen receptor, but it can cause effects that are both estrogenic and antiestrogenic. However, viewing dioxin and related compounds as endocrine disruptors that may alter multiple pathways sheds some light on the complexities of this potent class of growth dysregulators.

Animals↗
PubMed1991

Garbage wars '91. Report from the front.

In this first of a three-part series examining the status of waste management strategies available to non-commercial foodservice operators, Food Management looks at the use and recycling of polystyrene in light of the McDonald's Corp.'s decision to replace polystyrene with paper and paper-based packaging.

Environmental Pollutants↗
PubMed2001

The use of acute and chronic bioassays to determine the ecological risk and bioremediation efficiency of oil-polluted soils.

To compare the effectiveness of acute and chronic bioassays for the ecological risk assessment of polluted soils, soil samples from a site with an historical mineral oil contamination (< 50-3,300 mg oil/kg dry soil) at the Petroleum Harbour in Amsterdam, The Netherlands, were screened for ecological effects using acute and chronic bioassays. A two-step 0.001 M Ca(NO3)2 extraction at a final solution-to-soil ratio of 1:1 was used to prepare extracts for the acute bioassays. Acute bioassays (< or = 5 d) applied to the 0.001 M Ca(NO3)2 extracts from the polluted and reference soils included growth tests with bacteria (Bacillus sp.), algae (Raphidocelis subcapitata), and plants (Lactuca sativa), immobility tests with nematodes (Plectus acuminatus), springtails (Folsomia candida), and cladocerans (Daphnia magna), and the Microtox test (Vibrio fischeri). Chronic bioassays (four weeks) performed on the same soil samples included tests with L. sativa, F. candida, and earthworms (Eisenia fetida) and the bait-lamina test (substrate consumption). The acute bioassays on Microtox showed a response that corresponded with the level of oil pollution. All other acute bioassays did not show such a consistent response, probably because pollutant levels were too low to cause acute effects. All chronic bioassays showed sublethal responses according to the contaminant levels (oil and in some soils also metals). This shows that chronic bioassays on soil samples are more sensitive in assessing the toxicity of mineral oil contamination in soil than acute bioassays on soil extracts. A pilot scale bioremediation study on soils taken from the two most polluted sites and a control site showed a rapid decline of oil concentrations to reach a stable level within eight weeks. Acute bioassays applied to the soils, using Microtox, algae, and D. magna, and chronic bioassays, using plants, Collembola, earthworms, and bait-lamina consumption, in all cases showed a rapid reduction of toxicity, which could be attributed to the degradation of light oil fractions.

Animals↗
PubMed2003

Oxidation processes and clogging in intermittent unsaturated infiltration.

Intermittent infiltration of wastewater through a non saturated sand bed is an extensive treatment process aimed at eliminating organic pollution, oxidizing ammonia and removing pathogens. A 1D numerical model, IPOX, has been worked out to simulate the transfer and oxidation of dissolved organic matter and nitrogen in unsaturated sand beds. IPOX was calibrated after real scale tests performed in Spain and Burkina Faso. Simulations allowed us to point out the influence of (i) kinetics on oxidation performances and (ii) biomass development on the process sustainability. These results brought a new light on the sizing and operation of infiltration percolation and soil aquifer treatment (SAT) plants.

Ammonia↗
PubMed1980

The closed co-axial analgesia system.

A twin-tube system for nitrous oxide analgesia in dental surgeries is described. The system is a non-polluting modification of the Mapleson A system, employing the principle of co-axial tubing introduced by Bain & Spoerel (1972). Active, continuous and calibrated gas removal takes place via the co-axial tubing by means of an ejector flowmeter. Investigation of the dynamic pressure excursions occurring at the nose-piece are fully compatible with normal breathing. Gas contamination of the dental environment can be reduced by at least 90%. The system described is safe and easy to handle. It is made of light-weight material and is adaptable to the equipment available. No rebreathing takes place when using a fresh gas inflow of 150 ml/kg body weight/min.

Air Pollution↗
PubMed2003

Algal growth inhibition test: does shading of coloured substances really matter?

