Pesticides are among the most concerning environmental pollutants due to their toxicity, stability, mobility, and long-term effects on living organisms. Multi-residue (MRES) or current-use pesticides generally refer to a newer generation of pesticides developed in response to meet new purposes (or in a few cases, to serve as replacements to those identified in the Stockholm Convention in 2001).
While there are a variety of analytical methods available to analyze pesticides in environmental samples, most of those methods available in the industry focus narrowly on meeting regulatory levels for specific pesticide groups in effluent and drinking water. As the understanding of pesticides evolve, there is a growing 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. Given the nature of the sample matrices that are typically analyzed for pesticides in these more sophisticated studies, there is also a need for methods 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.
AXYS first started measurement of pesticides in 1978 with specific organochlorine compounds. Our scientists continue to advance the field, providing analysis in to new compounds with innovative methods that deal with complex matrices, background compounds, and low detection limit requirements. We cover a wide array of compounds associated with legacy and current use pesticides through either single compound or multi-residue (MRES) methods to support basic and more advanced investigation into pesticides for a wide variety of clients:
Organochlorine Pesticides (OC pesticides) are man-made insecticides, fungicides, and antimicrobial chemicals that persist in the environment despite bans and restrictions on their use. Nine of the 12 most hazardous persistent organic pollutants (POPs) initially targeted by the Stockholm Convention in 2001 are OC pesticides.
Acidic extractable herbicides (AEHs) represent one of the important classes of currently used agricultural chemicals. AEHs are phytotoxic compounds that are widely used to control many types of broadleaf weeds. Their high water solubility, low volatility, and heavy agricultural use promote their entry into the aqueous environment; and these compounds are generally classified as suspect or probable carcinogenic and teratogenic agents.
Carbamates are ester derivatives of carbamic acid and belong to a class of modern synthetic pesticides used in agriculture as insecticides, fungicides, herbicides, and nematocides. The nature of pesticide activity is determined by the specific ester used. In general, bioaccumulation of carbamate compounds in different species and food chains is low, although carbamate analytes can be highly toxic for invertebrates and fish. Certain carbamates may infiltrate drinking water as a result of groundwater contamination, raising concern for human exposure.
Synthetic pyrethroids are the most commonly used household insecticides. They are similar to naturally occurring pyrethrins (found in chrysanthemum flowers) and are considered to be non-toxic to humans despite their toxicity to invertebrates. Pyrethroids are unaffected by wastewater treatment processes and as a consequence are found in significant concentrations in effluents. Urban use of pyrethrins and pyrethroids may also result in runoff, potentially exposing aquatic life to harmful levels in water and sediment.
Glyphosphate and Glufosinate are both broad-spectrum, non-selective, systemic herbicides with similar structure, properties, and lifetime in the environment. They are generally considered to have low toxicity to mammals, bird, and aquatic species; but are currently the focus of renewed study.
Organophopsphorous pesticides (OPs) are phosphate esters that have broad spectrum insecticidal activity. OPs relative short persistence and less bioaccumulation favored their application as replacement pesticides over the organochlorine counterparts. Although there use is generally restricted in many countries, some OPs are still in use worldwide. As a result, these compounds are detected in a variety of matrices.
Organonitrogen pesticides (ONs) are currently used agricultural chemicals (such as herbicides, insecticides, and fungicides) that contain nitrogen. Traditional environmental monitoring efforts have been focused primarily on persistent environmental pollutants such as organochlorine (OCPs) and organophosphorous (OPs) pesticides as a result limited environmental data is available for ONs in the environment.
Triazine herbicides include a group of nitrogen containing chemicals that are used to control the growth of weeds through the inhibition of photosynthetic reactions. The triazine herbicides such as atrazine and simazine are some the most widely used herbicides worldwide, as a result, these compounds are some of the most commonly detected contaminates in water.
AXYS analyzes a large number of pesticides by separate methods – carbamates, acid extractable herbicides (phenoxy-acid herbicides), glyphosate and metabolites, and an extended list of pyrethroids. AXYS has also developed a multi-residue (MRES) pesticide method that provides analysis of 64 pesticides in aqueous, sediments, biosolids, and wastewater samples in a single analytical procedure, with an additional 14 ON compounds available with an incremental instrument run. Each of these are describe below, and our project managers can provide more specific information on the analytes covered in any of these methods.
