Per- and Polyfluoroalkyl Substances (PFASs) Presence in Industrial Waste Water

Toxic Effect and Treatment Process of Per- and Polyfluoroalkyl Substances (PFASs) Presence in Industrial Waste Water

Abstract

The presence of Per- and Polyfluoroalkyl Substances (PFASs) in water has raised concerns due to its potential adverse human health effects. These chemicals are toxic in nature and very stable which are not biodegradable. Researchers are studying the fate and transport phenomenon of these chemicals and developing techniques to removes them from contaminated water. Most of the existing water treatment technologies are not effective in removing them. Nanotechnology-based water treatment processes are creating interest because they show significant improvement in capturing PFASs and their replacement chemicals, such as GenX. This paper reviewed the potential human health effects of PFASs, also the current trend of water treatment technologies which are applied to remove/adsorb them from the water.

Keywords: Per- and Polyfluoroalkyl Substances, waster water, toxic chemical, water treatment

Introduction

 According to USEPA, “Per- and Polyfluoroalkyl substances (PFASs) are a group of manufactured substances that includes Perfluorooctanoic acid (PFOA), Perfluorooctane Sulfonate (PFOS), GenX, and many other chemicals”. Since the 1940s, these substances have been manufactured and commercialized to use in the various industry around the world, including the United States [1]. The most common and widely used chemicals of this type are Perfluorooctanoic acid (PFOA) and Perfluorooctane Sulfonate (PFOS) which are very rigid and do not degrade in the environment. They can accrue in the human body and causes significant health effects.

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 PFASs are widely found in various consumer products including food packages, commercial household products such as stain- and water-repellent fabrics, nonstick products (e.g., Teflon), polishes, waxes, paints, cleaning products, and fire-fighting foams (a major source of groundwater contamination at airports and military bases where firefighting training occurs) for their water and oil-repelling abilities [2].  They also found in workplaces, including production facilities or industries (e.g., chrome plating, electronics manufacturing or oil recovery) that use PFAS. Moreover, drinking water get contaminant with PFASs typically localized and associated with a specific facility (e.g., manufacturer, landfill, wastewater treatment plant, firefighter training facility). Which in-turns, causes living organisms including fish, animals, and humans to be contaminated by PFAS and PFAS have the ability to build up and persist over time.

 The need for removal of PFASs from wastewater is growing as the toxic effect of PFAS causes serious effect on human health. Traditional water purification technologies are mostly ineffective in removing PFASs and their replacement chemical such as GenX from the water. Conventional water treatment process such as coagulation/physical separation, oxidation, aeration, disinfection, are not able to remove any PFAS. Nanomaterials and nanotechnology-based water treatment processes show the significant removal of PFAS from the water. Granular activated carbon, powder activated carbon, nanofiltration, show effectiveness in removal of PFASs from water in some extent but they do not selectively remove PFASs. Ji et al., (2018) created an amine-functionalized covalent organic framework

Chemical Structure of the Selected Elements

 PFOA and PFOS are made up of “chains” of eight carbon atoms that are attached to fluorine and other atoms. Replacement chemicals, like GenX, tend to have fewer carbon atoms in the chain but have many similar physical and chemical properties as their predecessors (e.g. they both repel oil and water) [1]. In PFASs structures, all hydrogen atoms of the corresponding hydrocarbon compound are substituted for fluorine atoms. The polar carbon-fluorine bond is the most stable bond in organic chemistry. Therefore, PFASs are thermally and chemically more stable than the analogue hydrocarbons. Generally, they consist of a hydrophilic end group, i.e. sulfonate or carboxylate end group, and a hydrophobic perfluorinated carbon chain (Figure 1) [3].

Figure 1: Structural formula of perfluoroalkycarboxylates and sulfonates; in technical products also, molecules with shorter and longer perfluoroalkyl chain may occur to some extent

 GenX is the commercial name of perfluoro-2-propoxypropanoic acid (CAS No. 62037- 80-3). The chemical structure of GenX is shown in Figure 2. GenX is a type of per-and polyfluoroalkyl substances (PFAS), which are used in products ranging from food packagings such as popcorn bags and pizza boxes to household products like Teflon and electronic components [1].

Figure 2: GenX

Figure 3 shows the common anion of GenX when it dissolved in water it leaves the ammonium groups [4]. Table 1 represented the detail information (nomenclature and properties) about GenX.

Figure 3: GenX carboxylate anion that forms in water

Table 1 GenX nomenclature and properties

Toxic Effects

 There are lot of studies showing PFASs and GenX are toxic to a living organism such as human and it is very likely that people can be exposed to these toxic chemicals in various ways. If humans, or animals, ingest PFAS (by eating or drinking food or water that contain PFASs), the PFASs are absorbed and can accumulate in the body. PFASs stay in the human body for long periods of time. As a result, as people get exposed to PFAS from different sources over time, the level of PFAS in their bodies may increase to the point where they suffer from adverse health effects. Studies indicate that PFOA and PFOS can cause reproductive and developmental, liver and kidney, and immunological effects in laboratory animals. Both chemicals have caused tumors in animal studies. Studies found that exposure to PFASs can cause to the following health issues [1, 5]:

affect growth, learning, and behavior of infants and older children

lower a woman’s chance of getting pregnant

interfere with the body’s natural hormones

increase cholesterol levels

affect the immune system

increase the risk of cancer

low infant birth weights,

effects on the immune system,

cancer (for PFOA), and

thyroid hormone disruption (for PFOS).

Treatment Process of PFASs

 Since PFASs are not biodegradable, researcher applied common water treatment process to see how much they can remove. Common water treatment process including, Coagulation, Oxidation, Aeration, Disinfection, Riverbank filtration, Anion exchange, Reverse osmosis, Granulated activated carbon treatment, Nanofiltration, Ozofractionation, Electrochemical oxidation, Sonolysis, etc. Most of the conventional water treatment processes are failed to remove PFASs from the water. Recent nanotechnology-based selective removal of PFASs showed significant effectiveness in removing of these toxic chemicals from water.

Coagulation

Appleman et al., (2014) studied the full-scale water treatment systems for the removal of PFASs where they justified various techniques including coagulation if they were able to remove PFASs from the water. They applied coagulation followed by sedimentation or Dissolved Air Flotation (DAF) and/or filtration to treat the wastewater. The used coagulants included aluminum sulfate and polymer in one sample and aluminum sulfate in the second sample, and polyaluminum chloride in the third sample. The results found that, Coagulation followed by sedimentation did not lead to PFAS removal, but where DAF was used instead of sedimentation, a 49% removal of PFAS was observed. Figure 4 represents the typical coagulation method for water treatment.

