Chapter 7 Aerobiological Study 7.0 INTRODUCTION 137

Transcription

1 7.0 INTRODUCTION From health perspective, a biological contamination of the air seems to play a crucial role, especially for the people who have been already suffering from serious health problems (Araujo, 2008; Leung, 2006; Martins-Diniz, 2005). Airborne microorganisms act as an important factor and indicator of the level of air pollution. Among various airborne microorganisms fungal spores act as an important component of bio aerosols, which are ubiquitous in nature and are considered to act as indicator of the level of atmospheric bio pollution (Elbert et al., 2007). Fungi live as saprophytes on organic material or as parasites (mainly plant pathogens), so the majority of fungal spores in the air outdoors come from farms, forest stands and decomposing plant matter. The number of fungal airspora and their diversity vary seasonally and temporally. The dispersal and transport of airborne fungal spores are influenced by several meteorological factors, such as wind, rainfall, temperature, atmospheric pressure, solar radiation, and relative humidity (Troutt and Levetin 2001; Solomon, 1978). The greatest number of airborne spores was found to be in temperate and tropical regions and the least in desert (Lacey, 1981). Fungal propagules can serve as infective agents of plant diseases and, moreover, airborne fungi cause spoilage of foods and are responsible for many adverse health effects, the mycotoxins which they produce may affect humans and animals (Mohammed, et al., 2010). Because of their volume in the atmosphere and small size, fungal spores play an important role in respiratory allergies and cause a wide range of symptoms, including allergic rhinitis, asthma, chronic bronchitis, etc. (D amato,2000; Hasnain et al., 1998; Vijay et al., 1991). Exposure to air borne fungal spores is a special health concern in tropical region, as the warm and humid climate in the study area complement the microbial and plant growth. Fungal spores have long been known as one of the important environmental bio-particles causing dermatitis, respiratory infections (Reanprayoon and Yoonaiwong, 2012; Grinn-Gofron and Mika 2008; Garrett et al., 1997), sick building syndrome (Goncalves et al., 2010; Li and LaMondia, 2010; Kasprzyk and Worek, 2006) and cardiac disease along with allergic manifestation in human beings (Shukla and Shukla, ). Adverse health effects associated with fungal exposure are widely documented and extremely diverse, ranging from headaches to allergy and invasive infections (Chapman, 2006), causing respiratory allergy in 20 to 30% of 137

2 atopic individuals (Kurup et al., 2000). Particles of 10 µm are deposited easily into the bronchial tree and are associated with immediate hypersensitivity responses, while particles of 2.5 µm or less can easily penetrate the lower airway and are associated with delayed hypersensitivity with major allergic manifestations including asthma, rhinitis, and allergic bronchopulmonary mycoses (Burge, 2002; Kurup et al., 2000; Horner et al., 1995). Recently, several studies suggested that outdoor airborne fungal concentration is associated with the increase in admission and emergency visit for asthma exacerbations (Dales et al., 2004; Anderson et al., 2001; Lewis et al., 2000; Newson et al., 2000). Exposure to aeroallergens is a special health concern in study area, because the warm and humid climate in this subtropical area provides favourable environmental conditions for microbial and plant growth. Some species of fungi such as Cladosporium cladosporioides, C. herbarum, Penicillium brevicompactum, P. chrysogenum, Aspergillus candidus, A. niger and A. versicolor can provoke extreme allergic reactions and sick building syndrome in humans (Singh, 2001 and Simeray et al., 1995), and these may cause eye and sinus irritation, sore throat, headache, fatigue and dizziness (Buttner et al. 2001) and more specifically, sensitization to Cladosporium Alternaria, Aspergillus, and Fusarium has been associated with asthma severity (Kumar and Babu, 2010; Dennings et al., 2006). In this research work, an attempt has been made for the identification and quantification of the airborne fungal spores in atmosphere along with its monthly variation, diversity in the study area. There are a number of studies related to abiotic pollutants but very limited studies on biotic pollutants were performed so far. Hence, the basic objective here to assess the distribution characteristics and nature of airborne fungal spores in such areas.the investigation work has been confined to fungal spore, insect scales and their population in the atmosphere. The fungal organisms in the air spora were considered as spore type. The spores or any other living (hyphal fragments) or dead entity (Insect part) was placed under Other types. 138

