Week 7: Managing Environmental Health Risks: Bathing water

Hello again, readers!

The lesson of this week is about water. No, it’s not like the one we learnt last week. The water of this week is not potable water but bathing water. Meaning? It’s water used for bathing and swimming, not for drinking so don’t expect to drink this kind of water, okay? Good.

Bathing water can be divided into 2 types: (Outdoor) Bathing water and Pool water.

First, let’s talk about outdoor bathing water. This type of water is natural water (lake, river, beach, blah blah blah) and can be easily polluted with hazards like pathogens or discharges from sewage, nutrient inputs (which may lead to eutrophication and facilitate a massive growth of algae), Cyanobacteria, surface run-off, faeces,…. As a result, fever, diarrhea and vomiting or other severe health problems may appear on those who came in contact with this type polluted water. Okay that may sound like I’m making things up, there’s no way outdoor bathing water could be that bad right? WRONG! Don’t underestimate the danger of outdoor bathing water, especially if you are living in a bad environment. You know, in my country, nah that’s too big, in my city, most people don’t dare to bath in outdoor bathing water such as lake or river because those are really polluted. Just imagine, everyday, tons of sewage and garbage are thrown into a river, would you dare to bath in that river? ‘Cause that’s what happen in my city.

Next is pool water. Have you ever gone to a swimming pool? I’m sure that most of you have, at least once. Then do you know what type of hazards are there in the swimming pool? The picture below will show you.

Kết quả hình ảnh cho chemicals in pool, hot tub and spa water

Scary, right? Oh and don’t forget about the Microbiological hazards people brings to the pool when they come to use it, it can also cause direct impact on the skin, eyes and mucous membranes, or just put it simply, bad effect for your health.

However, don’t be too worry, there are ways to treat bathing water as well as laws for bathing water quality standards (otherwise nobody would dare to bath at all 😛 ).

In Europe, there are “Legal Obligations under the EU Bathing Water Directive 2006/7/EC:

  • Two main parameters used to monitor and assess the quality of bathing waters and to classify them:

– intestinal enterococci

– escherichia coli

  • Other parameters could be taken into account, such as the presence of cyanobacteria or microalgae.”

Moreover, bathing water is monitored yearly by Member States and base on their quality, bathing water are classified into 4 types: poor, sufficient, good and excellent. Therefore, you can find which place is suitable for bathing outdoor.

As for pool water, you can find your answer in this picture.

References and further reading:








That’s all for today I guess.

Alla prossima, ciao.



Week 6: Managing Environmental Health Risks: Potable water

Welcome to this week topic: Potable water. I must say, this is an interesting topic as potable water is one of the most important thing in our daily life. We can’t live without water. In fact, “water is your body’s principal chemical component and makes up about 60 percent of your body weight, every system in your body depends on water”. Moreover, various studies show that you need to consume at least 2 litters of water per day. So well yeah, potable water is important.

To start with, you probably wonder what is potable water, right? Potable water, also known as drinking water, is water that suitable for human consumption.

There are 2 main sources of potable water:

  • Groundwater/artificial groundwater
  • Surface water


Groundwater Surface water
Characteristics •Fresh water in the rock and soil layers beneath Earth’s land surface.

•Makes up more than one-fifth (22%) of Earth’s total fresh water supply

•Determined by the geology of the area

•Move slower

•Found over the land surface in streams, ponds, marshes, lakes or other fresh water sources.

•Move faster

Contamination Occurs when products such as gasoline, oil, road salts and chemicals, pharmaceuticals… or microbes due to poorly managed waste water treatment get into the groundwater. Can be affected by numerous physical variables such as

•topography, land cover,

•soil conditions, mineralogy, and ground-water conditions.

Contains microorganisms and bacteria.

Less contaminated due to natural filter More easily contaminated

Since groundwater and surface water are interconnected, the contaminants may share between these two. Moreover, neither of water source can ever be entirely free from water contaminants.

To determine water quality, you need to consider physical, chemical and microbiological properties of water. More information can be found here.

Next part of the lesson, we learn about water treatment.

Water treatment is “the act or process of making water more potable or useful, as by purifying, clarifying, softening, or deodorizing it.”

This treatment usually deals with viruses, bacteria, parasites and with changing physical characteristics such as turbidity, chemical contaminants (oil or gasoline residue, pesticides and herbicides) and organic material.

However, in my country, water treatment was sadly not being paid the attention it deserves. As a result, people in my country can only drink water from a bottle or boil water from the tap but not directly from the tap like in Finland.

References and further reading:









0674258592.01.MZZZZZZZ Environmental Health Revised Edition, Dade W. Moeller.

Week 5: Risk Assessment and Management

Okay so you know about the Environmental Health Hazards, right? I talked about it in the previous blog. This time, we will get to learn more about the Risk Assessment and Management, sound exciting isn’t it? XD

Managing Risks includes 3 following steps:

  1. Identification of hazards (This was what we learnt last week)
  2. Assessing the risk level (this contains two types: Likelihood and Severity of impact)

So yeah, in this step, you need to analyze and decide on how likely it is for the risk to happen as well as how severe the risk is on a scale of 1 to 5. The risk is calculated by multiplying the Likelihood with the Severity. You can find it in the table below how high the risk is after calculating, with 1 being insignificant in consequences and rare in likelihood.

Kết quả hình ảnh cho risk assessment

My group did a risk rating on Artificial colors and this is our result:


Scale 1-5 1. Insignificant 2.  Minor 3. Moderate 4. Major 5. Catastrophic
Likelihood 5. Almost certain
4. Likely
3. Moderate


2. Unlikely
1. Rare
      According to the result, our risk rating is: 3*3 = 9, which is HIGH.
    3. Deciding on the risk management option

There are 5 options can be used to influence the source, the pathway, the exposure or a combination simultaneously.

Kết quả hình ảnh cho hierarchy of hazard control

References and further reading:




0674258592.01.MZZZZZZZ Environmental Health Revised Edition, Dade W. Moeller.