Paste your esGalit Milstein
Grade 12
Yeshiva College
“Using Sagina Subulata (Irish moss) as a bio-indicator to monitor pollution levels in the environment”
Table of contents
Title page ………………………………………………………………………….1
Table of contents ………………………………………………………………2
Introduction …………………………………………………………………3 – 6
• General introduction
• Context
• Aim
• Hypothesis
• Scope
Literature Review ………………………………………………………. 6 – 12
Method ………………………………………………………………. 13 – 14
Results ……………………………………………………………………….15 – 19
Discussion ………………………………………………………………….19 – 21
• Analysis, significance and implications of results
Conclusion …………………………………………………………………22
Reference list …………………………………………………………….23 – 25
Plagiarism report …………………………………………………….…26
Introduction
General Introduction
Human impacts on the environment have become a major issue, with pollution being one of the biggest problems. Different types of pollution, whether present in land, air or water, will ultimately affect soil quality and, therefore, potentially cause the pH of the soil to change. pH is a measure of the hydrogen concentration of a substance. It is a number which expresses the acidity or alkalinity of a solution. 7 is a neutral pH. Values lower than 7 are more acidic (acids are substances which can release a hydrogen ion) and those higher than 7 are more alkaline (bases are substances which can donate a hydroxide ion). Depending on the type and extent of pollution, soil pH can be drastically affected. (Amil, et.al, 2011) This has become a major problem for plants growing in these types of polluted soil. The majority of plants grow optimally at a neutral pH of between 6 and 7. If the pH increases (the soil becomes alkaline) or the pH decreases (the soil becomes acidic) it will be difficult for certain plants to survive in these harsh environments (Jacobson, et.al, 1984). The pH of soil affects the amounts of nutrients and chemicals that are soluble in the soil water, thus decreasing the amounts of nutrients available to plants (examples of these nutrients include phosphorus, calcium and magnesium). Some nutrients are more available under acid conditions, while others are more available under alkaline conditions. pH of soil changes constantly as it is affected by rainfall patterns, decomposing organic matter and bacterial activity in the ground. pH affects the diversity of microbial species in soil as many microbes are unable to tolerate extremes of pH. Microbial enzymes are inactivated at extreme pH’s, preventing microbial activity in the soil. If soil is too acidic or too alkaline, there is an overall adverse effect on the growth of plants. Photosynthesis is affected and there are abnormalities in nitrogen and sulphur metabolism in the plant. Heavy metals are elements that display metallic properties. Examples include copper, iron and lead. Heavy metals occur naturally in soil in small amounts. Heavy metal pollution of soil occurs from industries, mines, waste disposal, fertilizers and pesticides. Heavy metal pollution of soil is hazardous to plants, animals, humans and ecosystems (Chibuike, et. al, 2014).
Acid rain is a common phenomenon resulting from air pollution and is formed when sulphur dioxide or nitrogen oxide reacts with water vapour to form sulphuric acid or nitric acid. These acidic substances become part of clouds and then fall to the earth as acid rain. Acid rain is very detrimental to plants since the acidic rain water forms part of the soil that the plants are growing in and this alters the pH of the soil, making the soil more acidic. For most plants, optimal pH for growth is neutral, but there are certain plants that thrive in either acid or alkaline conditions. As the soil pH drops, plants suffer visible symptoms. These include yellow spots on the leaves developing into brown colouration or other discolouration of the leaf and death of the leaf. The leaves may wilt and have blunted leaf tips. There may be yellowing of foliage. There may be a general stunting of growth of the plant. This includes poor stem development. Root development may also be affected when the root is unable to elongate as a result of abnormal cell division.
Soil acidity can be corrected by liming the soil using dolomitic limestone, consisting of magnesium and calcium carbonate. Calcium carbonate is found in shells, skeletons and corals. As lime dissolves in soil, calcium moves to the surface of the soil, reducing the acidity (Buni, 2014).
