Effect Of Disinfectants Used As Floor Cleaners On The Growth Of Plants

Does the growth of mung beans (Vigna radiate), measured in terms of seed vigour index depends on the concentration (measured in terms of volume percentage) of commonly used disinfectants – Lysol and Dettol exposed to the seeds?

Being an inquirer, observing phenomena and using my scientific knowledge and principles to analyze or explain them are my forte. The idea of the current investigation originates from a daily life observation. It was unfortunate to note that the potted plants in the small garden on our terrace were dying all of a sudden. While trying to find the reason behind this, it was found that our maid was disposing the unused water used for mopping floors on them. To delve further, it came to my mind that it may be the floor cleaners which she mixed in the water which may have caused these plants to die. Floor cleaners are disinfectants dissolved in alcohols. Most of them contain ammonia solution and are usually acidic in nature. They are mainly used to kill germs and bacteria on the floor and remove stains. When plants are exposed to them, various metabolic processes in them like synthesis of chlorophyll, water uptake by root hair cells, germination of seeds are disturbed. The chemical composition of floor cleaners depends on the type of it and thus the effect will vary too. The focus of this investigation is to understand is two -fold; firstly to understand that whether the percentage concentration of floor cleaner used has any effect on the growth parameters of plant or not; secondly to understand if there is any significant difference between the effect that a floor cleaner has on the plant and the type of it. We use a lot of household chemicals everyday for various purposes and most of them are either surfactants or ammonia based. But how do we dispose them? Do we follow any customized safe disposal method? In most cases, we do not as we just simply dump them into the drainage system which seeps into the water that plants use. In this way, disposal of household chemicals has been a major reason of water pollution and has a detrimental effect on the ecosystem. The relevance of the current investigation lies in the fact that how this sort of water pollution are affecting the growth of plants.

Mung beans(Vigna radiate ) are one of the essential part of daily nutrition and is a chief source of protein for vegetarian diet. It is used to obtain sprouts. Although, India is the main source of these plants yet now it is available in various parts of UK¹ . It is a kind of legume belonging to the „Fabaceae‟ group. It is a plant with an annual life span. This plant can grow vertically maximum up to 1.0 m of height² . There are various reasons behind choosing this seeds for the investigation which mainly are³ :

• The seeds are cheap and easily available in the local super market. 
• The germination of these seeds and their growth as well do not require any extreme conditions.
• The results obtained from these seeds are quite reliable. 
• The germination of seeds does not need any feeding as such. 
• Average temperature condition is good enough for the germination of seeds.

Measuring seed vigour is a useful tool to understand or get an insight about the germination or growth of seeds before it is sown into the field. As there are lot of physic-chemical factors playing a role in this process, a standard definition of seed vigour was given by ISTA Congress in 1977⁴ as – “the sum total of those properties of the seed which determine the level of activity and performance of the seed or seed lot during germination and seedling emergence”. Higher the value of seed vigour index, more the growth of the plant.


It is usually calculated according to the formula ⁵ given below-


Seed Vigour Index (SVI) = [G% * R] + SR .............................. (equation 1)


G% = Germination percentage = \(\frac{number\ of\ seeds\ germinated}{total \ number\ of \ seeds}\)


R = Length of root in cm


SR = number of secondary roots

Floor cleaners are mainly disinfectants dissolved in alcohols. They can affect the growth of plants in multiple ways⁶ : Floor cleaners contain detergents or surface active reagents. They have the ability to solubilise the waxy cuticle in leaves. Absence of waxy cuticles in leaves may cause the leave to dry and also reduces the heat tolerance of it. Detergents can also interfere with the water absorption by root hair cells as if water containing detergents dissolved in it are absorbed by root, it may destroy the lipid membrane of the root hair cells and that will inhibit the uptake of water and nutrients from soil which may cause the plant to die. Water soluble ionic salts are also part of the composition of the floor cleaners. Once it is mixed with the water, the osmotic pressure of the water rises and thus the water absorption of the root process of absorption of water from soil by root hair cells might slow down which will again dehydrate the plant and inhibit various metabolic functions in it. Floor cleaners are mostly acidic in nature. Presence of such acidic substances in the water exposed to plants will lower down the pH of the soil in which the plant grows and makes the soil unsuitable for growth of the plant.

