Given below are two statements: Statement I: Some microorganisms, especially protozoan, are able to survive conventional disinfection process. Statement II: Some carcinogens, such as chloroform, are created during chlorination process. In the light of the above statements, choose the most appropriate answer from the options given below:
Understanding Water Disinfection and Byproducts
The question asks us to evaluate two statements regarding water disinfection processes and their effects. Let's analyze each statement carefully.
Statement I: Some microorganisms, especially protozoan, are able to survive conventional disinfection process.
This statement discusses the effectiveness of conventional disinfection methods against different types of microorganisms. Conventional disinfection processes typically involve the use of chemicals like chlorine or chloramines, or physical methods like UV radiation. Certain microorganisms, particularly some types of protozoa, have life stages that are highly resistant to common disinfectants.
- Protozoa like Giardia lamblia and Cryptosporidium parvum form cysts or oocysts, which have protective outer walls.
- These cysts/oocysts are significantly more resistant to chlorine disinfection compared to bacteria or viruses.
- While disinfection reduces the overall microbial load, complete inactivation of these resistant protozoa often requires higher disinfectant doses, longer contact times, or alternative disinfection methods (like filtration or UV).
Based on the resistance of certain protozoans to conventional disinfection processes, Statement I is accurate.
Statement II: Some carcinogens, such as chloroform, are created during chlorination process.
This statement addresses the formation of harmful substances during the chlorination of water. Chlorination is a widely used disinfection method, but it can react with organic matter naturally present in raw water sources.
- When chlorine reacts with natural organic matter (like decaying plant material), it forms disinfection byproducts (DBPs).
- Trihalomethanes (THMs) are a major class of DBPs. Chloroform (CHCl\(_3\)) is the most common type of THM.
- Studies have shown that exposure to high levels of certain DBPs, including chloroform, may be associated with an increased risk of certain cancers (making them potential carcinogens).
- Regulatory bodies around the world set limits on the concentration of THMs and other DBPs in drinking water to minimize potential health risks.
Therefore, the formation of carcinogens like chloroform as a result of the chlorination process is a known phenomenon. Based on this, Statement II is also accurate.
Conclusion:
Both Statement I, concerning the survival of some protozoa after conventional disinfection, and Statement II, regarding the creation of carcinogens like chloroform during chlorination, are correct statements based on established scientific understanding of water treatment processes and their outcomes.
| Statement | Analysis | Correctness |
|---|---|---|
| Statement I: Protozoan survival after disinfection | Certain protozoa (e.g., Giardia, Cryptosporidium) cysts/oocysts are resistant to conventional chlorine disinfection. | Correct |
| Statement II: Carcinogen formation during chlorination | Chlorination of organic matter forms Disinfection Byproducts (DBPs) like Trihalomethanes (THMs) including chloroform, which are potential carcinogens. | Correct |
Revision Table: Water Treatment Key Points
| Topic | Key Concept | Relevance to Question |
|---|---|---|
| Water Disinfection | Process to kill or inactivate pathogens. Methods include chlorination, UV, ozonation. | Discussed in Statement I and II. |
| Conventional Disinfection | Commonly refers to chlorination. Effectiveness varies by microorganism type. | Central to Statement I regarding protozoa survival. |
| Protozoa | Single-celled eukaryotic microorganisms. Some are pathogenic and have resistant life stages (cysts, oocysts). | Specifically mentioned in Statement I for their resistance. |
| Chlorination | Using chlorine to disinfect water. Effective against many pathogens but reacts with organics. | The process mentioned in Statement II that creates byproducts. |
| Disinfection Byproducts (DBPs) | Compounds formed when disinfectants react with natural water constituents. | Chloroform (a THM) is a major DBP, as mentioned in Statement II. |
| Trihalomethanes (THMs) | A group of DBPs including chloroform, bromodichloromethane, dibromochloromethane, bromoform. | Chloroform, a type of THM, is named in Statement II as a carcinogen. |
| Carcinogen | A substance capable of causing cancer. | Chloroform is cited as a carcinogen formed during chlorination in Statement II. |
Additional Information on Water Safety
Ensuring safe drinking water involves a multi-barrier approach. This typically includes source water protection, coagulation, flocculation, sedimentation, filtration, and disinfection. While disinfection is crucial for killing most pathogens, it's not a perfect process and comes with challenges.
Alternative and advanced treatment methods are increasingly used to address the limitations of conventional disinfection:
- Ozonation: Effective against chlorine-resistant protozoa and viruses, and forms fewer regulated DBPs compared to chlorination, though it can form other byproducts.
- UV Disinfection: Highly effective at inactivating Giardia and Cryptosporidium by damaging their genetic material, making them unable to reproduce. It does not form significant chemical DBPs, but can affect water chemistry.
- Advanced Filtration: Membrane filtration (like reverse osmosis or nanofiltration) can physically remove protozoa, bacteria, viruses, and even dissolved organic matter that forms DBPs.
Utilities must balance the need for effective disinfection to prevent waterborne diseases with minimizing the formation of harmful DBPs. This is a key challenge in drinking water treatment.
Important Questions from Basics of Environment
The Wild Life (Protection) Amendment Act, 2022 seeks to implement the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Which of the following statements is correct about CITES?
1. CITES is an agreement between governments to ensure that international trade in the specimens of wild animals and plants does not threaten the survival of the species.
2. Under CITES, plant and animal specimens are classified into five categories based on the threat to their extinction.
3. The Convention requires countries to regulate the trade of all listed specimens through permits.
4. It also seeks to regulate the possession of live animal specimens.
Given below are two statements : One is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): Green hydrogen production will be critical for world community to achieve carbon neutrality by the year 2050.
Reason (R): The energy content of hydrogen gas is much higher than that of coal.
In the light of the above statements. choose the correct answer from the options given below :
For drinking and irrigation purposes, the availability of suitable water out of earth’s total water supplies is about less than
Permafrost is defining characteristic of which biome?
Identify the features associated with Kyoto Protocol.
(A) Heavier burden on developed countries to cut down greenhouse gas emissions.
(B) International emissions trading.
(C) Nationally determined contributions.
(D) Clean Development Mechanism.
Choose the correct answer from the options given below:
