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PubMedDate not supplied

[The short-term effects of air pollution on mortality. The results of the EMECAM project in the city of Barcelona, 1991-1995. Estudio Multicéntrico Español sobre la Relación entre la Contaminación Atmosférica y la Mortalidad].

BACKGROUND: Most of the studies which demonstrate the existence of a short-term relationship between air pollution and morbidity and the Mortality analyze the impact of "classic" pollutants which are by-products of combustion. However, the changes in the sources of these emissions, shifting basically toward road traffic, has made a change in air pollution, heightening the importance of the photochemical components, such as ozone (O3) and nitrogen dioxide (NO2). Barcelona is a city located in a mild climate zone, and its air pollution comes mainly from vehicle emissions. The main objective of this article is that of analyzing the relationship between the photochemical pollutants, NO2 and O3 and the death rate for different causes in the city of Barcelona throughout the 1991-1995 period, using the procedure for analysis set out as part of the EMECAM Project. METHODS: Daily changes in the number of deaths resulting from all causes, of the number of deaths for all causes of those over age 70, of the number of deaths resulting from cardiovascular diseases, and of the number of deaths resulting from respiratory-related causes are related to the daily changes in the photochemical pollutants using autoregressive Poisson models, controlling confusion-causing variables such as the temperature, the relative humidity, the systematic time structure and the autoregressive structure. RESULTS: Except for the relationship between O3 and the mortality for causes involving respiratory diseases, the relationships between photochemical pollutants and the mortality for all the causes considered were statistically significant. The risks related to dying as a result of rises in O3 were greater than as a result of rises in NO2, almost triple among cardiovascular diseases. The risks related to dying for all the causes are lower than for specific causes and than for those individuals over age 70. The results of the analysis by six-month periods are quite similar to the overall results, revealing, in any event, relative risks somewhat greater during the warm months (May to October). CONCLUSIONS: Photochemical pollution, especially that which is caused by O3, comprises a health risk. In the case of NO2, this might not be more than an indicators of the suspended particles or of other pollutants stemming from city traffic. There may be a certain adjustment between six-month periods of the impact of O3 on the mortality for causes of the circulatory system.

Age Factors↗
PubMed2000

Air pollution and respiratory health in Africa: a review.

OBJECTIVE: To bring into focus the existence of respiratory hazards due to air pollution as a result of industrialization, tobacco smoking (personal pollution), domestic pollution and vehicular fuel combustion on the African continent; and to stimulate health workers, and the various governments in Africa, to devote more attention to the subject of air pollution by engaging in and encouraging multidisciplinary research so that appropriate and effective control measures can be put in place. DATA SOURCES: Medline literature search through internet using the keywords: air pollution, cigarette smoking, domestic pollution, respiratory morbidity, Africa. The author's contributions to the subject of air pollution and respiratory morbidity are included. STUDY SELECTION: Relevant studies or articles from eastern, western, northern, southern and central parts of Africa are included in the review. DATA EXTRACTION: From individual study or article. DATA SYNTHESIS: Evidence of respiratory hazards sequel to the four main sources of air pollution in each part of Africa, are synchronised under the headings: introduction, respiratory impairment and the future. CONCLUSIONS: Respiratory impairment from the four main sources of air pollution is a major but highly neglected problem on the African continent. There is need for concerted efforts on the part of African governments, health administrators and health workers to ensure that necessary attention is given to multidisciplinary research on the subject so that meaningful control measures can be formulated, thereby ensuring clean air for the people to breathe.

Africa↗
PubMed2001

A novel toxicity fingerprinting method for pollutant identification with lux-marked biosensors.

A novel technique is described for the identification and quantification of environmental pollutants based on toxicity fingerprinting with a metabolic lux-marked bacterial biosensor. This method involved characterizing the toxicity-based responses of the biosensor to seven calibration pollutants as acute temporal-dose response fingerprints. An algorithm is described to allow comparisons of responses of an unknown pollutant to be made against the calibration data. This is based on predicting pollutant concentration at each of six different time points over the course of a 5-min assay. If the prediction is consistent between the unknown pollutant and a calibration pollutant at the 95% test level, this is considered to be a positive identification. All seven calibration pollutants could be successfully distinguished from each other with this technique. Environmental samples, individually spiked with single concentrations of pollutants, were compared in this way against the calibration pollutants. An 83% identification success was achieved, with no false positives at the 95% test level. This is a simple and rapid technique that potentially can be applied to monitoring of industrial wastewater or as a screening tool for regulators.

