Pesticides and Persistent Organic Pollutants
The issue of pesticides in surface or groundwaters is of worldwide concern. Pesticides are substances that are used to control pests, and the term includes insecticides, herbicides, biocides, and fungicides. These substances can accumulate in aquatic organisms and sediment, posing a risk to our health and the environment.
With their widespread use for agricultural applications such as crop protection, food storage and weed control, pesticides may run off into water courses. Here they can be found as such or as smaller molecules generated by their degradation, known as metabolites. These may percolate into the soil and eventually reach surface waters and groundwater. Their presence as contaminants in water intended for human consumption is therefore an issue.
Many pesticides & herbicides are part of a wider group of chemical contaminants known as persistent organic pollutants (POPs), which are organic substances which are also of global concern. Since they are highly persistent in the environment as they break down slowly, they have the potential for long-range transport and get into food chains. POPs are also lipophilic, meaning they can bioaccumulate in living organisms, particularly in the fatty tissue of animals and humans. They therefore pose a risk to our health and the environment.
Drinking Water Regulations
The most encountered POPs are organochlorine pesticides, industrial chemicals, and unintentional by-products formed during industrial processes. The European Union’s POPs regulation, titled Regulation (EU) 2019/1021, bans or restricts the production and/or use of POPs in member states.
Several additional substances have now been added to the list of Persistent Organic Pollutants. These are such as carcinogenic polycyclic aromatic hydrocarbons (PAHs) and certain brominated flame-retardants, as well as organometallic compounds such as tributyltin (TBT).
The Water Framework Directive sets out environmental quality standards for pesticides in surface water. The Directive sets maximum allowable concentrations of o.1 µg/l for any pesticide and 0.5 µg/l for total pesticides. The updated Drinking Water Directive (EU) 2020 (2020/2184) protects the quality of drinking water and forms part of the regulation of water supply and sanitation in the European Union.
The European Green Deal is then looking to set further targets to reduce the use of and risks from chemical pesticides by 50% by 2030.
The original Water Framework Directive (WFD) 2000/60/EC established a framework for EU water policy. The Groundwater Directive (GWD) 2006/118/EC provided a framework for the protection of groundwater against pollution. The Directive 2008/105/EC established the environmental water quality standards. These were all amended in 2022 to set new standards for a series of chemical substances of concern to address chemical pollution in water.
The annexes to this proposal set out more detail on the specific substances of concern.
Removing Pesticides and POPs with Activated Carbon
Activated carbon (also known as activated charcoal) is one of the most effective media for removing a wide range of organic contaminants from water intended for human consumption. In particular, it is very effective for the removal of pesticides and persistent organic pollutants.
Since its first application over 50 years ago for drinking water purification, granular activated carbon has established itself as a universally recognised solution for its proven effectiveness both for historical contaminants as new challenges such as PFAS, Chlorothalonil and many other POP.
In addition, the granular activated carbon installed in the water works can be recycled by thermal reactivation. The reactivated carbon may then be returned to the water works from which it was collected and put back into use for several more years.
Contact us for more information.
What Pesticides and POPs Can Be Removed Using Activated Carbon?
