This article was downloaded by: [Selcuk Universitesi] On: 28 December 2014, At: 05:20 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances and Environmental Engineering Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lesa20
Assessment of microbiological and chemical properties in a municipal landfill area a
b
Krzysztof J. Frączek , Dariusz R. Ropek & Anna M. Lenart-Boroń a
a
Department of Microbiology , University of Agriculture , Cracow , Poland
b
Department of Agricultural Environment Protection , University of Agriculture , Cracow , Poland Published online: 10 Jan 2014.
Click for updates To cite this article: Krzysztof J. Frączek , Dariusz R. Ropek & Anna M. Lenart-Boroń (2014) Assessment of microbiological and chemical properties in a municipal landfill area, Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances and Environmental Engineering, 49:5, 593-599, DOI: 10.1080/10934529.2014.859464 To link to this article: http://dx.doi.org/10.1080/10934529.2014.859464
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Journal of Environmental Science and Health, Part A (2014) 49, 593–599 C Taylor & Francis Group, LLC Copyright ISSN: 1093-4529 (Print); 1532-4117 (Online) DOI: 10.1080/10934529.2014.859464
Assessment of microbiological and chemical properties in a municipal landfill area 1 ´1 KRZYSZTOF J. FRACZEK , DARIUSZ R. ROPEK2 and ANNA M. LENART-BORON 1
Department of Microbiology, University of Agriculture, Cracow, Poland Department of Agricultural Environment Protection, University of Agriculture, Cracow, Poland
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
2
This study aimed at determining the environmental hazards for soils posed by a large municipal landfilll. The concentrations of heavy metals and Policyclic Aromatic Hydrocarbons, as well as microbial composition (i.e., mesophilic bacteria, actinomycetes, molds, Salmonella, Staphylococcus, Clostridium perfringens) in four soils within and in the vicinity of the landfill were evaluated and compared to waste samples. Both chemical and microbiological analyses revealed only limited contamination of surrounding areas. Although the increased alkalinity of soils was detected, the concentrations of heavy metals and Polycyclic Aromatic Hydrocarbons (PAHs) did not exceed the admissible values. All examined microbial groups were abundant in soil and waste. The highest microbial cell numbers were observed in warm summer and spring months. Although the site south of the landfill shows no trace of microbial contamination, pathogenic bacteria were found north of the landfill. This may suggest that there are other, more effective, transmission routes of bacteria than groundwater flow. Keywords: Landfill, soil contamination, soil microorganisms, pathogenic bacteria, heavy metals.
Introduction One of the consequences of growing industry and population is the process of continuous accumulation of waste in landfills. Such landfills may become a threat for the environment as various components, such as heavy metals or Polycyclic Aromatic Hydrocarbons (PAHs), are continuously leached out and may finally enter groundwater. This, in turn, may decrease its quality and pose a threat for human and animal health.[1] It is generally agreed that the levels of heavy metals and other highly toxic chemicals in municipal waste are low. Nevertheless, long-term dumping of untreated municipal waste and increasing heavy metal content (and therefore toxicity of urban refuse) that results from rapid industrialization, may lead to accumulation of pollutants and increase the potential hazard of municipal landfills.[2] Increased concentrations of soil contaminants, particularly heavy metals, but also PAHs may affect the chemical properties of soils and their biological activity.[3] Therefore, the present study determines the environmental risk for soils posed by a large municipal waste landfill in ´ DepartAddress correspondence to Anna M. Lenart-Boron, ment of Microbiology, University of Agriculture in Cracow, Mickiewicza Ave 24/28 30-059, Cracow, Poland; E-mail: [email protected] Received June 12, 2013.
´ southern Poland. Additionally, the sanitary condiTarnow, tion of soils within the landfill and in its vicinity, as well as of deposited waste, was verified to assess a putative health risk due to the environmental pollution resulting from the ´ neighborhood of the municipal waste landfill in Tarnow, southern Poland.
Materials and methods Soil sampling and study area The field study was conducted within and in the vicinity of ´ launched in 1985. Due to the municipal landfill in Tarnow, its mode of operation and consistently implemented modern waste disposal system, it is currently considered as one of the best organized landfills in southern Poland. In re´ has received almost cent years, the waste landfill in Tarnow 50,000 tons of unsorted municipal waste. In the landfill area, six sampling sites were selected; one within the active and one within the reclaimed sector, and four within areas proximate to the landfill. The field sites were chosen according to the pattern of landfill microbial emissions predicted based on topography, vegetation and groundwater flow direction (Fig. 1, Table 1). Sampling was performed once per season throughout 2 years (2010 and 2011), giving a data set consisting of 8 sampling dates per each site (4 times per year, for 2 consecutive years).
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
594
Fraczek et al.
Fig. 1. Location of the sampling sites within the landfill. Description of sampling sites is given in Table 1.
In the case of soils, for each sampling site, a composite sample (500 g) consisting of 5 subsamples (100 g) was collected in a grid (with a minimum distance between subsamples of 5 m) from the top 20 cm of soil in each season. In the case of wastes – composite samples were composed of 6 subsamples (3 boreholes from the depth of 0–20 cm and 3 from 80–100 cm from the surface). The composite samples were collected into sterile plastic bags and transported to the laboratory for microbiological and chemical analyses. Wastes collected at the examined landfill are mainly a mixture of unsorted municipal (domestic) waste, soil with stones, biodegradable wastes, debris and wastes from cleaning streets. Microbiological, chemical and physical analysis Triplicate fresh subsamples (10 g) were taken from the bulk 500 g sample for the serial dilution method.[4] One mL of 10fold serial dilutions of the samples were inoculated onto nu-
trient agar to enumerate mesophilic bacteria (48 h at 37◦ C), Wort agar for mold fungi (3 days at 28◦ C), Pochon agar for actinomycetes (5–7 days at 28◦ C), SS agar for Salmonella (48 h at 37◦ C), Wilson-Blair agar for Clostridium perfringens (36 h at 35◦ C in anaerobic conditions) and Chapman agar for Staphylococcus (48 h at 35◦ C). After incubation, visible colonies were counted and expressed as colony forming units per gram of soil or waste (cfu × g−1). Presumptive Salmonella spp. colonies were confirmed by streaking on CHROMagar Salmonella Plus (Graso Biotech, Jabłowo, Poland), while the presence of C. perfringens was confirmed using thioglycollate broth with resazurine. Genera of predominant groups of mesophilic bacteria were identified based on microscopic observations of Gram-stained smears, as well as based on biochemical characteristics according to Bergey’s Manual of Determinative Bacteriology.[5] Soil moisture was determined gravimetrically by comparing wet and dry soil weights. Soil pH was determined in distilled water in 1:2.5 solution using an electronic pH-meter with a glass electrode. Soil granulometric composition was assessed by aerometric measurements.[6] Prior to chemical analyses, soils were oven dried at 60◦ C for 90 min. Concentrations of Pb, Cd, Ni, Zn, Cu and Cr were estimated in soils digested with aqua regia followed by atomic absorption spectrometry (AAS).[7] The concentration of Hg was determined using atomic absorption spectrometry RA915+ with application of the pyrolysis technique.[8] The concentration of As was measured using graphite furnace AAS.[9] Contents of chlorides and sulfates both in soil and waste as well as fluorides in waste were determined by ion chromatography. The content of PAHs (naphtalene, phenanthrene, anthracene, fluoranthene, chrysene, benzo(a)anthracene, benzo(a)fluoranthene, benzo(a)perylene, benzo(a)pyrene) was estimated in soil by means of HPLC with UV detection and ultrasonic extraction in dichloromethane.[10] Content of bioavailable phosphorus in soil was measured spectrophotometrically by the molybdenum blue
´ Table 1. Location and characteristics of the sampling sites within the Tarnow–Krzy˙ z municipal waste landfill. Sample no.
