5797 Food toxicology DEGREE IN PHARMACY Year 2013 14 First - - PowerPoint PPT Presentation

“RISK ASESSMENT OF CHEMICALS GENERAL CONCEPTS”

5797‐Food toxicology

DEGREE IN PHARMACY Year 2013‐14 – First semester Professors: Eugenio Vilanova and Jorge Estévez Department: Applied Biology

Unidad de Toxicología y Seguridad Química

RISK ASESSMENT OF CHEMICALS GENERAL CONCEPTS

Eugenio Vilanova Gisbert

Universidad Miguel Hernández De Elche Unidad de Toxicología. Instituto Bioingeniería

http://tox.umh.es

Biological systems interact with thousands of substances in your environment: Exogenous substances

Exogenous substances

Once absorbed some have ENDOGENOUS BILOGICAL FUNCTIONS (Nutrients, vitamins and essential elements) Others without endogenous biological function in our body, we call them:

XENOBIOTICS

SOME numbers: Genes that encode proteins: prokaryotes: 2,000 insects: 7,000 higher animals: around 50,000 different enzymatic reactions in the cell: around 5000 Endogenous molecules Deifferent proteins in a cell: around 5,000 monomers of biopolymers and metabolic: around 5,000

EXOGENOUS MOLECULES with endogenous function: Essential nutrients: 31 molecules 9 amino acids, 10 trace minerals, 12 vitamins) Probably essential: 11 molecules Food components: some 10,000 (?) (considering only the monomers of biopolymers)

XENOBIOTICS

Xenobiotics of natural origin: ????? Several hundred thousands Industrial Xenobiotics: European register: >100,000 substances regular interaction: 10,000 substances

Biological systems have mechanisms to deal with the interaction with thousands of external molecules:

• destruction of foreign macromolecules (digestion and immune system)
• Some are used for endogenous functions

(nutrients, vitamins, oligo elements)

• Conversion to endogenous molecules (intermediary metabolism)
• Elimination of Xenobiotics (xenobiotic metabolism)

BUT...

CHEMICALS MECHANISM OF DETOXICATION (ADME) ELIMINATION DISPOSAL NERVOUS SYSTEM

MECHANISM OF DETOXICATION ELIMINATION

CHEMICALS NERVOUS SYSTEM

Biological systems have mechanisms to deal with the interaction with thousands of external molecules:

Interaction with xenobiotics are part of the normal physiology

• Elimination of Xenobiotics (xenobiotic metabolism)

BUT...

SOME Xenobiotics at low doses, in certain circumstances, can cause desired changes as a remedy of diseases:

THERAPEUTIC OR PROPHYLACTIC EFFECTS

in these circumstances we call:

MEDICINES, PHARMACEUTICAL DRUGS

The XENOBITICS or their metabolites at doses greater than the capacity of detoxication and disposal can cause : adverse effects to the health of the individual or ecosystem:

TOXIC EFFECTS.

On these circumstances we call them: TOXIC SUBSTANCES

• TOXICANTS
• TOXINS
• POISONS …

SOME Xenobiotics in certain circumstances can selectively kill a way of life "while" respecting others:

biocidal effects

In these circumstances we call:

• BIOCIDES (general concept or specific regulatory concept)
• PESTICIDES (insecticides, herbicides, fungicides, rodenticides,...)
• ANTIBIOTICS
• DISINFECTANT
• PLANT PROTECTORS

BUT ...

ALL BIOACTIVE SUBSTANCE REPRESENTS A HEALTH RISK TO NON-TARGET SPECIES

From the classic (archaic?) concept of study of the poison up to The current concept of

• CHEMICAL SAFETY
• risk assessment
• risk prevention

based on the modern science of Xenobiotics: molecular mechanisms of toxicity and biotransformation

TOXICOLOGY

Conceptual analogy with Pharmacology but it is dealing with pharmaceutical drugs used for therapy

¿Métodos para hacer estos ensayos

¿Why we need regulation internationally accepted ? To:  guaranty safety and confidence of the citizens (right to be safe and filling safe)  guaranty free circulation of goods For that, harmonizing:  Testing methods  Criteria of evaluation  Mutual acceptance

SOME BASIC PRINCIPLES: Priority: to guaranty safety of citizens The limits must not compromise other priority public health measures The proposal of a safety limit is a scientific process. Establishing a legal limit is a decision affected by other factors of technical viability and social sensitivity.

SOME CRITERIA for limits (1) SAFETY (1): based on a threshold. (2) (3) (4) (5) (6)

TOXIC EFFECT WITH THRESHOLD

For most toxic effects (not all): are believed to have a “threshold”: dose below that no toxic effect is caused A threshold can be established NOAEL: “No observed adverse effect level” The highest tested dose with no effect

Log (D O S IS )

EFFECT

TOXIC EFFECT WITH THRESHOLD

NOAEL

EVALUATION TOXICITY

Acute toxicity.

Determinacion DL50. Toxicidad aguda por via oral, dérmica y por inhalación Irritación cutánea y, en caso necesario. ocular. Se hará si no es corrosivo. Sensibilidad cutánea.

