Water pollution is a global challenge that has increased in developing and developed countries. The pollution levels have undermined billions of people’s economic growth and env health. Today international attention primarily focuses on water quantity, water-use efficiency, and allocation issues. But poor wastewater management has created severe water-quality problems in several parts of the world, worsening the water crisis.
Moreover, global water shortage caused by the physical scarcity of the resource and by the gradual deterioration of water quality in several countries is reducing the quantity of safe water.
Water Pollution is a Matter of Concern.
Human settlements, industries, and agriculture are significant sources of water pollution. Globally, eighty percent of municipal wastewater is discharged into water bodies in an untreated form. Industries are responsible for dumping millions of tons of heavy metals, solvents, toxic sludge, and other wastes annually.
Agriculture accounts for 70 percent of water usage worldwide. It plays a significant role in water pollution. Farms discharge large quantities of organic matter, agrochemicals, drug residues, sediments, and saline drainage into water bodies. The resultant water pollution poses risks to aquatic ecosystems. In addition, it poses risks to human health and productive activities.
Role of Agriculture in Water Pollution
It is proven that farming is the single largest user of freshwater resources. This sector uses a global average of 70 percent of all surface water supplies. Except for water lost through evaporation, agricultural water is recycled back to groundwater and surface water.
However, agriculture is both the cause and victim of water pollution. It is caused by its discharge of pollutants and sediment to the surface and groundwater. In addition, net soil loss by poor agricultural practices, and salinization and waterlogging of irrigated land are also a few factors.
It is a victim of wastewater and polluted surface and groundwater. The polluted water contaminate crops and transmit disease to consumers and farm workers. Consequently, it is essential to understand that agriculture is both a cause as well as a victim of water pollution.
Agriculture Causing Water Pollution
Farming accounts for 70 percent of total water consumption globally. You would be surprised to know that it is the single-largest contributor of non-point-source pollution to groundwater and surface water.
Agriculture intensification is usually accompanied by increased soil erosion, salinity, and sediment loads in water. Moreover, excessive use (or misuse) of farming inputs such as fertilizers to increase productivity may also lead to pollution.
Agricultural pollution can lead to contaminated water, food, fodder, the natural env, farms, and the atmosphere. Fertilizers can contaminate groundwater and surface water, such as antibiotics, silage effluents, organic livestock wastes, and processing wastes from plantation crops. Pollution caused by large-scale industrial farming, including fisheries and livestock, is considered point-source pollution.
Additionally, the pollution caused by small-scale family-sized farming is regarded as non-point-source pollution. Farms discharge large quantities of agrochemicals, sediments, organic matter, drug residues, and saline drainage into water bodies. Therefore, diagnosis and monitoring are critical requirements for the management of agricultural practices. Such practices will help mitigate these harmful impacts on water resources.
Agriculture as a Victim of Water Pollution
Farmers are looking at non-conventional water sources of marginal quality, including wastewater, with the increasing demand for agricultural commodities. Domestic and municipal wastewater presents an attractive option due to the high nutrient content, especially when conventional water resources are scarce or lacking nutrients.
It is important to note that the unsafe usage of non-conventional sources of water, such as wastewater in farming, can lead to several issues. It can lead to the accumulation of chemical and microbiological pollutants in crops, livestock products, and water and soil resources. All this will ultimately lead to severe health impacts among exposed food consumers and farm workers.
However, wastewater can be a valuable water source and nutrient. It is only possible if the waste water is adequately treated and safely applied, contributing to food security and livelihood improvement.
Water Pollution and Role of FAO
Water quality in agriculture is a focus area for the Food and Agriculture Organization of the United Nations (FAO). Under which different national and global projects and programs are identified. FAO looks at agriculture as a victim and cause of water pollution.
Based on that, it defines water quality-related activities in two categories. FAO is mandated to work with countries and other organizations to monitor, control, and mitigate pollution loads from exercises and the negative impacts of agricultural pollution on people’s health and the environment. FAO takes a multidimensional approach to cover all socio-economic, health, environmental, and food safety aspects.
