4.4 Water Pollution (DP IB Environmental Systems & Societies (ESS): HL): Flashcards

Industrial effluent is wastewater discharged by industrial facilities after production processes, which may contain harmful substances such as heavy metals and toxic chemicals.

Oil spills can harm aquatic life and cause long-term environmental damage.

Plastic pollution refers to the accumulation of plastic products in the environment, negatively affecting wildlife, habitat, and humans.

Plastic debris accumulates in marine environments, causing problems such as harm to wildlife, disruption of habitats, and pollution of the water, which affects both animals and humans.

Plastic pollution can negatively affect wildlife, habitats and humans.

False.

Plastic pollution affects both wildlife and humans, as it can degrade habitats and impact water quality.

Microplastics are small plastic particles less than 5mm in diameter, often formed from the breakdown of larger plastic debris or from products like cosmetics and clothing.

Microplastics are ingested by small marine organisms, which are then eaten by larger predators, leading to bioaccumulation and biomagnification of plastics and toxins up the food chain.

Plastics can absorb harmful chemicals from the environment, which can then enter the food chain.

Plastic pollution harms marine wildlife through ingestion of plastics and entanglement in plastic debris, both of which can result in injury or death.

Plastics in the ocean can provide a means for invasive species to spread to new areas, disrupting local ecosystems.

Gyres are large, rotating systems of ocean currents that trap and accumulate plastics, forming large patches of debris such as the Great Pacific Garbage Patch.

Plastics can release toxic additives like bisphenol A (BPA), which can interfere with the reproductive systems of aquatic species.

Two management strategies are reducing plastic production and use (such as banning single-use plastics) and cleanup efforts to remove existing plastic pollution from the environment.

Water quality is the measurement of the chemical, physical and biological characteristics of water.

A water quality index (WQI) combines multiple measurements into a single value or score that provides an assessment of the overall water quality of a particular water body.

Chemical characteristics of water include the levels of dissolved substances like minerals, pollutants, and nutrients.

Turbidity is a measure of the clarity or cloudiness of water, which is affected by suspended particles.

Monitoring water quality at various locations helps to assess potential impacts of pollution sources, identify issues, and implement management strategies.

A high WQI indicates good water quality.

False.

Biological characteristics refer to the presence of microorganisms and invasive species, not dissolved nutrients.

Biochemical oxygen demand (BOD) is a measure of the amount of dissolved oxygen required to break down organic material in a given volume of water through aerobic biological activity.

A high BOD value means more oxygen is needed for decomposition, indicating a larger amount of organic matter and higher pollution levels.

BOD values are usually expressed in milligrams of oxygen consumed per litre of water (mg/L) or as a percentage of the initial dissolved oxygen level.

Species such as bloodworms and Tubifex worms are tolerant of organic pollution and low oxygen, so they are likely to be found in such areas.

The BOD test involves measuring the initial dissolved oxygen concentration and then the concentration after a specific incubation period.

The introduction of sewage increases the BOD, as more organic matter leads to higher oxygen consumption for decomposition.

Total suspended solids (TSS) is the concentration of solid particles suspended in water, measured as mass per volume (e.g. mg/L).

Turbidity is measured using a Secchi disc; the depth at which the disc disappears is recorded as an indicator of water clarity.

Eutrophication is the process where water bodies receive excess mineral nutrients, mainly nitrates and phosphates, leading to excessive growth of algae and plants.

An algal bloom is a rapid increase in the population of algae in a water body, often resulting in a dense growth that can cover the water surface.

Hypoxia is a condition where there are low oxygen levels in water, making it difficult for aquatic life to survive.

Anoxia is the severe or complete depletion of oxygen in water, resulting in conditions unsuitable for most aquatic organisms.

The main mineral nutrients involved in eutrophication are nitrates and phosphates.

Blocking sunlight prevents underwater plants from photosynthesising, leading to their death and a decrease in dissolved oxygen.

During eutrophication, the decomposition of dead plants and algae by bacteria uses up dissolved oxygen in the water, which can lead to hypoxia or anoxia.

False.

Eutrophication often causes fish kills and reduces fish stocks due to low oxygen levels.

A dead zone is an area in a water body where oxygen levels are too low (anoxia or hypoxia) to support most aquatic life.

Positive feedback in eutrophication occurs when nutrients released by decomposition promote further algal and plant growth, reinforcing the cycle and worsening the ecosystem's condition.