3 7.1 METHODOLOGY Sampling was made using a Personal Volumetric Sampler Burkard Sampler Burkard Manufacturing Company Limited, England (Plate 7.1) directly on the glass slides for 5 or 10 minutes according to the locations (mining and non-mining areas), on each of 3 days a week (alternate days) during January to January The main body of the spore trap has a 2x14mm slit for air intake. The flow rate was adjusted to 10 l/min. Spores were collected on petroleum jelly and then mounted on microscope slides in glycerol jelly and protected with a cover glass. The flow rates of the two traps were checked weekly. The orifices were cleaned weekly as well. The daily preparations were analyzed by optical microscope (100x magnification), with two longitudinal sweeps per slide. A correction factor has been used to determine the quantity of spores per cubic meter of air. This correction factor is based on the system of capture used (volume of air per unit of time, size of the orifice, area of the sample surface, number of rotations (two for spores) and the features of the microscope lens. The data used correspond to the mean daily values expressed as the number of spores per cubic meter of air. 7.2 SAMPLE ANALYSIS The prepared slides were examined microscopically through Motic Digital Biological Microscope, DMW B1-223 (Plate 7.2) at the Stress Biology and Drug Discovery Laboratory, Department of Botany, Banaras Hindu University. This was supported with software, Motic Images Fungal spore were identified by using an oil immersion lens (100X total magnification). Burkard daily slides were analyzed for some of the most common airborne fungal spores by optical microscope using the two longitudinal traverse method as previously described. Alternaria, ascospores, basidiospores, Cladosporium, Curvularia, Drechslera, Torula, Periconia, Cercospora, Nigrospora, other spores, Penicillium/Aspergillus, and smut spores were the most commonly counted spore types. The concentration of each spore type, as well as the total concentration of all the fungal spores were calculated and expressed as spores per cubic meter of air. The spore types identified were ordered systematically according to the 9th edition of the Dictionary of the fungi by Barnett and Hunter (1999) which is supported by the latest advances in the knowledge of the ultra structure, biochemistry and molecular biology of these organisms. 139

4 Plate7.1:Personal Volumetric Sampler (Burkard Sampler) at one of the sampling location of the study area Plate 7.2: Scanning of Samples using Motic Digital Microscope 140

5 7.3 RESULTS & DISCUSSION The fungal spores identified were assessed quantitatively as well as qualitatively as shown in Figures 7.1 and 7.2 to 7.6 respectively Quantitative study As seen in Figure 7.1 fungal spore in the study area varies from 19,796-30,364 spores/m 3. The maximum fungal spore concentration were recorded during September (30,364spores/m 3 ) while lowest were reported for February month (19,796 spores/m 3 ) during the study period. In which predominant fungal spores were belong to Deuteromycotina group. Figure 7.1: Total Atmospheric Fungal Spores Concentration Per Month in The quantitative study of selected fungal spores over a study period confirms the dominant abundance of Cladosporium spores, with highest total count 1, spores/m 3 of during different months and recorded highest (1,2345) during September per cubic meter of air. Table 7.1, depicts the identified fungal spores on monthly basis in the study area. This indicates higher spore count of Cladosporium. The abundance of spores (conidia) in the atmosphere is due in a large part to their ability to exist and thrive on a wide array of substrates. The abundance of Cladosporium throughout the year may be attributed to the structural features of the spores such as 141

6 small size, thin exine and smooth wall which favour and facilitate the transport of airborne spores (Shaheen, 1992) and also it can live on many kinds of plants. Table 7.1: Monthly Variation of Identified Fungal Spores in the Study Area Fungal Species Taxonomic Group Jan Feb Mar Apr May June Months July Number of spores/m 3 of air Aug Sep Oct Nov Dec Jan 2012 Cladosporium Deuteromycotina Drechslera Curvularia Alternaria Torula Nigrospora Epicoccum Bipolaris Periconia Fusarium Sporidesmium Tetraploa Helminthosporiu m Pithomyces Cordana Annulohypoxylon stagium Trichothecium Aspergillus Ascomycotina Claviceps Spicaria Hypoxylon Pleospora Smut Basidiomycotin a Puccinia Cunnighmallea Zygomycotina