Algorithms↗
PubMedDate not supplied

Outdoor air pollution and emergency room visits at a hospital in Delhi.

Several reports from large metropolitan cities have indicated significant association between acute morbidity and mortality from cardio-respiratory disorders and daily levels of major pollutants in the ambient air. Despite the wide-spread public concern about the adverse health effects of air pollution, there is substantial uncertainty regarding the effects of these pollutants at a concentration typical of Delhi, which is one of the ten most polluted cities in the world and the most polluted city in India. This study was undertaken to correlate the daily levels of various pollutants with the number of patients visiting the All India Institute of Medical Sciences (AIIMS, New Delhi) casualty for aggravation of certain defined cardiorespiratory disorders. Daily counts of patients visiting the emergency room of the AIIMS for acute asthma, acute exacerbation of chronic obstructive airway disease (COAD) and acute coronary event was obtained in prospective manner from January 1997 to December 1998. Daily mean levels of ambient CO, NOx and SO2 were monitored along with temperature and humidity. Data was analysed using one day time lag for events of interest. Time series analysis was undertaken using Poisson regression and population averaged general estimation equation, correcting for auto-correlation, days of the weak and season. The ambient levels of pollutants exceeded the national air quality standards on most of the days, over the two year period. Further, emergency room visits for asthma, COAD and acute coronary events increased by 21.30%, 24.90% and 24.30% respectively on account of higher than acceptable levels of pollutants. It is concluded that there is considerable burden of cardiorespiratory diseases in Delhi due to high levels of ambient air pollution.

Acute Disease↗
PubMed2004

[Influence of dissolved organic matter (DOM) on environmental behaviors of organic pollutants in soils].

Dissolved organic matter (DOM) is an important component of solutions in terrestrial and aquatic ecosystems through its influence on acidity, nutrient availability, and toxicity. DOM could enhance the apparent solubility of organic pollutants and alter adsorption-desorption equilibrium of organic pollutants on soil. The enhancement of organic pollutants desorption in the presence of DOM could facilitate the mobility of organic pollutants in soil. On the other hand, the sorption of DOM by solid sorbents in soil could also enhance the retention of DOM-associated organic pollutants in soil. Furthermore, as a photosensitizer, DOM could promote the photogradation of organic pollutants in soil. And under certain condition, DOM also affected the hydrolysis of organic pollutants in soil solution. The effects of DOM on environmental behaviors of organic pollutants in soils were related to the physico-chemical characteristics of organic pollutants, DOM, and soil.

Adsorption↗
PubMed2004

[Lead absorption by weeds from lead-polluted soil].

A pot experiment with red soil was installed in 2002 and 2003 to study the impact of lead pollution on weed growth, its lead and nutrients uptake, and AMF colonization. The results showed that lead pollution had no significant influence on weed growth, and the absorbed lead was mainly accumulated in root system. The impact of lead pollution on nutrients uptake by weeds was depended on weed species, their growth stages, and kinds of nutrients. No significant difference was found between lead treatment and control in nutrient contents except potassium in Digitaria adscendens at its early growth stages, and lead had little influence on the absorption of nutrients by Kummerowia striata, Ixeris chinensis, Digitaria adscendens and Echinochloa crusgalli var. mitis. The phosphorus content in Ixeris chinensis and Digitaria adscendens at their ripen stage sampled from lead-polluted soil was significantly higher than that from control, while the nitrogen content in matured Echinochloa crusgalli var. mitis sampled from polluted soil was significantly lower than that from the control. There existed great difference of mycorrhizal colonization among various weed species. The infection rate of Kummerowia striata and Digitaria adscendens showed a slight difference between lead treatment and control both at vegetative and ripen stage. Lead pollution hindered the colonization of Ixeris chinensis. In lead-polluted soil, the AMF infection rate of Ixeris chinensis was 45.52% at vegetative stage and 74.64% at ripen stage, while in the control, it was 69.44% at vegetative stage and 82.21% at ripen stage. Echinochloa crusgalli var. mitis, an annual weed, showed an opposite response of AMF colonization to lead pollution. The colonization rate of AMF in Echinochloa crusgalii var. mitis root was higher under lead pollution condition, being 82.45% at vegetative stage and 91.36% at ripen stage, while in the control, it was 59.19% and 78.28%, respectively.

