Contaminación por monóxido de carbono: un problema de salud ambiental / Carbon monoxide contamination: an environmental health problem

El monóxido de carbono es considerado uno de los mayores contaminantes de la atmósfera terrestre. Sus principales fuentes productoras responsables de aproximadamente 80 por ciento de las emisiones, son los vehículos automotores que utilizan como combustible gasolina o diesel y los procesos industriales que utilizan compuestos del carbono. Esta sustancia es bien conocida por su toxicidad para el ser humano. Sus efectos tóxicos agudos incluida la muerte han sido estudiados ampliamente; sin embargo, sus potenciales efectos adversos a largo plazo son poco conocidos. En los últimos años, los estudios de investigación experimentales en animales y epidemiológicos en humanos han evidenciado relación entre población expuesta en forma crónica a niveles medios y bajos de monóxido de carbono en aire respirable y la aparición de efectos adversos en la salud humana especialmente en órganos de alto consumo de oxígeno como cerebro y corazón. Se han documentado efectos nocivos cardiovasculares y neuropsicológicos en presencia de concentraciones de monóxido de carbono en aire inferiores a 25 partes por millón y a niveles de carboxihemoglobina en sangre inferiores a 10 por ciento. Las alteraciones cardiovasculares que se han descrito son hipertensión arterial, aparición de arritmias y signos electrocardiográficos de isquemia. Déficit en memoria, atención, concentración y alteraciones del movimiento tipo parkinsonismo, son los cambios neuropsicológicos con mayor frecuencia asociados a exposición crónica a bajos niveles de monóxido de carbono y carboxihemoglobina.

Carbon monoxide is considered to be a major factor contaminating earths atmosphere. The main sources producing this contamination are cars using gasoline or diesel fuel and industrial processes using carbon compounds; these two are responsible for 80 percent of carbon monoxide being emitted to the atmosphere. This substance has a well-known toxic effect on human beings and its acute poisonous effects (including death) have been widely studied; however, its long-term chronic effects are still not known. During the last few years, experimental research on animals and studies of human epidemiology have established the relationship between chronic exposure to low and middle levels of carbon monoxide in breathable air and adverse effects on human health, especially on organs consuming large amounts of oxygen such as the heart and brain. Harmful cardiovascular and neuropsychological effects have been documented in carbon monoxide concentration in air of less than 25 ppm and in carboxyhaemoglobin levels in blood of less than 10 percent. The main cardiac damage described to date has been high blood pressure, cardiac arrhythm and electrocardiograph signs of ischemia. Lack of memory, attention, concentration and Parkinson-type altered movement are the neuropsychological changes most frequently associated with chronic exposure to low levels of carbon monoxide and carboxyhaemoglobin.

Role of bougainvilleas in mitigation of environmental pollution.

Environmental pollution adversely affects health of the people. Industrialization, urbanization, over exploitation of natural resources and increasing number of automobiles have aggravated the pollution manifold though there are various ways to mitigate the environmental pollution. Bio-remediation by using selected plant species is an effective method to control pollution which is universally accepted. Bougainvillea is a pollution tolerant plant and can help in the mitigation of air pollution besides its ornamental value in the landscaping. From the rich germplasm collection in NBRI Botanical Garden, tolerant plants have been experimented for road side plantation in view of mitigating the environmental pollution.

Low frequency noise and stress: bronchitis and cortisol in children exposed chronically to traffic noise and exhaust fumes.

A correlation of respiratory diseases to traffic related air pollution and noise was observed in an interview study. Since in that study the exposure was subjectively assessed, in the present field study nitrogen dioxide as indicator for vehicle exhausts and the mean night-time noise level were measured outside the children's windows in representative locations. Based on these measurements each child was placed in one of the following categories: low, medium or high traffic immission (ambient emissions). The physician contacts due to bronchitis of 68 children were assessed retrospectively from the files of the participating paediatricians. Saliva samples were collected from all children and the cortisol concentration was estimated. Children under high noise exposure (L(night, 8h) = 54-70dB(A)) had in comparison to all other children significantly increased morning saliva cortisol concentrations, indicating an activation of the hypothalamus-pituitary-adrenal (HPA) axis. Analysing a subgroup of children without high noise exposure showed, that children with frequent physician contacts due to bronchitis did not have increased morning saliva cortisol. However, multiple regression analysis with stepwise exclusion of variables showed that bronchitis was correlated more closely to morning salvia cortisol than to traffic immissions. On the other hand, the rate of physician contacts due to bronchitis increased in a dose dependent manner and significantly with increasing traffic immissions. From these results it can be concluded that high exposure to traffic noise, especially at nighttime, activates the HPA axis and this leads in the long term to an aggravation of bronchitis in children. This seems to be more important than the effect of exhaust fumes on bronchitis symptoms. The results of the present study should be subjected to further investigation using specially designed studies.

A study on the activities of a few free radicals scavenging enzymes present in five roadside plants.

The road side plants are continuously exposed to the high levels of oxides of nitrogen and sulphur dioxide, emitted from automobile. Resistance to automobile exhaust pollution was studied with Nerium indicum Mill, Boerhaavia diffusa L., Amaranthus spinosus L., Cephalandra indica Naud., and Tabernaemontana divaricata L., growing on the edges of Delhi Road, National Highway 2 (NH 2) near Dankuni, West Bengal. By analysing the activities of a few enzymes like superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and phenolic peroxidase, it appears that among the five plants examined,Amaranthus and Cephalandra are equipped with a very good scavenging system to combat effects of air pollution.

Blood lead levels of a population group not occupationally exposed to lead in Singapore.

A survey was conducted between 1995 and 1997 to assess the impact of introduction of unleaded petrol and other public health measures on the blood lead level of the population. The geometric mean blood lead level of 269 government employees as determined by graphite furnace atomic absorption spectroscopy, was 66.0 microg/l, much lower than that recorded before introduction of lead-free petrol. Using multiple regression analysis, factors significantly associated with blood lead levels were: exposure to traffic, age (>50 years) and active smoking. Passive smoking, exposure to recent paint work, consumption of alcohol and traditional medicine were found not to be significantly associated with the blood lead level.

Respiratory symptoms and pulmonary function of traffic policemen in Thonburi.

A cross-sectional study was conducted to assess whether traffic policemen working in Thonburi district of Bangkok had poorer respiratory health than the normal Thai population. The benefits of wearing masks as a preventative measure against the respiratory hazards of air pollution were assessed. Traffic policemen (n = 629) who had worked in Thonburi and male subjects (n = 303, the control group) were evaluated for respiratory symptoms using the British Medical Research Council questionnaire. Their pulmonary function was measured by spirometry. Only non-smokers were included in the final analysis and it was found that traffic policemen (n = 242) suffered significantly more cough or phlegm (18.6% vs 7.8%, P = 0.005) and more rhinitis symptoms (17.8% vs 7.8%, P = 0.009) than the control subjects (n = 129). The traffic policemen also had a significantly higher prevalence of abnormal air flow (FEV1 < 80% predicted) than the control group (21.1% vs 12.4%, P = 0.04). The mean values of FEV1 and FVC of the traffic policemen were significantly lower than the control group (3.29 +/- 0.5 L vs 3.43 +/- 0.5 L, P = 0.01 for FEV1 and 3.86 +/- 0.5 L vs 3.98 +/- 0.6 L, P = 0.047 for FVC). Traffic policemen who did not use protective masks had not only a significantly higher prevalence of abnormal FEV1 but also a significantly higher prevalence of abnormal FVC than the control group (35% vs 14%, P = 0.046). They also had higher relative risks of abnormal FEV1 (2.76 vs 1.63) and FVC (2.51 vs 1.23) than those who used protective masks. Multivariate analyses with controlling for age, height, and pack-years of cigarette smoking, revealed that the traffic policemen were significantly and independently associated with lower FEV1 and FVC. In conclusion, the traffic policemen who work in Thonburi have more cough and rhinitis symptoms and lower FEV1 and FVC than the normal Thai population. Traffic policemen who do not use protective masks have higher relative risks of abnormal FEV1 and FVC than those who use them.