The incidence of acid rain world-wide is significant in Eastern Europe (Germany, Poland, Switzerland), Eastern United States and is increasing in China and India. These are countries with high levels of pollution from factories and cars, causing acid rain (Wondyfraw, 2014).
Mpumalanga, in South Africa contains about half of South Africa’s maize lands. It also has 12 coal burning power plants, the most in South Africa. Levels of air pollution In Mpumalanga are the highest in the country and amongst the highest in the world. This poses significant environmental and health risks (The Guardian, 2014).
Context
Bio indicators are living organisms that can be used to monitor the health of an environment. They are used in both aquatic and terrestrial environments. Some examples of bioindicators include moss, lichen, frogs, aquatic insects, algal species and marine seaweeds. Bioindicator species effectively indicate the condition of the environment because of their moderate tolerance to environmental variability. Characteristics of an effective bioindicator include:
• Good indicator ability- they can provide a measurable response as they are sensitive to the environmental stress, but will not die from it. They respond in proportion to the degree of contamination. Their response reflects the response of the ecosystem.
• Abundant and common- the biomarker has an adequate local population density, is common and relatively stable.
• Well studied- the biomarker is ecologically well understood. It is easy and cheap to study.
• Economically or commercially important- the biomarker is being harvested for other purposes and there is a public awareness of the species. Some examples of bioindicators include moss, lichen, frogs, aquatic insects, algal species and marine seaweeds (Holt, et. al, 2011)
Sagina Subulata (Irish moss) was chosen for this experiment as it is a potential bioindicator of air pollution (specifically acid pollution for this project). Sagina Subulata is indigenous in Europe from Iceland to Spain. It is also indigenous in Southern Sweden and Romania. It is not indigenous in South Africa, but it is grown here as it is one of the best low growing ground covers [Perennials.com].
Mosses lack a real root system or a well developed cuticle layer. They therefore absorb nutrients and heavy metals directly from the atmosphere (Zhou, et. al, 2017).
Moss displays habitat diversity, has a simple structure, grows rapidly and has a high capacity for metal accumulation. In view of its ability to grow quickly, it is possible to collect and record results in a short period of time.
This particular topic was chosen as it is important to identify effective bio-indicators that are fast growing and can be used to assay pollution levels.
Aim
To determine if moss is a sensitive bio-indicator to monitor pollution levels in the environment, by exposing growing moss plants to different levels of acidity (simulating acid rain).
Hypothesis
Moss is a sensitive bio-indicator to monitor levels of air pollution (in the form of acid rain).
Scope
Sagina Subulata (Irish moss) was grown and exposed to different levels of acidic conditions. The growth of these plants was monitored over a period of 4 weeks and all results were collected, recorded and analysed.
Acid rain has two aspects. It deposits acidity as well as nutrients such as sulphur and nitrogen (Wondyfraw, 2014). Acid mine drainage is the flow of polluted water from old mining areas. The water may contain high levels of salts, sulphates, iron and toxic metals. The contaminated water can pollute the soil and rivers, making them acidic, lowering their pH. Acid mine drainage is prevalent in Gauteng (Greenpeace Africa, 2011).
It has been noted that pollution levels are best monitored when using moss and lichen together due to the difference in their metal uptake and retention (Szczepaniak, 2003).
This research investigated whether moss can be used to indicate low pH levels in soil.
Literature review
Various studies have been performed since the 1970’s to the present time to assess the effectiveness of moss as a bioindicator for heavy metal air pollution.
Europe, Asia, Africa and North America have been involved in large-scale monitoring surveys of the levels of heavy metals in the air. China has been lagging behind Europe in terms of surveying heavy metal pollution. In a recent study, (Zhou, et.al, 2017), Haplocladium microphyllum, a species of moss indigenous to Taizhou, in the Jiangsu Province in China, was used as a bioindicator for heavy metal air pollution. Taizhou is a region that has undergone rapid urbanization and as a result it consists of 34 000 industrial enterprises, including electrical, chemical, building material, pharmaceutical and textile industries. Samples of moss were collected from 60 sites. The moss was dried, ground into powder, placed in flasks, wet digested until they became solutions and concentrations of heavy metals were measured by coupled plasma atomic emission spectroscopy. Results showed that the levels of cadmium and mercury were exceptionally high and the government was informed of the results.