Location
1
Soil 1
2
Soil 2
3
Soil 3
4
Soil 4
5
Waste 1
6
Waste 2
GPS coordinates
pH
Description
N50◦ 02’35” E21◦ 01’54” N50◦ 02’54” E21◦ 01’52” N50◦ 02’26” E21◦ 01’58”
8.12
N50◦ 02’21” E21◦ 02’01” N50◦ 02’31” E21◦ 02’51” N50◦ 02’37” E21◦ 02’52”
5.66 n/a
Within the landfill, nearby the active sector Outside the active sector, about 250 m to the north Within the landfill, outside the reclaimed sectors, to the south-east Outside the landfill, about 250 m to the south Within the reclaimed sector
n/a
Within the active sector
5.05 8.28
Sand > 0.1 mm (%)
Dust 0.1–0.02 mm (%)
Clay particles < 0.02 mm (%)
24
40
36
26
41
33
21
38
41
28
39
33
n/a
n/a
n/a
n/a
n/a
n/a
595
Microbiological and chemical properties in a municipal landfill method,[11] while the contents of total nitrogen, vanadium and phenol were assessed according to the methodologies of Bremner,[12] Cappuyns and Slabbinck,[13] and Yang and Humphrey,[14] respectively. The results of heavy metal, PAH and phenol concentrations were compared with Polish regulations.[15] For each group of the processed samples, blanks (sterile deionized water and reagents) were included throughout the entire sample preparation and analytical process.
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
Statistical analysis Statistical analysis of the results was performed using Statistica software (StatSoft, Tulsa, OK, USA). Significant differences between the numbers of microorganisms, isolated from the triplicate subsamples of the composite samples collected at different sites, were assessed by ANOVA with the least significant difference (LSD) test (P < 0.05). Similar analysis was chosen to ascertain seasonal differences in the microbial numbers within the waste. Moreover, Pearson correlation coefficient (r) was used to determine the relationship between the CFU numbers of microbial groups and contaminant concentrations in soil and waste.
Results and discussion The analyses showed that soils surrounding the waste landfill are acidic, while the soils inside the landfill are alkaline (Table 1). The reported values are similar to those obtained
´ by Kalwasinska et al.,[16] who conducted the study within the municipal landfill in Torun´ and also detected an increase in the pH of soils within the landfill, as compared to the background levels. This could have been caused by the effect of landfill leachate, which becomes alkaline (pH 8.0–8.5) over time, especially for long-term exploited landfills.[17] This is the case of the examined landfill that has been operated for over 20 years. Moreover, high alkalinity of municipal waste that contains ashes and slag from the combustion of stone coal and coke in household furnaces can be observed in Polish landfills.[17] The concentrations of chemical contaminants, i.e., metals, phenol or PAHs did not exceed the admissible values in any of the examined sites (Table 2). These results are consistent with the ones obtained by Domska and Warechowska,[1] who studied the effect of the municipal waste on the accumulation of heavy metals landfill in Wegorzewo in soils and did not find any transgressions of the admissible values, even the ones established for agricultural soils. The concentration of vanadium in the examined soil and waste samples is even less than the average concentration generally found in soils.[13] Although the heavy metal concentration in soils did not exceed the admissible values, their concentrations in waste samples was even less. There are conflicting reports on heavy metal concentrations in waste and soils surrounding landfill sites, as Tripathi and Misra [18] or Esakku et al.[19] reported transgressions of the admissible concentrations of heavy metals in waste landfillsurrounding soils.
´ Table 2. Concentrations (mg × kg−1) of total heavy metals and PAHs in different sites of the municipal waste landfill in Tarnow. Contaminant Sites 1 (soil) 2 (soil) 3 (soil) 4 (soil) 5 (waste) 6 (waste) Admissible valuea
Pb (0.5)
Cd (0.05)
Ni (0.4)
Zn (0.4)
Cu (0.8)
Cr (0.2)
Hg (0.005)
As (0.1)
27.4 16.4 10.8 18.6 < 0.30 0.48 50
0.82 0.51 < 0.50 < 0.50 < 0.10 < 0.10 1
24.3 4.71 24.0 < 3.20 < 0.30 0.50 35
67.9 27.4 23.6 29.4 < 0.50 2.35 100
12.0 < 2.40 7.19 2.61 < 0.30 < 0.30 30
5.78 < 2.30 4.82 < 2.30 < 0.50 < 0.50 50
0.067 0.071 0.015 0.056 < 0.005 < 0.005 0.5
< 4.60 < 4.60 < 4.60 < 4.60 < 0.05 0.14 20
Total N (0.1)
Phenol (0.5)
Fluoride (1)
< 0.10 < 0.10 < 0.10 < 0.10 n/a n/a —
< 0.50 < 0.50 < 0.50 < 0.50 n/a n/a 0.05
n/a n/a n/a n/a < 1.00 < 1.00 —
Contaminant Sites 1 (soil) 2 (soil) 3 (soil) 4 (soil) 5 (waste) 6 (waste) Admissible valuea a
V (0.005)
Sulfate (25)
Chloride (25)
PAH (0.5)
15.90 5.90 17.80 9.40 n/a n/a —
29.0 < 25.0 37.3 < 25.0 251 2266 —
< 25.0 < 25.0 < 25.0 < 25.0 269 1144 —
0.82 0.48 < 0.48 < 0.48 n/a n/a 1
Journal of Laws of the Republic of Poland.[15] Least detectable amounts are provided in parentheses.
Bioav. P (1) 4.75 3.16 4.18 5.00 n/a n/a —
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
596
Fraczek et al.
Uncontrolled waste landfills located in sandy areas may contaminate the soil surface layers with heavy metals, particularly Cu and Zn. This is the result of relatively high water permeability of those soil types and thus the easiness of contaminants’ migration into the soil profile.[1] The situation observed in this research, i.e., the relatively low content of chemical pollutants, may be caused by the actively promoted policy aiming at elimination of the most dangerous waste (batteries, electronic scrap, mercury thermometers, etc.) and the fact that the landfill has applied remedial measures for several most recent years. These measures consist in surrounding the landfill with a few dozen to a few hundred meters-wide green belt of trees, construction of the landfill sectors in the form of embanked basins that are sealed with geomembrane liners and drained to collect leachate. Leachate is collected in concrete tanks, where it is pre-treated and then redirected to a municipal treatment plant. The mean value of total mesophilic bacteria in soils ranged from log 5.92 to log 6.32 cfu × g−1 in sites 3 and 1, respectively (Table 3). These fluctuations are not uncommon, e.g., the total number of heterotrophic bacteria recorded by Obire et al. in their studies conducted within a landfill on Eagle Island ranged from log 5.62 to log 6.83 cfu × g−1 soil.[20] The numbers of mesophilic bacteria and C. perfringens in the waste samples collected from the reclaimed sector (site 5) was over twice higher than in site 6. Such result indicates that the number of mesophilic bacteria increased with time even despite the fact that the active usage of the landfill was stopped. However, the numbers of other pathogenic bacteria was much higher in the active sector. For all samples, the most abundant mesophilic bacteria were identified as Bacillus, Clostridium, Corynebacterium, Enterococcus, Salmonella, Staphylococcus and Streptococcus. All these genera have been reported to be associated with waste and waste biodegradation.[20] The highest mean number of actinomycetes was found in site 4. The concentrations of chemical pollutants were very low here, while the bioavailable phosphorus content was the highest, which could have affected the growth of these microorganisms.[21] The highest number of fungi was observed in site 3 (i.e., log 4.81 cfu × g−1 soil),
where pH was alkaline and the recorded value was similar to that ascertained in the waste sample from the reclaimed sector (site 5). The fungal number in the waste sample from the active sector (i.e., log 5.25 cfu × g−1 soil) was higher than that found in the reclaimed sector. This was probably due to the high amount of organic matter and better aeration of waste as compared with other sites. Similar values were reported by Obire et al.,[20] whose research showed that the numbers of viable fungi in soils surrounding the landfill ranged from log 4.26 to 5.40 cfu × g−1 soil. Another group of microorganisms comprised pathogenic and potentially pathogenic bacteria: C. perfringens, Salmonella and Staphylococcus. Both Salmonella and C. perfringens indicate poor sanitary condition of soils.[16] The highest numbers of these pathogens were detected in site 2. Waste samples, collected from the active sector, were characterized by higher number of Salmonella compared to those collected from the reclaimed sector (Table 3). The numbers of Salmonella found in the soil samples may be considered as relatively high; these bac´ teria are not abundant in soils. For instance, Kalwasinska et al.[16] did not detect Salmonella in soils collected near the ´ Similarly, Flores-Tena et al. waste landfill site in Torun. found Salmonella only in air samples, although numerous pathogenic and opportunistic bacteria were reported in soils.[22] The correlation analysis revealed a strong positive relationship between the number of mesophilic bacteria and the concentrations of Pb, Cd, Zn and PAHs (Table 4). This is a surprising result, because it was expected that these environmental contaminants inhibit the bacterial proliferation in soils. However, mesophilic bacteria are a complex and diverse community; hence, the presence of species tolerant to heavy metals and PAHs is not unusual among members of this group.[23] On the other hand, strong negative correlations were found between the numbers of actinomycetes, fungi and Staphylococcus and concentrations of most contaminants. For C. perfringens, the calculated correlation coefficients were generally moderate, while the correlations for Salmonella were negative for all considered factors, but their values were low.