Figure 4: Coagulation method to remove impurities from water.

Oxidation

 Oxidation and disinfection processes including ozonation, aeration packed towers, potassium permanganate, ultraviolet (UV) treatment, chlorination (Cl2) with and without chloramination, and chlorine dioxide, all of these processes proved mostly ineffective in removing of PFAS (Appleman et al., 2014). Typical oxidation and disinfection process is shown in figure 5.

Figure 5: Oxidation and disinfection method

Anion Exchange

 Iron infused anion exchange resin was designed for arsenic removal and it was further used for PFASs removal by Appleman et al., (2014). The resin was successful in reducing some of the PFAS levels. In particular, PFHpA was partially removed (46%), as were PFOA (75%), and PFBS (81%). PFNA, which was only detected in one of the two raw water samples, exhibited >67% removal. It is possible that certain AIX resins can target PFAS sorption by ion exchange and/or hydrophobic interactions. Detail Anion exchange method is given in figure 6.

Figure 6: Anion exchange method for water treatment

Reverse Osmosis (RO)

 Figure 7 depicts the water treatment technology for reverse osmosis which can be used for removal of PFASs from the water.

Figure 7: Reverse osmosis principle

Appleman et al., (2014) in their full-scale water treatment for PFASs removal, among other existing practice they used reverse osmosis technique to remove PFASs. They applied polyamide Hydranautics ESPA2 membranes in a three-stage array with a 12 gfd flux rate and 85% recovery in one site, and used Toray and Hydranautics RO membranes with an RO flux rate of 12 gfd and 80% recovery for another site. Results found that RO was most effective in removing PFASs from water compared to all other techniques they used.

Granulated Activated Carbon (GAC)

Granulated activated carbon was used to remove PFASs from water in different water facilities by Appleman et al., (2014). They utilized Calgon F600 (coal-based) media and was set up with two contactors, a lead and a lag, that run-in series with a flow between 1.4 and 1.5 m3/min, and an empty bed contact time (EBCT) of approximately 13 min in each contactor. Results found that GAC treatment was effective in removing PFASs from the water.

Amine-Functionalized Covalent Organic Frameworks

 Recently Ji et al., (2018) created aa amine functionalized covalent organic frameworks for next-generation water treatment of PFASs removal [6]. The idea of this system was to remove PFASs and GenX from water by selective adsorption. The cost and performance limitations of current PFAS removal technologies motivate authors to develop selective and high-affinity adsorbents. Covalent organic frameworks (COFs) are unexplored yet promising adsorbents because of their high surface area and tunable pore sizes. Authors reduced the azide-functionalized COFs to the corresponding amine functionalized networks and demonstrate their promise as adsorbents for PFAS. The COFs amine groups interact with the anionic head group of PFAS, along with ample hydrophobic surface area that further support adsorption. The optimized materials, with amine loadings of 20–28%, bind 13 PFAS with high affinity and rapid kinetics. Figure 8 depicts the amine functionalized covalent organic frameworks.

Figure 8: Amine functionalized covalent organic frameworks for PFASs adsorption

Results & Discussion

 Table 2 represents the results of currently available water treatment mostly they are not able to remove PFASs from water effectively [7]. Some technique may be able to remove PFASs but they have other challenges too such as maintaining cost, operation cost and other.

Table 2 Results of different type of water treatment processes

While all other techniques are not effective in reducing PFASs from water, amine functionalized covalent organic frameworks shows significant improvement and selective removal of PFASs and GenX from the water. Figure 9 depicts the removal efficiency of PFASs by amine functionalized covalent organic frameworks where it shows 12 out of 13 PFASs removes effectively. Figure 10 shows, GenX removal efficiency.

Figure 9: PFASs removal efficiency

Figure 10: GenX removal efficiency

Later, in Figure 11 the GenX removal efficiency by amine functionalized covalent organic frameworks was compared with Granular activated carbon, and powder activated carbon; nevertheless, the amine functionalized covalent organic frameworks shows the highest efficiency.

Figure 11: GenX removal efficiency comparison among different approaches

Conclusion

 In conclusion, this project reviewed the toxic effects of PFASs and other replacement chemicals of PAFSs such as GenX and their available removal technology. Most of the conventional water treatment processes such as coagulation followed by physical separation processes, and chemical oxidation, aeration, and disinfection, were unable to remove PFASs. Some techniques, such as granular activated carbon, anion exchange, and reverse osmosis show effectiveness to some extent. Amine functionalized covalent organic frameworks showed significant removal efficiency where this technique removes impurities selectively.

References

[1] https://www.epa.gov/pfas/basic-information-pfas (accessed on 11-18-2018).

[2]. Lau, C., Anitole, K., Hodes, C., Lai, D., Pfahles-Hutchens, A., & Seed, J. (2007). Perfluoroalkyl acids: a review of monitoring and toxicological findings. Toxicological sciences, 99(2), 366-394.

[3]. https://www.riwa-rijn.org/wp-content/uploads/2015/05/137_ptfe_report.pdf (accessed on 11-18-2018).

[4]. Hopkins, Z. R., Sun, M., DeWitt, J. C., & Knappe, D. R. (2018). Recently Detected Drinking Water Contaminants: GenX and Other Per‐and Polyfluoroalkyl Ether Acids. Journal‐American Water Works Association.

[5]. https://www.atsdr.cdc.gov/pfas/health-effects.html (accessed on 11-19-2018).

[6]. Ji, W., Xiao, L., Ling, Y., Ching, C., Matsumoto, M., Bisbey, R. P., … & Dichtel, W. R. (2018). Removal of GenX and Perfluorinated Alkyl Substances from Water by Amine-Functionalized Covalent Organic Frameworks. Journal of the American Chemical Society, 140(40), 12677-12681.

[7]. Hopkins, Z. R., Sun, M., DeWitt, J. C., & Knappe, D. R. (2018). Recently Detected Drinking Water Contaminants: GenX and Other Per‐and Polyfluoroalkyl Ether Acids. Journal‐American Water Works Association.

Experiment of the Effect of Different Dissolved Substances on the Rate of Ice Melting

3: Murriama and her friend, Sara, were enjoying their favourite ice blocks. Halima noticed that her ice block melted faster than Sara’s. She wondered why they melted at a different rate.

Q. Design and conduct an investigation to determine “if different dissolved substances impact the  rate at which ice melts”.