Absorption↗
PubMed2004

Indoor air pollution and airway disease.

Scientific interest in indoor pollution has been increasing since the second half of the 1980s. Growing scientific evidence has shown that because people generally spend the majority of their time indoors, indoor pollution plays a significant role in affecting health and is thus an important health issue. Indoor environments include dwellings, workplaces, schools and day care centres, bars, discotheques and vehicles. Common indoor pollutants are environmental tobacco smoke, particulate matter, nitrogen dioxide, carbon monoxide, volatile organic compounds and biological allergens. In developing countries, relevant sources of indoor pollution include biomass and coal burning for cooking and heating. Concentrations of these pollutants can be many times higher indoors than outdoors. Indoor air pollution may increase the risk of irritation phenomena, allergic sensitisation, acute and chronic respiratory disorders and lung function impairment. Recent conservative estimates have shown that 1.5-2 million deaths per year worldwide could be attributed to indoor air pollution. Approximately 1 million of these deaths occur in children aged under 5 years due to acute respiratory infections, and significant proportions of deaths occur due to chronic obstructive pulmonary disease and lung cancer in women. Today, indoor air pollution ranks tenth among preventable risk factors contributing to the global burden of disease. Further research is necessary to better evaluate the respiratory health effects of indoor pollution and to implement protective programmes for public health.

Air Pollution, Indoor↗
PubMed2005

[Environmental quality of soil polluted by mercury and lead in polymetallic deposit areas of western Hunan Province].

The environmental quality of soil polluted by mercury and lead in typical polymetallic deposit areas of western Hunan province and its natural and human causes were studied. It was found that western Hunan province is a high regional geochemical abnormal region on mercury and lead. The concentrations of mercury and lead in soils in mercury deposit areas were 1 315 and 3.1 times higher than that of the average background of soils in China respectively, while those in soils in lead-zinc deposit areas were 14.8 and 16.1 times higher. Using geoaccumulation index developed by Muller, it was found that either mercury deposit area or lead-zinc deposit area in western Hunan province is polluted by the two elements, the majority soils in mercury deposit areas are seriously polluted by mercury with middle polluted or light polluted by lead, while the majority soils in lead-zinc deposit areas are middle polluted or middle-heavily polluted by lead and middle-heavily polluted by mercury. The sources of metal pollutants in soils in the deposit areas are natural and human causal, the spatial distribution of mercury and lead are dominated by original geochemical situation but seriously affected by human mining activities.

China↗
PubMed1990

Risk assessment and risk management of noncriteria pollutants.

Noncriteria air pollutants are synonymous with hazardous air pollutants (HAPs), air toxics or toxic air pollutants (TAPs). The term noncriteria pollutants refers to all air pollutants except for the criteria pollutants (SOx, PM, NOx, CO, O3, and Pb). Air toxics are pervasive in our environment worldwide in varying degrees. Uses of these chemicals are varied and numerous; their emissions are ubiquitous, and they include organic compounds such as chlorinated hydrocarbons, dioxins, aldehydes, polynuclear aromatic hydrocarbons, and heavy metals such as chromium, nickel, cadmium, and mercury. There are more than 70,000 chemicals that are in use commercially in the United States, and we know relatively little about their ambient concentrations, persistence, transport and transformation as well as their effects on health and the environment, many of which take decades to emerge. The United States Environmental Protection Agency, under the authority of Section 112 of the Clean Air Act, is mandated to regulate any air pollutant which, in the Administrator's judgment, "causes, or contributes to, air pollution which may reasonably be anticipated to result in an increase in serious irreversible or incapacitating reversible illness." For such regulatory decision-making, EPA's Office of Health and Environmental Assessment (OHEA) provides scientific assessment of health effects for potentially hazardous air pollutants. In accordance with risk assessment guidelines developed by OHEA over the years, Health Assessment Documents (HADs) containing risk assessment information were prepared and were subjected to critical review and careful revision to produce Final Draft HADs which serve as scientific databases for regulatory decision-making by the Office of Air Quality Planning and Standards (OAQPS) in its risk management process. EPA developed databases such as the Integrated Risk Information System (IRIS) and the National Air Toxics Information Clearinghouse (NATICH) and a technical assistance response system called the Air Risk Information Support Center (AIR RISC), in addition, to help in implementation of the National Air Toxics Program by state and local regulators.

Air Pollutants↗
PubMed1989

Influence of air pollution on extrinsic childhood asthma.