´ Table 3. Numbers (log cfu × g−1)∗ of the selected microbial groups in different sites of the municipal waste landfill in Tarnow. Sites Microrganisms Mesophilic bacteria Actinomycetes Fungi C. perfringens Staphylococcus Salmonella ∗
1 (soil)
2 (soil)
3 (soil)
4 (soil)
5 (waste)
6 (waste)
F value
6.33 (0.08) 4.29 (0.10) 4.50 (0.04) 1.76 (0.08) 2.80 (0.08) 1.32 (0.04)
6.04 (0.06) 4.34 (0.09) 4.56 (0.04) 2.24 (0.11) 2.96 (0.07) 1.79 (0.05)
5.93 (0.05) 4.23 (0.09) 4.81 (0.05) 2.01 (0.08) 2.98 (0.08) 1.52 (0.06)
6.10 (0.06) 4.38 (0.08) 4.58 (0.06) 1.94 (0.07) 2.96 (0.06) Not detected
7.43 (0.11) 3.64 (0.12) 4.86 (0.05) 3.51 (0.10) 3.47 (0.11) 2.16 (0.11)
7.09 (0.09) 3.88 (0.05) 5.25 (0.08) 3.01 (0.12) 3.56 (0.11) 2.73 (0.09)
16.92 2.57 3.06 9.25 5.48 21.22
Values are the means while standard deviations are given in parentheses (n = 3, P < 0.05). Limit of detection (LOD) is 1 cfu. Bolded values are significant with P < 0.05.
597
Microbiological and chemical properties in a municipal landfill
Table 4. Correlation coefficients (r) between the selected soil and waste contaminants and the numbers of microorganisms (n = 3; P < 0.05). Microbial group
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
Mesophilic bacteria Actinomycetes Fungi C. perfringens Staphylococcus Salmonella
Pb
Cd
Ni
Zn
Cu
Cr
Hg
PAH
pH
0.98 0.23 −0.83 −0.54 −0.80 −0.32
0.95 −0.24 −0.52 −0.60 −0.94 −0.15
0.32 −0.91 0.41 −0.56 −0.68 −0.03
0.98 −0.14 −0.59 −0.64 −0.94 −0.24
0.69 −0.67 −0.01 −0.71 −0.92 −0.18
0.51 −0.81 0.22 −0.66 −0.82 −0.12
0.59 0.66 −0.97 0.16 −0.16 −0.12
0.95 −0.87 −0.51 −0.62 −0.95 −0.18
0.29 −0.25 0.46 −0.68 −0.69 −0.22
In general, heavy metals have an inhibitory effect on the growth of bacteria, fungi and actinomycetes.[21] Heavy metals in high concentrations (e.g., exceeding the limits given in the Polish Regulation of the Minister of Environment on soil quality standards) reduce biomass of microorganisms and decrease soil activity, and even if they do not reduce their numbers, they decline microbial biodiversity.[21] Even though the heavy metal concentrations detected in the analyzed landfill do not exceed the limit values, the negative correlations between the numbers of some microbial groups and concentrations of heavy metals, and PAHs were recorded. Toxic effects of these pollutants may lead to changes in the community structure and higher level of physiological adaptation or tolerance.[24] Since municipal waste is a known source of microorganisms, the seasonal variation in numbers of different microbial groups in the waste and soil samples was also compared. The highest mean numbers of mesophilic bacteria and Staphylococcus were observed for soil and waste samples, in summer (Table 5, Figs. 2a, 2b). In general, the greatest abundances of the microbial groups were found in warm seasons, while in winter months, these values were generally low, except for fungi in the waste samples and C. perfringens in the soils (Table 5, Fig. 2e). These results are not uncommon, as summer months, characterized by higher temperatures, promote bacterial proliferation.[25] Only C. perfringens unexpectedly deviates from this pattern. The increased number of molds in winter may be the effect of raised temperature of waste mass [26] and psychrotrophic nature of numerous mold species, which are more tolerant to low temperatures and may grow even below 10◦ C.[27]
Therefore, the inhibitory effect of low temperatures combined with increased temperature of waste may result in the higher numbers of mold fungi in the waste samples, in winter. This study indicates that the long-term exploitation of the landfill site did not have as much adverse effect on the surrounding soil environment as could be expected based on literature data. However, the negative impact of landfills depends greatly on the quality of stored waste. Our results showed low level of heavy metals and PAH contaminants for the waste samples; hence, these compounds might not have polluted the surrounding soils. On the other hand, stored waste was a significant source of various microbial groups, including pathogens. The landfill’s active sector was the abundant source of microorganisms, whereas the microbial numbers detected in the reclaimed sector were even greater. However, the impact of the landfill microbial populations on the adjacent soil environment was limited. The acquired data showed that the sampling sites located south of the landfill lacked some strains specific to the landfill bacterial community. Unexpectedly, such an impact was observed for the sites located north of the landfill, as evidenced by the increased level of Salmonella and C. perfringens. This may suggest that there are other, more effective, transmission routes of bacteria than groundwater flow, as was initially assumed due to the sloping of terrain from north to south. The fact that Salmonella or C. perfringens were not detected in soils south of the landfill may prove the effectiveness of the landfill’s sealing. On the other hand, the occurrence of these bacteria north of the landfill could have been due to the natural sources, such as wild animals that may be
Table 5. Comparison of the numbers (log × cfu g−1)∗ of selected microbial groups in the landfill waste over different seasons. Season Microbial group Mesophilic bacteria Actinomycetes Fungi C. perfringens Staphylococcus Salmonella ∗
Spring
Summer
Autumn
Winter
F value
7.05 (0.08) 3.72 (0.08) 5.12 (0.06) 3.46 (0.04) 3.56 (0.09) 2.56 (0.09)
7.54 (0.07) 4.08 (0.05) 5.03 (0.06) 3.45 (0.05) 3.70 (0.06) 2.65 (0.09)
7.39 (0.08) 3.57 (0.06) 4.65 (0.05) 3.08 (0.07) 3.31 (0.11) 2.55 (0.10)
6.93 (0.9) 3.45 (0.06) 5.34 (0.07) 3.22 (0.05) 3.38 (0.011) 2.32 (0.08)
1.48 15.56 2.86 1.93 2.41 1.21
Values are the means while standard deviations in parentheses (n = 3, P < 0.05). Bolded values are significant with P < 0.05.