Activated carbon, primarily in granular or powder form, has excellent adsorption capacity for a wide range of highly persistent, toxic chemicals and organic micropollutants in drinking water. Some of those pollutants effectively removed with activated carbon technology are noted in the tables below:
| 2,4-D (2,4-dichloro phenoxy acetic acid) | Cypermethrin | Isodrin |
| Acetamiprid | DDT (Dichloro-diphenyl-trichlorethane) | Isoproturon |
| Acetochlor | Deethylatrazine (DEA) | Lindane |
| Aclonifen | Deisopropylatrazine (DEDIA) | Linuron |
| Alachlor | Dichlorvos | Malathion |
| Aldrin | Deltamethrin | MCPA (2-methyl-4-chlorophenoxyacetic acid) |
| Algicides | Demeton-O | Mecoprop (MCPP) |
| Aminomethylphosphonic acid (AMPA) | Diazinon | Metabolites |
| Atrazine | 3,4- Dichloroaniline | Metaldehyde |
| Azinphos-ethyl | 1,4 -Dichlorobenzene | Metolachlor |
| Benzotriazole | 2.4- Dichlorophenol | Metazachlor ESA & OXA |
| Bentazone | 1,3- Dichloropropene | Methiocarb |
| Bifenox | Dicofil | Monuron |
| Biphenyl | Dieldrin | Mirex |
| Bifenthrin | Dikegulac (Diprogulic acid) | Nicosulfuron |
| Bromacil | Dimethoate | N-nitrosodimethylamine (NDMA) |
| Carbendazim | Dinitro-ortho-cresol (DNOC) | Ozone breakdown products |
| Carbofuran | Dinoseb | Parathion |
| Chlordane | Diuron | Pendimethalin |
| Chloridazon & metabolites | Endocrine disrupting compounds (EDC) | Permethrin |
| Chlorfenvinphos | Endosulfan | Picloram |
| Chlorpyrifos | Endrin | Propyzamide |
| Cyclodienes | Esfenvalerate | Propazine |
| Chlormequat | Ethofumesate | Quinoxyfen |
| Chlorothalonil | Flufenacet | Simazine |
| Chlorotoluene | Glyphosate | Terbutryn |
| Chlorotoluron | Heptachlor & epoxide | Thiacloprid |
| Clopyralid | Hexachlorobenzene | Thiamethoxam |
| Clothianidin | Hexachlorobutadiene | Toxaphene |
| Cyanazine | Hexachlorocyclohexanes | Triclopyr |
| Cyazofamid | Imazapyr | Triclosan |
| Cybutryne | Imidacloprid | Trifluralin |
Granular activated carbon (GAC) also is widely used to remove halogenated hydrocarbons from ground waters because they are not normally found in surface waters due to their volatility. They are poorly biodegradable and will persist in the groundwater for long periods of time. The removal efficiency of GAC for chlorinated hydrocarbons depends on the molecular size, the polarity and number of chlorine atoms.
Some of the many other synthetic organic chemicals, hydrocarbon pollutants and non-biodegradable compounds removed with activated carbon technology are found in the tables below:
| Acrylamide | 1,2 -Dichloroethane | PFAS (Per-and poly fluoroalkyl substances |
| Alkanes | 1,1 -Dichloroethylene | PFOS (Perfluorooctane sulfonate) |
| Aniline | Dichloromethane (methylene chloride DCM) | PFOA (Perfluorooctanoate) |
| Anthracene & Benzoanthracene | Di chloropropane | PFBS (Perfluorobutane sulfonic acid) |
| Aromatic compounds | Diethylhexyl phthalate DEHP | PFHxS (Perfluorohexane sulfonate) |
| BDEs (Bromodiphenylethers) | Diethyl phthalate | Phenols |
| Benzene | Dioxins | Polychlorinated Biphenyls (PCB) |
| Benzoperylene | Fluoranthene & Benzofluoroanthene | Polychlorinated dibenzo -p dioxins |
| Benzopyrene | Geosmin | Polychlorinated dibenzofurans |
| Benzotriazole | Hexabromobiphenyl | Polycyclic aromatic hydrocarbons (PAH) |
| BPA (Bisphenol A) | Hexabromocyclododecane (HBCDD) | Tetrachloroethane |
| Carbon tetrachloride – (Tetrachloromethane) | Indenopyrene | Tetrachloroethylene (Tetrachloroethene/PCE & perc) |
| Chlorobenzene | 2- Methylisoborneol (MIB) | Tetrachloromethane |
| Chloroalkanes | Naphthalene | Toluene |
| Chlorocresol | Nonylphenol (NP) | Tributyl tin (TBT) |
| Bis(2-chloroethyl) ether | Octylphenol | Trichlorobenzenes |
| Chloroform (Trichloromethane TCM) | Pentachlorobenzene | Trichloroethylene (Trichloroethene TCE) |
| 4-Chloro-2-nitrotoluene | Pentachlorophenol | Vinyl chloride (chloroethene) |
| Chrysene |
How can Chemviron help?