A crossed comparative study was done with 248 extrinsic asthmatic children living either in polluted or non-polluted areas (mean emission per year of sedimentary material greater than or less than 300 mg/m2/day, respectively) to establish the influence of air pollution on childhood extrinsic asthma. The mean number of wheezing crises per year was significantly higher for the children living in polluted areas (10.4 versus 7.69). In addition, incidence of severe asthma (types II, III, and IV) in children living in polluted areas was markedly increased whereas the slight form of asthma (type I) was more frequent in children living in non-polluted areas. No correlation, however, between the wheezing episodes and levels of atmospheric contaminants (fumes and SO2) was detected when a group of 84 extrinsic asthmatic children living in polluted areas was studied longitudinally for a year. The data indicate that air pollution, as an isolated agent, plays a transient role in the appearance of wheezing episodes in subjects with extrinsic asthma. Results also suggest that the air pollution may potentiate wheezing episodes via alternative mechanisms.

Air Pollution↗
PubMed1996

Cardiovascular disease and environmental pollutants: the Arctic aspect.

Environmental pollution in the Arctic is due to long range transport from lower latitudes or to local industrial activities. Since the latter are not different from point source exposure in the rest of the world the paper focuses on the former aspect which is the main type of environmental pollution in the western Arctic. The environmental pollutants of major significance are heavy metals (mercury, cadmium, lead) and persistent organic pollutants (PCB's, pesticides) and the main exposure is through the traditional diet of sea mammals (mercury, cadmium, persistent organic pollutants) and through smoking (cadmium). There is rather strong evidence that lead is a (weak) risk factor for high blood pressure even at low levels of exposure. Apart from lead there is little evidence that the above mentioned pollutants are significantly related to cardiovascular diseases. Since the pollutants, however, are found in the traditional diet together with n-3 polyunsaturated fatty acids, monounsaturated fatty acids, and selenium which are believed to promote cardiovascular health there is an indirect link between the pollutants and cardiovascular disease. This becomes relevant when dietary guidelines are developed for arctic populations. Epidemiological evidence from Greenland relevant for this discussion is presented, i.e. i) findings from a countrywide interview survey on dietary habits which show that sea mammals are widely consumed and appreciated for health and other reasons and that there is virtually no fear of pollution, and ii) mortality results which do not support the hypothesis that the low rate of ischemic heart disease in Inuit is due to their traditional diet.

Arctic Regions↗
PubMed2006

Air pollution in Boston bars before and after a smoking ban.

BACKGROUND: We quantified the air quality benefits of a smoke-free workplace law in Boston Massachusetts, U.S.A., by measuring air pollution from secondhand smoke (SHS) in 7 pubs before and after the law, comparing actual ventilation practices to engineering society (ASHRAE) recommendations, and assessing SHS levels using health and comfort indices. METHODS: We performed real-time measurements of respirable particle (RSP) air pollution and particulate polycyclic aromatic hydrocarbons (PPAH), in 7 pubs and outdoors in a model-based design yielding air exchange rates for RSP removal. We also assessed ventilation rates from carbon dioxide concentrations. We compared RSP air pollution to the federal Air Quality Index (AQI) and the National Ambient Air Quality Standard (NAAQS) to assess health risks, and assessed odor and irritation levels using published SHS-RSP thresholds. RESULTS: Pre-smoking-ban RSP levels in 6 pubs (one pub with a non-SHS air quality problem was excluded) averaged 179 microg/m3, 23 times higher than post-ban levels, which averaged 7.7 microg/m3, exceeding the NAAQS for fine particle pollution (PM2.5) by nearly 4-fold. Pre-smoking ban levels of fine particle air pollution in all 7 of the pubs were in the Unhealthy to Hazardous range of the AQI. In the same 6 pubs, pre-ban indoor carcinogenic PPAH averaged 61.7 ng/m3, nearly 10 times higher than post-ban levels of 6.32 ng/m3. Post-ban particulate air pollution levels were in the Good AQI range, except for 1 venue with a defective gas-fired deep-fat fryer, while post-ban carcinogen levels in all 7 pubs were lower than outdoors. CONCLUSION: During smoking, although pub ventilation rates per occupant were within ASHRAE design parameters for the control of carbon dioxide levels for the number of occupants present, they failed to control SHS carcinogens or RSP. Nonsmokers' SHS odor and irritation sensory thresholds were massively exceeded. Post-ban air pollution measurements showed 90% to 95% reductions in PPAH and RSP respectively, differing little from outdoor concentrations. Ventilation failed to control SHS, leading to increased risk of the diseases of air pollution for nonsmoking workers and patrons. Boston's smoking ban eliminated this risk.