Conclusions from the study regarding the use of moss analysis to detect metal deposition were that it is a suitable technique for monitoring atmospheric pollution. Furthermore, measuring pollutant levels in bioindicators is less costly than using instruments, making it possible to collect large numbers of samples.
Figure 1a : Location of Taizhou in China Figure 1b: Location of 60 moss sampling sites in Taizhou
Int. J. Environ. Res. Public Health 2017, 14, 430 3 of
Figure 2: Table illustrating potential ecological risk assessment of heavy metals in Taizhou following atmospheric deposition.
Int. J. Environ. Res. Public Health 2017, 14, 430 3 of
Elements Range Mean Ecological risk level
Cd 11.90-833.33 250.89 Very high
Cr 0.17-2.15 0.79 low
Cu 3.25-26.13 10.76 low
Hg 36.82-219.38 135.17 considerable
Ni 1.10-9.00 3.92 low
Pb 1.67-17.07 8.43 low
Zn .01-17.51 3.72 low
In an earlier study, Zahari, et. al, (2014) evaluated the levels of certain heavy metals that were deposited in a specific industrial area and aimed to identify what was causing the deposition of these heavy metals. Pieces of moss and the topsoil were collected from the industrial area. Only the youngest segments of the moss plants were selected. These young segments showed tissue production of the last three years. This ensured that the experiment was conducted on recently grown plants therefore showing recent soil pollution. This supported the use of accurate standards and consequently accurate results.
The following elements were analysed in this investigation; iron, zinc, manganese and nickel. All the data that was acquired in this investigation was checked and verified by several scientists. The final results that were obtained show that the heavy metals were not evenly distributed in the industrial area because only iron appeared in the moss tissue and zinc, manganese and nickel were found in the topsoil. From this experiment it was discovered that moss cannot take up all heavy metals. It is an indicator for the presence of only certain heavy metals. This study also shows that moss is able to absorb elements directly from the atmosphere.
Figure 3: A table showing the different species of Bryophytes and which heavy metal pollutants they are able to detect
Different species of Bryophytes Heavy metals detected
Philonotis fontana Pb
Pohlia nutans Cu
Merceya ligulata Cu, Fe
Merceya gedeana Cu, S
Bryum psedotriquetrum Pb, Zn
Dicranella varia Pb, Zn
Fontinalis antipyrietica Zn
Hypnum cupressiforme Pb
Plagiothecium denticulatum Pb,Cu,Zn
Physcomitrium pyriforme Pb,Cu,Zn, Mn
Hydrogonium gracilentum Pb
http://isebindia.com/05_08/07-10-3.html
The European Moss survey has been monitoring heavy metal deposition from the atmosphere since 1990. There are thousands of moss sampling sites across Europe. It is relatively cheap to collect mosses. This enables useful monitoring information to be obtained every five years.
Nitrogen pollution is a big threat to biodiversity, ecosystem services and human health. Nitrogen is leached from the soil into lakes and rivers where it causes eutrophication (increase in the algal population which starves the water of oxygen and harms plant and animal life). Mosses are very good at absorbing nitrogen and therefore prevent nitrogen from leaching into the water. However, if mosses become overloaded with nitrogen, it is detrimental to them.
Spatial distribution of nitrogen in mosses appears to mirror atmospheric nitrogen deposition across Europe to a high degree and is a potentially valuable tool for identifying areas at risk from high nitrogen deposition.
