Current Use Pesticides

Increased public and regulatory attention during and 1970s and 1980s resulted in bans for many legacy pesticides and has led to the development and licensing of new pesticides with less persistence. This group of newer compounds is called current-use or modern pesticides. High usage, new concerns regarding the prevalence and effects of these compounds in the environment at low levels, and concerns of synergies between compounds at low levels have created a need for analytical methods with much lower detection limits than traditional reference methods. These tools support further study to understand the fate and occurrence of these pesticides and their degradation products at low levels.

Pesticide is a general term used to describe a diverse group of chemicals that are used to control pests.  The naming and classification system of pesticides varies greatly; major groups may be based on the type of organism they control such as herbicides (plants), insecticides (insects), and fungicides (fungi). Subdivisions are based on chemically related compounds – organophosphorous (OP), organonitrogen (ON), organochlorine (OC), triazine (TZ) and pyrethroid (PY) pesticides.

While there are a variety of analytical methods available to analyze pesticides and herbicides in environmental samples, most of these methods focus on  meeting regulatory levels for effluent and drinking water .  These methods focus on specific pesticide groups such as OC, ON, or OP pesticides. Over the last few years AXYS has developed a new high-resolution analytical method to monitor a wide range of pesticides in a single analysis with higher specificity and sensitivity than established reference methods. A key driving force for this method has been the need for low detection limits for application to transport and pathway surveys, mass balance studies on large waterways, atmospheric tracking and deposition and other scientific studies. A second goal was for the method to have a high degree of specificity to allow detection and quantification of small amounts of pesticides in the presence of many other potentially interfering compounds. This method was developed into the EPA Method 1699 released in December 2007, “Pesticides in Water, Soil, Sediment, Biosolids, and Tissue”.

The AXYS multi-residue (current-use) pesticide method provides analysis of 64 pesticides in aqueous, solid environmental, and wastewater samples in a single analytical procedure. In addition to these, 14 ON compounds are also available through the method with an incremental instrument run. The total analytes consist of 35 OC, 20 OP, 7 TZ, 14 ON and 2 PY pesticides. The method uses gas chromatography with high resolution mass spectrometry to quantify pesticides at concentrations lower than prescribed by established reference methods. The high resolution of the mass spectrometer minimizes the potential for false positives even in complex sample matrices. Detection limits in the low pg/L can be achieved for most compounds in ambient water. AXYS also analyzes other groups of pesticides - carbamates, acid extractable herbicides (phenoxy-acid herbicides), glyphosate and metabolites, and an extended list of pyrethroids by separate methods.

During the 1970s and 1980s after the detrimental effects of pesticides like DDT became known, OC pesticides were replaced with less persistent pesticides. These new pesticides had different physical-chemicals properties than OCs and different environmental fates. In 1992, it was estimated that over 453 million kg of pesticide was used in the USA. Among pesticides, herbicides accounted for 70% of total usage, and insecticides 17%. OPs accounted for the majority of insecticide usage (Kannon et al, 2005 1). Atrazine is the predominantly used herbicide worldwide. While agriculture application accounts for over 75% of pesticides used, urban usage is increasing. Pesticides enter the environment through surface run-off, direct discharge and through atmospheric long-range transport. Due to high water solubility and a short soil half-life, many current use pesticides do not tend to accumulate in the environment, however due to their wide usage in agriculture and urban applications they are often found in surface water and sediments. This is leading municipal and provincial/state governments to further investigate pesticide usage and consider the possible ban or restriction of certain pesticide products, such as those containing diazinon and chlorpyrifos, or a complete ban on pesticides used for cosmetic purposes only. 

Current use pesticides are generally more target specific and are less persistent in the environment than legacy pesticides; however they may be more acutely toxic. Humans are exposed to pesticides through the eating of vegetables, drinking of water contaminated with pesticides, urban application, and inhalation of air near pesticide applications.  With an increasing presence in streams, the effects on aquatic species are a growing concern. Studies have shown that exposure to OP pesticides can affect the neurological and immune systems in animals. Once in the body, many OP compounds metabolize into dialkyl phosphate metabolites. Atrazine is linked to ovarian cancer and can be toxic to freshwater fish, invertebrates, and aquatic plants and has been banned by the European Union. There remains a lack of knowledge on the fate and effects of degradation products of current use pesticides and what, if any, the combined effects of multiple pesticides may be. As more research is conducted there will likely be increased regulation usage.

AXYS specializes in measurement of current-use pesticides to nanogram or lower concentrations from standard sample sizes. Our specialized sampling and analytical procedures may allow for much lower detection limits and reduced sample sizes in water and solid matrices. We deliver legally defensible data under ISO 17025 certified systems applying methods accredited by NELAP and CALA. Electronic Data Deliverables (EDD), customized for download to our clients’ relational databases, are available in addition to standard format report and full data packages.

Please contact one of our Project Managers at 1 888 373 0881 or +1 (250) 655-5800 to discuss how AXYS can support your analytical advantage.

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1 Kannan K., J Ridal, and J. Struger (2005).  Pesticides in the Great Lakes. In the Handbook of Environmental Chemistry Vol 5 Part N - Persistent Organic Pollutants in the Great Lakes. Edited by R. A. Hites, Springer-Verlag Berlin Heidelberg, p 151-199 (2005).