Research by the Delfland Water Board into environmental DNA (eDNA) for detecting discharges and leaks from greenhouse horticulture shows promising results. With this new technique, the Water Board can measure DNA traces of tomatoes and peppers in surface water. These data provide inspectors with indications of the source of a discharge or leak. Currently, due to broad-based crop protection products, the source is often difficult for inspectors to trace back to a single grower.
Collaboration with the sector is taking place to reduce discharges, including from horticulture. With success, because the number of discharges is decreasing. Nevertheless, nutrients and crop protection agents are still too often found in the water coming from greenhouses. Leaks are often unconscious and discharges are due to calamities.
The Water Board is not always able to detect discharges and leaks. This is due to broad-based crop protection products that can no longer be traced back to one specific crop. That is why Delfland commissioned a study into the possibility of using the eDNA method for detection. The research was financed from the innovation fund of the Water Board in collaboration with Datura.
How does it work?
When the Water Board determines a discharge, a sample of the water is taken for examination in a laboratory. They examine the sample for approximately 300 substances in the water, this is an extensive and expensive investigation that often takes a long time.
This water also contains traces (eDNA) of the crop that is grown in the greenhouse from which the discharge originates. They can be found much faster and cheaper and that makes it easier for us to find the source. For the time being, the research has focused on tomatoes and peppers. With this method, the source can be traced with 99% certainty. Both a positive and negative test provide insight into the search area.
Now that the Water Board knows that this method is promising, it will be put into practice. It is also being investigated whether other water boards can develop an eDNA test for other crops.
Want to see details about the study? That can be done here.