Multiple moss samples are collected between April and October, during the wet season in Europe. The moss samples are cleaned and are then dried with heat. The concentration of heavy metals is measured using analytical techniques such as plasma emission or mass spectroscopy. The Moss Survey Co-ordination Centre performs data processing, construction of maps and the final report. (Howard, et. al, 2015).
Figure 4: Countries participating in the European Moss Survey 2010/11. All 26 countries will report on heavy metals, 14 countries will report on nitrogen and 6 countries will report on selection POP’s (persistent organic pollutants) concentration in mosses: http://flnp.jinr.ru/naa
Moss growing on urban trees in Portland, Oregon, can be used to detect cadmium air pollution (US Forest service Pacific Northwest Research Station). Even though moss has only been recently used as a bioindicator to help monitor environmental health; it has been used for decades by the forestry industry for the same purpose. The Pacific Northwest Research Station started research on moss in 2013. The research involved seven scientists. The study used a large sample (346) of moss (Orthotrichum lyellii), a species of moss that grows on trunks of hardwood trees in Portland. Samples were gathered from a random grid of trees. Refer to figure 4. Accuracy of results in this study was determined by the fact that many scientists were involved in this research, and a large sample size was randomly obtained. However, by using one species of moss, it does not predict if all moss species will react in the same manner.
The results from the tests revealed two big hotspots of cadmium levels in moss. The DEQ placed a mobile air-quality monitoring instrument at the two hotspots and took continuous readings for a month. This was done to verify that the moss plants had correctly picked up levels of the heavy metal. Their results then correlated with the results that were achieved when using the moss plants. This indicated that the moss plants were excellent bioindicators of heavy metals found in the atmosphere. Since moss was a successful bioindicator for cadmium, scientists are currently working on moss being able to identify 22 other metals in the atmosphere (USDA Forest Service Pacific Northwest, Research Station Portland, 2016).
Figure 5: Map showing the relative cadmium levels in moss that were placed at the different locations around Oregon
http://dx.doi.org/10.1016/jscitotenv,2016
Folkeson (1979) determined the effect of different concentrations of heavy metal air pollution on nine different moss and lichen species. Iron, copper, zinc, lead, nickel and cadmium were used in different concentrations. The species of lichen and moss was taken from 57 locations in coniferous woodlands in Sweden. It was found that the moss frequently showed higher metal concentrations than the lichen. This meant that the moss was a better indicator of the pollution caused by heavy metals.
Figure 6: a) Map showing the Pb contents in moss species taken from different countries (Netherlands, Germany and Poland), using moss samples taken during 1990-1992 (Herpin et al. 1996); b, c) two moss species out of the four used in the investigation are bio indicators / bio monitors for controlling the atmospheric deposition of different chemical elements
http://www.eisn-institute.de/fields-of-teaching-research-and-management/bioindicators-biomonitors/examples-for-biomonitoring/
The research studies discussed above relate to moss plants being used as bio- indicators of atmospheric heavy metal pollution. This relates to the current hypothesis being tested. However, the investigations above measure the concentration of heavy metals within the moss plants and are carried out in large areas over long periods of time. The current research will only focus on how air pollution (acid rain) affects the growth of the moss plants.
Method
• Moss plants were purchased from Schaffler’s Nursery at the end of February 2017. The species of the moss is Sagina Subulata, which is Irish moss. The moss plants were all the same age and had already grown to a seedling stage.
• A thin layer of soil (100g) was placed into 7 shallow pots. The pots are round. They are 9cm high and 26cm in width.
• The garden soil is Premium Potting Soil, consisting of a blend of composted bark coco peat and ‘’Just Organic Fertilizer’’, 100% organic. It was purchased from Schaffler’s Nursery.
• The soil was evenly spread in the pot. The amount of soil was measured with a scale.
• Segments of equal size (16 cm²) of the moss plants were placed firmly into the soil surface in each pot.
• The pots were labelled pH 1 to PH 7 using a marker.
