Polluted Earth: Most Water Undrinkable

Water is essential for human life, but it is becoming increasingly scarce due to pollution and waste. While the amount of freshwater on Earth has remained constant, the population has grown, intensifying competition for a clean water supply. Inadequate management of wastewater and the natural presence of chemicals, such as arsenic, fluoride, and lead, have contaminated the drinking water of hundreds of millions of people. According to the United Nations, water use has grown at more than twice the rate of population increase in the past century. This has led to a water crisis, with more than 40% of freshwater ecosystems found to be severely polluted.

Industrial and agricultural wastewater contaminates drinking water

Industrial wastewater is contaminated water produced by industrial activity. It can contain high concentrations of dissolved solids (salts), naturally occurring radionuclides, and metals, as well as other pollutants used in drilling and well completion. Industrial wastewater is often discharged into bodies of water, where it can contaminate drinking water supplies. For example, in North Carolina, residents living near coal-fired power plants were informed that their water contained elevated levels of chromium-6 and other chemicals. Similarly, in Albany, Georgia, groundwater was polluted with cyanide and chloroform from various industries, posing health risks to the residents.

The US Environmental Protection Agency (EPA) regulates 94 chemicals in drinking water sources, but there are many other potentially dangerous chemicals that are not currently regulated. A News21 analysis of EPA data revealed that the drinking water of more than 244 million people in the US contains contaminants linked to industrial practices. This highlights the need for better regulation and treatment of industrial wastewater to ensure safe drinking water for the population.

Agricultural wastewater, on the other hand, is produced by agricultural activities such as farming and livestock operations. It can contain high levels of nutrients from fertilizers, pesticides, and animal waste, which can contaminate nearby water sources. In the US, about 40% of the land is used for agriculture, and these agricultural chemicals can move through the air, soil, soil water, streams, wetlands, and groundwater, affecting both surface water and groundwater quality.

The use of fertilizers and pesticides in agriculture can have significant impacts on water quality. Increased levels of nutrients from fertilizers draining into streams can stimulate algal blooms, affecting stream health, recreational uses, and increasing treatment costs for drinking water. Pesticides transported into streams pose risks to aquatic life, fish-eating wildlife, and drinking water supplies. Additionally, wastewater from livestock operations can contain high levels of animal waste, which can contaminate water sources if not properly managed.

The use of wastewater for irrigation in agriculture is becoming more common due to the depletion of freshwater resources and water stress caused by climate change. While it helps meet the growing demand for water in the agricultural sector, it also raises concerns about human health risks. Exposure to contaminants in wastewater-irrigated crops can pose risks to farmers, agricultural workers, their families, and communities living in proximity. Therefore, comprehensive research is needed to assess the multiple exposure routes, long-term health implications, and a wider range of contaminants, especially in regions heavily dependent on wastewater irrigation.

Natural chemicals in groundwater, e.g. arsenic, fluoride

While the precise amount of Earth's water that is undrinkable due to pollution is unknown, it is estimated that 2.5% of the Earth's fresh water is unavailable, either due to being locked in glaciers, polar ice caps, the atmosphere, and soil, or due to being highly polluted. According to the UNEP, researchers surveyed over 75,000 bodies of water in 89 countries and found that more than 40% were severely polluted.

Now, focusing on the topic of natural chemicals in groundwater, specifically arsenic and fluoride:

Arsenic and fluoride are natural chemical constituents that can be found in groundwater. They are considered the most significant natural groundwater contaminants in terms of their health effects and geographical extent. Arsenic and fluoride occur naturally in groundwater and can potentially affect the drinking water and health of hundreds of millions of people worldwide. Arsenic, in particular, is a significant concern, with up to 220 million people potentially exposed to hazardous concentrations. Fluoride also poses a risk, with approximately 180 million people potentially affected.

The presence of harmful levels of arsenic and fluoride in groundwater results from a combination of factors. Firstly, it is due to the existence of arsenic- or fluoride-rich minerals in geologic materials. Secondly, certain chemical conditions can facilitate the dissolution and release of these minerals into groundwater. For example, if a well is drilled in a geologic formation containing arsenic-bearing minerals and lacking oxygen, the extracted groundwater will contain dissolved arsenic and iron. On the other hand, water in shallow wells typically has enough dissolved oxygen to remove arsenic through the precipitation of iron minerals.

The health effects of consuming water with high concentrations of arsenic and fluoride can be severe, particularly in rural areas where alternative water sources may not be readily available due to poverty. Additionally, private domestic well owners may unknowingly consume groundwater rich in arsenic or fluoride, as private wells are often excluded from government testing and regulation. Switching to a confirmed safe water source is the simplest mitigation measure. Other options include blending water sources to achieve compliant contaminant concentrations or employing filtering processes, although this can be costly.

It is worth noting that groundwater is generally protected from the biological contamination found in surface water bodies, making it a frequently used source of drinking water. However, certain natural chemical elements, such as arsenic and fluoride, can occur in concentrations that pose a significant health threat when consumed over an extended period. Spatial prediction maps of these elements can help prioritize areas for groundwater quality testing and allow for the quick determination of safe and unsafe groundwater sources.

Water scarcity and pollution in developing world countries

Water scarcity and pollution are pressing issues in the developing world, with profound implications for human health, the environment, and socioeconomic stability. The availability of clean water is essential for human well-being, sustainable development, and the maintenance of peaceful and secure communities. However, water scarcity and pollution pose significant challenges to these goals, particularly in developing nations.