Lysol is a popular disinfectant manufactured by the company Reckitt Benckiser. It is mainly composed ⁷ of antiseptics like – lactic acid, 4-chloro-2-benzyl hydroxybenzene, dimethyl benzyl ammonium chloride dissolved in ethanol and propan-2-ol as solvents. It also contains trace amount of hydrogen peroxide. The most active ingredient of Dettol is chloroxylenol⁸ which acts as an insecticide and has anti bacterial properties. Castor oil, pine oil, ethanol and castor oil are used as solvent in it. Trace amount of surfactants like SDS (Sodium do decyl sulphate) are also found in it.

A research article titled – “The Effects of Household Chemicals on Household Plants” by Amy Hall, John Wood, Chris Kolososki and Matt Howell can be considered as a relevant literature reference for this investigation. It was based on a study of the effect of different brands on glass cleaners and soaps on different variety of seeds. As mentioned in the abstract it was clearly noted that⁹ – “The plants that are receiving chemicals appear to growing at a noticeably slower rate than the control plants, and more of them are dying”.

Null hypothesis
Commonly used floor cleaners – Lysol and Dettol has no effect on the growth of Mung beans.

Alternate hypothesis
Commonly used floor cleaners – Lysol and Dettol have a negative impact on the growth of Mung beans. As the % concentration of floor cleaners increases, the seed vigour index decreases.

There are two independent variables in this investigation-

Brand of floor cleaner used-
Lysol and Dettol. These two brands are chosen as these two are the most commonly used floor cleaners. Moreover, Lysol is ammonia based alkaline disinfectant while dettol is not. This would enable us to investigate the effect of ammonia as well as alkalinity on the growth of plants.

% concentration of floor cleaner used –
The % concentration (volume %) of floor cleaner used was varied by adding the floor cleaner using a graduated pipette to 100 cm³ of tap water. The values of concentration chosen were – 1.00%, 2.00%, 3.00%, 4.00%,5.00%, 6.00%, 7.00%,8.00%, 9.00% and 10.00%. The values of concentration are chosen within this range as the recommended dosages¹⁰ of the floor cleaners lies in the range of 1.00% to 10.00%.

The dependent variable of the investigation is the seed vigour index. Growth of a plant can be measured can be measured in various aspects – root length, germination %, shoot length, number of leaves, chlorophyll content and many more. Seed vigour index is a standard protocol to monitor the growth as well as to understand the feasibility of crops grown as already discussed in the background information. The seed vigour index will be calculated using the equation -1 (refer to Page 2).

Protective clothings like safety masks, safety gloves and lab coats were used as exposure of the floor cleaners used and inhalation of their vapors may cause nausea and vomiting. None of the materials used were ingested or inhaled as consuming them may cause toxic health effects like respiratory disorders, cardiac disorders.

Minimum amount of seeds were used. Any methodology that might give rise to any undesirable ethical issues were not entertained.

All waste and unused materials were diluted by adding tap water and disposed off safely into the waste bin.

A 10.00 % solution of Lysol was made by adding 10.00 ± 0.05 cm³ (using a graduated pipette) of Lysol to 90.00 cm³ of tap water (using a graduated measuring cylinder) in a 100 cm³ glass beaker. 1.00 ±0.05 cm³ of this stock solution was added to 9.00 ± 0.05 cm³ of tap water in a test tube to prepare 1.00 % of the Lysol solution. Similarly 2.00%, 3.00%, 4.00%, 5.00%,6.00%, 7.00%, 8.00% and 9.00% solutions were prepared by using 2.00 cm³ , 3.00 cm³ , 4.00 cm³ , 5.00 cm³ , 6.00 cm³ , 7.00 cm³ , 8.00 cm³ and 9.00 cm³ of the stock solution to 8.00cm³ , 7.00 cm³ , 6.00 cm³ , 5.00 cm ³ , 4.00 cm³ , 3.00 cm³ , 2.00 cm³ and 1.00 cm³ of tap water. The Dettol solutions were prepared in the same way. All the test tubes were labelled using a permanent marker and kept on the test tube stand. A 10.00 cm³ graduated pipette was used to add both the stock solution and tap water.