• The pots were placed in a shady area on a table on a covered veranda.
• Serial dilutions of the 0.1M hydrochloric acid were prepared as follows:
1. Solution 1- 100ml of HCl, pH1
2. Solution 2- 10ml HCl added to 90ml distilled water, pH 2
3. Solution 3- 10ml of solution 2 added to 90 ml distilled water, pH3
4. Solution 4- 10ml of solution 3 added to 90ml distilled water, pH4
5. Solution 5-10 ml of solution 4 added to 100ml distilled water, pH5
6. Solution 6-10 ml of solution 5 added to 90ml distilled water, pH 6
7. Solution 7- 100ml of distilled water, pH 7 (control)
• Each container had a total volume of 100 ml.
• pH sticks were used to verify the different pH levels to ensure that they were accurate.
• The solution from each container was transferred to its own sealed, labelled bottle for storage until needed.
• A syringe was used to measure the amount of solution that was placed in each bottle.
• 15 ml of each solution was used to water the respective pot plants. For example, pH 1 solution was used to water moss plant in pot labelled pH 1, etc. A syringe was used for this.
• The pot plants were watered every third day at 7am over a four week period.
• Each week results were recorded, showing the growth rate of the different moss plants by looking at how big an area they actually spread across. This was done by placing a piece of transparent plastic over the growing moss plant and cutting the plastic around the growth. The plastic was then stuck on to a sheet of paper and the length and breadth of the growth was measured. This was then used to calculate the area of the growth. By doing this many times, an average could be calculated at the end of the experiment.
• The height of the moss plant was measured using a ruler from the base of the moss to the highest point of its growth.
• The length of time of the moss survival and change in colouration of the leaves of the different moss was also recorded.
• All results were collected and recorded into a table and then plotted onto different graphs. These results were then analysed, so that appropriate discussions and conclusions could be made.
• There are no ethical considerations to take into account since the experiment was carried out on a small scale so there was no destruction to wildlife and there was no human threat. Few moss plants were used in the investigation, so there was no depletion of resources.
Results
Figure 7 : Graph showing growth in area (cm²) of moss plants over a 4 week period after being watered with solutions of pH ranging from pH 1 to pH 7
• The initial area of the moss plants was 16cm². After being watered with solutions of hydrochloric acid and distilled water, ranging in pH from 1-7, the area of the moss plants was measured weekly over a 4 week period.
• The results showed a decrease in the area of the moss plants when watered with solutions of pH 1 at the end of week 4 of the experiment.
• The areas of the moss plants watered with solutions of pH 2 and pH 3 remained the same at the end of week 4.
• The area of the moss plants watered with solutions of pH 4, 5, 6,7, increased, with the largest increase in the moss plant watered with the solutions of pH 6 and pH 7.
Figure 8: Table showing the average increase in the area of moss plants over 4 weeks watered with solutions of pH ranging from pH 1 to pH 7
pH % INCREASE IN AREA OF MOSS
pH 1 -9.4% (negative)
pH 2 0%
pH 3 0%
pH 4 14.1%
pH 5 19.1%
pH 6 25.1%
pH 7 25.1%
Figure 9: Graph showing growth in height over 4 weeks of moss plants watered with solutions of pH ranging from pH 1 to pH 7
• The height of the moss plants was measured over a four week period.
• The initial height of the moss plants before the experiment was started was ½ cm.
• The results showed a decrease in height of the moss plants watered with a solution of pH 1.
• The height of the moss watered with a solution of pH 2, remained the same.
• The height of the moss watered with the solution of pH 3 increased slightly.
• The heights of the moss plants watered with solutions of pH ranging from pH 4-7 increased, with the largest increase in the height of the moss plant watered with the solution of pH 6.