Air Movements↗
PubMed2006

Management of agricultural nonpoint source pollution in China: current status and challenges.

Water quality in China shows an overall trend of deterioration in recent years. Nonpoint source pollution from agricultural and rural regions is the leading source of water pollution. The agricultural nonpoint source pollutants are mainly from fertilization of cropland, excessive livestock and poultry breeding and undefined disposal of daily living wastes in rural areas. Agricultural nonpoint sources contribute the main source of pollution to most watersheds in China, but they are ignored in management strategy and policy. Due to the lack of full understanding of water pollution control and management and the lack of perfect water quality standard systems and practical legislative regulations, agricultural nonpoint source pollution will become one of the biggest challenges to the sustainable development of rural areas and to society as a whole. The system for agricultural nonpoint source pollution control in China should include an appropriate legislation and policy framework, financing mechanisms, monitoring system, and technical guidelines and standards. The management of agricultural nonpoint source pollution requires multidisciplinary approaches that will involve a range of government departments, institutions and the public.

Agriculture↗
PubMed1996

Protein Profile Variation in Cultivated and Native Freshwater Microorganisms Exposed to Chemical Environmental Pollutants

Assimilation of 35S-precursors into microbial proteins was used to investigate toxicity and adaptational responses that occur in nutrient enriched and natural freshwater samples experimentally contaminated with benzene, toluene, trichloroethylene (TCE), or xylene. Experiments were conducted to analyze (1) the potential of using microbial community protein profiles for responsive identification of chemical pollutant exposure, (2) the inhibition of microbial productivity through reduction in rate of protein synthesis caused by specific chemical pollutants, and (3) whether selection of subpopulations in freshwater microbial communities challenged with chemical pollutants leads to adaptive strategies mediated by production of particular polypeptides. The results show that distinct banding patterns of polypeptides in the range of 30 to 100 kilodaltons that were obtained following collective cultivation of freshwater microorganisms differ with each chemical pollutant. Protein yield and radioisotope incorporation were reduced within ten minutes of micro-bial exposure to chemical pollutants in the following order: xylene < toluene < benzene < TCE. Adaptation of the freshwater microbial community to chemical pollutants prior to radioisotope incorporation produced differences in polypeptide profiles, in the banding patterns of radioactive polypeptides, and in the rate of radioisotope incorporation. The rate of radioisotope incorporation by freshwater microorganisms pre-adapted to chemical pollutants was lowest with xylene (88.1% reduction), followed by TCE (84.0% reduction),toluene (67.3% reduction), and benzene (43.5% reduction). In long-term radioisotope incorporation experiments, protein yield and polypeptide radioactivity was higher in the presence of chemical pollutants than in uncontaminated control samples, suggesting increased metabolic productivity attributable to the chemical pollutants.

Journal Article↗
PubMed1981

Yeasts from marine and estuarine waters with different levels of pollution in the state of rio de janeiro, Brazil.

Yeast counts were made at 24 marine and estuarine sites in the vicinity of Rio de Janeiro, Brazil. Mean salinities of estuarine sites ranged from 14.2 to 27.4 per thousand, and mean temperatures ranged from 25 to 28 degrees C. Total coliform counts varied from 80% above 100,000 colony-forming units (CFU)/100 ml at heavily polluted sites to 100% below 100 CFU/100 ml at unpolluted sites. Total yeast counts above 100 CFU/100 ml were typical of heavily and moderately polluted water but atypical of lightly polluted and unpolluted water. Mean total yeast counts were 2,880 CFU/100 ml for heavily polluted sites, 202 CFU/100 ml for moderately polluted sites, and 3 CFU/100 ml for lightly polluted and unpolluted sites. Total yeast counts had a positive response to increased pollution levels, and Candida krusei and phenotypically similar yeasts as a group were prevalent in polluted estuarine water but rare in unpolluted seawater. The 549 strains of yeasts and yeast-like organisms isolated were grouped into 67 species, of which the 21 most prevalent made up 86% of the total yeast population. The prevalent genera in the polluted estuary were Candida, Rhodotorula, Torulopsis, Hanseniaspora, Debaryomyces, and Trichosporon.