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
598
Fraczek et al.
Fig. 2. Maximum (dark), mean (grey) and minimum (light grey) numbers of the analyzed microbial groups in soils in different seasons [cfu × g−1]. (a) Mesophilic bacteria; (b) Staphylococcus spp.; (c) actinomycetes; (d) mold fungi; (e) C. perfringens; and (f) Salmonella spp.
present in the relatively large area covered with trees that surrounds the landfill.
Conclusion Based on the following study it may be concluded that the remedial measures applied by the examined landfill are efficient enough to prevent the chemical contamination of the surrounding environment. On the other hand, microbiological contamination of soils was still detected, mostly north of the landfill. This may indicate that the waterborne transmission route may not be as effective in the case of the examined landfill, as other ones, e.g., the airborne transmission. To prevent such contamination of the surrounding areas, it would be useful to assure solid isolation barriers yet at the design stage of landfills.
Funding The study was supported by the Ministry of Science and Higher Education in Poland (Project no. N N305 227237).
References [1] Domska, D.; Warechowska, M. The effect of the municipal waste landfill on the heavy metals content in soil. Contemp. Probl. Mgmt. Environ. Protect. 2009, 4, 95–105.
[2] Anikwe, M.A.N.; Nwobodo, K.C.A. Long term effect of municipal waste disposal on soil properties and productivity of sites used for urban agriculture in Abakaliki, Nigeria. Biores. Technol. 2002, 83, 241–250. [3] Renella, G.; Ortigoza, A.L.R.; Landi, L.; Nannipieri, P. Additive effects of copper and zinc on cadmium toxicity on phosphatase activities and ATP content of soil as estimated by the ecological dose (ED50). Soil Biol. Biochem. 2003, 35, 1203–1210. [4] Reynolds, J. Serial dilution protocols. American Society for Microbiology. Microbe Library: Washington, DC, 2005. Available at http://www.microbelibrary.org/library/laboratory-test/ 2884-serial-dilution-protocols (accessed May 2013). [5] Holt J.G., Bergey’s Manual of Determinative Bacteriology, 9th Ed.; Lippincott Williams & Wilkins: Philadelphia, PA, 1994. [6] Carter, M.R.; Gregorich E.G. Soil Sampling and Methods of Analysis, 2nd Ed.; Taylor and Francis: London, 2006. [7] Ayeni, K.E. Heavy metals pollution in selected industrial locations. Contin. J. Renew. Ener. 2010, 1, 9–14. [8] US Environmental Protection Agency (US EPA). Direct AA Mercury Determination in Coal, ASTM D6722–01 EPA7473; Author: Washington, DC, 2006. Available at http://www.plasmatronics. com.br/Det Merc carvao.pdf (accessed May 2013). [9] Rosas, I.; Belmont, R.; Armienta, A.; Baez, A. Arsenic concentrations in water, soil, milk and forage in Comarca Lagunera, Mexico. Water Air Soil Pollut. 1999, 112, 133–149. [10] Dost, K.; Ideli, C. Determination of polycyclic aromatic hydrocarbons in edible oils and barbecued food by HPLC/UV–Vis detection. Food Chem. 2012, 133, 193–199. ´ [11] Konieczynski, P.; Wesołowski, M. Bioavailable inorganic forms of nitrogen and phosphorus in extracts of herbs, flowers and bark of medicinal plants. Chem. Spec. Bioavail. 2007, 19, 109– 115. [12] Bremner, J.M. Total nitrogen. In Methods of Soil Analysis Chemical and Microbiological Properties; Black, C.A., Ed.; American Society of Agronomy: Madison, WI, 1965; 1149–1178.
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
Microbiological and chemical properties in a municipal landfill [13] Cappuyns, V.; Slabbinck, E. Occurrence of vanadium in Belgian and European alluvial soils. Appl. Environ. Soil Sci. 2012, 1–12. [14] Yang, R.; Humphrey, A. Dynamics and steady state studies of phenol degradation in pure and mixed cultures. Biotechnol. Bioeng. 1975, 17, 1211–1235. [15] Polish Ministry of Agriculture and Rural Development. Journal of Laws of the Republic of Poland; No. 02.165.1359; Author: Warsaw, Poland, 2002. Available at http://geoportal.pgi.gov.pl/ css/powiaty/prawo/Dz.U.02.165.1359 standardy jakosci gleb (accessed June 2013). ´ ´ [16] Kalwasinska, A.; Swiontek-Brzezinska, M.; Burkowska, A. Sanitary quality of soil in and near municipal waste landfill sites. Pol. J. Environ. Stud. 2012, 21, 1651–1657. ´ ´ [17] Słomczynska, B.; Słomczynski, T. Physico-chemical and toxicological characteristics of leachates from MSW landfills. Pol. J. Environ. Stud. 2004, 13, 627–637. [18] Tripathi, A.; Misra, D.R. A study of physico-chemical properties and heavy metals in contaminated soils of municipal waste dumpsites at Allahabad, India. Int. J. Environ. Sci. 2012, 2, 2024–2033. [19] Esakku, S.; Palanivelu, K.; Kurian, J. Assessment of Heavy Metals in a Municipal Solid Waste Dumpsite, In Proceedings of Workshop on Sustainable Landfill Management, Dec 3–5, 2003; Allied Publishers Pvt., Ltd.: Chennai, India. 139–145. [20] Obire, O.; Nwaubeta, O.; Adue, S.B.N. Microbial community of a waste-dump site. J. Appl. Sci. Environ. Mgt. 2002, 6, 78–83.
599
[21] Wyszkowska, J.; Kucharski, J.; Borowik, A.; Boros, E. Response of bacteria to soil contamination with heavy metals. J. Elementol. 2008, 13, 443–453. [22] Flores-Tena, F.J.; Guerrero-Barrera, A.L.; Avelar-Gonzalez, F.J.; ˜ C. Pathogenic and opRamirez-Lopez, E.M.; Martinez-Saldana, portunistic Gram-negative bacteria in soil, leachate and air in San Nicolas landfill at Aguascalientes, Mexico. Rev. Latinoam. Microbiol. 2007, 49, 25–30. [23] Hu, Q.; Qu, H.; Zeng, J.; Zhang, H. Bacterial diversity in soils around a lead and zinc mine. J. Environ. Sci. 2007, 19, 74–79. [24] Tobor-Kapłon, M.A.; Bloem, J.; Romkens, P.F.A.M.; d’Ruiter, P.C. Functional stability of microbial communities in contaminated soils. Oikos. 2005, 111, 119–129. [25] Fraczek, K.; Grzyb, J.; Ropek, D. Microbiological hazard to the environment posed by the groundwater in the vicinity of municipal waste landfill site. Ecol. Chem. Eng. S. 2011, 18, 211– 221. [26] Yessiler, N.; Hanson, J.L. Analysis of Temperatures at a Municipal Solid Waste Landfill, In Proceedings of the Ninth International Waste Management and Landfill Symposium, Sardinia, Italy, Oct 6–10, 2003; Christensen, T.H.; Cossu, R.; Stegman, R., Eds.; CISA, 2003; 1–10. [27] Kostadinova, N.; Krumova, E.; Tosi, S.; Angelova, M. Isolation and identification of filamentous fungi from island Livingston, Antarctica. Biotechnol. Biotechnol. SE. 2009, 23, 267–270.
Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances and Environmental Engineering Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lesa20
Assessment of microbiological and chemical properties in a municipal landfill area a
b
Krzysztof J. Frączek , Dariusz R. Ropek & Anna M. Lenart-Boroń a
a
Department of Microbiology , University of Agriculture , Cracow , Poland
b
Department of Agricultural Environment Protection , University of Agriculture , Cracow , Poland Published online: 10 Jan 2014.
Click for updates To cite this article: Krzysztof J. Frączek , Dariusz R. Ropek & Anna M. Lenart-Boroń (2014) Assessment of microbiological and chemical properties in a municipal landfill area, Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances and Environmental Engineering, 49:5, 593-599, DOI: 10.1080/10934529.2014.859464 To link to this article: http://dx.doi.org/10.1080/10934529.2014.859464
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Journal of Environmental Science and Health, Part A (2014) 49, 593–599 C Taylor & Francis Group, LLC Copyright ISSN: 1093-4529 (Print); 1532-4117 (Online) DOI: 10.1080/10934529.2014.859464
Assessment of microbiological and chemical properties in a municipal landfill area 1 ´1 KRZYSZTOF J. FRACZEK , DARIUSZ R. ROPEK2 and ANNA M. LENART-BORON 1
Department of Microbiology, University of Agriculture, Cracow, Poland Department of Agricultural Environment Protection, University of Agriculture, Cracow, Poland
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
2
This study aimed at determining the environmental hazards for soils posed by a large municipal landfilll. The concentrations of heavy metals and Policyclic Aromatic Hydrocarbons, as well as microbial composition (i.e., mesophilic bacteria, actinomycetes, molds, Salmonella, Staphylococcus, Clostridium perfringens) in four soils within and in the vicinity of the landfill were evaluated and compared to waste samples. Both chemical and microbiological analyses revealed only limited contamination of surrounding areas. Although the increased alkalinity of soils was detected, the concentrations of heavy metals and Polycyclic Aromatic Hydrocarbons (PAHs) did not exceed the admissible values. All examined microbial groups were abundant in soil and waste. The highest microbial cell numbers were observed in warm summer and spring months. Although the site south of the landfill shows no trace of microbial contamination, pathogenic bacteria were found north of the landfill. This may suggest that there are other, more effective, transmission routes of bacteria than groundwater flow. Keywords: Landfill, soil contamination, soil microorganisms, pathogenic bacteria, heavy metals.
Introduction One of the consequences of growing industry and population is the process of continuous accumulation of waste in landfills. Such landfills may become a threat for the environment as various components, such as heavy metals or Polycyclic Aromatic Hydrocarbons (PAHs), are continuously leached out and may finally enter groundwater. This, in turn, may decrease its quality and pose a threat for human and animal health.[1] It is generally agreed that the levels of heavy metals and other highly toxic chemicals in municipal waste are low. Nevertheless, long-term dumping of untreated municipal waste and increasing heavy metal content (and therefore toxicity of urban refuse) that results from rapid industrialization, may lead to accumulation of pollutants and increase the potential hazard of municipal landfills.[2] Increased concentrations of soil contaminants, particularly heavy metals, but also PAHs may affect the chemical properties of soils and their biological activity.[3] Therefore, the present study determines the environmental risk for soils posed by a large municipal waste landfill in ´ DepartAddress correspondence to Anna M. Lenart-Boron, ment of Microbiology, University of Agriculture in Cracow, Mickiewicza Ave 24/28 30-059, Cracow, Poland; E-mail: [email protected] Received June 12, 2013.
´ southern Poland. Additionally, the sanitary condiTarnow, tion of soils within the landfill and in its vicinity, as well as of deposited waste, was verified to assess a putative health risk due to the environmental pollution resulting from the ´ neighborhood of the municipal waste landfill in Tarnow, southern Poland.
Materials and methods Soil sampling and study area The field study was conducted within and in the vicinity of ´ launched in 1985. Due to the municipal landfill in Tarnow, its mode of operation and consistently implemented modern waste disposal system, it is currently considered as one of the best organized landfills in southern Poland. In re´ has received almost cent years, the waste landfill in Tarnow 50,000 tons of unsorted municipal waste. In the landfill area, six sampling sites were selected; one within the active and one within the reclaimed sector, and four within areas proximate to the landfill. The field sites were chosen according to the pattern of landfill microbial emissions predicted based on topography, vegetation and groundwater flow direction (Fig. 1, Table 1). Sampling was performed once per season throughout 2 years (2010 and 2011), giving a data set consisting of 8 sampling dates per each site (4 times per year, for 2 consecutive years).
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
594
Fraczek et al.
Fig. 1. Location of the sampling sites within the landfill. Description of sampling sites is given in Table 1.
In the case of soils, for each sampling site, a composite sample (500 g) consisting of 5 subsamples (100 g) was collected in a grid (with a minimum distance between subsamples of 5 m) from the top 20 cm of soil in each season. In the case of wastes – composite samples were composed of 6 subsamples (3 boreholes from the depth of 0–20 cm and 3 from 80–100 cm from the surface). The composite samples were collected into sterile plastic bags and transported to the laboratory for microbiological and chemical analyses. Wastes collected at the examined landfill are mainly a mixture of unsorted municipal (domestic) waste, soil with stones, biodegradable wastes, debris and wastes from cleaning streets. Microbiological, chemical and physical analysis Triplicate fresh subsamples (10 g) were taken from the bulk 500 g sample for the serial dilution method.[4] One mL of 10fold serial dilutions of the samples were inoculated onto nu-
trient agar to enumerate mesophilic bacteria (48 h at 37◦ C), Wort agar for mold fungi (3 days at 28◦ C), Pochon agar for actinomycetes (5–7 days at 28◦ C), SS agar for Salmonella (48 h at 37◦ C), Wilson-Blair agar for Clostridium perfringens (36 h at 35◦ C in anaerobic conditions) and Chapman agar for Staphylococcus (48 h at 35◦ C). After incubation, visible colonies were counted and expressed as colony forming units per gram of soil or waste (cfu × g−1). Presumptive Salmonella spp. colonies were confirmed by streaking on CHROMagar Salmonella Plus (Graso Biotech, Jabłowo, Poland), while the presence of C. perfringens was confirmed using thioglycollate broth with resazurine. Genera of predominant groups of mesophilic bacteria were identified based on microscopic observations of Gram-stained smears, as well as based on biochemical characteristics according to Bergey’s Manual of Determinative Bacteriology.[5] Soil moisture was determined gravimetrically by comparing wet and dry soil weights. Soil pH was determined in distilled water in 1:2.5 solution using an electronic pH-meter with a glass electrode. Soil granulometric composition was assessed by aerometric measurements.[6] Prior to chemical analyses, soils were oven dried at 60◦ C for 90 min. Concentrations of Pb, Cd, Ni, Zn, Cu and Cr were estimated in soils digested with aqua regia followed by atomic absorption spectrometry (AAS).[7] The concentration of Hg was determined using atomic absorption spectrometry RA915+ with application of the pyrolysis technique.[8] The concentration of As was measured using graphite furnace AAS.[9] Contents of chlorides and sulfates both in soil and waste as well as fluorides in waste were determined by ion chromatography. The content of PAHs (naphtalene, phenanthrene, anthracene, fluoranthene, chrysene, benzo(a)anthracene, benzo(a)fluoranthene, benzo(a)perylene, benzo(a)pyrene) was estimated in soil by means of HPLC with UV detection and ultrasonic extraction in dichloromethane.[10] Content of bioavailable phosphorus in soil was measured spectrophotometrically by the molybdenum blue
´ Table 1. Location and characteristics of the sampling sites within the Tarnow–Krzy˙ z municipal waste landfill. Sample no.