Figure 10 : Table showing colour changes in moss plants over a 4 week period after being watered with a solution of distilled water and hydrochloric acid with a range of pH 1 to pH 7
pH Week 1 Week 2 Week 3 Week 4
pH 1 black black black black
pH 2 green yellow yellow yellow
pH 3 green green yellow yellow
pH 4 green green green green
pH 5 green green green green
pH 6 green green green green
pH 7 green green green green
Figure 11: Table showing survival of plants over 4 weeks after being watered with a solution of distilled water and hydrochloric acid with a range of pH 1 to pH 7
Week 1 Week 2 Week 3 Week 4
pH 1 died died died died
pH 2 grew slowly dried out dried out dried out
pH 3 grew slowly grew slowly dried out dried out
pH 4 grew slowly grew slowly grew slowly grew slowly
pH 5 grew grew grew grew
pH 6 grew grew grew grew
pH 7 grew grew grew grew
Discussion
Analysis, significance and implications of results
The growth of Sagina Subulata was measured after the moss plants were exposed to solutions with a pH value ranging from pH 1 to pH 7. The growth was assessed by measuring the changes in the area of the moss plants and by measuring the changes in the height of the moss plants. Figure 7 shows the changes in the area of the moss plants when watered with solutions of pH 1 to pH 7.The results show that when Sagina Subulata (Irish moss) was exposed to varying levels of acidity, ranging from pH 1 to pH 7, the plants grew at a pH between 4-7, with optimum growth noted at a pH of 6.The plants exposed to pH 1 died after a few days and were burned by the hydrochloric acid. The areas of the plants exposed to pH 2 and pH 3 remained the same. The area of the plants exposed to pH 4-7 increased, with the largest increase in the plants exposed to pH 6 and pH 7 (36cm).
With regard to increases in height of the moss plants, figure 9 shows that the plants exposed to pH1 did not increase in height, plants exposed to pH 2, remained the same in height, plants exposed to pH 3 increased slightly in height, plants exposed to pH 4-7 increased in height, with the plants exposed to pH 6 growing the highest to 5cm. The plants exposed to pH 7 grew in height to 3cm.
Figure 10 shows the colour changes of the plants exposed to the different pH values. The plants exposed to pH 1, discoloured to black within the first few days of the experiment. The plants exposed to pH 2 discoloured to yellow during the first week. The plants exposed to pH 3 discoloured to yellow in the third week. The plants exposed to pH 4, 5, 6 ,7 remained green for the duration of the experiment.
Figure 11 shows the survival of the moss plants over one month after being exposed to solutions ranging from pH 1 to pH 7. Plants exposed to pH 1, died within the first few days of the experiment. Plants exposed to pH 2 did not show growth in area or height of the moss plant and discoloured and dried out between weeks 2 and 3. Plants exposed to pH 3 grew slowly and discoloured and dried out between weeks 3 and 4. Plants exposed to pH 4-7 grew at a slow to moderate pace and remained green and alive at the end of the 4th week of the experiment.
Most plants grow by absorbing nutrients from the soil. The ability of a plant to do this depends on the nature of the soil. The make- up of the soil (sand, silt, clay and organic material) and the soil acidity (pH) determine the extent to which nutrients are available to plants.
Even though Sagina Subulata is not indigenous in South Africa, it is grown locally as it is a popular groundcover plant. Its properties are therefore well documented. It does not grow well in conditions of drought and soggy, wet soil. Soil pH requirements for optimal growth range are between 5.8 to 6.2. Growth is generally at a slow to medium rate (Whipker, 2015).
The major impact that extremes in PH have on plant growth are related to the availability of plant nutrients or the soil concentration of plant toxic materials.
In highly acidic soils, aluminium and manganese can become more available and are toxic to the plant. Acid rain is one of the causes of release of toxic substances such as aluminium into the soil. At low pH levels, beneficial nutrients such as calcium, phosphorous and magnesium are less available to the plant.
Furthermore, low pH decreases microbial populations which convert nitrogen and sulphur into forms that the plant can use.