7 7.3.2 Qualitative study The components of the air spora were grouped under four taxonomic groups viz., Ascomycotina, Basidiomycotina, Deuteromycotina and Zygomycotina. Some identified fungal spores are shown in Plates 7.3 and 7.4. Description of various taxonomic groups are given below- Deuteromycotina: The group Deuteromycotina was significantly contributed to the total aerospora and dominant among all groups, both quantitatively and qualitatively. The fungal spores falls under Deuteromycotina in the study area are Cladosporium, Dreschlera,Curvularia,Alternaria,Torula,Nigrospora,Epicoccum,Bipolaris,Perconia, Fusarium,Sporidesmium,Tetraploa,Trichothecium,Helminthosporiumand Pithomyces. Cladosporium a dominant fungus that contributed 39% to the total airspora and important from allergic point of view, was found almost throughout the period of investigation and is usually have distinctive scars at both ends where they were joined both to the spore at one end and to the conidiophores at the other. Apart from Cladosporium, Alternaria, Fusarium, Aspergillus and Torula were also present throughout the study period. Table 7.2 and Figure 7.2 thus display dominant spore type and percentage contribution in the study area. Monthly variation of different fungal spores in air is shown in Figures 7.3 (a), (b) (c) (d) and (e). Figure 7.3 (a) indicates higher concentration of Curvularia it starts increasing its concentration from June (1433 spores/m 3 ) and reaches its maximum during September (1765spores/m 3 ), while concentration of Alternaria is almost consistent during various months. Its concentration also starts increasing from June (1566 spores/m 3 ) to September (1600 spores/m 3 ). 143

8 a b c d e f g h i j k l a)alternaria b)cladosporium c)curvularia d)periconia e)helminthosporium f) Dreschlera g) Cordana h) Pithomyces i)pleospora j)tetraploa k)torula l)torula m)spicaria Plate 7.3 Microscopic Pictures of Air Borne Fungal Spores in the Study Area 144

9 a b c d e f g h i j k l a) Bipolaris b) Hypoxylon) c) Epicoccum d) Uredosore e) Nigrospora f) Fusarium g) Trichothecium h) Ustillago i) Cunnighamella j) Insect wing k) Insect wing l) Insect part Plate 7.4 Microscopic Pictures of Air Borne Fungal Spores in the Study Area 145

10 Table 7.2: Fungal Spore Type Identified in the Atmosphere of Study Area Phylum Spore Type Percentage of Category Frequency representation (% days) Ascomycotina Aspergillus 5.3 L ** Claviceps 2.3 L * Spicaria 4.3 A *** Pleospora 1.5 M ** Hypoxylon 1.3 M ** Basidiomycotina Puccinia 1.2 L * Ustilago 2.5 M *** (Smut spores) Zygomycotina Cunninghamel 1.0 L ** la Deuteromycotina Alternaria 6.6 M *** Bipolaris 1.3 L ** Cladosporium 39.0 A ** Curvilaria 4.9 L ** Epicoccum 1.2 L ** Fusarium 1.8 L * Helminthospo L ** rium 4.0 Nigrospora 3.6 L * Periconia 1.65 M ** Pithomyces 3.0 L ** Tetraploa 1.7 L * Torula 2.5 M ** Trichothecium 2.4 M ** Drechslera 2.2 Sporidesmium 1.9 Cordana 1.4 Annulohypoxy lon stagium 1.5 Representativeness (A; abundant; M; moderate and L; low). Frequency (***Very Frequent, ** Frequent and * Unfrequent) A *** M ** L * L * 146

11 Figure 7.2: Dominant Spore Type and their Percentage Contribution to the Total Air Spora Figure 7.3(a): Monthly Variation of Drechslera, Curvularia, Alternaria and Torula in Study Area Figure 7.3 (b) depicts the higher concentration of Nigrospora with gradual increase during rainy season (June to September). Concentration of Epicoccum starts increasing from June (344 spores/m 3 ) to September (412 spores/m 3 ). Figure7.3(c) shows the monthly variation of Sporidesmium, Tetraploa, Trichothecium and Pithomyces in study area. Among all four species Pithomyces was abundantly 147