Eutrophication begins when water bodies receive excess nitrates and phosphates.

When an algal bloom forms, it can block sunlight from reaching underwater plants.

Decomposition of dead algae by bacteria uses up dissolved oxygen in the water.

Water pollution management strategies are methods and approaches used to prevent, reduce, and clean up pollution in water bodies by addressing human activities, pollutant release, and ecosystem restoration.

The three main stages are: human activity producing the pollutant, releasing the pollutant into the environment, and the impact of the pollutant on ecosystems.

Eutrophication is the process by which excess nutrients, especially nitrates and phosphates, enter water bodies leading to algal blooms and ecosystem damage.

False.

The amount of material released determines the impact of pollution. Higher quantities usually cause greater environmental damage.

There are three types of strategies for managing the impacts of pollution: changing human activity, regulating and reducing quantities of pollutants released at the point of emission, and cleaning up the pollutants and restoring the ecosystem after pollution has occurred.

The strategy is the reduction of human activities producing pollutants, which targets the source of pollution.

An example of an alternative to synthetic fertilisers is organic fertilisers, such as compost or manure.

Phosphate-free detergents are used to minimise water pollution by reducing the amount of phosphates entering water bodies and causing eutrophication.

Buffer strips are areas of vegetation planted along waterways to absorb excess nutrients and reduce pollution.

Wastewater treatment plants are used to remove nutrients such as nitrates and phosphates from sewage before water is released into natural water bodies, reducing the risk of eutrophication.

Dredging is the removal of nutrient-rich mud and sediments from the bottom of water bodies to reduce pollution and help restore aquatic ecosystems.

Restoring wetlands is an example of habitat restoration, which helps filter nutrients naturally and improve ecosystem health.

Bioaccumulation is the process where toxins accumulate in the tissues of organisms over time, often becoming more concentrated at higher levels of the food chain.

Bacteria breaking down untreated sewage consume dissolved oxygen, which can lead to oxygen depletion and the death of fish and other aquatic life.

Polychlorinated biphenyls (PCBs) are a type of persistent organic pollutant that can persist in the environment for decades.

Tributyltin (TBT) disrupted the endocrine systems of marine animals, especially causing reproductive problems in molluscs and severe declines in oyster populations.

Large pieces of plastic can cause entanglement or ingestion problems for marine animals.

Thermal pollution is the release of warm water from industrial or power plant processes into natural water bodies, which can lower dissolved oxygen and harm species adapted to cooler conditions.

The main contributors to harmful algal blooms in freshwater environments are cyanobacteria (blue-green algae).

Dinoflagellates are responsible for many marine HABs and can sometimes produce red tides that are toxic to marine life.

Harmful algal blooms can release toxins such as cyanotoxins and neurotoxins, which can contaminate drinking water and cause health issues like liver damage, nervous system effects, or paralytic shellfish poisoning in humans.

A dead zone is an area in a water body where oxygen levels are so low (hypoxic or anoxic) that most marine organisms cannot survive.

False.

Anoxic waters lack oxygen completely, while hypoxic waters have low but not zero oxygen.

Nutrient runoff from agriculture can cause eutrophication by fueling excess algal growth, which leads to hypoxic or anoxic conditions when the algae die and decompose.

Sewage treatment is the process of removing harmful substances from wastewater so it can be safely returned to the environment or used for domestic purposes such as toilets, showers, and drinking water.

The main goal of sewage treatment is to remove harmful substances from wastewater to prevent pollution, protect public health, and conserve water by recycling treated water.

Sewage treatment prevents pollution, protects public health, and helps conserve water.

Primary treatment is the stage in sewage treatment where large solid materials and some suspended solids are removed from wastewater by processes such as screening, grit removal, sedimentation, and skimming.

During primary treatment, large objects are removed by screening, sand and gravel settle in the grit chamber, and floating materials are removed by skimming.

Secondary treatment is the stage in sewage treatment where organic matter is broken down by biological processes involving bacteria and other microorganisms, usually with the help of aeration.

Aeration pumps oxygen into the wastewater, encouraging bacteria to break down organic pollutants.

In secondary treatment, bacteria convert organic waste into carbon dioxide, water, and activated sludge.

Tertiary treatment is the final stage of sewage treatment where remaining nutrients, chemicals, and pathogens are removed through processes like chemical treatment, nutrient removal, and filtration.

Chlorine or ultraviolet light is used to disinfect the water and kill pathogens during tertiary treatment.