Coloured substances are often assumed to behave differently in the algal growth inhibition test due to shading of the algae. We have investigated EU-notifications of new substances and found no significant differences in algal test results between colours and non-colours. A modified method to differentiate between shading and toxicity is not satisfactory, because the method used to determine the shading effect is incorrect. Due to the shaking of the test flasks in the algal test intermittent light conditions are achieved which lead to a higher growth rate than expected from proposed tests with constant reduced light conditions. This will result in overestimation of the shading effect and thus to underestimation of chemical toxicity. Furthermore, we showed in experiments with the reference substance potassium dichromate that reduced light can reduce the measurable toxicity of chemicals. Comparing our results with approaches proposed in the literature, a simple approach to reduce effects of undesired shading when testing coloured substances is to achieve light saturation for the algae by increasing illumination at least to the upper limit given in test guidelines (120 microEs(-1)m(-2)) and, optionally, to reduce the light path by choosing smaller test volumes.

Coloring Agents↗
PubMed2002

Multipoint moss passive samplers assessment of urban airborne polycyclic aromatic hydrocarbons: concentrations profile and distribution along Warsaw main streets.

Polycyclic aromatic hydrocarbons (PAHs) distribution along 28 km of Warsaw main street have been surveyed in July 2000 using moss passive samplers as a simple and economic surrogate of direct air sampling. Altogether 74 samplers at 39 crossroads with traffic lights were placed on the lamp post approximately/=3.5 m above ground. PAHs levels determined in samplers are in range from 828 to 3573 ng/g moss dry weight. The spatial spread of pollution within this range is statistically close to normal distribution with mean value of 2332 ng/g. Variability within and between study areas are rationalized in terms of urban environmental factors. PAHs concentrations profiles across the town have appeared uniform. The dominant compounds are phenantrene, fluoranthene and pyrene. Their contribution is 49-68% of total PAHs burden.

Air Pollutants↗
PubMed2005

Photochemical mineralization of dissolved organic nitrogen to ammonium in the Baltic sea.

Solar-radiation-induced photochemistry can be considered as a new source of nutrients when photochemical reactions release bioavailable nitrogen from biologically nonreactive dissolved organic nitrogen (DON). Pretreatments of Baltic Sea waters in the dark indicated that >72% of DON was recalcitrant to biological mineralization. When this DON (16-21.5 microM) was exposed to simulated solar radiation, the concentration of NH4+ increased 0.5-2.5 microM more in irradiated waters than in the dark controls. The photochemical production of NH4+ and the dose of absorbed photons were used to calculate the apparent quantum yield spectrum for photoammonification [mol NH4+ (mol photons)(-1) nm(-1)] at wavelengths (lambda) of 290-700 nm (phiNH4,lambda). The modeled mean rates of photoammonification based on phiNH4,lambda were 143 and 53 micromol NH4+ m(-2) d(-1) at the surface and in the whole water column, respectively, of Baltic Sea stations during summer. The results of this study indicate thatthe rate of photoammonification approximately equals and periodically exceeds the rate of atmospheric deposition of reactive inorganic nitrogen to the northern Baltic Sea. Forthese stratified surface waters beyond riverine input of labile nitrogen, photoammonification can periodically be the largest source of new bioavailable nitrogen.

Atlantic Ocean↗
PubMedDate not supplied

Novel photoreactors for heterogeneous photocatalytic wastewater treatment.

Heterogeneous photocatalysis is an effective treatment method for removal of toxic pollutants from industrial wastewaters. A novel, thin film slurry photoreactor was evaluated in this work for its effectiveness in removing phenol. The efficiency of parameters, initial phenol and catalyst concentrations and the light intensity on phenol removal was studied. The reactor performed well giving near complete removal of phenol even at a higher concentration of 500 mg/l.

Disinfectants↗
PubMed2006

[The impact of some bad habits and environmental factors on the somatic status of male adolescents].