A petri dishes were taken and washed with 1% solutions of NaOCl and dried in air. Two filter papers were kept on the dish. 2.00 ± 0.05 cm³ of tap water was added to it using a graduated pipette. Ten seeds were kept in them. The seeds were allowed to germinate for 1 day. Next day, the number of seeds germinated (out of 10 ) were counted and noted down. Then, the seed was allowed to grow for 7 days and after 7 days, the root length was measured using a ruler in cm and the number of secondary roots was counted. This was taken as a control and the same procedure was used for all other % of both Lysol and Dettol- 1.00%, 2.00%, 3.00%, 4.00%, 5.00%, 6.00%, 7.00%, 8.00%, 9.00% and 10.00% (stock solution). In total, 21 (10 for Lysol, 10 for Dettol and 1 for control ) petri dishes and 210 ( 10 seeds in each of the 21 petri dish) seeds were used. All the petri dishes were placed near a window sill so that they receive optimum sunlight.

• A tiny root of pinkish white colour emerged from the seed after 1 day. 
• More number of seeds were germinated in the control petri dish in comparison to the ones with Lysol and Dettol.
• Trace amount of shoot development was noted in the direction of light with tiny leaves of light green colour.
• The roots were growing at a faster rate than the shoots.

Germination percentage = \(\frac{number\ of\ seeds\ germinated \ out \ of \ 10}{total \ number\ of\ seeds\ in\ the\ petri\ dish\ (10)}\)X 100



Average = \(\frac{sum\ of\ all\ values\ of\ excluding\ the\ anomalous\ one}{number\ of\ values}\)

Standard deviation has been calculated using the formula given below


\(\underline{S}_{}.D=\frac{\sum(x-x_{avg})}{number\ of\ values}\); x = value ; x_avg = average value

Graph-1 indicates a scattered plot of seed vigour index against % concentration of floor cleaner used. The seed vigour index is plotted along the y axes as it is the independent variable while the % concentration of floor cleaner used is plotted along the x axes. The error bars are plotted for each and every data point in percentage deviation using MS-Excel. It is very clearly noted that with the rise in % concentration of Lysol and Dettol, the seed vigour index decreases.

For Dettol, the seed vigour index decreases from 311.7 to 166.2 as the % concentration increases from 0% (control) to 10.00% while that for Lysol it decreases from 311.7 to 27.6 as the concentration increases from 0.00% to 7.00%. The value of seed vigour index in control is 311.7 (0.00% concentration) and all other values of seed vigour index in presence of Lysol and Dettol is lower than that. This shows clearly that both Lysol and Dettol has a negative impact on the growth of plant as well as the germination rate.

For Lysol, there is a significant decrease of seed vigour index from 115.5 to 22.1 as the concentration changes from 5.00% to 6.00% while in Dettol the decrease is much smooth if the point at 5.00% is ignored as an anomalous point. For Lysol, the value of seed vigour index becomes zero from 8.00% which shows that at and above 8.00% concentration of Lysol the seed cannot germinate at all and thus this concentration of Lysol inhibits the germination and growth of plants. In case of Dettol any such concentration values are not observed as there is a positive value of seed vigour index at all values of concentration. This again shows that Dettol is much more favourable in comparison to Lyzol for the growth of the plant.

The mean seed vigour index in control, Lysol and Dettol are 311.7, 72.39 and 164.35 respectively (refer to Table-7). This clearly indicates that both Dettol and Lysol have a negative impact on the growth as the value is less than that in control. As the magnitude of mean seed vigour index is lower in case of Lysol in comparison to Dettol, we can again conclude that Dettol is comparatively better for the growth than Lysol.