Location
1
Soil 1
2
Soil 2
3
Soil 3
4
Soil 4
5
Waste 1
6
Waste 2
GPS coordinates
pH
Description
N50◦ 02’35” E21◦ 01’54” N50◦ 02’54” E21◦ 01’52” N50◦ 02’26” E21◦ 01’58”
8.12
N50◦ 02’21” E21◦ 02’01” N50◦ 02’31” E21◦ 02’51” N50◦ 02’37” E21◦ 02’52”
5.66 n/a
Within the landfill, nearby the active sector Outside the active sector, about 250 m to the north Within the landfill, outside the reclaimed sectors, to the south-east Outside the landfill, about 250 m to the south Within the reclaimed sector
n/a
Within the active sector
5.05 8.28
Sand > 0.1 mm (%)
Dust 0.1–0.02 mm (%)
Clay particles < 0.02 mm (%)
24
40
36
26
41
33
21
38
41
28
39
33
n/a
n/a
n/a
n/a
n/a
n/a
595
Microbiological and chemical properties in a municipal landfill method,[11] while the contents of total nitrogen, vanadium and phenol were assessed according to the methodologies of Bremner,[12] Cappuyns and Slabbinck,[13] and Yang and Humphrey,[14] respectively. The results of heavy metal, PAH and phenol concentrations were compared with Polish regulations.[15] For each group of the processed samples, blanks (sterile deionized water and reagents) were included throughout the entire sample preparation and analytical process.
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
Statistical analysis Statistical analysis of the results was performed using Statistica software (StatSoft, Tulsa, OK, USA). Significant differences between the numbers of microorganisms, isolated from the triplicate subsamples of the composite samples collected at different sites, were assessed by ANOVA with the least significant difference (LSD) test (P < 0.05). Similar analysis was chosen to ascertain seasonal differences in the microbial numbers within the waste. Moreover, Pearson correlation coefficient (r) was used to determine the relationship between the CFU numbers of microbial groups and contaminant concentrations in soil and waste.
Results and discussion The analyses showed that soils surrounding the waste landfill are acidic, while the soils inside the landfill are alkaline (Table 1). The reported values are similar to those obtained
´ by Kalwasinska et al.,[16] who conducted the study within the municipal landfill in Torun´ and also detected an increase in the pH of soils within the landfill, as compared to the background levels. This could have been caused by the effect of landfill leachate, which becomes alkaline (pH 8.0–8.5) over time, especially for long-term exploited landfills.[17] This is the case of the examined landfill that has been operated for over 20 years. Moreover, high alkalinity of municipal waste that contains ashes and slag from the combustion of stone coal and coke in household furnaces can be observed in Polish landfills.[17] The concentrations of chemical contaminants, i.e., metals, phenol or PAHs did not exceed the admissible values in any of the examined sites (Table 2). These results are consistent with the ones obtained by Domska and Warechowska,[1] who studied the effect of the municipal waste on the accumulation of heavy metals landfill in Wegorzewo in soils and did not find any transgressions of the admissible values, even the ones established for agricultural soils. The concentration of vanadium in the examined soil and waste samples is even less than the average concentration generally found in soils.[13] Although the heavy metal concentration in soils did not exceed the admissible values, their concentrations in waste samples was even less. There are conflicting reports on heavy metal concentrations in waste and soils surrounding landfill sites, as Tripathi and Misra [18] or Esakku et al.[19] reported transgressions of the admissible concentrations of heavy metals in waste landfillsurrounding soils.
´ Table 2. Concentrations (mg × kg−1) of total heavy metals and PAHs in different sites of the municipal waste landfill in Tarnow. Contaminant Sites 1 (soil) 2 (soil) 3 (soil) 4 (soil) 5 (waste) 6 (waste) Admissible valuea
Pb (0.5)
Cd (0.05)
Ni (0.4)
Zn (0.4)
Cu (0.8)
Cr (0.2)
Hg (0.005)
As (0.1)
27.4 16.4 10.8 18.6 < 0.30 0.48 50
0.82 0.51 < 0.50 < 0.50 < 0.10 < 0.10 1
24.3 4.71 24.0 < 3.20 < 0.30 0.50 35
67.9 27.4 23.6 29.4 < 0.50 2.35 100
12.0 < 2.40 7.19 2.61 < 0.30 < 0.30 30
5.78 < 2.30 4.82 < 2.30 < 0.50 < 0.50 50
0.067 0.071 0.015 0.056 < 0.005 < 0.005 0.5
< 4.60 < 4.60 < 4.60 < 4.60 < 0.05 0.14 20
Total N (0.1)
Phenol (0.5)
Fluoride (1)
< 0.10 < 0.10 < 0.10 < 0.10 n/a n/a —
< 0.50 < 0.50 < 0.50 < 0.50 n/a n/a 0.05
n/a n/a n/a n/a < 1.00 < 1.00 —
Contaminant Sites 1 (soil) 2 (soil) 3 (soil) 4 (soil) 5 (waste) 6 (waste) Admissible valuea a
V (0.005)
Sulfate (25)
Chloride (25)
PAH (0.5)
15.90 5.90 17.80 9.40 n/a n/a —
29.0 < 25.0 37.3 < 25.0 251 2266 —
< 25.0 < 25.0 < 25.0 < 25.0 269 1144 —
0.82 0.48 < 0.48 < 0.48 n/a n/a 1
Journal of Laws of the Republic of Poland.[15] Least detectable amounts are provided in parentheses.
Bioav. P (1) 4.75 3.16 4.18 5.00 n/a n/a —
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
596
Fraczek et al.
Uncontrolled waste landfills located in sandy areas may contaminate the soil surface layers with heavy metals, particularly Cu and Zn. This is the result of relatively high water permeability of those soil types and thus the easiness of contaminants’ migration into the soil profile.[1] The situation observed in this research, i.e., the relatively low content of chemical pollutants, may be caused by the actively promoted policy aiming at elimination of the most dangerous waste (batteries, electronic scrap, mercury thermometers, etc.) and the fact that the landfill has applied remedial measures for several most recent years. These measures consist in surrounding the landfill with a few dozen to a few hundred meters-wide green belt of trees, construction of the landfill sectors in the form of embanked basins that are sealed with geomembrane liners and drained to collect leachate. Leachate is collected in concrete tanks, where it is pre-treated and then redirected to a municipal treatment plant. The mean value of total mesophilic bacteria in soils ranged from log 5.92 to log 6.32 cfu × g−1 in sites 3 and 1, respectively (Table 3). These fluctuations are not uncommon, e.g., the total number of heterotrophic bacteria recorded by Obire et al. in their studies conducted within a landfill on Eagle Island ranged from log 5.62 to log 6.83 cfu × g−1 soil.[20] The numbers of mesophilic bacteria and C. perfringens in the waste samples collected from the reclaimed sector (site 5) was over twice higher than in site 6. Such result indicates that the number of mesophilic bacteria increased with time even despite the fact that the active usage of the landfill was stopped. However, the numbers of other pathogenic bacteria was much higher in the active sector. For all samples, the most abundant mesophilic bacteria were identified as Bacillus, Clostridium, Corynebacterium, Enterococcus, Salmonella, Staphylococcus and Streptococcus. All these genera have been reported to be associated with waste and waste biodegradation.[20] The highest mean number of actinomycetes was found in site 4. The concentrations of chemical pollutants were very low here, while the bioavailable phosphorus content was the highest, which could have affected the growth of these microorganisms.[21] The highest number of fungi was observed in site 3 (i.e., log 4.81 cfu × g−1 soil),
where pH was alkaline and the recorded value was similar to that ascertained in the waste sample from the reclaimed sector (site 5). The fungal number in the waste sample from the active sector (i.e., log 5.25 cfu × g−1 soil) was higher than that found in the reclaimed sector. This was probably due to the high amount of organic matter and better aeration of waste as compared with other sites. Similar values were reported by Obire et al.,[20] whose research showed that the numbers of viable fungi in soils surrounding the landfill ranged from log 4.26 to 5.40 cfu × g−1 soil. Another group of microorganisms comprised pathogenic and potentially pathogenic bacteria: C. perfringens, Salmonella and Staphylococcus. Both Salmonella and C. perfringens indicate poor sanitary condition of soils.[16] The highest numbers of these pathogens were detected in site 2. Waste samples, collected from the active sector, were characterized by higher number of Salmonella compared to those collected from the reclaimed sector (Table 3). The numbers of Salmonella found in the soil samples may be considered as relatively high; these bac´ teria are not abundant in soils. For instance, Kalwasinska et al.[16] did not detect Salmonella in soils collected near the ´ Similarly, Flores-Tena et al. waste landfill site in Torun. found Salmonella only in air samples, although numerous pathogenic and opportunistic bacteria were reported in soils.[22] The correlation analysis revealed a strong positive relationship between the number of mesophilic bacteria and the concentrations of Pb, Cd, Zn and PAHs (Table 4). This is a surprising result, because it was expected that these environmental contaminants inhibit the bacterial proliferation in soils. However, mesophilic bacteria are a complex and diverse community; hence, the presence of species tolerant to heavy metals and PAHs is not unusual among members of this group.[23] On the other hand, strong negative correlations were found between the numbers of actinomycetes, fungi and Staphylococcus and concentrations of most contaminants. For C. perfringens, the calculated correlation coefficients were generally moderate, while the correlations for Salmonella were negative for all considered factors, but their values were low.
