Water is a chemical substance that covers about 71% of earth surface. Water molecules contain one oxygen and two hydrogen atoms connected by covalent bonds. Earth and living-beings are highly depend on water, since their body is composed mostly of water, especially groundwater.
Groundwater is only 0,61% of the entire world’s water but an important role in growing crops, public supply, and industrial process. This type of water is refilled by the surface water bodies in a natural cycle.
The quality of water can be measured by how water looks, smells and tastes because naturally, water is colorless, odorless and tasteless. Water quality of chemical attributes is measuring the many and kind of elements or molecules dissolved or suspended in the water.
The parameter used to measure this are alkalinity, pH, hardness, nitrates, nitrites an ammonia, ortho-and total phosphates, and dissolved oxygen and biochemical oxygen demand. The presence of certain biological microorganism can also determine the quality. Water quality determines its qualification for consumption. Drinking water requires higher quality since it will replace the loss of human body liquid. You may also read: 9 Chemicals in Water Supply; Substances; Pollution; Treatment
Agricultural chemicals are widely used in the modern era since the demand for food is always increasing. The most used agricultural chemical is pesticide as it can eliminate pest with ease and fertilizer to increase the harvest. This main property of agricultural chemicals sometimes can induce overuse in hope to maximize the farming result. The excessive use of the agricultural chemical can lead to a residual and sedimented chemical. This excess chemical will later runoff by rain or water current and contaminate the near ecosystem like water body or soil.
Surface water has more chance being contaminated than groundwater since surface water can directly be contacted to water runoff. Meanwhile, groundwater contamination usually comes from the soil around it and determine by the leachability of the contaminants. You may also read: 10 List of Inorganic Water Pollutants – Substances – Effects
Effects of Agricultural Chemicals on Water Quality
Here are the harmful effects of agricultural chemicals on water quality:
1. Water acidity pH
The level of water acidity is obtained by measuring the concentration of hydrogen ion, the level range from 0 (most acidic) to 14 (most basic). Level 7 is marked as neutral and the normal pH of distilled water. Natural water could have pH ranging from 6.5 and 8.5 based on the geological and atmospheric conditions where the water come from.
Water with pH level below 6.5 or above 8.5 is classified as a secondary contaminant in drinking water and can possibly damage plumbing. Ammonia emission that resulted from natural fertilizer such as manure will cause acidification of the environment including water.
2. Water alkalinity
Alkalinity level doesn’t always mean the water has basic pH, it’s more to the water ability to neutralize acidity. This is done by measuring bicarbonates, carbonates, and hydroxides in water. Extensive use of an agricultural chemical in long-term will deteriorate soil and water quality, such as increasing alkalinity.
Alkaline water that is consumed can lead to metabolic alkalosis where normal body pH being agitated. Alkalosis will later lead to hypocalcemia and affect bone health. You may also read about Chemicals Used in Organic Farming
3. Water Organism and Microorganism
The herbicide used in agricultural chemical could be dissolved in irrigation and brought to near water body. This can affect the water ecosystem, especially for the plants. Several herbicides could be deadly to small water plants and bacteria that is important as a primary food source for another organism. You may also read about Effects of Household Chemicals on Plant Growth
4. Dissolved oxygen
Dissolved water is the amount of oxygen in the water. Dissolved water need oxygen to survive. Organo-phosphates insecticide such as parathion and malathion can alter the growth and quantity of algae.
The overabundance of this micro-aquatic plant life will lead to increasing bacteria that consume algae and later depletes the dissolved oxygen supply, suffocating fish and another water organism. This condition is called eutrophication (algal blooms) and also can be induced by nitrates.
5. Mineral content (nutrients)
Pure water doesn’t contain additional nutrients, but water found in nature could contain absorbed minerals depends on geological condition. The common minerals that can be found in water are calcium, magnesium, and sodium. Nitrates (NO3) is usually used as a fertilizer for the agricultural industry.
The extensive use of this chemical resulting in the chance of its residue to pollute soil and groundwater. Consuming water that contains too many nitrates can risk the condition of blue baby disease for pregnant women since it’s reducing the blood’s ability to carry oxygen.
6. Metal content
Agricultural chemicals are also responsible for metal water. The heavy metals that are contained agricultural chemical are cadmium (Sd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni) and zinc (Zn). These metals could seep and absorbed into the groundwater.
7. Surface water salinization
Agricultural irrigation usually preferred using salt waters for intensive plantation. This irrigation will later evaporate in water cycle but left salt behind.
The action can increase the salt concentration in water and soil called salinization. A high concentration of salt will lead to ecological damage. Untreated soil and water salinization can affect crops grow and soil fertility.
The agricultural chemical that can be dangerous to water is not only the active ingredient, the additives such as solvents, buffers, emulsifiers, and preservatives can affect water quality too. The risk group that can be easily affected by agricultural chemical contaminated water is people that live in the agricultural area.
Thus, there are some harmful effects of agricultural chemicals on water quality. So, we must be wise to use it, do not create any damage to nature for living.
Tips to Use Safe Agricultural Chemicals
Agricultural chemicals contamination can be mitigated with a proper action. The action will include multisectoral involvements. If you are a farmer or use agricultural chemicals, there are some tips on how to reduce the contamination risk :
- Used registered and legal agricultural products; organochloride and organophosphates pesticide have been banned from use in most of the countries for their hazardous content. But some farmer still uses them for their versatility. You may also read: List of Banned Agricultural Chemicals that People Still Use
- Read and understand the product label and instructions. Every chemical needs different managing ways, just because two products are insecticide doesn’t mean both use the same handling. The instruction can also include how to decontaminate and what to avoid the product.
Water quality testing usually includes the physical, chemical and biological test. The physical test measures water temperature, suspended solids, and turbidity. The chemical test includes pH test, alkalinity test, nutrients and chemical oxygen demand.
The biological testing includes some indicator such as plant, animal and microbial that may indicate ecosystem problem. Meanwhile, after knowing the harmful effects of agricultural chemicals on water quality, hope we do not be cruel human to destroy nature by bad chemicals.