It is difficult to predict a trend from the graph as there are certain anomalies or fluctuations from the trend in both Lysol and Dettol. In Dettol, as the % concentration increases from 1.00 to 4.00, the magnitude of seed vigour index decreases from 237.6 to 207.3. The value at 5.00% can be regarded as an anomalous point. Deviations from the trend are again observed at 8.00% and 10.00% as the values are higher than the preceding values instead of being lower. On the contrary, the effect with Lysol follows a trend of decreasing values of seed vigour index with increase in % concentration except just one point which is at 7.00%.

As seed vigour index is a cumulative measurement of three factors together-germination %, root length and number of secondary roots, it can be easily claimed that effect of the type of the floor cleaners on these three factors individually are not same. To be more clear, it can be said that the way Dettol influences germination % and root length are not same. For example- in case of Dettol for concentrations 2.00% to 5.00% the root length decreases from 2.58 cm to 2.40 cm while the germination % remains same(refer to Table-4). Thus, we can claim that the way % concentration and type of floor cleaners affects or influences germination %, root length and number of secondary roots are not same which thus results in an anomaly or deviations from the trend as observed in Graph-1.

Based on the difference in the values of seed vigour index between Lysol and Dettol, the graph can be divided into two zones- 1.00% to 4.00% and 6.00% to 10.00%. As already said earlier, the data point at 5.00% is neglected as it is an anomalous reading for Dettol. It can be easily noticed that the difference between the values of seed vigour index for Lysol and Dettol is much lower in Zone A (1.00% to 4.00%) than that in Zone –B (6.00% to 10.00%). This is because that in Lysol, the seed vigour index becomes zero from 8.00% onwards. This indicates that at lower concentrations (1.00% to 4.00%) both of them has certain similarity in their affect towards the plant growth while at higher concentration (8.00% and above) Lysol is found to be comparatively more detrimental for plant growth.

As shown in Graph-2, the germination % reduces in presence of Lysol and Dettol in comparison to control (tap water). For each and every % concentration, the germination % is much lower in case of Lysol than Dettol (the blue line is always at a lower value of y axes than the red line). From 1.00 % to 4.00%, the values of germination % are much closer as mostly for Dettol it is 80% while for Lysol it is 70%. The germination % decreases abruptly from 60% to 0 as the % concentration increases from 7.00% to 8.00% and above. On the contrary, germination % has no zero values in case of Dettol. This clearly enables us to claim that Dettol is more favourable for the germination of the seeds in comparison to Lysol. But, a detrimental effect on seeds germination is observed for both Lysol and Dettol.

A close observation of both Graph-3 and Graph-4 reveals that there is a similarity in the way Lysol and Dettol has affected the root length and the number of secondary roots. In both cases, the values has decreased in comparison to the control value. The differences in the values of y axes between the red line (Dettol) and blue line (Lysol) are higher in case of number of secondary roots than that in case of root length. Mathematically analysing this may be because the values of y axes in case of Graph-4 are of higher magnitude than that in case of Graph-3. Again, we can also claim that the effect on the number of secondary roots is more than the effect on the root length.

An independent T test was conducted to understand if there is any significant statistical difference between the way Lysol and Dettol affects the growth of the plant. The T tests was conducted as –

• Seed Vigour Index (dependent variable) is continuous. 
• The independent variables has two independent categories – Lysol and Dettol. 
• There are 10 cases (10 values of % concentration) in each categories.

Null hypothesis(H_o) There is no significant statistical difference between the effect of Lysol and Dettol on the growth and germination of mung bean.


Alternate hypothesis(H₁) There is significant statistical difference between the effect of Lysol and Dettol on the growth and germination of mung bean.

The investigation was intended to answer the research question-

Does the growth of mung beans (Vigna radiate), measured in terms of seed vigour index depends on the concentration (measured in terms of volume percentage) of commonly used disinfectants – Lysol and Dettol exposed to the seeds?