Water Pollution by Livestock
Agricultural pressures on water quality come from cropping, livestock systems, and aquaculture. All these three have expanded and intensified to meet increasing food demand related to population growth and changes in dietary patterns. The livestock sector has grown significantly and strengthened faster than crop production in practically all countries.
Therefore, the associated waste, including manure, can severely affect water quality. In the past two decades, we have witnessed the emergence of a new group of agricultural pollutants in the form of veterinary medicines. These medicines include vaccines, antibiotics, and growth promoters or hormones. These pollutants move from farms through the water to drinking water sources and ecosystems.
Additionally, zoonotic waterborne pathogens are another primary concern. FAO, in its report, has concluded that there has been a rapid increase in aquaculture worldwide in marine, brackish-water, and freshwater env. Fish excreta and uneaten feeds from fed aquaculture contaminate water. Increased production combined with greater use of fungicides, antibiotics, and anti-fouling agents – may pollute downstream ecosystems.
Large Scale Livestock Systems
Livestock production covers seventy percent of all agricultural land and thirty percent of the planet’s surface. The livestock sector contributes to water-quality degradation from local to global. The structural changes in the livestock sector are linked with developing industrial and intensive livestock production systems.
Livestock systems often involve large nos of animals concentrated in relatively small areas. Intensive livestock systems increasingly depend on feed concentrates traded internationally and domestically. These changes exert growing pressure on the env, particularly on water quality. Most water used for livestock drinking and servicing returns to the env in liquid manure, slurry, and wastewater.
Livestock excreta contain considerable quantities of nutrients, oxygen-depleting substances, pathogens, and, in intensive systems, also heavy metals, drug residues, hormones, and antibiotics. When livestock is concentrated, the production of wastes tends to go beyond the buffering capacity of surrounding ecosystems. As a result it pollutes both the surface waters and groundwater.
Water Pollution Due to the Expansion of Agricultural Systems.
As you might be awear agricultural systems have expanded and intensified as a response to the ever-increasing food demand for the growing world population. Land clearing and agricultural expansion have contributed to higher pollutant loads in water.
However, the most significant impacts have been caused by specific unsustainable patterns of agricultural methods. Overusing agrochemicals, water, animal feeds, and drugs designed to increase productivity. But they result in higher env pollution loads, including rivers, lakes, aquifers, and coastal waters.
The world population doubled between 1970 and 2015, but the production of cereals almost tripled. The production of vegetables increased fourfold, tomato production increased fivefold, and soybean production increased eightfold.
This initial increase in production has been achieved through expanding agricultural land and introducing new crop varieties—the intensive use of agrochemicals and agrotechnology. Irrigation is a significant factor in agricultural intensification. Big irrigation projects have been essential for increasing food security globally, particularly in developing countries.
Nevertheless, irrigation and drainage have often been associated with a loss of water quality caused by salt, pesticides, fertilizer runoff, and leaching. Mineral fertilizers have been in use since the nineteenth century for supplementing natural nutrient sources and recycling to raise crops and animals. Still, the use of such fertilizers has increased dramatically in recent decades. Today, the world consumes ten times more mineral fertilizer than it did in the sixties.
Water Pollution Due to Aquaculture
The demand for fish and shellfish for food, feed, and other products has grown faster than for any other agricultural commodity in the last several decades. Wild fish catches plateaued in the nineties, and all increases in fish production are now derived from aquaculture.
Aquaculture has expanded dramatically and now produces nearly half the total fish consumed. The growth of aquaculture has occurred in developing countries, and the greatest concentration of aquaculture is in low-income developing nations.
There has been a gradual increase in the proportion of fed species in aquaculture that require externally produced foods. This form of production accounts for seventy percent of the total output, compared with fifty percent in 1980. Fed and intensive aquaculture can export feces, uneaten feed, and drugs to water bodies.
Carnivorous species are highly valued in aquaculture, requiring significant inputs of fishmeal and other pelleted feeds. Many types of non-fed aquaculture, like mussel farming, can filter and clean waters, but different types, such as intensive caged crab culture, may disrupt natural nutrient cycles and result in water quality degradation. Market pressures and differentiation are increasing the intensity of production and leading to increased concentrations of single species. These measures have increased the use of antibiotics, fungicides, and anti-fouling agents, contributing to downstream pollution.