Possible requirements: Stopwatch [not necessary to purchase ice blocks to conduct this investigation).

 

PROBLEM SOLVING:

Introduction:

On a Saturday evening, in Detroit, the largest city in Michigan, United states, Murriama and Sara, two mutual best friends, were casually trying out their ice blocks from their favourite grocery store, Honey Bee La Colmena. Sara got hers, owned by a company called the House of Flavours, while Murriama got hers from Michigan’s favourite ice block brand, Dean’s Country Fresh Super Rainbow, Michigan’s favourite ice cream brand. While pleasantly enjoying their favourite ice blocks, Murriama noticed that the ice block she was having melted faster than that of Sara’s. She wondered why the melting occurred at a different rate. The reason why I have decided to work on this particular investigation is because I found the question to be very intriguing of a subject to research and conduct an investigation about. It also triggered my curiosity about why Murriama’s ice block melted faster than that of Sara’s. Henceforth, it was for the sole purpose of research and to investigate further into it in depth. This particular question can be tested by experimentation. Four weeks were provided for the completion of this student research project and it is initially possible for the question to be tested in the given time; design, conduct, analyse, construct etc. Throughout the experiment I performed, I determined that the addition of foreign, dissolved substances to ice does essentially impact the rate at which the ice melts, measuring time alongside. 

Aim:

The main aim of my extensive research project is to design and conduct an investigation which efficiently determines if different dissolved substances i.e. table salt (calcium chloride), raw sugar and/or sand (extracted/sampled/collected from Bondi Beach), impact the rate at which ice melts, within a constant temperature, under certain safe conditions. I will also initially measure the time it takes for each dissolved solution, in the ice cube to melt, using a stopwatch. Therefore, the aim is to observe the effects of dissolved substances e.g. table salt, raw sugar and sand against time, further impacting the rate at which ice melts by either increasing, decreasing or depressing the freezing point.

QUESTIONING AND PREDICTING:Background Research:

¾ of the solutions used in this experiment are dissolves containing dissolved substances-

Salt

Sugar

Sand

(Distilled Water)

No solute

Pure distilled water has a melting/ freezing point of 0C (32F).

Table salt and raw sugar are soluble substances and dissolve in water while sand does not dissolve in water.

Experiments with ice cubes containing salt and sugar should show that cubes with sugar and salt melt faster than the cubes with only normal water. Initially, the ice cubes containing salt should melt faster than the cubes with the sugar solution. Valid reason= “heat absorption”.

The salt or sugar in an ice cube absorbs the surrounding heat energy faster than frozen water itself. Due to salt and sugar absorbing heat so quickly, water molecules move faster, resulting in a faster melting rate.

–          (Linking to the real world=) This is part of the reason: cities extensively use salt to melt ice; salt absorbing heat energy quicker, thereby promoting increased rate of melting.

Salt impacting the rate at which ice melts:

The ionic compound salt (sodium chloride- table salt) lowers the freezing point of the water  freezing point depression. The salt makes it harder for the water molecules to bond together in their rigid structure.

When a single molecule of salt dissolves, it breaks into two ions, a sodium ion and a chloride ion, thereby effectively doubling the ‘freeze blocking’ effect. [Calcium chloride is more effective/efficient at melting ice- break down into three ions instead of two: one calcium ion and two chloride ions.]

Sugar impacting the rate at which ice melts:

Sugar lowers the freezing point of water by binding with the water molecules and creating more space between them. Hence, this helps them- overcome the electrostatic forces binding them into a solid structure.

When a molecule of sugar dissolves in water, we end up with a single molecule in solution. This extra molecule prevents water molecules from combining with ice crystals and freezing normally, thereby depressing the freezing point.

Sand impacting the rate at which ice melts:

If heated naturally from the sun or a warm temperature, sand can melt just like all other substances which are at a higher temperature than ice. The actual texture of sand does not cause ice to melt. Sand, unless it is at a higher temperature than the ice, would not melt.

Salt lowers the freezing point of ice by dissolving into a liquid water within the ice and lowering the freezing point from 0C to below 0.

When using table salt will essentially dissolve into separate sodium ions and chloride ions.

Sugar and salt melt ice by lowering water’s melting and freezing points.

Normal tap water has already dissolved impurities or chemicals in it which will affect the rate at which ice melts- use of distilled water in my experiment.

The total process of dissolution–decomposition into ions plus hydration–absorbs heat.

Hypothesis:

The hypothesis of my extensive study was that if there was a precedent change in the independent variables i.e. table salt, raw sugar, sand and distilled water, then there would be a predicted change in time, impacting the rate at which ice melts with observant levels of increased or decreased freezing points. My hypothesis also outlines that the salt solution will be the most impactful at affecting the rate at which the ice melts, rather than the rest of the solutions, with the solute sand being the least effective. Throughout the process of planning and investigating this research project, it is possible that this hypothesis can be tested by experimentation. By comparing the effect of the dissolved substances against time, measured in seconds, it would be possible to prove or disprove the drawn hypothesis and work on relevant regulation and conservation practices, determining if different dissolved substances do impact the rate at which ice melts.

PLANNING INVESTIGATIONS:

Risk Assessment: Risks:

Breaking of glass equipment- create sharps that could essentially cut/ infect or introduce chemical or fluid into body.

Spillage of water- create detrimental spills which have potential consequences of injuring a person. 

Ingestion/ Consumption of solutes- sand salt, sugar- not meant to be ingested; experimental solutes and harmful for the body.

Frost bite from being in contact with ice- cause numbness, pain or burning sensations to skin.

Injury to self or others through the use of toothpicks- stab, poke etc. which leads to a physical injury or hazard.

Contact with hot surfaces or equipment (e.g. stainless-steel pot): physical injuries i.e. burns etc. to self or others.  

State how I intend to minimise the risks:

Breaking of glass equipment: wear PPE (personal protection equipment), use stable surface or use a holder.

Spills (Water): Wipe the wet surface till it is dried up, prevent yourself or be cautious around any water spills or use a larger beaker.

Ingestion/ Consumption of solutes: Preventing yourself or your peers from ingesting the solutes

Frost bite: Wear gloves, use a holder or equipment to pick the ice up.

The use of toothpicks/sharp objects: Wear protective hand wear, have a stable hold on toothpick whilst using.

Contact with hot surfaces of equipment: Use kitchen mitts while handling hot objects etc., Use handle of the appliance, turn off switch and wait for the surface to cool down.