Graph-1 clearly reveals that both Dettol and Lysol has a negative impact on the growth of mung beans as the value of seed vigour index in presence of them is much lower than that in control (tap water). The mean value of seed vigour index for control, Lysol and Dettol are 311.7, 72.39 and 164.35 respectively (refer to Table-7). It can be claimed that Lysol has more negative impact than Dettol as – zero values of seed vigour index are observed for Lysol while not for Dettol at and above 8.00% concentration, the values of germination %, root length as well as number of secondary roots are much lower in case of Lysol than Dettol as revealed in Graph- 2,3 and 4. As the values of % concentration increases, the difference in between the effects of Dettol and Lysol becomes much more significant. For example, in all the graphs, the difference of height (indicating the values in y axes which is seed vigour index in Graph-1, germination % in Graph-2, root length in Graph-3 and number of secondary roots in Graph-4) between the red line (for Dettol) and blue line (for Lysol) increases. It is difficult to predict a trend from the graph as there are certain anomalies or fluctuations from the trend in both Lysol and Dettol. In Dettol, as the % concentration increases from 1.00 to 4.00, the magnitude of seed vigour index decreases from 237.6 to 207.3. The value at 5.00% can be regarded as an anomalous point. Deviations from the trend are again observed at 8.00% and 10.00% as the values are higher than the preceding values instead of being lower. On the contrary, the effect with Lysol follows a trend of decreasing values of seed vigour index with increase in % concentration except just one point which is at 7.00%. A T test was conducted as a part of inferential statistics which clearly has shown the calculated value of t to be higher than the critical value. Thus, the null hypothesis is rejected and the alternate hypothesis has been accepted which clearly indicates a significant statistical difference between the effect of Lysol and Dettol in plants.

The scientific justification for the results obtained here must be explained from two perspectives- both Dettol and Lysol have a negative impact on the growth of plant and Lysol has more negative impact on the growth in comparison to Dettol. The first point can be explained based on the fact that both Dettol and Lysol are acidic in nature. They reduce the pH of the medium below 3 which is not at all conducive for the growth of the plant. At low pH, the availability of nutrients in the soil decreases and thus the absorption of nutrients by the plant roots become difficult. Moreover, both of these solutions contain dissolved solutes which increase the osmotic pressure of the water which delays the process of water absorption by the root hair cells12. Lysol is an ammonia based solution. At low p^H, ammonia gets converted into nitrate which causes the roots to get decolourised and die eventually on continuous exposure13 . Use of ammonia can also interfere with certain metabolic pathways in the plant. Ammonia has been reported to have an inhibitory effect on the rate of respiration in the plant by decreasing the rate of oxidation of DPNH to DPN in the electron transport system in the mitochondria14. Ammonia also alters the permeability of the cell membranes which stops the flow of certain nutrients ions and molecules through it15 . These harmful effects of ammonia clearly reveals why Lysol (having ammonia as a solvent) has a higher negative impact on the growth of the mung beans in comparison to Dettol which does not contain ammonia.

• The growth of the plant can be measured in terms of germination %, root length, shoot length and number of secondary roots. The current investigation deals with the correlation of % concentration of floor cleaners with the growth of plants. The growth of plant has been measured in terms of seed vigour index instead of one particular factor like root length, shoot length or germination %. Using seed vigour index as the parameter to measure the growth gives a realistic and overall idea about the growth of the plant. 
• The conclusion of the investigation has been made in a triangulation research approach. Claims made in the conclusion are supported from three aspects – Graph 1 (which compares the seed vigour index with % concentration), Graph-2,3 & 4 (that individually compares germination %, root length and number of secondary roots against % concentrations) and inferential statistics (T test). This makes the claim more evident and logically supported. 
• Data has been collected as an average of ten samples (ten seeds in each petri dish) which invariably optimizes the effect of random errors in the investigation. As it can be seen from the values of standard deviation, the random error is not at all significant.

• As shown in Graph-1, there are certain anomalies in the data collected like magnitude of seed vigour index for Dettol at 5.00% and 8.00% deviates fro the trend line significantly. This confirms the existence of a major systematic error in the investigation which could be the growth of fungus on the seeds taken as samples. To prevent this, the seeds must have been sterilised with 1% solution of sodium hypochlorite and dried before putting them into the pteri dish. 
• Fluctuations of temperature and sunlight is also another major methodological limitation here. The investigation was conducted over a period of time and it is absolutely not possible to control the temperature or keep it constant over a period. This can be optimized by performing the experiment in an incubator or a greenhouse at a controlled environment. Intensity of sunlight has also varied as it is an environmental factor and is beyond human control. Error borne out of this can also be nullified if the investigation is conducted in a space devoid of sunlight and a UV lamp is taken as a controlled and alternative source of sunlight. 
• There are multiple sources of random error arising out of the uncertainties of the apparatus used. To optimize this, data was collected in ten trials and average value was considered.

