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Analysis, fate and risks of organic contaminants in river basins under water scarcityValencia, 7-8 February 2011

Introduction to Pesticides: general environmental problems, regulations in US and Europe, toxic effects and

environmental levels

SAMA-Food and Environmental Safety Research GroupFacultat de Farmàcia

Y. Picó

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Definition by FAO

Any substance or mixture of substances intended for preventing, destroying or controlling any pest, including vectors of human or animal disease, unwanted species of plants or animals causing harm during or otherwise interfering with the production, processing, storage, transport or marketing of food, agricultural commodities, wood and wood products or animal feedstuffs, or substances which may be administered to animals for the control of insects, arachnids or other pests in or on their bodies. The term includes substances intended for use as a plant growth regulator, defoliant, desiccant or agent for thinning fruit or preventing the premature fall of fruit. Also used as substances applied to crops either before or after harvest to protect the commodity from deterioration during storage and transport.

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CharacteristicsA pesticide is any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest.

“Pesticide” includes herbicides, fungicides, insecticides, or any other substance used to control pests.

Pesticides are carefully regulated by the Environmental Protection Agency (EPA) in United States and for the European Union (UE) which review studies to determine the risks posed by individual pesticides.

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History of pesticides

Modern ChemistryOrganic ChemistryWorld War IWorld War IISilent Spring publishedVietnam war (Agent

Organge)EPA CreatedDDT withdrawal

175018301914-181939-4519621963-7319701972

Other Milestones

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Classification of Organic Pesticides by Chemistry

• Organochlorine• Organophosphorus• Carbamates

• Phenoxy herbicides *• Triazines *• Imidazolinone *• Sulfonylureas *

• Alifatic nitrogen• Amide• Antibiotic• Aromatic• Benzimidazole• Benzothiazole• Conazole

Insecticides

Herbicides

Fungicides

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More than 1000 active ingredients

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Organochlorinep,p’-DDT Organophosphorus

Chlorpyriphos

Pyrethroid insecticidesCypermethrin

BenzimidazoleCarbendazim

NitroguanidineImidachloprid

DinitrophenolDinoprop

CarbamatePirimicarb

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World-wide pesticide sales in 2004 were $32.665 billion

Herbicides44%

Insecticides26%

Fungicides25%

Others5%

Latin America14%

Western Europe24%

Asia Pacific25%

North America27%

Rest of the World10%

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Crop surface and pesticide use

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Environmental problem

Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, including non-target species, air, water and soil.

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What Happens after Application?When pesticides are applied the goal is that they will remain in the target area long enough to control a specific pest and then degrade into harmless compounds without contaminating the environment.Once applied, many pesticides are mobile in the environment (air, soil, water).This movement can be beneficial (moving pesticide to target area, such as roots) but can also reduce the effect on the target pest and injure non-target plants and animals.

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Pesticide Movement &Degrade

• Runoff *• Leaching *• Degradation

– Microbial *– Physical

– Hydrolysis *– Photolysis *– Pyrolysis *

• Volatilization *

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Factors influencing a pesticide’s fate

• Properties of the pesticide• Conditions where & when applied• Application method

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Properties of the pesticideWater Solubility/dissolvability - more soluble pesticides have lower sorption and are more mobile in the environment as they are leached or moved with runoff.

Persistence – the amount of time a pesticide remains in the environment, measured by half-life. Pesticides with longer half-lives pose a greater threat to the environment.

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Compound Soil Half-life KOC Water Sol. (ppm)

DDT 3-10 yrs -- 0.006

chlordane 2-4 yrs -- 0.1

parathion (methyl) 5 days 9800 57

chlorpyrifos (Lorsban) 30-90 days 4600 1

terbufos (Counter) 21-35 days 578 5

aldicarb (Temik) 70 days 28 6,000

carbofuran (Furadan) 30-90 days 45 320

carbaryl (Sevin) 10 days 230 40

permethrin (Pounce, Ambush) 30 days 10,600 0.04

esfenvalerate (Asana) 35 days 5,300 0.002

atrazine 60 days 100 33

alachlor 15 days 170 242

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Metabolism & Degradation

Pesticide metabolites can be as toxic as the parent compound

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Directive 91/414/EEC on the placing of plant protection products on the

market. Plant protection products cannot be placed on the market or used

without prior authorisation

Maximum Residue Levels (MRLs) for pesticide residues in food and feed

are covered by Regulation (EC) No 396/2005.

Directive 1107/2009/EEC concerning the placing of plant protection

products on the market has been published on 24 November 2009.

European Legislation (I)

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EFSA’s Founding Regulation 178/2002, states that the Authority shouldcollect and analyse data in its fields of expertise. EFSA carries out two different types of data collection activities:

harmonised collection of EU-wide data required by EU regulations on an ongoing basis in order to assess and monitor trends over time and help inform risk management policies and measures;

specific data collection to support risk assessments and other tasks.