Over one billion people in developing countries face inadequate access to clean water, and this scarcity disproportionately affects women and girls. By 2025, it is estimated that 1.8 billion people will reside in regions with absolute water scarcity, according to UN-Water. This lack of access to clean water has dire health consequences, as up to 80% of illnesses in the developing world are linked to poor water quality and inadequate sanitation. Diseases such as cholera, typhoid fever, malaria, and diarrheal illnesses are prevalent, with diarrheal diseases alone claiming the lives of two million people annually, the majority of whom are children.

Several factors contribute to water scarcity in developing countries. Firstly, population growth and changing living conditions have increased the demand for water. Secondly, economic development and industrialization have transformed water ecosystems, leading to a loss of biodiversity and further straining water resources. Agriculture consumes the most water, and inefficient practices and pollution from fertilizers and pesticides contribute to water scarcity and pollution. Climate change is another significant factor, altering weather patterns and causing droughts and floods that disrupt water cycles. Additionally, prevailing economic policies and planning approaches can influence water scarcity, and poverty and governance issues hinder effective water management in developing nations.

Pollution is a critical aspect of water scarcity, as it renders water sources unusable. Toxic substances such as oil, metals, plastics, pesticides, and industrial waste contaminate water bodies, while changes in pH, temperature, and salinity create stressful conditions for ecosystems. The introduction of pathogenic organisms further compromises water quality. These pollutants can seep into the earth, polluting groundwater and rendering it unsafe for consumption or other applications. Additionally, insufficient wastewater and sewage treatment in developing countries constrain access to freshwater, exacerbating the problem.

Addressing water scarcity and pollution in the developing world requires collective efforts and sustainable solutions. Improving water infrastructure, promoting water conservation, and implementing effective wastewater treatment systems are crucial steps. Additionally, global initiatives, such as the Ramsar Convention for wetland protection and Canada's funding for WASH services during the COVID-19 pandemic, contribute to enhancing water access and sustainability. By tackling these challenges, we can ensure that communities in the developing world have access to this fundamental resource, fostering better health, environmental sustainability, and overall human development.

Population growth and its impact on water demand

Water is essential for all life on Earth, yet it is a finite resource. Population growth is a key factor in the increasing demand for water, and it is driving water scarcity worldwide.

The planet's supply of freshwater is fixed, and the world's population is growing, especially in areas where water is already scarce. The World Bank has identified 45 "water-poor" countries that are physically short of water and economically impoverished. These countries have an average fertility rate of 4.8 children per woman, nearly twice the world average, and their populations are expected to double by 2050. This rapid population growth makes water problems more challenging to solve.

Population growth fuels an increase in food needs, and agriculture uses a lot of water. More people mean more farming to meet the increased food demands. Food production uses and wastes large volumes of water, and wastewater from agricultural activities is a significant source of environmental pollution. The depletion of groundwater is a concern for world food production, which must increase by 70% by 2050 to meet the demands of the growing population.

The growing population also puts pressure on energy production, which requires freshwater. The modification of natural waterways through dams or levees can have irreversible effects on the natural landscape, endangering the natural flow of water and the wildlife that depends on it.

The impact of population growth on water demand is further exacerbated by outdated and decaying infrastructure in many urban areas, which causes serious inefficiency in water transportation, leaving many without access to water. Climate change is another factor, intensifying droughts and altering rainfall patterns, further threatening water supplies.

To address the impact of population growth on water demand, investments in family planning programs can help slow population growth and reduce water stress. Additionally, creative solutions and sustainable water management practices are needed to meet the water needs of a growing global population.

Tracking water pollution with Earth Observation technologies

Our planet is facing a triple crisis of climate change, biodiversity loss, and pollution. These crises are taking a toll on our oceans, rivers, seas, and lakes. Water is the basis of all life on Earth, yet approximately one in seven people worldwide do not have access to safe water. Water can become unsafe due to contamination by various organic and inorganic compounds due to various natural and anthropogenic processes.

To address this crisis, Earth Observation (EO) technologies have been used to track, over long time periods, the extent to which freshwater ecosystems are changing. EO technology, combined with modeling of highly complex dynamic systems, can provide monitoring and forecasting information on water quality and quantity. This information can guide water professionals in making quick and data-informed decisions, achieving regulatory compliance at a low cost, and improving the day-to-day performance of operations. For example, the Group on Earth Observations (GEO) Blue Planet Initiative collaborated with the UN Environment Programme to integrate Earth Observation data to support informed decision-making and meet water management demands.

EO technologies can be integrated into existing decision-support systems to help prepare for and respond to water quality hazards. For instance, the US Environmental Protection Agency considers environmental risks due to acid mine drainage (AMD) to be one of the most significant issues, and EO technologies can assist in monitoring AMD across vast mining districts. The spectral signature of Fe3+ possesses distinct characteristics that may be useful for diagnostic identification using Earth observations. Additionally, researchers can train machine learning networks to analyze historical time series observations to identify significant pollution events and compare them to current conditions to understand how AMD sites have changed annually and seasonally.

Furthermore, remote sensing spectroscopy, combined with cloud data systems, can be useful in monitoring water quality associated with AMD. The multi-sensor approach provides higher observation frequency and more detailed spatial information on algal blooms. While this practice shows promise, more research is needed to find algorithms applicable across various sensors, and in-situ testing is crucial for validating results.

In conclusion, EO technologies have the potential to revolutionize the way we monitor and manage water quality and quantity. By providing timely and accurate data, EO technologies enable informed decision-making, improve environmental performance, and help ensure access to safe water for all.

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