Niveles de contaminación por ruido en una de las principales avenidas de la ciudad de México / Noise pollution levels in a large street in Mexico city

Se reportan los resultados de la medición de los niveles de contaminación por ruido, encontrados en seis horarios a lo largo de las 24 hr del día, en una de las principales avenidad de la ciudad de México en el año de 1993. Las mediciones se efectuaron mediante un sonómetro a las: 4.00, 8.00, 11.00, 15.00, 19.00 y 23.00 hr. El nivel de ruido en el percentil 10 (NR10) en los horarios estudiados fué de 80.3, 104.8, 100.9, 103.8, 95.6 y 95.2 dB "A" a las 4.00, 8.00, 11.00, 15.00, 19.00 y 23.00 hrs. respectivamente. El nivel de ruido en el percentil 50 (NR50) en los horarios estudiados fué de 67.7, 90.5, 87.5, 90.5, 86.5, y 77.2 dB "A" respectivamente. El nivel de ruido en el percentil 90 (NR90) fué de 60.2, 85.6, 82.1, 86.8, 84.7 y 73.9 dB "A". La correlación entre el ruido y la cantidad de automóviles circulantes fué de r=0.86. estos datos muestran que los niveles de ruido en calles de denso tráfico en la ciudad de México, se mantienen por arriba de la norma considerad como saludable (70 dB), a lo largo del día asociados al tráfico automotor

Relatório de impacto no meio ambiente: o uso do metanol como combustível / Report of impact on the environment: the use of methanol as fuel

Este relatório nasceu de uma monografia destinada a fornecer subsídios à sociedade brasileira em geral a respeito das vantagens e cuidados do uso do metanol como combustível, em caráter emergencial e por tempo limitado. Seu preparo começou em meados de dezembro de 1989, quando, em carta datada de 4 de janeiro de 1990 fomos solicitados pelo Ministério das Minas e Energia a ampliá-lo e transformá-lo em estudo de impacto ambiental para atender à resoluçäo número 15/89, fruto da reuniäo de 07/12/89 do Conselho Nacional do Meio Ambiente. Neste estudo, preparado em uma semana dada à urgência da solicitaçäo, procura-se fazer uma análise global dos efeitos, positivos e negativos, resultantes da introduçäo de metanol no mercado de combustíveis do país.

Estudo de impacto no meio ambiente: o uso do metanol como combustível / Study of impact on the environmente: the use of methanol as fuel

Este documento nasceu de uma monografia destinada a fornecer subsídios à sociedade brasileira em geral a respeito das vantagens e cuidadedos do uso do metanol como combustível, em caráter emergencial e por tempo limitado. Procura-se fazer uma análise global dos efeitos, positivos e negativos, resultantes da introduçäo de metanol no mercado de combustíveis do país.

Urinary excretion of lead, zinc, copper and cadmium among auto-workers

Garages and auto-repair shops may be polluted with lead and other heavy metals. Twenty four hour urine samples of 77 auto workers from Mansoura City and 9 control subjects of comparable age were analyzed for lead, zinc, and copper. The urinary excretion of lead was significantly increased in welders and electricians. There was a high significant increase in urinary zinc excretion in welders, electricians and car painters; while the urinary copper excretion showed a significant increase in, only, the electricians. The cadmium content of urine of auto-workers was comparable with controls. It has been concluded that the assessment of urinary lead, when substantiated by careful medical surveillance of auto-workers may be a good means for control of lead intoxication in this industry