12 present with maximum concentration during September (899 spores/m 3 ).Which was followed by Trichothecium with maximum concentration (699 spores/m 3 ) during the same month. Figure 7.3 (b): Monthly Variation of Nigrospora, Epicocum, Bipolaris and Periconia in the Study Area Figure 7.3(c):Monthly Variation of Sporidesmium, Tetraploa, Trichothecium and Pithomyces in the Study Area 148

13 Similarly, Figure 7.3 (d) represents monthly variation among four species namely, Cordana, Helminthosporium, Annulohypoxylon stagium and Fusarium. Higher spore concentration was recorded for Fusarium with consistent higher concentration during rainy season,i.e., June (1455 spores/m 3 ), July(1466 spores/m 3 ), August (1533 spores/m 3 ) and September (1544 spores/m 3 ) which was followed by Helminthosporium. Figure 7.3 (e) depict the seasonal variation of Cladosporium with higher concentration during September month. Figure 7.3(d):Monthly Variation of Cordana, Helminthosporium, Annulohypoxylon stagium and Fusarium in the Study Area Figure 7.3(e): Monthly variation of Cladosporium in the Study Area 149

14 Ascomycotina: The Ascomycotina spores, second in order of dominance, contributed 14.7 % to the total identified air spora during study period. Figure 7.4 depict the Ascomycotina group. Five types of ascospores (namely Aspergillus, Claviceps, Spicaria, Pleospora and Hypoxylon) were encountered only due to the favourable environmental conditions for their formation and release with their seasonal maxima in rainy season. The incidence of most of the ascospores in the air depends upon the occurrence of rainfall considered as wet spora. The concentration of Aspergillus start increasing from the month of July (1,766 spores/m 3 ) and reaches at maximum during September ( spores/m 3 ). While other species like Spicaria, Pleospora, Hypoxylon and Claviceps shows higher concentration from the month of July to September. Observations clearly indicate their predominance in air during the months of July to September which shows spores having close correlation between rainfall and release of ascospores. These group of fungi release ascospores after the period of rain. Figure 7.4: Monthly Variation of Aspergillus,Spicaria,Pleospora, Hypoxylon and Claviceps in the Study Area Basidiomycotina: The Basidiomycotina occupied third in order of their abundance and contributed 3.7% to the total identified air spora. This group is represented by Smut and Puccina. Their concentration starts increasing from March and reaches to 150

15 maximum in September. After September gradual decrease in fungal spore concentration takes place (Figure 7.5). As the rainy season associated with 20 to 30 C (temperature range) and more than 75% of relative humidity. This promotes the growth of both the fungal spore concentration. Figure 7.5: Monthly Variation of Basidiomycotina group in the Study Area Figure 7.6: Monthly Variation of Cunnighamella (Zygomycotina group) in the Study Area 151

16 Zygomycotina: Figure 7.6 represents the monthly variation of Zygomycotina group which is represented by a single fungal species, i.e., Cunnighmella. This reported 1% among the entire identified taxonomic group. Cunnighmella was less recorded in summer months, i.e., 134 spore/m 3 and 156 spore/m 3 in April and May, respectively. Maximum concentrations were recorded during month of September (289 spore/m 3 ). Their presence was restricted to rainy days. These spores depended on rain to get into atmosphere and occur in high concentration only after rainfall. 7.4 OTHER TYPES Besides these identified spore types, i.e., Deuteromycotina, Ascomycotina, Zygomycotina and Basidiomycotina, there exist other types biological particles of significantly less percentage (Plate 7.2). This includes hyphal fragments, epidermal hair, insects, algal filaments and protozoans cysts. 7.5 SUMMARY This chapter deals with aerobiological status of the study area. This consists of different types of micro biota. Among various groups, Deuteromycotina represents highest percentage which was followed by Ascomycotina, Zygomyotina and Basidiomycotina. Among all the fungal spores Cladosporium represented highest concentration during all the season. This was followed by Alternaria, Fusarium, Aspergillus and Torula. In general, the spore load was maximum during intermittent rainy and dry period and decreased during prolonged rains or dry periods. Thus, the existing environment of the study area harbours a wide variety of fungi. The occurrence of fungal spores, their seasonal variation according to meteorological parameters and their implications are well revealed. 152