Viele Tier- und Pflanzenarten sind vom Aussterben bedroht oder sind bereits verloren. Zu viele, meint eine neue britische Studie: Auf 58 Prozent der Erdoberfläche sei die Artenvielfalt gefährlich reduziert. Man geht davon aus, dass die Natur 10 Prozent weniger Tier- und Pflanzenarten gerade noch verkraften könne – das sei eine „sichere Grenze“, sagt der britische Biowissenschaftler Tim Newbold.
Beleid en debat
Recent monitoring studies in several countries have revealed a world-wide contamination of creeks, rivers and lakes with neonicotinoid insecticides, with residue levels in the low μg/L (ppb) range. At least two main areas of concern can be identified: reduced capacity for decomposition of organic debris by aquatic organisms and starvation of insectivores and other vertebrate fauna that depend on invertebrates as a major or only food source.
In the early 2000s, Italian beekeepers began to report bee mortality events linked to maize sowing. Evidence pointed to three neonicotinoids (imidacloprid, clothianidin, thiamethoxam) and a phenylpyrazole (fipronil) used for seed dressing that were dispersed in the environment during sowing. Following these events and based on the precautionary principle, in September 2008, the Italian Ministry of Health suspended these four active ingredients as maize seed dressing.
Het neonicotinoïde insecticide clothianidine is in Nederland toegelaten als middel voor behandeling van zaden van suikerbieten en voederbieten ter voorkomen van schade door insecten. De stof is zeer persistent in de bodem met een halfwaardetijd van 545 dagen, en spoelt bovendien gemakkelijk uit naar het grondwater of komt door afspoeling in het oppervlaktewater terecht.
Surface water monitoring for pesticides in agricultural areas of California is one of the California Department of Pesticide Regulation’s (CDPR’s) key environmental monitoring activities. The Salinas, Santa Maria and Imperial valleys have previously been designated as high priority areas for long-term surface water monitoring due to high pesticide use. This 2013 study is a continuation of the agricultural monitoring project.
Pesticide occurrence was determined in two suburban surface waters in eastern Massachusetts, USA during 2009 and 2010. Out of 118 collected samples, 45 samples showed detections of one or more target pesticides. Among the herbicides, 2,4-D was the most frequently detected and imidacloprid was the most frequently detected insecticide. Regulatory phaseout of chlorpyrifos and diazinon from residential use by 2004 was reflected in the results by the absence of chlorpyrifos detections and lower detection frequencies of diazinon.
In 2010, my life changed when Dr Henk Tennekes and I traded books. His was: The systemic insecticides: a disaster in the making and ours was: The Year of the Bumblebee: Observations in a small Nature Reserve. Dr Henk Tennekes, an independent toxicologist based in the Netherlands, was the first researcher to recognise the extreme toxicity of low levels of systemic neonicotinoid insecticides that have become widespread in the environment.
Regional Environment Awareness Cameron Highlands (REACH) president Ramakrishnan Ramasamy said most rivers in the highland, known for its tourism and agriculture, are heavily polluted. He said data from the Department of Environment (DoE) and the Drainage and Irrigation Department (DID) showed that only about 10 per cent of 123 rivers were in Class I and Class II, while the remainder were in Class III and Class IV. He also said three rivers had been declared biologically dead, and came under Class V of the classification.
New monitoring in the Bay Delta shows that the water is a soup of urban and agricultural insecticides, herbicides and fungicides. When combined, pesticides at sublethal levels can have deadly synergistic effects on fish. “The Sacramento River and San Joaquin River have been monitored for years, but historically there has been little monitoring in the Delta itself,” says Michelle Hladik, an environmental chemist who leads the USGS Pesticide Fate Research Group.