´ Table 3. Numbers (log cfu × g−1)∗ of the selected microbial groups in different sites of the municipal waste landfill in Tarnow. Sites Microrganisms Mesophilic bacteria Actinomycetes Fungi C. perfringens Staphylococcus Salmonella ∗
1 (soil)
2 (soil)
3 (soil)
4 (soil)
5 (waste)
6 (waste)
F value
6.33 (0.08) 4.29 (0.10) 4.50 (0.04) 1.76 (0.08) 2.80 (0.08) 1.32 (0.04)
6.04 (0.06) 4.34 (0.09) 4.56 (0.04) 2.24 (0.11) 2.96 (0.07) 1.79 (0.05)
5.93 (0.05) 4.23 (0.09) 4.81 (0.05) 2.01 (0.08) 2.98 (0.08) 1.52 (0.06)
6.10 (0.06) 4.38 (0.08) 4.58 (0.06) 1.94 (0.07) 2.96 (0.06) Not detected
7.43 (0.11) 3.64 (0.12) 4.86 (0.05) 3.51 (0.10) 3.47 (0.11) 2.16 (0.11)
7.09 (0.09) 3.88 (0.05) 5.25 (0.08) 3.01 (0.12) 3.56 (0.11) 2.73 (0.09)
16.92 2.57 3.06 9.25 5.48 21.22
Values are the means while standard deviations are given in parentheses (n = 3, P < 0.05). Limit of detection (LOD) is 1 cfu. Bolded values are significant with P < 0.05.
597
Microbiological and chemical properties in a municipal landfill
Table 4. Correlation coefficients (r) between the selected soil and waste contaminants and the numbers of microorganisms (n = 3; P < 0.05). Microbial group
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
Mesophilic bacteria Actinomycetes Fungi C. perfringens Staphylococcus Salmonella
Pb
Cd
Ni
Zn
Cu
Cr
Hg
PAH
pH
0.98 0.23 −0.83 −0.54 −0.80 −0.32
0.95 −0.24 −0.52 −0.60 −0.94 −0.15
0.32 −0.91 0.41 −0.56 −0.68 −0.03
0.98 −0.14 −0.59 −0.64 −0.94 −0.24
0.69 −0.67 −0.01 −0.71 −0.92 −0.18
0.51 −0.81 0.22 −0.66 −0.82 −0.12
0.59 0.66 −0.97 0.16 −0.16 −0.12
0.95 −0.87 −0.51 −0.62 −0.95 −0.18
0.29 −0.25 0.46 −0.68 −0.69 −0.22
In general, heavy metals have an inhibitory effect on the growth of bacteria, fungi and actinomycetes.[21] Heavy metals in high concentrations (e.g., exceeding the limits given in the Polish Regulation of the Minister of Environment on soil quality standards) reduce biomass of microorganisms and decrease soil activity, and even if they do not reduce their numbers, they decline microbial biodiversity.[21] Even though the heavy metal concentrations detected in the analyzed landfill do not exceed the limit values, the negative correlations between the numbers of some microbial groups and concentrations of heavy metals, and PAHs were recorded. Toxic effects of these pollutants may lead to changes in the community structure and higher level of physiological adaptation or tolerance.[24] Since municipal waste is a known source of microorganisms, the seasonal variation in numbers of different microbial groups in the waste and soil samples was also compared. The highest mean numbers of mesophilic bacteria and Staphylococcus were observed for soil and waste samples, in summer (Table 5, Figs. 2a, 2b). In general, the greatest abundances of the microbial groups were found in warm seasons, while in winter months, these values were generally low, except for fungi in the waste samples and C. perfringens in the soils (Table 5, Fig. 2e). These results are not uncommon, as summer months, characterized by higher temperatures, promote bacterial proliferation.[25] Only C. perfringens unexpectedly deviates from this pattern. The increased number of molds in winter may be the effect of raised temperature of waste mass [26] and psychrotrophic nature of numerous mold species, which are more tolerant to low temperatures and may grow even below 10◦ C.[27]
Therefore, the inhibitory effect of low temperatures combined with increased temperature of waste may result in the higher numbers of mold fungi in the waste samples, in winter. This study indicates that the long-term exploitation of the landfill site did not have as much adverse effect on the surrounding soil environment as could be expected based on literature data. However, the negative impact of landfills depends greatly on the quality of stored waste. Our results showed low level of heavy metals and PAH contaminants for the waste samples; hence, these compounds might not have polluted the surrounding soils. On the other hand, stored waste was a significant source of various microbial groups, including pathogens. The landfill’s active sector was the abundant source of microorganisms, whereas the microbial numbers detected in the reclaimed sector were even greater. However, the impact of the landfill microbial populations on the adjacent soil environment was limited. The acquired data showed that the sampling sites located south of the landfill lacked some strains specific to the landfill bacterial community. Unexpectedly, such an impact was observed for the sites located north of the landfill, as evidenced by the increased level of Salmonella and C. perfringens. This may suggest that there are other, more effective, transmission routes of bacteria than groundwater flow, as was initially assumed due to the sloping of terrain from north to south. The fact that Salmonella or C. perfringens were not detected in soils south of the landfill may prove the effectiveness of the landfill’s sealing. On the other hand, the occurrence of these bacteria north of the landfill could have been due to the natural sources, such as wild animals that may be
Table 5. Comparison of the numbers (log × cfu g−1)∗ of selected microbial groups in the landfill waste over different seasons. Season Microbial group Mesophilic bacteria Actinomycetes Fungi C. perfringens Staphylococcus Salmonella ∗
Spring
Summer
Autumn
Winter
F value
7.05 (0.08) 3.72 (0.08) 5.12 (0.06) 3.46 (0.04) 3.56 (0.09) 2.56 (0.09)
7.54 (0.07) 4.08 (0.05) 5.03 (0.06) 3.45 (0.05) 3.70 (0.06) 2.65 (0.09)
7.39 (0.08) 3.57 (0.06) 4.65 (0.05) 3.08 (0.07) 3.31 (0.11) 2.55 (0.10)
6.93 (0.9) 3.45 (0.06) 5.34 (0.07) 3.22 (0.05) 3.38 (0.011) 2.32 (0.08)
1.48 15.56 2.86 1.93 2.41 1.21
Values are the means while standard deviations in parentheses (n = 3, P < 0.05). Bolded values are significant with P < 0.05.
