New environmental pollution control tool

The researchers used the sensitivity of a few-day-old fish embryos to create a tool capable of identifying some toxic chemicals.

By determining the rate of oxygen utilization in developing fish embryos sensitive to pollutants and stressful conditions, the technology can detect the occurrence of low concentrations of toxic substances before they bring significant harm. Researchers at Purdue University, Marshall Porterfield, professor of agricultural and biological engineering, said the technology could be used as an early warning system for environmental pollution or even biological weapons.

Respiration is the process by which animals and other living organisms consume oxygen to produce energy, which is often the first function in fish affected by contaminants. New technology uses optical fibers to quickly control the above operation and produce results in minutes.

Porterfield said: 'For example, you get a common cold virus. Before the symptoms develop and you are aware of the presence of the virus, it attacks your cells. Similarly, other organisms are affected by contaminants before changes in behavior appear. Our technology detects non-measurable changes and acts as an early warning system. '

In the study published in the journal Environmental Science and Technology, the system recognized the presence of some common pollutants, such as widely used herbicides atrazine - even at concentrations. Near or below the permitted concentration for drinking water by the US Environmental Protection Agency (EPA).

Marisol Sepulveda, principal author and professor of natural resources and forestry at Purdue said: 'This means that our technology not only helps control environmental quality but can also be used to enforce important water quality standards'.

The experiment also showed changes in respiratory activity of fish embryos when cadmium metal appears at concentrations lower than 60 times the EPA limit. During the study, contaminants did not destroy the eggs of fathead minnows, a fish commonly used for research purposes. This demonstrates the ability of the new tool to determine the smallest change before they become serious.

In the first laboratory, the researchers placed a small optical electrode outside the two-day-old embryos of big-headed minnows. Brian Sanchez, a co-author of the time, is a PhD student at Purdue, who says that with a diameter of 1.5 millimeters, they are a little smaller than a pin.

A fluorescent agent covers the electrode tip, its optical properties vary depending on the oxygen concentration. This allows researchers to take measurements at locations only micrometers apart, moving the electrode with a computer-controlled motor. That information allows researchers to calculate the respiration rate of egg embryos.

Purdue University researchers use an optical electrodes to determine the oxygen consumption of two-day-old fathead embryos, about half the size of a pin.By monitoring bad changes in these tiny fish eggs, the new technology can be used as an environmental pollution control device or even a biological weapon (Photo: Marshall Porterfield)

Using the self-search technique developed by Porterfield over the past decade, he and his team determined the presence or absence of each egg's contaminant. This allows each workpiece to control itself and provide more reliable results

Porterfield said the new technology could be used on other organisms. Study co-author Hugo Ochoa-Acuña has begun to modify the technology to work with a type of crustacean. The first actual test version can be completed in 4 years with the current schedule, Porterfield said. This new technology is being tested with fixed eggs in laboratory conditions but the plan is to make the tool more flexible.

Porterfield also said he thinks the technology could have a variety of applications. It can be combined with tumor cells to look for potential cancer drugs or new therapeutic targets. During the study, new technology identified four of the five pollutants tested, all reacting to organisms in different ways: atrazine, cadmium, pentachlorophenol and cyanide. It is impossible to determine the low concentration of malathion pesticides, probably because the big-headed minnows embryos need more time to become clear. Toxins can slow respiration by directly interfering or they can force organisms to consume more oxygen to provide more energy to counteract the effects of toxins.

Sepulveda said other similar technologies are widely used to control the movement of gills and other activities of green gills with electrodes attached to the fish body. Purdue's system may have an advantage because it records breathing activity during the sensitive phase of the fish and the optical effect does not consume oxygen or needs the same size.

This study, funded by Purdue's Environmental Center and the US Department of Education, differs from Sanchez's studies. He focused on finding genes and proteins as biological indicators for the impact of contaminants on fish.

Sanchez said: 'This study is much more interesting because of its potential application in protecting human health'.