With regard to the effect of pH on the rate of photosynthesis, it has been shown that when the soil pH is not optimum for a certain plant, the enzymes involved in photosynthesis slow down or denature. Optimum pH for photosynthesis in a moss plant is pH 6 (Heber, et. al, 1976).
In a study performed to assess the effects of simulated acid rain on Boreal Forest Floor Feather moss, the effect of five years of treatment with simulated acid rains ranging in pH from 2.5-5.6 on Canadian boreal forest floor feather moss and lichens was studied. The results showed overall that at pH 5.6, the mosses grew better than at lower pH values. In a second experiment, the growth and chlorophyll content was measured after two years of being sprayed with a solution with a pH of 3.2. It was shown that photosynthesis was inhibited after a five year spray programme with solutions of pH less than 3.5. It was also shown that all acidic sprays caused substantial depletion of calcium and magnesium in shoot tips (Hutchinson TC, 1987).
The results obtained in this research are in keeping with the published literature that there is an optimum pH level (pH 6) at which moss grows maximally and at which the enzyme systems for photosynthesis work the best. As discussed, at pH levels of 1-3, moss does not grow well and eventually discolours and dies. Moss grows at pH levels between 4-7, but shows optimal growth at pH 6.
Even though methodology involving the use of moss as a bioindicator has become more sophisticated over time, the literature supports the fact that mosses are ideal for monitoring trends in deposition of pollutants over time and across places.
It is important to use bioindicators for the monitoring of air pollution as it causes seven million premature deaths annually world-wide, making poor air quality one of the most severe environmental health risks in the world (Zhou, et.al, 2017).
Conclusion
The hypothesis of this research project is that moss is a sensitive bio-indicator to monitor levels of air pollution, specifically acid rain. According to the literature, moss is a suitable bio-indicator for monitoring atmospheric pollution. Furthermore, moss and lichen are complementary in monitoring air pollution levels.
The main findings in this research project supported the hypothesis, that moss is a sensitive bio-indicator to monitor acid rain. The results generally showed that at low pH levels (pH 1-3), the moss plants did not grow well. The moss plants grew when exposed to solutions with a pH ranging from 4-7, with the optimum growth being noted at a pH of 6. These findings concur with those in the literature.
The investigation in this research project was performed on a small, simple scale. One species of moss was used (Sagina Subulata) and one type of pollution was looked at (acid rain). The solutions which were used to water the moss plants were not identical to that of acid rain, but suggestive of it. Additionally the effects of the range of pH solutions on the moss plants mimicked what is observed on a larger scale in nature.
In order to make the research project more scientifically accurate, perhaps lichen and moss can be used in combination for monitoring acid rain. Additionally, more accurate measurements of toxic substances in the moss plant can be considered.
Reference List
1.Amil, A, Riaz S, Ashraf M, Foolad M.R, “Gene expression profiling of plants under salt stress,” Saudi Journal of Biological Sciences, vol.30 (5), 435-458, 2011. Available at:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4336437/
(Accessed 9th August 2016 at 16h00)
2.Buni, A, “ Effects of liming acidic soils on improving soil properties and yield of Haricot bean”, Journal of Environmental and Analytic Toxicology, vol. 5 (1), 1-4, 2014.