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Directive 76/464/EEC: established two lists of priority pollutants

Directive 78/659/EEC: regulates the quality of freshwaters in

order to support fish life

Directive 60/2000/EC (Water Framework Directive): established

the framework for the protection of freshwaters, coastal waters

and groundwaters

Decision 2001/2455/EC: approved a list of 33 priority pollutants

Directive 2008/105/EC: established the quality standards for the

priority pollutants in water

European Legislation (II)

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Water Framework Directive (2000/60/EC)List of Priority substances

(2455/2001/EC)

Brominated diphenylethers Cadmium and its compounds C10-13-chloroalkanes HexachlorobenzeneHexachlorobutadiene HexachlorocyclohexaneMercury and its compoundsNonylphenolPentachlorobenzenePolycyclic aromatic hydroc.Tributyltin compounds

AnthraceneAtrazineChlorpirifosDi(2-ethylhexyl)phthalateDiuron EndosulfanIsoproturonLead and its compoundsNaphthaleneOctylphenolPentachlorophenolSimazineTrichlorobenzenesTrifuralin

AlachlorBenzeneChlorfenvinphos1,2-dichloroethaneDichloromethaneFluorantheneNickel and its compoundsTrichloromethane

Subject to study for their identification as possible dangerous priority substances Identified as dangerous priority substances

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MRL future in EU

• One Regulation where all MRLs will be established, monitored and controlled at EU level

• Rapid alert system in place• Regular review of MRLs in force• Establishement of tolerances and enforcement via River Basin

Plans

FUTURE

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Current status in EU

• Some harmonised EU MRLs• Establishing temporary MRLs• Default approach (LoD = 0.01 mg/kg or highest

acceptable EU member MRL)• For dringking water, maximum level of individual

pesticide 0.1 µg/L, sum of various pesticides 0.5 µg/L

NOW till 2011

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Pesticide Laws and Regulations in the USA• Federal

– Federal Insecticide, Fungicide, and Rodenticide Act (1972)

– Federal Food, Drug, and Cosmetic Act (1939)– Worker Protection Standard (1992) – Food Quality Protection Act (1996)

• State laws vary

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Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)

• Control of distribution, sale, use • Gives US EPA authority to

– Study pesticide consequences– Require pesticide purchase registration

• Requires – Pesticide applicator certification – Registration, proper labeling

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Federal Food, Drug, and Cosmetic Act (FFDCA)

• Allows US EPA to establish tolerances for pesticides in food

• Small fraction of marketed food tested for pesticide residue

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Food Quality Protection Act (FQPA)

Health-based standard for pesticides in foods

Requires US EPA to review tolerances for pesticide tolerances in food

Focus on children

““I WANT A SPRAY THAT KILLS EVERYTHING BUT ISNI WANT A SPRAY THAT KILLS EVERYTHING BUT ISN’’T DANGEROUS.T DANGEROUS.””

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Toxic EffectsToxicity: the ability of a compound to cause injury or death Oral LD50 values for: 

Pesticide mg/kg

DDT 113-118

chlordane 457-590

methyl parathion 14

chlorpyrifos 135-163

terbufos 2-5

malathion 885-2800

aldicarb 1

carbaryl 850

carbofuran 8-14

permethrin 430-4,000

rotenone 60-1500

nicotine 50-60

sabadilla 4,000

pyrethrins 1200-1500

microbials NA

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Toxic Effects

• LOW numbers indicate GREATER toxicity!!• LD50 values are not complete indicators even for

acute toxicity. • Toxicity is influenced by route of exposure,

dilution, and combinations with other chemicals. • Other types of injury (besides death) occur. • Many individuals are more susceptible than

average. • Test animals may not accurately represent

humans.

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Toxic Effects

OBVIOUSLY … Environmental toxicity is also an issue ... toxicity to fish (pyrethroids, rotenone, many others), bees (carbaryl, many others), birds (DDT, now Furadan), and plants (lead arsenate, others) are all concerns.

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• Wiser Conclusions: – Persistent pesticides have caused and continue to

cause problems. We should not allow current and new compounds and use patterns to pose the same risks.

– Transport in water, on soil, etc. moves compounds to unwanted sites; at these sites the pesticides pose health risks or may be more persistent. Challenge: to identify environmental transport risks of specific compounds and select chemicals and use patterns that minimize risks.

– Most insecticides are broad-spectrum poisons that affect humans, other vertebrates, beneficial insects, etc. Challenge: to develop pesticides with selective toxicity.

– We do not know the answers to all the questions about the risks posed by pesticides.

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Environmental occurrence

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Environmental occurrencePesticides in surface waters by substance in England and Wales, 1998 to 2007

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Environmental LevelsAtrazine concentrations at Niagara-on-the-Lake, Wolfe Island and Quebec City sampling stations in 1995 and 2000

Atrazine concentrations in the St. Lawrence River, 1995-2002.

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Environmental Levels

Metabolite concentrations for alachlor, as well as acetochlor and metolachlor (not shown), were greater than parent compounds for much of the year.

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Temporal variability in atrazine, diazinon, and norflurazon concentrations from lake and river samples collected September and November 2004, and May 2005, Lac du Flambeau Reservation and vicinity, Vilas County, Wis

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