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
598
Fraczek et al.
Fig. 2. Maximum (dark), mean (grey) and minimum (light grey) numbers of the analyzed microbial groups in soils in different seasons [cfu × g−1]. (a) Mesophilic bacteria; (b) Staphylococcus spp.; (c) actinomycetes; (d) mold fungi; (e) C. perfringens; and (f) Salmonella spp.
present in the relatively large area covered with trees that surrounds the landfill.
Conclusion Based on the following study it may be concluded that the remedial measures applied by the examined landfill are efficient enough to prevent the chemical contamination of the surrounding environment. On the other hand, microbiological contamination of soils was still detected, mostly north of the landfill. This may indicate that the waterborne transmission route may not be as effective in the case of the examined landfill, as other ones, e.g., the airborne transmission. To prevent such contamination of the surrounding areas, it would be useful to assure solid isolation barriers yet at the design stage of landfills.
Funding The study was supported by the Ministry of Science and Higher Education in Poland (Project no. N N305 227237).
References [1] Domska, D.; Warechowska, M. The effect of the municipal waste landfill on the heavy metals content in soil. Contemp. Probl. Mgmt. Environ. Protect. 2009, 4, 95–105.
[2] Anikwe, M.A.N.; Nwobodo, K.C.A. Long term effect of municipal waste disposal on soil properties and productivity of sites used for urban agriculture in Abakaliki, Nigeria. Biores. Technol. 2002, 83, 241–250. [3] Renella, G.; Ortigoza, A.L.R.; Landi, L.; Nannipieri, P. Additive effects of copper and zinc on cadmium toxicity on phosphatase activities and ATP content of soil as estimated by the ecological dose (ED50). Soil Biol. Biochem. 2003, 35, 1203–1210. [4] Reynolds, J. Serial dilution protocols. American Society for Microbiology. Microbe Library: Washington, DC, 2005. Available at http://www.microbelibrary.org/library/laboratory-test/ 2884-serial-dilution-protocols (accessed May 2013). [5] Holt J.G., Bergey’s Manual of Determinative Bacteriology, 9th Ed.; Lippincott Williams & Wilkins: Philadelphia, PA, 1994. [6] Carter, M.R.; Gregorich E.G. Soil Sampling and Methods of Analysis, 2nd Ed.; Taylor and Francis: London, 2006. [7] Ayeni, K.E. Heavy metals pollution in selected industrial locations. Contin. J. Renew. Ener. 2010, 1, 9–14. [8] US Environmental Protection Agency (US EPA). Direct AA Mercury Determination in Coal, ASTM D6722–01 EPA7473; Author: Washington, DC, 2006. Available at http://www.plasmatronics. com.br/Det Merc carvao.pdf (accessed May 2013). [9] Rosas, I.; Belmont, R.; Armienta, A.; Baez, A. Arsenic concentrations in water, soil, milk and forage in Comarca Lagunera, Mexico. Water Air Soil Pollut. 1999, 112, 133–149. [10] Dost, K.; Ideli, C. Determination of polycyclic aromatic hydrocarbons in edible oils and barbecued food by HPLC/UV–Vis detection. Food Chem. 2012, 133, 193–199. ´ [11] Konieczynski, P.; Wesołowski, M. Bioavailable inorganic forms of nitrogen and phosphorus in extracts of herbs, flowers and bark of medicinal plants. Chem. Spec. Bioavail. 2007, 19, 109– 115. [12] Bremner, J.M. Total nitrogen. In Methods of Soil Analysis Chemical and Microbiological Properties; Black, C.A., Ed.; American Society of Agronomy: Madison, WI, 1965; 1149–1178.
Downloaded by [Selcuk Universitesi] at 05:20 28 December 2014
Microbiological and chemical properties in a municipal landfill [13] Cappuyns, V.; Slabbinck, E. Occurrence of vanadium in Belgian and European alluvial soils. Appl. Environ. Soil Sci. 2012, 1–12. [14] Yang, R.; Humphrey, A. Dynamics and steady state studies of phenol degradation in pure and mixed cultures. Biotechnol. Bioeng. 1975, 17, 1211–1235. [15] Polish Ministry of Agriculture and Rural Development. Journal of Laws of the Republic of Poland; No. 02.165.1359; Author: Warsaw, Poland, 2002. Available at http://geoportal.pgi.gov.pl/ css/powiaty/prawo/Dz.U.02.165.1359 standardy jakosci gleb (accessed June 2013). ´ ´ [16] Kalwasinska, A.; Swiontek-Brzezinska, M.; Burkowska, A. Sanitary quality of soil in and near municipal waste landfill sites. Pol. J. Environ. Stud. 2012, 21, 1651–1657. ´ ´ [17] Słomczynska, B.; Słomczynski, T. Physico-chemical and toxicological characteristics of leachates from MSW landfills. Pol. J. Environ. Stud. 2004, 13, 627–637. [18] Tripathi, A.; Misra, D.R. A study of physico-chemical properties and heavy metals in contaminated soils of municipal waste dumpsites at Allahabad, India. Int. J. Environ. Sci. 2012, 2, 2024–2033. [19] Esakku, S.; Palanivelu, K.; Kurian, J. Assessment of Heavy Metals in a Municipal Solid Waste Dumpsite, In Proceedings of Workshop on Sustainable Landfill Management, Dec 3–5, 2003; Allied Publishers Pvt., Ltd.: Chennai, India. 139–145. [20] Obire, O.; Nwaubeta, O.; Adue, S.B.N. Microbial community of a waste-dump site. J. Appl. Sci. Environ. Mgt. 2002, 6, 78–83.
599
[21] Wyszkowska, J.; Kucharski, J.; Borowik, A.; Boros, E. Response of bacteria to soil contamination with heavy metals. J. Elementol. 2008, 13, 443–453. [22] Flores-Tena, F.J.; Guerrero-Barrera, A.L.; Avelar-Gonzalez, F.J.; ˜ C. Pathogenic and opRamirez-Lopez, E.M.; Martinez-Saldana, portunistic Gram-negative bacteria in soil, leachate and air in San Nicolas landfill at Aguascalientes, Mexico. Rev. Latinoam. Microbiol. 2007, 49, 25–30. [23] Hu, Q.; Qu, H.; Zeng, J.; Zhang, H. Bacterial diversity in soils around a lead and zinc mine. J. Environ. Sci. 2007, 19, 74–79. [24] Tobor-Kapłon, M.A.; Bloem, J.; Romkens, P.F.A.M.; d’Ruiter, P.C. Functional stability of microbial communities in contaminated soils. Oikos. 2005, 111, 119–129. [25] Fraczek, K.; Grzyb, J.; Ropek, D. Microbiological hazard to the environment posed by the groundwater in the vicinity of municipal waste landfill site. Ecol. Chem. Eng. S. 2011, 18, 211– 221. [26] Yessiler, N.; Hanson, J.L. Analysis of Temperatures at a Municipal Solid Waste Landfill, In Proceedings of the Ninth International Waste Management and Landfill Symposium, Sardinia, Italy, Oct 6–10, 2003; Christensen, T.H.; Cossu, R.; Stegman, R., Eds.; CISA, 2003; 1–10. [27] Kostadinova, N.; Krumova, E.; Tosi, S.; Angelova, M. Isolation and identification of filamentous fungi from island Livingston, Antarctica. Biotechnol. Biotechnol. SE. 2009, 23, 267–270.