Experimental Variables:

Independent Variable (thing tested)= dissolved substances

Table salt (calcium chloride)

Raw Sugar

Sand (sample collected from Bondi Beach)

Dependent Variable (thing measured)= Time for ice to melt

Variables to be controlled (constants)=

Temperature [room temperature etc.]

Amount of solute [ ¼ tsps. each]

Amount of ice/ water [5ml]

Start time [7:20 pm]

Location of experiment [Living room etc.]

Person conducting the experiment (reaction time of humans vary; person to person)

The use of the same stopwatch throughout (the entire experiment)

Ice cube tray kept the same throughout the experiment 

Control Group: Distilled Water [no solutes] (the independent variable which will not influence the results)

CONDUCTING INVESTIGATIONS:

Materials/ Equipment:

3× ¼ tsp/ 1.25 ml teaspoon (measuring spoon)

1× 50ml beaker/measuring cup

1× 1/4 tsp (1.25ml) of table salt (sodium chloride) [Brand: Woolworths. Himalayan Pink Fine Table Salt]

1× 1/4 tsp (1.25ml) of raw sugar [Brand: CSR. Raw Sugar]

1× 1/4 tsp (1.25ml) of sand [Extracted/sampled/collected from Bondi Beach]

3× Stopwatch [Brand: Casio]

1× Plastic Double-ended Toothpick pack

1× Refrigerator [Brand: Samsung]

1× Plastic Ice cube tray (28 cubicles) 

1× 3 to 5 gallon (11.4 to 19 litre) stainless-steel pot with a stainless-steel cover

1× Heat resistant glass bowl

1× Baking rack

Ice (no solute) [for distilled water]

[∴ All equipment and materials that I have used in this experiment were easily obtained at low cost and from household items, whereas the sand was extracted from Bondi Beach, in the hopes of making this experiment accessible to perform/conduct and also to least worry about committing to plastic pollution when buying the sand from stores.

Why I have used distilled water instead of tap water: In order to conduct this experiment, I have used distilled water as one of my solutions/ control group/ replacement for tap water since tap water contains already-dissolved impurities and chemicals which might affect the initial rate at which the ice melts, making it complex for the experiment to be valid.]

Method:

Distilled Water:

Put the baking rack on the bottom of the stainless-steel pot.

Fill the pot halfway with tap water.

Place the glass bowl in the pot, so that it floats on the surface of the water. The baking rack should ensure that the bottom of the glass bowl doesn’t touch the pot.

Turn the pot cover upside down and place it on top of the pot.

Fill the inverted pot cover with ice.

Bring the water to a boil and let it boil for about 30-45 minutes.

Wait for the condensed water to cool down.

Repeat steps 1-7 to acquire the correct measurement of a 100 ml. 

Initial Method:

(The following steps were repeated 2 more times for reliability and to give a total of each replicate, with the solutions in the same ice cube tray: )

Pour cooled distilled water into the 50ml beaker/measuring cup and measure 5ml of water for each cubicle.

Add 5ml (1 TSP) of distilled water to each 15 ice cubicles of the ice tray; 3 for table salt (sodium chloride), 3 for raw sugar, 3 for sand and 6 for distilled water only (no solution).

Measure ¼ tsp of salt, sugar and sand using three ¼ teaspoons.

Add the measured ¼ tsp of sand, salt and sugar in each of the filled-up cubicles of the ice cube tray; 3 for sugar, 3 for salt and 3 for sand.

Dissolve/ mix each solution with toothpicks.

Put them in the refrigerator and wait for an estimated 3-4 hours for the ice to melt.

Take the ice cube tray out of the refrigerator and prepare to use the stopwatches.

Start your timer on each of the stopwatches together and write down the starting time.

Observe each of the four ice cubes with dissolved salt, sand, sugar and the ice cube with distilled water only and wait for them to completely melt.

Poke around with a toothpick to check up on the progress of the ice cubes during the process of melting.

Stop a stopwatch and write down the end time when the first ice cube completely melts.

Repeat the same steps for the other three solutions and also another two times using the rest of the frozen solution left in the ice cube tray, further testing for reliability.

Conduct this experiment independently since reaction times of humans may vary and in the same, constant room to ensure that temperature remains constant.

PROCESSING AND ANALYSING DATA

Results: 

SALT solution

 

SUGAR solution

SAND solution

 

DISTILLED WATER (ONLY)

 

Figure 1: Before dissolving the solutes in the distilled water; table salt, raw sugar and sand.

 

SALT solution

SUGAR solution

 

SAND solution

DISTILLED WATER ONLY

 

Figure 2: After dissolving the solutes in the distilled water; dissolved substances: table salt, raw sugar and sand.

 

 

SALT solution

SUGAR solution

SAND solution

 

DISSOLVED WATER ONLY

 

Figure 3: The solutions have been frozen in the refrigerator for an approximate of 3½ hours at a temperature of 38 F (3.3C).

First Trial                         [Friday, 6th September. 2019 7:20 pm]

 

SAND: Took 5400 sec (1 hr 30 mins) to successfully melt.

DISTILLED WATER ONLY: Took 6000 sec (1 hr 40 min) to successfully melt.

SALT: Took 300 sec (5 mins) to successfully melt.

SUGAR: Took 3300 sec (55 mins) to successfully melt.  melt.

Second Trial                   [Saturday, 7th September 2019 7:20 pm]

 

SALT: Took 480 sec (8 mins) to successfully melt.

SAND: Took 5700 sec (1 hr 35 mins) to successfully melt.

DISTILLED WATER ONLY: Took 6600 sec (1 hr 50 min) to successfully melt.

SUGAR: Took 3720 sec (1 hr 2 mins) to successfully melt.  melt.

Third Trial                   [Sunday, 8th September 2019 7:20 pm]

…..

SALT: Took 900 sec (15 mins) to successfully melt.

DISTILLED WATER ONLY: Took 7200 sec (2 hrs) to successfully melt.

SAND: Took 6120 sec (1 hr 42 mins) to successfully melt.

SUGAR: Took 4080 sec (1 hr 8 mins) to successfully melt.

Dissolved Substances

Start Time

End time (for melting)

Initial Time

Time (in sec)

Salt

7:20 pm

7:25 pm

5 mins

300 secs

Sugar

7:20 pm

8:17 pm

55 mins

3300 secs

Sand

7:20 pm

8:50 pm

1 hr 30 min

5400 secs

Dissolved water (only)

7:20 pm

9:00 pm

1 hr 40 min

6000 secs

∴The following table above states a simple perspicuous explanation that dissolved substances do indeed impact the rate at which ice melts. For the first trial performed, it is visible that salt had the most impact on the ice melting, resulting in  a  faster rate of the ice melting, whereas the solution with sand and distilled water only had the least impact on the ice melting, resulting to a decreased rate of the melting of the ice.  