Tertiary treatment processes remove excess nitrogen and phosphorus to prevent eutrophication.

True.

Tertiary treatment removes remaining nutrients, chemicals, and pathogens, making the effluent safe for discharge or reuse.

A major challenge for low income countries is limited sewage treatment infrastructure and high costs, which can lead to health risks from untreated wastewater.

Social and economic inequality means that wealthier communities have better access to sewage treatment, while poorer or marginalised groups may lack proper sanitation facilities.

A biotic index is a numerical score that provides an indirect measure of water pollution by assessing the presence, abundance, and diversity of indicator species and their tolerance to pollution.

A high biotic index value indicates that the aquatic ecosystem is clean and less polluted, with a diverse community of pollution-sensitive species.

Biotic indices are tools used to assess the overall health and pollution levels of an aquatic ecosystem.

The three main factors are species diversity, tolerance values, and relative abundance of indicator species.

The first step is the selection of indicator species based on their sensitivity or tolerance to pollution.

An indicator species is an organism used to assess the quality of an environment or indicate the presence of specific environmental conditions, such as pollution.

Bloodworms and Tubifex worms are common indicator species of polluted water.

Stonefly and mayfly nymphs are usually found in clean and well-oxygenated water, indicating good quality.

False.

A high diversity and abundance of diatoms usually indicates clean, well-oxygenated water.

The common reed is tolerant of high nutrient levels and is often found in polluted waters.

Indicator species cannot provide accurate quantitative figures for the amount of pollution present and can be affected by other factors like predators or disease.

A water quality index (WQI) is a single number representing the overall quality of water in a specific area, calculated by combining results from multiple water quality tests.

The main advantage is that it simplifies complex water quality data into a single clear score, making it easier to assess and compare water quality across locations.

Common parameters measured in WQI include pH, dissolved oxygen, and biochemical oxygen demand.

False.

A WQI score of 100 usually indicates excellent water quality, but specific uses may require testing for different contaminants not included in the score.

Scientists study these aspects of indicator species to assess the pollution levels and overall health of aquatic ecosystems.

Drinking water standards are regulations that define the acceptable quality of water for human consumption.

Drinking water standards differ by country because of variations in local resources, infrastructure, and needs.

Drinking water standards are regulations that define the acceptable quality of water for human consumption.

A contaminant is any substance, such as bacteria or chemicals, that may make water unsafe for human consumption.

False.

There are no globally accepted standards for drinking water. Standards differ by country.

The World Health Organization (WHO) drinking water guidelines are recommendations to help countries ensure safe drinking water, especially where no national standards exist.

WHO guidelines are recommendations, not enforceable laws, but can be adopted by countries as a framework.

The WHO guidelines address contaminants such as bacteria, chemicals (e.g. fluoride, lead, nitrate), and physical properties of water such as pH and turbidity.

Developed countries like the UK and USA have statutory drinking water standards, often based on WHO guidelines.

Drinking water standards help EIAs evaluate the impact of projects on local water sources, ensuring safe water for surrounding communities.

An Environmental Impact Assessment (EIA) is a study that assesses the potential environmental effects of proposed projects.

International companies use WHO standards as a minimum to avoid environmental harm and maintain a positive reputation.

Water pollution is the introduction of harmful contaminants into water bodies, making the water unsafe for humans, wildlife, and ecosystems.

Reducing water pollution is important for protecting drinking water sources, conserving biodiversity, and supporting overall ecosystem health.

Disposing of waste such as chemicals, oils, and medicines down sinks or drains can contaminate local water sources and groundwater.

Individuals can conserve water at home by taking shorter showers, turning off taps while brushing teeth, or using water-efficient appliances.

Using eco-friendly products helps ensure fewer harmful chemicals end up in water sources.

A biodegradable product is one that can be broken down naturally by microorganisms, reducing harm to the environment.

False.

Community clean-ups both remove pollutants and help educate members of the community about the importance of keeping water sources free from waste.

Peaceful protest can draw public attention to water pollution issues and encourage companies or governments to take action.

Community science projects involve local residents in monitoring water quality and providing valuable data to identify pollution trends and sources.

Lobbying is when groups or organisations work to influence lawmakers to create or strengthen regulations protecting water quality.

Legal action against polluters can lead to financial penalties for companies or stricter operational requirements.

Reporting visible pollution to local authorities helps them take action before pollution spreads further, making it easier to contain and treat.