Type Method and Matrices Organochlorine Pesticides (OC Pests) AXYS provides experienced and accredited services to measure OC pesticides by either GC-HRMS (MLA-028) or GC-MS (MLA-007) to achieve detection limits, from standard sample sizes, with low detection ranges for a wide range of matrices including soil, sediment, biosolid, tissue, puff, serum, puff, filter, high volume/passive sampling, and aqueous matrices. AXYS measures OC pesticides by either GC-HRMS or GC-MS and GC-ECD to achieve detection limits from standard sample sizes in the low ng/L range for water and ng/g range for soil, sediments, biosolids, tissue, and serum. We also measure OC pesticides using the high resolution multiresidue method below. Acidic Herbicides (AEHs) AXYS employs GC-HRMS analysis (MLA-037) for AEHs in water/effluent, soil/sediment/biosolids, and high-volume XAD matrices. AXYS method employs hydrolysis to capture the total of the salt, acidic and ester forms of the analytes. Samples are spiked with isotope labelled surrogate standard solution, hydrolyzed, derivatized and extracted. The analyte concentrations are determined by the isotope dilution/internal standard quantification method. Carbamate Pesticides AXYS provides analysis for 20 carbamate analytes using LC-MS/MS (MLA-047) in water/effluent, soil/sediment/biosolids, high-volume XAD matrices. Pyrethroid Pesticides AXYS provides analytical methods by GC-HRMS (MLA-046) for determination of concentrations of pyrethroids, pyrethrins, and piperonyl butoxide (BTO) in aqueous, solid, and high volume XAD matrices. We also measure 2 important synthetic pyrethroids using the high-resolution multi-residue (MRES) method below. Glyphosate and Metabolite AXYS has developed a LC-MS/MS (MLA-054) based analytical method with improved specificity and detection limits for analysis of glyphosate, glufosinate, and a major degradation product of glyphosate aminomethylphosphonic acid (AMPA) in aquatic samples varying from clean water to high organic content groundwater. Samples from both agricultural and urban areas are analyzed with detection limits in the range of 30 to 50 ng/L. AXYS also provides a method for analysis of glyphosate, glufosinate, and AMPA in soil and sediment samples with detection limits in the 10 to 25 ng/g range. Multi-Residue (MRES) Pesticide Analysis Using a high-resolution mass spectrometry platform (MLA-035), AXYS provides a multi-class pesticide method that can be used for analysis of 76 pesticides, metabolites, and degradation products in aqueous, environmental solid, tissue, high-volume and passive sampling matrices, and wastewater samples in a single analytical procedure method. The method quantifies pesticides at concentrations lower than prescribed by established reference methods, and 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. Covered in the method are:
- Organochlorine Pesticides (34)
- Organophosphorus Pesticides (19)
- Organonitrogen Pesticides (14)
- Triazines (7)
- Pyrethroids (2)
Baseline PBDE Levels Established in Lake Ontario
In collaboration with the New York State Department of Environmental Conservation, analysis of high volume Lake Ontario surface water samples collected on XAD-2 resin and filters for PBDEs, PCBs, dioxins and furans, and OC pesticides in 1999 resulted in a joint publication “Establishing Baseline Levels on PBDEs in Lake Ontario Surface Water”.
Metro Vancouver Multi-Year Project to Study POPS and CECs loading in WWTP and diffusion in the Receiving Environment
AXYS has provided Alkylphenol, Sterols and Hormones, Dioxins, PCB congeners, PAHs, Alkylated PAHs, Pyrethroids, and Organochlorine Pesticides analysis for the characterization of WWTP effluent, storm water/ CSO effluent, and its subsequent diffusion to receiving waters and receiving water sediments. Resident fish are also measured on a scheduled basis.
Supporting Great Lakes AOC Investigations
AXYS provided analysis for the Great Lakes Area of Concern Investigation, including ambient water, high-volume sampling, precipitation, fish and sediment samples. Axys tested for PAHs, Dioxins, PCBs, OC pesticides including chlorobenzenes, current use pesticides (OC, ON, OP, triazine, pyrethroids), perfluorinated compounds, PBDPE, and PPCPs.
AXYS Helps Develop and Validate EPA Pesticide Methods
AXYS developed and validated EPA method 1699 based on AXYS Method MLA-035 (full current-use pesticides), and the Organochlorine Pesticides only option based on AXYS Method MLA-028.
Ontario Ministry of Environment
AXYS supported multiple projects analyzing POCIS samples for analytes such as PPCPs, Hormones, Acid Extractable Herbicides, Multi-residue Pesticides, Glyphosate and Carbamates. This study showed that POCIS sampling could detect background concentrations of hormones and PPCPs in remote locations around the Great Lakes.