Available at: http://dx.doi.org/10.4172/2161-0525.1000248
(Accessed 15th June 2017 at 20h00)
3.Chibuike, G.U, Obiora S.C, “Heavy metal polluted soils: Effects on plants and bioremediation methods”, Journal of Applied and Environmental Soil Science,vol (2014), 1-12, 2014. Available at:
http://www.hindawi.com/journals/aess/2014/752708
(Accessed 24th April 2017 at 20h00)
4.Folkeson L, “Interspecies calibration of heavy-metal concentrations in nine mosses and lichens,” Water, Air and Soil Pollution, vol. 11(2)
253 – 260, 1979. Available at:
http://link.springer.com/article/10.1007%2FBF00286637?LI=true
(Accessed 6th February 2017 at 20h00)
5.Greenpeace Africa: Acid mine drainage in Johannesburg, 27 January 2011. Available at:
http://www.greenpeace.org/africa/en/news/Ac
(Accessed 15th June 2017 at 20h30)
6.Heber,U, Andrews, T.J, “Effects of pH and oxygen on photosynthetic reactions of intact chloroplasts”, Journal of Plant Physiology, vol 57 (2), 277-285, 1976. Available at: http://www.ncbi.nlm.nih.gov/pms/articles/PMC542007/
(Accessed 20th June 2017 at 20h00)
7.Holt, E.A, Miller, S.W, “Bioindicators: Using organisms to measure environmental impacts”, Nature Education Knowledge, volume 2 (3)8, 2011. Available at:
http://www.nature.com/scitable/knowledge/library/bioindicators
(Accessed 22nd May 2017 at 21h00)
8.Howard, C.M, Sutton, M.A, “European Nitrogen Assessment.” European Science Foundation. Chapter 2. 12-20, 2015
Available at:
http//www.nine-esf.org/node/360/ENA-book.html
(Accessed 11th May 2017 at 20h00)
9.Hutchinson, T.C, “Lead, Mercury, Cadmium and Arsenic in the Environment. Scope 3.” Chapter 3, 35-41, 1987. Available at:
http://www.dge.carnegiescience.edu/SCOPE 31
(Accessed 8th May 2017 at 14h00)
10.Jacobson J.S, Troiano J, Heller L, “Stage of Development Response and Recovery of Radish Plants from Episodic Exposure to Simulated Acidic Rain,” Oxford Journals – Journal of Experimental Botany, vol. 36 (1),
159 -167, 1984.
Available at:
http://jxb.oxfordjournals.org/content/36/1/159.abstract
(Accessed 9th August 2016 at 18h00)
11.Szczepaniak K, “Aspects of the biomonitoring studies using mosses and lichens as indicators of metal pollution,” Environmental research, vol 93 (3), 221 – 230, 2003. Available at:
http://www.sciencedirect.com/science/article/pii/S0013935103001415
(Accessed 6th February 2017 at 20:10pm)
12.The Guardian: “South Africa’s coal-fired power stations carry heavy health costs”, 09/09/2014. Available at:
http://www.the guardian.com/global-development
(Accessed 15th June 2017 at 21h00)
13.U.S. Forest Service Pacific Northwest Research Station, “Moss is a useful bio indicator of cadmium air pollution,” Science Journal of the Total Environment, vol. 2 (2), 550 – 565, 2016.
Available at:
https://www.fs.fed.us/pnw/news/2016/04/moss-study.shtml
(Accessed 16th June 2017 at 20h00)
14.Whipker,B: e-gro. Volume 4 (2), January 2015. Available at:
http://www.e-gro.org/pdf/2015-402.pdf
(Accessed 16th June 2017 at 20h00)
15.Wondyfraw,M, “Mechanisms and effects of acid rain on the environment”, Journal of Earth Science and Climatic Change, vol 5 (6), 1-3, 2014
Available at: http://dx.doi.org/10.4172/2157-7617.1000204
(Accessed 13th February at 20h00)
16.Zahari M, Abdullah R, Asiah I Izzati N, “Statistical analysis of heavy metal concentration in moss and soil as indicator of industrial pollution,” International Journal of Science, Environment, vol. 3, (3), 762 – 775, 2014.
Available at: http://www.ijset.net/journal/305.pdf
(Accessed 13th February 2017 at 20h20)
17.Zhou, X, Chen, Q, Liu, C, Fang, Y, “Using Moss to assess airborne heavy metal pollution in Taizhou, China”, International Journal of Environmental Research and Public Health, vol. 14 (4), 430-440, 2017
Available at: http://www.ncbi.nlm.nih.gov/pubmed/28420186
(Accessed 26th April 2017 at 20h30)
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