Featured Research

from universities, journals, and other organizations

Environmental impact of insecticides on water resources: Current methods of measurement and evaluation show shortcomings

Date:
January 14, 2013
Source:
Universität Koblenz-Landau
Summary:
Common practice for the monitoring of insecticides in water resources reveals shortcomings. Until now water samples have mostly been taken on fixed dates, for example once per month. However, insecticides enter water resources very irregularly and, even though their concentrations exceed the threshold levels only for a short time, their harmful effect is present. The consequence: If one bases the evaluation upon the zero values often measured within the scope of regular sampling, the overall evaluation underestimates the actual risks.

Water samples should be taken, when insecticides are applied or severe periods of rain wash these into the water.
Credit: Carsten Bruehl, University of Koblenz-Landau

Common practice for the monitoring of insecticides in water resources reveals shortcomings. This is shown by a current study conducted by the Landau-based Institute of Environmental Sciences of the University of Koblenz-Landau. Until now water samples have mostly been taken on fixed dates, for example once per month. However, insecticides enter water resources very irregularly and, even though their concentrations exceed the threshold levels only for a short time, their harmful effect is present. The consequence: If one bases the evaluation upon the zero values often measured within the scope of regular sampling, the overall evaluation underestimates the actual risks.

Related Articles


Compared with herbicides and fungicides, which have a largely preventive effect and are frequently applied, insecticides are employed only in cases of acute insect infestation. Accordingly, correspondingly high doses are applied discretely to fields in order to achieve the desired results. Although insecticides often show only short half-lives in the environment, these highly toxic substances potentially enter water resources, where they can be harmful to aquatic insects and other invertebrates. These organisms react very sensitively to insecticides, so that aquatic community compositions can be changed in favour of less sensitive species.

Consequently, the monitoring of water resources requires that samples be taken particularly when insecticides are applied or severe periods of rain wash these into the water. Due to lack of personnel, insufficient financial allocation and logistical restrictions, however, mostly regular fixed dates are chosen.

Current practice unsuitable

"Our study shows that current methods of sampling for the investigation of insecticides in water resources are unsuitable," declares Ralf Schulz of the Institute of Environmental Sciences in Landau. "Accordingly, by way of example, on the basis of weekly monitoring of a typical agricultural stream none of the total of six insecticide concentration peaks per year described by model calculations is found. Daily sampling detects only two of the six peaks. Only event-related sampling enables the detection of all these peaks. Assuming that the overall costs increase according to the number of fixed-interval samples, on the other hand, the event-related procedure greatly reduces the costs. Furthermore, the benefits are substantially greater. Current practice wastes considerable sums of money, as many of the fixed intervals do not coincide with periods of high insecticide concentrations."

If water resource monitoring detects no insecticide pollution in waterways and, as a result, no exceeding of the threshold levels this is therefore often not because the water resources are in fact unpolluted, but because the samples are taken at the wrong point in time. "The values resulting from this sampling therefore give a completely false picture of the true impact of insecticides," adds Sebastian Stehle, principal author of the Landau study. "Including results in the evaluation according to which no pollution has been detected distorts the evaluation and simulates a false sense of safety. Samples showing no evidence of insecticide pollution should therefore not be considered -- at least as long as environmental impact monitoring takes place statically. Still better would be event-related sampling, at least in high-risk areas."

Efficient counter-measures

The environmental pollution of water resources could be reduced with a number of cost-effective and efficient measures: For example, the border strips between area used for agricultural purposes and water resources would have to be widened and effectively structured. Hedges at the edge of the field would reduce the spray drift. Furthermore, constructed wetlands should be furnished with plants, which according to previous studies of the Institute of Environmental Sciences in Landau are capable of reducing pesticide exposure up to 70 per cent.

"Particularly agriculture is fully conscious of its dependence upon natural production factors, such as soil and water, and would like to produce healthy products as free as possible of residues," states Ralf Schulz. "In addition, with these measures agriculture can make a very important positive contribution to the protection of nature and biodiversity in a 'culture landscape of the future'."


Story Source:

The above story is based on materials provided by Universität Koblenz-Landau. Note: Materials may be edited for content and length.


Journal Reference:

  1. Sebastian Stehle, Anja Knäbel and Ralf Schulz. Probabilistic Risk Assessment of Insecticide Concentrations in Agricultural Surface Waters: A Critical Appraisal. Environmental Monitoring and Assessment, 12 December 2012

Cite This Page:

Universität Koblenz-Landau. "Environmental impact of insecticides on water resources: Current methods of measurement and evaluation show shortcomings." ScienceDaily. ScienceDaily, 14 January 2013. <www.sciencedaily.com/releases/2013/01/130114092523.htm>.
Universität Koblenz-Landau. (2013, January 14). Environmental impact of insecticides on water resources: Current methods of measurement and evaluation show shortcomings. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2013/01/130114092523.htm
Universität Koblenz-Landau. "Environmental impact of insecticides on water resources: Current methods of measurement and evaluation show shortcomings." ScienceDaily. www.sciencedaily.com/releases/2013/01/130114092523.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) — The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Arctic Warming Twice As Fast As Rest Of Planet

Arctic Warming Twice As Fast As Rest Of Planet

Newsy (Dec. 18, 2014) — The Arctic is warming twice as fast as the rest of the planet, thanks in part to something called feedback. Video provided by Newsy
Powered by NewsLook.com
Prenatal Exposure To Pollution Might Increase Autism Risk

Prenatal Exposure To Pollution Might Increase Autism Risk

Newsy (Dec. 18, 2014) — Harvard researchers found children whose mothers were exposed to high pollution levels in the third trimester were twice as likely to develop autism. Video provided by Newsy
Powered by NewsLook.com
Ivory Trade Boom Swamps Law Efforts

Ivory Trade Boom Swamps Law Efforts

Reuters - Business Video Online (Dec. 17, 2014) — Demand for ivory has claimed the lives of tens of thousands of African elephants and now a conservation report says the illegal trade is overwhelming efforts to enforce the law. Amy Pollock reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins