Water use is ubiquitous throughout the agricultural processes that give rise to most of the foods we eat. Fifty years ago, people assumed this resource was infinite given that they consumed less food than we do today and thus required only one-third of our current water volume use. Now, the competition for water has intensified as the task of feeding seven billion people competes with industrial uses of water for biofuel production, for example, as well as to support urbanization. In this milieu, the reuse of agricultural wastewater that either flows off farm fields (also known as irrigation tailwater) or is effluent from the processing of crops and processed food is increasingly common.
But the details of this solution to water scarcity should not be trivialized. Agricultural wastewater often scores high in organic matter as well as salts, nutrients, pesticides and other chemicals used for the protection of crops and the increase of crop yields. Given the concentrations of these other materials, agricultural wastewater is often blended with lower-salinity source water or even desalinized in order to address the issue of its high salt content. Still, the reuse of contaminated water is an ever-present concern, which can significantly compromise human health by exposing individuals to produce polluted by pathogens or man-made chemicals.
Spectrophotometry as a tool for characterizing natural water and ensuring the water quality of reused water
Natural water can be carefully characterized using spectrophotometry to determine the normal or allowed range of certain substances such as natural organic matter, nitrates, trace organics, chromium (VI) and humic substances (items that contain humic acid, produced during the biodegradation of dead organic matter). Among the substances a farmer or scientist can test for, the main types of UV spectra used to characterize natural water include nitrate, humic-like substances, suspended solids, and chloride.
For farmers and their associated scientists, spectrophotometry can be used to determine the characteristics of source water and then apply this standard to repurposed agricultural wastewater in order to maintain water quality within safe ranges. Beyond the effectiveness of UV-Vis spectrophotometry as a method for water quality analysis, this technique is also fast, has low maintenance costs and is not a source of secondary pollution. Furthermore, developments in on-line spectrophotometry analysis enable farmers and their associated scientists to implement a real-time water quality analysis system that can immediately alert workers when water may be contaminated or simply fails to meet established standards. Already, spectrophotometers are popularly used to determine the shelf life of meat products as well as for tea leaf quality analysis. Thus, their systematic use for testing the water quality is quickly gaining credence as an important means for analyzing water quality.
Following proposed agricultural water standards starts with spectrophotometric water quality analysis
Recently, the FDA has revised its water standards to include new requirements including standards for record keeping, water treatment, testing and general water quality constraints. The goal of these changes is to decrease the likelihood that pathogens and chemicals in reused water are then used in the growing and harvesting of produce. Thus, at each stage of a farmers’ use of water in their operations (from water extraction from a ground well to its use in irrigation to washing produce), the use of a spectrophotometer to monitor water quality and to record the results of all findings following inspections will be essential for maintaining water quality as well as remaining in compliance with FDA requirements.
Maintaining water quality is not simply a question of protecting human health, which is, of course, essential. Pollution from farming can also cost billions of dollars in damages to the environment. For example, the number of lakes with harmful algal blooms will likely increase by 20 percent in the first half of this century, while the costs from agricultural pollution will likely skyrocket as farmers spend more to treat contaminated water. By carefully monitoring water using real-time and other spectrophotometric systems, farmers and associated scientists can determine when water supplies are contaminated, how quickly water contamination worsens, and subsequently which techniques are most effective for preventing or managing this contamination. In order to determine how spectrophotometric analysis can assist your work in the agricultural industry, please contact HunterLab today.