The most effective carbon to be used for water treatment may depend on several factors. This includes the nature of the contaminants to be removed, their range of concentrations, the final treatment level required, and the overall treatment operation involved.
Performance Evaluation to Ensure the Most Effective Solution is Proposed
Since each water source may contain different combinations of pollutants, it may be appropriate to first carry out a laboratory test on a representative water sample. Such a test would be to assess the likely carbon performance and so consider the most appropriate technical solution. Our technical team can assist in a first evaluation of the treatment of the water as a result of our worldwide experience of more than 70 years in drinking water treatment.
Isotherm testing to evaluate the removal of organics from liquids using activated carbon is quick but is often more effective at comparing different carbons than definitive performance results. Pilot testing is much more effective at indicating likely carbon usage. However, it can be time-consuming, but Chemviron can provide support and advice with our pilot units which include our range of smaller mobile carbon filters.
Alternatively, the Accelerated Column Test (ACT) was developed by our company as an improved technique that combines the speed of an isotherm test, with the accuracy of a pilot column. The ACT is a bench-scale procedure that simulates a full-scale system to provide breakthrough test data for the removal of organic impurities in water but in a much shorter time.
The ACT can be applied to all types of water and as Chemviron have been running these tests for well over forty years, we have an extensive reference library.
FILTRASORB® Activated Carbons for High Performance
FILTRASORB® carbons are the most widely used granular carbons for drinking water treatment. This is primarily due to their excellent adsorption capacity, proven performance lifetime, and high durability for multiple reactivation cycles.
FILTRASORB® activated carbons are re-agglomerated activated carbons. They are produced from selected grades of bituminous coal, by a twin-stage process that agglomerates the product before steam activation. This agglomeration stage provides improved kinetics that can significantly increase the adsorption capacity over a single stage, direct activated product that may have similar specifications on paper.
The re-agglomeration process creates a pore structure within the FILTRASORB® carbons that is particularly effective for the removal of trace impurities in drinking water. These carbons have demonstrated excellent performance for a wide range of pesticides and PFAS.
As a result of its high adsorption capacity and high number of transport pores, FILTRASORB® granular activated carbon range is a benchmark for trapping the new generations of micropollutants. With our depth of experience in this field, Chemviron can work with you to advise on the appropriate carbons for your specific application.
Spent Carbon Recycling and Mobile Carbon Filters for Sustainability and Cost Saving
Once the installed granular activated carbon that has been installed in water works becomes less effective in use, it can be recycled by thermal reactivation. The reactivated carbon may then be returned to the water works from which it was collected and put back into use for several more years. Thermal reactivation involves treating the spent carbon in a high-temperature furnace under a controlled atmosphere where the undesirable organics on the carbon are thermally destroyed. Recycling activated carbon by thermal reactivation is a sustainable and environmentally friendly technology that meets all our objectives to minimise waste and reduce CO2 emissions.
If the treatment application is for groundwater, temporary or peak treatment, why not consider using mobile carbon filters that are available for rental. These are activated carbon filters that can be used on-site as both a water purification vessel and then transported to and from the site without needing any on-site carbon exchange. Chemviron has a range of units of different sizes and capabilities for water treatment. In addition, the spent carbon may be easily returned in the mobile carbon filter to our reactivation centre for recycling by reactivation for reuse.
If you need technical support to evaluate the treatment proposed, help with the choice of activated carbon, our reactivation service, our mobile carbon filter service or just some further advice in your activated carbon design solution, please contact us – contact our technical team.