Dissolved Substances

Start Time

End time (for melting)

Initial Time

Time (in sec)

Salt

7:20 pm

7:28 pm

8 mins

480 secs

Sugar

7:20 pm

8:22 pm

1 hr 2 mins

3720 secs

Sand

7:20 pm

8:55 pm

1 hr 35 min

5700 secs

Dissolved water (only)

7:20 pm

9:10 pm

1 hr 50 min

6600 secs

∴Compared to the first trial, the second trial has also very similar results with the salt solution being the first to melt followed by sugar, sand and then the solution with distilled water only (no solutes). Furthermore, it also highlights how these dissolved substances impacted the rate at which the ice melted, with some efficiently depressing the freezing point at a fast rate. 

Dissolved Substances

Start Time

End time (for melting)

Initial Time

Time (in sec)

Salt

7:20 pm

7:35 pm

15 mins

300 secs

Sugar

7:20 pm

8:28 pm

1 hr 8 mins

3300 secs

Sand

7:20 pm

9:02 pm

1 hr 42 mins

5400 secs

Dissolved water (only)

7:20 pm

9:20 pm

2 hrs

6000 secs

∴The following table above emphasises on the context of how dissolved substances impact the rate at which ice melts. With a comparison with the other trials, the third trial also states that salt aids in melting ice the fastest followed by sugar. The least reactive dissolved substances that impact the rate at which ice melts include sand etc., further proving how dissolved substances i.e. table salt, raw sugar, sand etc. impact the rate at which ice melts, either by lowering the freezing point or increasing the rate of ice melting.

Solute

Mean Time (seconds)

Salt

560 (secs)

Sugar

3700 (secs)

Sand

5740 (secs)

Distilled water

6600 (secs)

Final Table(s):

 

 

Time (seconds)

  Solute

Salt

Sugar

Sand

Distilled Water

T1

300

3300

5400

6000

T2

480

3720

5700

6600

T3

900

4080

6120

7200

Mean Time

560

3700

5740

6600

Discussion:

The initial experiment results outline that dissolved substances i.e. table salt, raw sugar, sand etc. along with the controlled group, distilled water, do indeed impact the rate at which ice melts, also signifying the consequential occurrences of low freezing points. Throughout the conduction of three trials in my experiment, it is observant that dissolved substances play an impactful role when it comes to making ice melt, especially salt, sugar and sand. Prior to the results for all the three trials, it is visible that salt is the most effective and melts the ice cube the fastest. This is because this ionic compound lowers the freezing point of the water/ freezing point depression making it harder for the water molecules to bond together in their rigid structure eventually forcing the water molecules to move faster, resulting at a faster melting rate. When a single molecule of salt dissolves, it breaks into two ions, a sodium ion and a chloride ion, thereby effectively doubling the ‘freeze blocking’ effect, alongside melting ice the fastest compared to the controlled group, distilled water, and the other solutes, sugar and sand. [Salt initially took 560 seconds (mean time) to melt.]

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Sugar is also one of the solutes which absorbs the surrounding heat energy the fastest than the control group, distilled water, and the rest of the solutes, except salt. Sugar lowers the freezing point of water by binding with the water molecules and creating more space between them. Hence, this helps them overcome the electrostatic forces binding them into a solid structure. When a molecule of sugar dissolves in water, we end up with a single molecule in solution. This extra molecule prevents water molecules from combining with ice crystals and freezing normally, thereby depressing the freezing point. [Sugar initially took 3700 seconds (mean time) to melt].

However, the solute sand does not melt ice any faster than salt or sugar. This is because the actual texture of the sand does not cause the ice to melt. If heated naturally from the sun or a warm temperature, sand can melt just like all other substances which are at a higher temperature than ice. Sand, unless it is at a higher temperature than the ice, would not melt. [Sand initially took 5740 seconds (mean time) to melt].

Furthermore, through observing the three trials, it is visible that the ice cube containing only distilled water, was the least effective at melting ice the fastest, further determining that the “different” dissolved substances i.e. salt, sugar and sand, effectively impact the rate at which ice melts on a diverse spectrum. Furthermore, when compared to the controlled group, distilled water, it is shown that the ice cube containing distilled water only was least effective at impacting the initial rate at which the ice cubes melted. [Distilled water initially took 6600 seconds (mean time) to melt].

In the experiment conducted, there are some strengths and weaknesses. The following identified are as follows:

–          There is a tighter control of variables, making it easier to comment on cause and effect.

–          Utilised accessible, household and cheap items for equipment.

–          The experiment is relatively easier to replicate.

–          It is also cheaper and less time-consuming than other methods.

–          Not a subject to human error if tried for reliability for a duration of more than three times.

–          The experiment demands more characteristics – the participants aware of experiment, may change their behaviour.

–          The experiment conducted had low ecological validity making it difficult to generalise to other situations.

–          There were few experimenter effects, may be bias when experimenter’s expectations affect behaviour.

–          (Where the experiment was conducted: artificial environment- implying that there was low realism.)

–          (Subject to human error if not tried more than three times.)

Some future improvements that could be proposed for this experiment to be more effective are as follows:

–          Making repeated measurements in order to eliminate error in  measuring i.e. measurement of water, solutes etc.

–          Increasing the sample size of solutes or perhaps a bigger ice cube tray/ amount of water etc.

–          Introduction of more independent variables; the solutes, in order to highlight an even diverse range of dissolved substances and how those affect the initial rate at which the ice melts.

–          Repeating the experiment a few more than three times in order to strengthen reliability.

Ideas for future investigations proposed:

Some ideas for future investigations could include an investigation with different solutes or different solvents. Furthermore, they could also include/utilise the same solutes, but conducted at different temperatures. There could also be an entirely different experiment with different solutes, solvents etc. and in a different format.

This investigation can also be efficiently linked to the real world. During winter, many cities and municipalities, across the world, extensively depend on salt, especially rock salt, in order to de-ice their roadways when the weather gets bad. This process runs through the analogy of road salt works lowering the freezing point of water via freezing point depression. The freezing point of the water is lowered once the salt is added, so it the salt makes it more difficult for the water to freeze. Henceforth, this investigation determines how dissolved substances may affect the rate at which ice melts, also interlinking this to a real-life scenario occurring and how some dissolved substances are more effective than others. 

Conclusion: 

The initially drawn hypothesis that dissolved substances impact the rate at which ice melts, especially amongst the three solutes; table salt (sodium chloride), raw sugar and sand, and the solution with only distilled water, where salt is the most efficient at melting ice and sand being the least effective, is supported by the results. In the experiment conducted, it has been made clear on how salt had melted ice the fastest, followed by sugar whilst having sand and the controlled group, distilled water, to be the least effective at melting ice the fastest. This helps outline and support the main aim of this investigation task and further convey the context of observing the effects of table salt, raw sugar and sand against time and how it may impact on how the ice melts via freezing point depression. However, the analytical results identified indicates a rejection of hypothesis where it states how the solute sand will take the longest to melt. The results support otherwise, outlining that the solution with only distilled water takes the longest to melt.

 

Bibliography- References:

Paul G. Jasien. Roles of Terminology, Experience, and Energy Concepts in Student Conceptions of Freezing and Boiling. Journal of Chemical Education 2013

Richard Earl Dickerson. Molecular thermodynamics. Physical chemistry monograph series 1969.

Mike w. (& Tom J.). Melting Ice. Department of Physics. University of Illinois at Urbana 2007. [Internet] Available from: https://van.physics.illinois.edu/qa/listing.php?id=1624

Greg Haney. Charts, Graphs and Adding infographics to a worksheet. Excel All-In-One for Dummies 2019.

F. Key Kidder. What Motivates your Employees 2011. Volume 6 Issue 7. Laboratory Hazards and Risks. [Internet] Available from:  https://www.labmanager.com/lab-health-and-safety/2011/09/laboratory-hazards-and-risks#.XXDoGygzbIU

Andy Claus. Experiments with Salt and Sugar Ice cubes. Sciencing. [Internet] Available from: https://sciencing.com/experiments-salt-sugar-ice-cubes-8526160.html

Clearway Community Solar. Science Center: Home experiment for kids. How substances affect water’s freezing point. [Internet] Available from: https://www.clearwaycommunitysolar.com/blog/science-center-home-experiments-for-kids/global-warming-ice-melting-experiment-for-kids/

Caroline Hubor. Research paper ideas on how to melt ice the fastest. Sciencing. [Internet] Available from: https://sciencing.com/research-ideas-melt-ice-fastest-8529455.html

Lunar and Planetary Institute. Explore Ice Worlds. Melting point. [Internet] Available from: https://www.lpi.usra.edu/education/explore/ice/activities/investigations/melting_point/

Lee Morgan. Substances That Affect the Rate of Melting Ice. Sciencing. [Internet] Available from: https://sciencing.com/substances-affect-rate-melting-ice-7464647.html

Fred Senese. Why does salt melt ice. Antoine Frostburg. General Chemistry Online. [Internet] Available from: https://antoine.frostburg.edu/chem/senese/101/solutions/faq/why-salt-melts-ice.shtml

 

Controlling Exposure to Harmful Substances in the Workplace

Control of exposure to substances harmful to health by the UK government was first implemented during the late 19th century (Piney 2001). Today, Control of Substances Hazardous to Health (COSHH) assessments are used to address the risk associated with chemicals and how they may be used safely. This report considers three cleaning products which are used on a daily basis in the office environment in which I work: Freshline Bleach, Lifeguard 3 Way Toilet Cleaner and Mr Muscle Professional Kitchen Cleaner. COSHH assessments for these products are included in Appendix I.