AIM: The aim of the study was to investigate whether some bad habits of sedentary lifestyle influence the occurrence of diagnoses in male adolescents, divided according to their environment into urban, rural and and island groups. PATIENTS AND METHODS: A total of 437 male adolescents underwent physical examination and functional diagnostic tests at Occupational Medicine Clinic in Rijeka, in order to evaluate their fitness for military service. The method of physical examination and anthropologic measurements was used. The results were analyzed by the Stat Soft, Statistics 6.0 software. Pearson chi-squared-test test and correlation matrices were used. RESULTS: The results showed obesity to be present in a relatively high percentage of subjects from urban area (10.94%) and rural area (13.19%), whereas asthenia was more pronounced in islanders (8.69%), yielding a statistically significant between-group difference (p<0.05). In contrast to asthenia, the islanders had the lowest percentage of flatfoot, with a significant difference from the two other groups (p<0.05). Refraction errors, primarily myopia, were not influenced by the place of residence. The incidence of myopia in all three groups was slightly over 20%. Contrary to our expectation, bronchial asthma was most common in the islanders (5.43%), however, there data could not be considered representative because of the rather big rate of migration from the inland to prevent relapses of respiratory diseases. The incidence of mild kyphoscoliosis ranged from 5.55% in the subjectss from rural settings up to 11.95% in the islanders, without a statistically significant between-group difference. DISCUSSION: It is difficult to identify the causes of differences in body weight among adolescents from urban, rural and island settings. It is not so easy to criticize the former for predominantly sedentary life, watching TV, video or Internet. Physical activity cannot be readily performed in towns because of the increasing presence of pollutants in the atmosphere. The prevalence of bronchial asthma was slightly higher than expected, which was explained by the permanent residence of atopics on the islands in order to prevent disease relapses. The lowest incidence of flatfoot among islanders was explained by their free lifestyle, barefoot walking along the rocky seaside, and high level of physical activity. Refraction errors including myopia as the leading diagnosis were equally present in the three groups, exceeding 20%. Besides heredity, the sight is influenced by intensified effects of ultraviolet radiation that causes changes of the eye structure. Also, neon signs and lights as well as too strong night streetlights lead to phototoxic vision damage in adolescents. Study results showed that male adolescents who lead physically inactive life should not to be blamed for the occurrence of the mentioned diagnoses. Like all of us they are daily affected by harmful pollutants that cause damage to the eyes, cardiovascular, respiratory and other organ systems. This study has helped identify the causes of the mentioned diseases in the group of male adolescents, emphasizing the role of occupational medicine. Specialists in occupational medicine should be involved in the monitoring of somatic and other parameters in adolescents from the early school age. In this period, it is still possible to reduce or and even prevent the occurrence of the mentioned diagnoses by examinations, education, exercises and diets. In this way, the candidates for military service would be healthier and fit.

Adolescent↗
PubMed1998

Mercury levels along the food chain and risk for exposed populations.

Mercury was not regarded as a pollutant of primary importance until many deaths due to mercury poisoning occurred in the 1950s. More recently, adverse health effects have been documented at relatively low exposure levels, and monitoring data must now be interpreted in this light. The Mediterranean basin has been studied in great detail over the past 20 years because of the anomalous natural presence of mercury. Marine animals of this basin have higher mercury body burdens than the same (or similar) species in the Atlantic. The mercury found in marine organisms is mainly in the form of methyl mercury. Long-term and frequent intake of seafood with high mercury levels by populations living in coastal fishing villages is associated with a toxic risk, especially in pregnant women. High blood and hair concentrations of mercury have repeatedly been found in fishermen of Tyrrhenian coastal villages. In some cases these concentrations have been associated with an increase in DNA damage in blood cells. High mercury levels in hair and blood of people from a fishing village of Madeira have also been found. This information deserves renewed scrutiny with regard to preventive efforts needed.

Animals↗
PubMed1982

Hospital hydrotherapy pools treated with ultra violet light: bad bacteriological quality and presence of thermophilic Naegleria.

The microbiological quality of eight halogenated and two u.v.-treated hydrotherapy pools in hospitals was investigated. The microbiological quality of halogenated hydrotherapy pools was comparable to halogenated public swimming pools, although in some Pseudomonas aeruginosa and faecal pollution indicators were more frequent due to bad management. On the other hand u.v.-treated hydrotherapy pools had very bad microbiological quality. Apart from faecal pollution indicators, P. aeruginosa was present in very high numbers. Halogenated hydrotherapy pools were not highly contaminated with amoebae, and Naegleria spp. were never detected. On the other hand u.v.-treated pools contained very high numbers of thermophilic Naegleria. The Naegleria isolated were identified as N. lovaniensis, a species commonly found in association with N. fowleri. Isoenzyme analysis showed a different type of N. lovaniensis was present in each of two u.v.-treated pools.

Amoeba↗
PubMed1986

Determination of "heavy" organotin pollution of water and shellfish by a modified hydride atomic absorption procedure.

Tin speciation in aquatic environment is very complex. To the natural SnIV and methylated compounds, human activities add mainly butylated, octylated, phenylated or even methylated derivatives. The most environmentally significant, due to their high toxicity and direct introduction in water through biocidal use, are the trisubstituted ones. Several sophisticated speciation procedures have been proposed, they are not susceptible of common use. We propose a simple and fast procedure allowing routine global distinction of "heavy" tin species that are most susceptible of exerting harmful effects. This AA method use the differences in volatility of stannanes generated by reduction with NaBH4. SnIV and the methylated species have very close response coefficients whereas "heavy" compounds respond very slightly at room temperature and are eliminated in a -40 degrees C cold trap. "Heavy" tin determination in water is thus obtained by the difference between two hydride AA experiments, one performed on the untreated sample ("light tin") and the other on a UV mineralised subsample (total tin). (The mineralisation of organotins is realised by UV irradiation-2 hours--in a quartz container--yields 95-100%.) The analysis of shellfish tissue relies also on two experiments. Total tin is measured on a mineralised sample and "light tin" is obtained on a subsample "solubilised" with an Ultra Turrax homogeneizer in a diluted HCl solution.

Animals↗
PubMed1975

A study of the N2O5-SO2-O3 reaction system.

Infrared spectroscopy was used to follow the rates of the chemical changes in gaseous N(2)O(5)-SO(2) and N(2)O(5)-SO(2)-O(3) mixtures. Several results of interest to atmospheric scientists were obtained. (I) SO(3) was not a detectable product of these reaction systems, and no significant SO(2) removal occurred. From the kinetic treatment of these results, estimates were derived for the upper limits of the rate constants of the reactions 1 and 2: NO(3) + SO(2) leads to NO(2) + SO(3) (1); N2O5 +SO2 leads to N(2)O(4) + SO(3) (2); k(1) less than or equal to 4.2 1. mole-minus 1sec-minus 1; k(2) less than or equal to 2.5 x 10-minus 2 1. mole-minus1sec-minus 1 at 30 degrees C. These data suggest that reactions 1 and 2 are not important removal paths for SO(2) in the sunlight irradiated, NO(x)hydrocarbon polluted atmospheres. (II) The near ultraviolet absorption spectrum of pure N(2)O(5) has been determined. From these results and estimates of the actinic irradiance, it was shown that the rate of photochemical decomposition of N(2)O(5) by the absorption of solar light in the urban atmosphere is an unimportant factor among the reactions which establish the N(2)O(5) and NO(3) concentrations. (III) It has been observed that gaseous SO(3) and NO(2) react rapidly to form a relatively nonvolatile white solid. Preliminary data suggest a 1:1 mole ratio for this adduct. The significance, if any, of this and related compounds in urban aerosol formation must be evaluated.

Air Pollution↗
PubMed2003

On the local and regional influence on ground-level ozone concentrations in Hong Kong.

Hong Kong is a densely populated city situated in the fast developing Pearl River Delta of southern China. In this study, the recent data on ozone (O3) and related air pollutants obtained at three sites in Hong Kong are analyzed to show the variations of O3 in urban, sub-urban and rural areas and the possible regional influences. Highest monthly averaged O3 was found at a northeastern rural site and lowest O3 level was observed at an urban site. The levels of NOx, CO, SO2 and PM10 showed a different spatial pattern with the highest level in the urban site and lowest at the rural site. Analysis of chemical species ratios such as SO2/NOx and CO/NOx indicated that the sites were under the influences of local and regional emissions to varying extents reflecting the characteristics of emission sources surround the respective sites. Seasonal pattern of O3 is examined. Low O3 level was found in summer and elevated levels occurred in autumn and spring. The latter appears different from the previous result obtained in 1996 indicating a single maximum occurring in autumn. Principal component analysis was used to further elucidate the relationships of air pollutants at each site. As expected, the O3 variation in the northeastern rural area was largely determined by regional chemical and transport processes, while the O3 variability at the southwestern suburban and urban sites were more influenced by local emissions. Despite the large difference in O3 levels across the sites, total potential ozone (O3+NO2) showed little variability. Cases of high O3 episodes were presented and elevated O3 levels were formed under the influence of tropical cyclone bringing in conditions of intense sunlight, high temperature and light winds. Elevated O3 levels were also found to correlate with enhanced ratio of SO2 to NOx, suggesting influence of regional emissions from the adjacent Pearl River Delta region.

Air Pollutants↗
PubMed1994

Molecular dosimetry of DNA damage induced by polycyclic aromatic hydrocarbons; relevance for exposure monitoring and risk assessment.

Polycyclic aromatic hydrocarbons (PAH) form a large group of organic chemicals that are widely distributed in our environment as pollutants of air, water and soil. Several PAH are carcinogenic in rodents, while exposure to these compounds has been associated with various types of human cancer. Upon entering the body, PAH may be converted into reactive electrophilic species, which can give rise to the formation of DNA adducts. DNA adduct formation is considered to be the initial event in chemical carcinogenesis. In this paper, two methods are illustrated that are widely used to determine PAH-DNA adduct formation, namely 32P-postlabelling, and immunochemical analysis with specific antibodies. The applications of the 32P-postlabelling assay comprise the following: A study of interspecies differences in PAH bioactivation in vitro, with microsomal preparations isolated from liver tissue of various rodent species and of human origin; the results indicate that there are considerable qualitative differences between the adduct patterns obtained, which is relevant with respect to extrapolation from animal to man. The analysis of DNA adduct formation in fish retrieved from marine environments polluted to various extents with PAH; results of these studies show a correlation between liver-DNA adduct levels in these fish and the degree of PAH contamination in the aquatic environment. Biomonitoring of PAH exposure through analysis of adducts in blood cells obtained from heavy and light smokers; the data show a fair correlation between PAH-DNA adduct levels in white blood cells and cotinine content in blood plasma, the latter being used as a marker for exposure to cigarette smoke.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2001

Potential application of immobilized and perfused hepatocytes in environmental toxicology studies.

Conventional cellular models have contributed significantly to the understanding of many aspects of cell physiology and molecular biology. In these models cells are metabolically less active, due to the inefficient oxygenation and waste product buildup. Therefore perfusion methods for the cells are expected to improve cell activities. Cells have to be fixed in or on an appropriate inert carrier or support, which enables cellular perfusion, maintains integrated cellular functions and makes a bioreactor. Since isolated hepatocytes are extensively used in biomedical studies including those dealing with environmental pollutants or toxins and in xenobiotic biotransformation investigations, an efficient hepatocyte perfusion model has to be available for researchers. This research article is focusing on the value of hepatocyte immobilization as a laboratory bioreactor model and is shedding light on its potentiality in research related to public health. We demonstrate the application of this cellular model as a means to study representative phase I and phase II biotransformation reactions using hexobarbital hydroxylation and 7-ethoxycoumarin deethylation and 4-chloro 2-dinitrobenzene glutathione. Both phase I and phase II drug biotransformation in hepatocytes was demonstrated in this study non-destructively to the cells and in an efficient way. In spite of the aforementioned advantages, immobilized hepatocytes yet have relatively limited applications compared to conventional hepatocyte cellular systems. Reasons for this discrepancy are discussed. This cellular system may become popular due to the better performance of immobilized hepatocytes as compared to conventional hepatocyte culture and due to economic and ethical reasons. Naturally its applicability will cover several biomedical areas including basic research in environmental toxicology and other public health issues.

Animals↗