The investigation can be extended in many other perspectives. One of them can be studying the role of effect of other household items like soaps instead of floor cleaners on the growth of plant. The investigation can be conducted in the similar process just be replacing the floor cleaners with soap solutions of different brands. Even items like caffeine can also be used to understand the effect of it on growth of plant as caffeine is a major source of fertiliser for the growth of the plant.

Caines, Kimberly. “The Effect of Household Ammonia on Plant Growth.” Home Guides | SF Gate, 29 Dec. 2018, homeguides.sfgate.com/effect-household-ammonia-plant-growth-102287.html. Accessed on December 22, 2019 1.22 pm (IST)

Dettol - Molecule of the Month - November 2002,https://www.chm.bris.ac.uk/motm/dettol/dettolh.htm Accessed on December 20, 2019 1.13 pm (IST)

The Effects of Household Chemicals on Household Plants, jrscience.wcp.muohio.edu/nsfall99/FinalArticles/TheEffectsofHouseholdChem.html. Accessed on December 21, 2019 11.45 am (IST)

Gentili, et al. “Effect of Soil PH on the Growth, Reproductive Investment and Pollen Allergenicity of Ambrosia Artemisiifolia L.” Frontiers, Frontiers, 24 Aug. 2018, https://www.frontiersin.org/articles/10.3389/fpls.2018.01335/full Accessed on December 14, 2019 1.30 pm (IST)

Gillespie, Claire. “What Type of Bean Seeds to Use for a Science Experiment.” Sciencing, 2 Mar. 2019, sciencing.com/type-seeds-use-science-experiment-7915838.html. Accessed on December 1, 2019 9.30 pm (IST)

H. M. VINES5 AND R. T. WEDDING. SOME EFFECTS OF AMMONIA ON PLANT METABOLISM AND A POSSIBLE MECHANISM FOR AMMONIA TOXICITY 1. DEPARTMENT OF PLANT BIOCHEMISTRY, UNIVERSITY OF CALIFORNIA CITRUS EXPERIMENT STATION, Accessed on December 26, 2019 11.45 am (IST)

“How Do Household Chemicals Affect Plants?” Hunker,http://www.hunker.com/12003385/how-do-household-chemicals-%20affect-plants. Accessed on December 10, 2019 3.12 pm (IST)

“Lysol Cleaning Products and Tips: Lysol®.” Lysol Cleaning Products and Tips | Lysol®, https://www.lysol.com/ Accessed on December 2, 2019 9.30 pm (IST)

“Lysol.” Lysol - an Overview | ScienceDirect Topics, https://www.sciencedirect.com/topics/medicine-and-dentistry/lysol Accessed on December 10, 2019 12.45 pm (IST)

Mungbean, hort.purdue.edu/newcrop/afcm/mungbean.html. Accessed on December 3, 2019 11.10 am (IST)

Nicholas Dove. The Effect of Increasing Temperature on Germination of Native Plant Species in the North Woods Region. University of Vermont, July 2010, underc.nd.edu/assets/156376/fullsize/dove2010.pdf. Accessed on December 22, 2019 1.30 pm (IST)

P.C. GUPTA. SEED VIGOUR TESTING. seednet.gov.in/PDFFILES/Chapter%2015.pdf. Accessed on December 4, 2019 11.45 am (IST)

“Using Mung Beans in the Lab.” Welcome, www.saps.org.uk/secondary/teaching-resources/755-using-mungbeans-in- the-lab. Accessed on December 2, 2019

Wulff, Renata D. “Environmental Maternal Effects on Seed Quality and Germination.” Seed Development and Germination, 2017, pp. 491–505., doi:10.1201/9780203740071-18. Accessed on December 3, 2019 11.30 am (IST)