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Chemicals used in office cleaning products and the processes involving these products
The three cleaning products assessed in this report contain a number of different chemicals. The components of each of these products are listed in Table 1, together with their toxicity, targets organs/organ systems and the recommended occupational exposure limits for these chemicals. The main targets organs for the chemicals in these products are the eyes and skin but the respiratory and digestive systems may also be affected if these products are inhaled or ingested.
Freshline Bleach is used for general cleaning and disinfecting purposes. In the office, it is used dilute for cleaning floors (e.g. corridors and toilet floors). A working solution is typically prepared in a mop bucket using tap water for dilution and the floors mopped. At the end of the procedure, the dilute solution is emptied down the drain and both mop bucket and mop rinsed in clean tap water. This bleach is also used neat for cleaning toilets and drains into which it is poured straight from the 5 litre container. Lifeguard 3 Way Toilet Cleaner is a cleaner, disinfectant and deodorizer that is used in the office to remove limescale and uric acid deposits on toilet bowls and urinals. The product is typically poured neat into the toilet bowl/urinal from the 1 litre container. Mr Muscle Professional Kitchen Cleaner is a cleaning spray used to clean all kitchen work surfaces, utensils and other equipment. This is sprayed neat onto surfaces and then wiped off using a disposable cloth.
Potential hazards for workers during handling of chemicals
The COSHH assessment included in Appendix I identifies the risk associated with the chemicals in each of the three cleaning products. There is the potential for all workers (both cleaning staff and office workers) to be exposed to these chemicals in the workplace. Cleaning staff are at the greatest risk of exposure at they will be handling the concentrated products. There is a risk of splashback from the bleach and toilet cleaner when pouring this into the toilet. There is also the potential for individuals to come into contact with undiluted chemicals during disposal of empty containers. Workers using bleach may inhale vapour if this is used in a poorly-ventilated area.
If cleaning cloths are used for multipurposes with a variety of different cleaning products without being properly rinsed between uses, there is also the potential for reactions to take place between chemicals in the different products which could be hazardous for workers. For example, if bleach comes into contact with acid, toxic gas may be liberated which could then be inhaled. There is also the potential for chemical reactions to take place if different cleaning products are used together, e.g. when cleaning toilets.
Monitoring workplace exposure and minimising the risk of exposure
The COSHH assessment identified Freshline Bleach and Lifeguard 3 Way Toilet Cleaner as medium hazards and Mr Muscle Professional Kitchen Cleaner as low hazard. For both the bleach and toilet cleaner in particular, it is essential that correct safety precautions are taken during the handling, use and disposal of these products.
Monitoring workplace exposure to the chemicals in these products is difficult and levels of exposure cannot be measured qualitatively. Regular inspections of the office kitchen and toilets will detect spillages that have not been cleaned up thoroughly which could mean workers are exposed to higher than normal levels of concentrated products. Keeping a record of the quantities of each product used (e.g. by asking staff to complete a log when they take a new container) would provide an indicator of the amounts being used within the office as a whole on a monthly/annual basis which may provide some indicator of occupational exposure levels. There is a designated health and safety officer within the office but regular inspections are not conducted and no formal training sessions are held to ensure that new staff joining the company are familiarised with correct office safety procedures.
A number of measures can be taken to minimise the risk of exposure. The COSHH assessments for all chemicals should be kept in a place where they can be found easily and all workers should familiarise themselves with these assessments and be aware of first aid measures and correct procedures for cleaning up spillages and disposal of solid waste. Training sessions for staff should be arranged if necessary. All workers using cleaning products must wear suitable personal protective equipment as detailed in the COSHH assessment (e.g. eye protection when working with concentrated toilet cleaner and eye protection, PVC/rubber gloves and protective overalls when working with concentrated bleach). Regular inspections would monitor whether correct working procedures are being followed and written reports from each inspection would provide a record over time.
In case of spillage of concentrated bleach or toilet cleaner on clothing, bags should be available to contain the soiled article(s) of clothing to send for cleaning and these should be clearly labelled with the hazard. PVC or rubber gloves should be replaced regularly and should be rinsed well with water if they have come into contact with concentrated solutions of bleach or toilet cleaner ensuring that no door handles or other surfaces are touched and contaminated with concentrated product. All spillages should be cleaned up thoroughly to minimise the risk of workers exposure to concentrated product and both spilt product and any solid waste associated with the spillage disposed of safely.
The risk of splashing is reduced by using spray containers (as in the case of Mr Muscle Professional Kitchen Cleaner), rather than the larger bottles or containers which hold the bleach and toilet cleaner, and less of the product is likely to be used with these types of containers. If concentrated bleach or toilet cleaner is spilt on toilet seats, it is important that this is cleaned up thoroughly to minimise the risk of skin contact. In all cases where concentrated bleach has been used in sinks, this should be rinsed thoroughly with copious amounts of water to reduce the risk of workers’ exposure and also to ensure safe disposal of the product. Previously, cleaning staff used to clean the office in the early evening when many staff were still working. This meant that neat bleach or toilet cleaner would be poured into toilet bowls or urinals and workers may then wish to use them, which significantly increased the likelihood of exposure to concentrated products. We have now requested that cleaning staff work later in the evening two nights per week when staff have already left and it is only on these occasions that the toilets are cleaned.
Cloths used for cleaning the kitchen should be rinsed thoroughly at the end of each use and not left where workers or even food could come into contact with concentrated products. Empty containers should be rinsed out well with water before disposal and the top of the container should be replaced to minimise the risk of individuals (i.e. office workers or waste disposal workers) coming into contact with undiluted chemicals. Products should be used in a well-ventilated area, particularly in the case of bleach. The office kitchen is poorly ventilated and has no windows that can be opened but the windows in the toilets can be opened before using products in these areas.
Correct storage of products will minimise the risk of workers’ exposure to chemicals. These products should ideally be stored in a locked storage area for which only suitable trained staff have access, and all products stored in original, closed containers, kept upright, in a cool place away from direct sunlight.
Plan of action for improvement
An audit showed that many staff were not aware of the risks from chemicals in cleaning products used in this office and that correct procedures for their safe use, disposal and storage were not being followed. Following this, a number of new measures have been, or will be, implemented. Training sessions have been arranged for all existing office staff to ensure they are familiar with COSHH assessments and safety procedures and these will be repeated when new staff join the company. Ensuring cleaning staff are correctly trained poses a greater challenge as these staff are recruited from an external agency who are responsible for their own training and quality control; however, the health and safety officer has worked with this agency to ensure that staff are familiar with safety procedures. No sand or other inert absorbable material was available in the office in case of large spillages. This has now been obtained and all staff are familiar with where this is stored.
A small, lockable cupboard was previously used for storing cleaning products but this was sometimes left unlocked. Furthermore, containers of kitchen cleaner were left in the cupboard under the sink in the kitchen close to where clean crockery is stored, and toilet cleaner was also frequently left in toilet cubicles. The COSHH assessment identified that Lifeguard 3 Way Toilet Cleaner should be kept away from chlorine-releasing agents and sodium hypochlorite; therefore bleach and toilet cleaner should not be stored together in the same cupboard as there is a risk that they may come into contact (e.g. in case of spillage). A second, lockable cupboard suitable for the storage of these chemicals will be purchased with one month and the two products stored separately. Staff will be trained to ensure that no products are left lying around in the kitchen or toilet areas and are returned to the storage area after each use, which should always be kept locked.
The disposable cloths used for cleaning the kitchen were previously being rinsed with water after use, left to dry and re-used. In order to minimise the risk of exposure of office staff to the cleaning product, these cloths will now be disposed of after a single use. Protective overalls worn by cleaning staff will be washed on a weekly basis and PVC/rubber gloves changed regularly.
Regular inspections are now carried out by the office health and safety officer on a monthly basis to ensure correct procedures are being followed.
Conclusions
Everyday cleaning products used in the office can pose a potential hazard to workers. It is therefore important that COSHH assessments are performed to assess the risk posed by the chemicals contained within these products. All workers should be aware of the correct procedures for the safe handling, use and disposal of these chemicals and should take the necessary precautions to minimise their risk of exposure (e.g. through use of personal protective equipment where appropriate).
Reference list
Health and Safety Executive 2007. List of approved workplace exposure limits. Retrieved 26th September 2008 from:
http://www.hse.gov.uk/coshh/table1.pdf
Piney, M. 2001, ‘OELs and the effective control of exposure to substances hazardous to health in the UK (version 3)’. Retrieved 26th September 2008 from:
http://www.hse.gov.uk/coshh/oel.pdf
The Physical and Theoretical Chemistry Laboratory 2008, Chemical and other safety information. Oxford University. Retrieved 26th September 2008 from:
http://msds.chem.ox.ac.uk
Bibliography
Health and Safety Executive 2008. Control of Substances Hazardous to Health – COSHH. Retrieved 26th September 2008 from:
http://www.hse.gov.uk/coshh/
Health and Safety Executive 2008. COSHH: A brief guide to the regulations. Retrieved 26th September 2008 from:
http://www.hse.gov.uk/pubns/indg136.pdf
Table 1. Chemicals used in office cleaning products: toxicity, target organs and recommended exposure limits (Health and Safety Executive 2007).

Solution

Toxicity

Target organs and organ systems

Workplace exposure limit
 

Long-term exposure limit

Short-term exposure limit

Freshline Bleach
Sodium hypochlorite solution (

Poses little hazard if stored correctly
Inhalation of chlorine-containing vapour may cause irritation to nose, throat and lungs
Repeated or prolonged contact of the concentrated solution with the skin may cause irritation and eventual dermatitis
Contact with the eyes may cause irritation and inflammation
Ingestion may cause irritation to mouth, throat and stomach

Eyes, skin, respiratory system, digestive system

Chlorine 0.5 ppm

Chlorine 1 ppm

Mr Muscle Professional Kitchen Cleaner
2-Butoxyethanol (

Cleaner is unlikely to be an irritant during normal use; prolonged contact with the skin may cause irritation

Skin (prolonged contact only)

25 ppm 1000 ppm

50 ppm None listed

Lifeguard 3 Way Toilet Cleaner
Phosphoric acid (5-15% v/v) Alkyl alcohol ethoxylate (

Contact with the eyes may cause severe irritation with risk of serious injury Contact with the skin may cause irritation Inhalation may cause irritation to nose, throat and lungs
Ingestion may cause irritation to mouth, throat and stomach

Eyes, skin, respiratory system, digestive system

None listed 2 ppm None listed

None listed 4 ppm None listed

Assessment Reference:
Date:26th July 2008
Review Date: 25th July 2009
1) Assessor Details [Client: please complete Section 1]

 
2) Process Description [Client: I’ve included all three products in one assessment – you may prefer to put each on a separate COSHH assessment pro forma]

Materials Used In Process

Risk Phrases (R)

Safety Phrases (S)

Freshline bleach
Sodium hypochlorite solution (Mr Muscle Professional Kitchen Cleaner 2-Butoxyethanol (Lifeguard 3 Way Toilet Cleaner Phosphoric acid (5-15% v/v) Alkyl alcohol ethoxylate ( 

R31 (contact with acid liberates toxic gas) R34 (causes burns) None required R41 (risk of serious damage to eyes) R38 (irritating to skin)

S2 (keep out of reach of children)
S2 (keep out of reach of children) S26 (in case of contact with eyes, rinse immediately with plenty of water and seek medical advice) S2 (Keep out of reach of children) S26 (in case of contact with eyes, rinse immediately with plenty of water and seek medical advice) S28 (after contact with skin, wash immediately with plenty of water) S37/39 (wear suitable gloves and eye/face protection)

 
[Client: the codes for both risk phrases and safety phrases are standard for COSHH assessments and were taken from The Physical and Theoretical Chemistry Laboratory, Oxford University website, accessed from: http://msds.chem.ox.ac.uk/]
3) Specific Considerations

Hazards Identification

Protective Equipment Required

Freshline Bleach
Contact with acids liberates toxic chlorine gas Inhalation of chlorine-containing vapour may cause irritation to nose, throat and lungs
Repeated or prolonged contact of the concentrated solution with the skin may cause irritation and eventual dermatitis
Contact with the eyes may cause irritation and inflammation
Ingestion may cause irritation to mouth, throat and stomach
Mr Muscle Professional Kitchen Cleaner Prolonged contact with the skin may cause irritation Lifeguard 3 Way Toilet Cleaner Contact with the eyes may cause severe irritation with risk of serious injury Contact with the skin may cause irritation Inhalation may cause irritation to nose, throat and lungs
Ingestion may cause irritation to mouth, throat and stomach

PVC or rubber gloves, protective overall and eye shield should be worn when handling concentrate; respiratory protection not required Personal protective equipment not typically required Eye protection required when handling neat product; other personal protective equipment not normally required

Specific First Aid

Specific Spillage Actions

Freshline Bleach
Eyes
Keeping eyes open, immediately irrigate with water or eyewash for at least 10 mins; obtain medical advice immediately
Skin contact Remove contaminated clothing; wash thoroughly with plenty of running water; obtain medical advice if symptoms develop
Inhalation
If exposed to chlorine gas or other vapours, individual should obtain fresh air; obtain medical attention
Ingestion
Do not induce vomiting; if individual is conscious, wash out mouth with water and give water to drink; obtain medical attention immediately Mr Muscle Professional Kitchen Cleaner Eyes Rinse immediately with copious amounts of water, holding the eyelids open; obtain medical attention immediately Skin contact Wash thoroughly with soap and water Inhalation Remove individual from source of exposure Ingestion Do not induce vomiting; remove product from mouth; give the individual a small amount of water to drink; obtain medical attention Lifeguard 3 Way Toilet Cleaner Eyes Rinse immediately with plenty of water holding the eyelids open; seek medical attention immediately Skin contact Wash thoroughly with soap and water Inhalation Remove individual from source of exposure Ingestion Do not induce vomiting; remove product from mouth; give the individual a small amount of water to drink; obtain medical attention

Small spillages: dilute with plenty of water Large spillages: absorb with sand, earth or granules (do not use sawdust or paper) and dispose with a licensed waste management company; wash down site of spillage with water Hose site of spillage with plenty of water to dilute to at least 2.5% unless this would contaminate either a water course or vegetation – in this case, either (1) collect the spilt solution, dilute as above and pour down a waste water drain or sewer or (2) absorb with sand, earth or granules and dispose with a licensed waste management company Hose site of spillage with plenty of water to dilute to at least 2.5% unless this would contaminate either a water course or vegetation – in this case, either (1) collect the spilt solution, dilute as above and pour down a waste water drain or sewer or (2) absorb with sand, earth or granules and dispose with a licensed waste management company

 

Disposal method

 

Freshline Bleach Rinse out all containers with water before disposal Mr Muscle Professional Kitchen Cleaner Dilute small quantities with water (to at least 2.5%) and pour down a wastewater drain; rinse out all containers at least twice and either recycle or dispose of as commercial waste Lifeguard 3 Way Toilet Cleaner Dilute small quantities with water (to at least 2.5%) and pour down a wastewater drain; rinse out all containers at least twice and either recycle or dispose of as commercial waste. For larger quantities, dispose as commercial waste

4) Hazard Category

Hazard Category

Hazard Description

Freshline Bleach Medium Mr Muscle Professional Kitchen Cleaner Low
Lifeguard 3 Way Toilet Cleaner
Medium Hazard

Irritant; contact with acid liberates toxic chlorine gas (see risk phrases above) Eye and skin irritant (see risk phrases for component chemicals above)

I have familiarised myself with the risks created and safe working practices during the use and handling of chemicals. I shall adhere to COSHH regulations and safe laboratory practices as explained to me during the COSHH assessment.