Journal Article↗
PubMed2005

Air pollution and atopy.

Relationships between air pollutants and atopy can be studied within 3 different settings. In vitro, exposure of pollen to air pollutants induce morphological changes and seems to facilitate extrusion on allergenic material out of the pollen grain. In animal as well as in human experiments, air pollutants, especially diesel exhaust particulates, are able to trigger an IgE-response. Epidemiological surveys also show that air pollutants trigger symptoms in patients. In contrast, whether or not air pollutants can induce de novo allergic diseases is still a matter of debate. Some surveys suggest that, in humans also, air pollutants, especially diesel-exhaust particulates, could trigger allergic sensitization and development of atopic diseases. At home, other pollutants can be involved: volatile organic compounds have pro-inflammatory properties and favour T-cell sensitization. Relationship between exposure to secondhand tobacco smoke or occupational hazards and atopic sensitization have led to discordant results.

Air Pollutants↗
PubMed2006

A fuzzy logic approach to assess groundwater pollution levels below agricultural fields.

A fuzzy logic approach has been developed to assess the groundwater pollution levels below agricultural fields. The data collected for Kumluca Plain of Turkey have been utilized to develop the approach. The plain is known with its intensive agricultural activities, which imply excessive application of fertilizers. The characteristics of the soils and underlying groundwater for this plain were monitored during the years 1999 and 2000. Additionally, an extensive field survey related to the types and yields of crops, fertilizer application and irrigation water was carried out. Both the soil and groundwater have exhibited high levels of nitrogen, phosphorus and salinity with considerable spatial and temporal variations. The pollution level of groundwater at several established stations within the plain were assessed using Fuzzy Logic. Water Pollution Index (WPI) values are calculated by Fuzzy Logic utilizing the most significant groundwater pollutants in the area namely nitrite, nitrate and orthophosphate together with the groundwater vulnerability to pollution. The results of the calculated WPI and the monitoring study have yielded good agreement. WPI indicated high to moderate water pollution levels at Kumluca plain depending on factors such as agricultural age, depth to groundwater, soil characteristics and vulnerability of groundwater to pollution. Fuzzy Logic approach has shown to be a practical, simple and useful tool to assess groundwater pollution levels.

Agriculture↗
PubMed2024

Microbial diversity and metabolic pathways linked to benzene degradation in petrochemical-polluted groundwater.

The rapid advance in shotgun metagenome sequencing has enabled us to identify uncultivated functional microorganisms in polluted environments. While aerobic petrochemical-degrading pathways have been extensively studied, the anaerobic mechanisms remain less explored. Here, we conducted a study at a petrochemical-polluted groundwater site in Henan Province, Central China. A total of twelve groundwater monitoring wells were installed to collect groundwater samples. Benzene appeared to be the predominant pollutant, detected in 10 out of 12 samples, with concentrations ranging from 1.4&#xa0;&#x3bc;g/L to 5,280&#xa0;&#x3bc;g/L. Due to the low aquifer permeability, pollutant migration occurred slowly, resulting in relatively low benzene concentrations downstream within the heavily polluted area. Deep metagenome sequencing revealed Proteobacteria as the dominant phylum, accounting for over 63&#xa0;% of total abundances. Microbial &#x3b1;-diversity was low in heavily polluted samples, with community compositions substantially differing from those in lightly polluted samples. dmpK encoding the phenol/toluene 2-monooxygenase was detected across all samples, while the dioxygenase bedC1 was not detected, suggesting that aerobic benzene degradation might occur through monooxygenation. Sequence assembly and binning yielded 350 high-quality metagenome-assembled genomes (MAGs), with 30 MAGs harboring functional genes associated with aerobic or anaerobic benzene degradation. About 80&#xa0;% of MAGs harboring functional genes associated with anaerobic benzene degradation remained taxonomically unclassified at the genus level, suggesting that our current database coverage of anaerobic benzene-degrading microorganisms is very limited. Furthermore, two genes integral to anaerobic benzene metabolism, i.e, benzoyl-CoA reductase (bamB) and glutaryl-CoA dehydrogenase (acd), were not annotated by metagenome functional analyses but were identified within the MAGs, signifying the importance of integrating both contig-based and MAG-based approaches. Together, our efforts of functional annotation and metagenome binning generate a robust blueprint of microbial functional potentials in petrochemical-polluted groundwater, which is crucial for designing proficient bioremediation strategies.

Groundwater↗