SHORT TERM (28 DAYS)

Toxicidad oral a dosis repetitivas (estudio de 28 días). No si hay estudio a 90 días Otras vías (inhalación, dérmica, según proceda).

SUBCRONIC TOXICITY.

Estudio via oral durante 90 días. Otras vías si procede.

CRONIC TOXICITY (2 years)

Toxicidad oral a largo plazo (2 AÑOS) Carcinogenicidad (2 años)

GENOTOXICITY.

Mutagenicidad invitro Genotoxicidad in vivo..

REPRODUCTION TOXICITY.

Teratogenicidad. Reproduccion a multiples generaciones Fertilidad y desarrollo.

METABOLISM

Absorción, distribución y excreción, tras la administración tanto oral como dérmica. Metabolismo.

ESTUDIOS ADICIONALES

• Neurotoxicidad. Neurotoxicidad retardada en gallinas adultas.

Metabolismo en vegetales (para agroquímicos) Efectos tóxicos de metabolitos procedentes de vegetales. Estudios de mecanismos para clarificar los efectos detectados. Efectos tóxicos sobre el ganado y los animales domésticos.

HUMAN DATA

Datos existentes de exposición humana epidemiológicos Estudios copn voluntarios Métodos de diagnóstico y tratamiento.

RESUMEN de toxicología en los mamíferos y CONCLUSIONES.

Resumen de toxicología en los mamíferos y conclusiones. Propuesta de NOAEL, IDA, AOAEL y otros parámetros. Evaluación global de los datos toxicológicos.

ESTABLishing the lowest relevant NOAEL

Estudy NOAEL Subacute dermal (28 dias) 110 mg/Kg/day Subchronic dermal (90 days) in dogs 35 mg/Kg/day Subchronic oral 90 days in rats 50 mg/Kg/day Subchronic oral 1 year dogs 25 mg/Kg/day Chronic-carcinogenicity oral (2 years) in rat (systemic effects) 10 mg/Kg/day Reproduction 3 generation oral in rats (systemic maternal effects) 25 mg/Kg/day Teratogenicity in rabbit (10 days, GD 6-16) (systemic maternal effects) 50 mg/Kg/day … AND OTHER STUDIES AS REQUIRED FOR REGISTRATION) Lowest relevant NOAEL: "The NOAEL is established as 10 mg/Kg/day on the basis of decrease in the body weight gain observed at the next higher tested dose in a 2 year oral study in rat 10 mg/Kg/day

ACCEPTABLE DAILY INTAKE (ADI)

A DOSE WE CAN CONSIDER THAT HUMAN POPULATION CAN BE EXPOSED FOR LIFE WITHOUT RISK NOAEL is usually obtained from animal experimentation We need extrapolation to human We need to consider the interindividual variability in the sensitivity We need a safety factor for

NOAEL  (SAFETY FACTOR)  ADI

Equivalent concepts: Reference dose (RfD), Acceptable exposure level (AEL), Tolerable daily intake, (Other)

SAFERTY FACTOR

Other names: “uncertainty factor “(UF) “assessment factor” (AF)

From Cassaret y Doull, Principals in Toxicology, 2005

INTERSPECIES DIFFERENCES INTER INDIVIDUAL HUMAN DIFFERENCES KINETIC

KINETIC KINETIC DINAMIC DINAMIC

SAFETY FACTOR (Uncertainty factor, UF) (Assessment factor, AF)

10 x extrapolation frm animal tohuman 10 x for human interindividual variability

 Usually UF= 100 Possible additional factors:

• 3 x when NOAEL is from subchronic study indeed of chronic
• N x if other uncertainties are observed (2x, 3x, or 10x).

Then UF may be 200x, 300x, 1000x

Proposal of a limit in water

(substance with threshold) We need: To know the toxicological properties and to establish:

• 1. Estimate a ADI from the NOAEL and a safety factor for an adult
• 2. Establish the standard water consumption:

(2 Litres /day in adults of 60-70 Kg bw) (1.5 L/d children of 30 Kg bw) (1 L/d infants 10 Kg bw)

• 3. Allocation in water: proportion of the ADI we accept to be

exposed via drinking water (usually <10% of the ADI)

MAC

LIMIT OR ALLOWABLE MAXIMUM CONCENTRATION IN WATER:

CONCENTRATION THAT WOULD PROVIDE 10% OF THE MAXIMUM DAILY INTAKE IN 2 LITERS OF WATER

MAC = ADI x (%contribution from water) Daily intake

For example in drinking water, it is assumed: Estimated consumption: 2 liters / person / day Contribution: 10% of the intake is due to the drinking water. It is assumed that the food is also contaminated and may provide 90% of the maximum permitted intake

MAC = ADI x 10 mg/L

100 x 2L

NOAEL (mg/Kg/day) x 70 (60) Kg body weight/person x 10/100 Contribution (mg/Litre) UF (10-100-1000) x 2 Litre /day NOAEL x 70 (60) (mg/Litre) UF x 2 x 10

EXAMPLE: A PESTICIDE for post-harvest thiabendazol, NOAEL =10 mg /Kg/day UF=100. ADI= NOAEL/UF =10/100 = 0,1 mg/Kg/day For adult of 60 Kg bw = 0.1x60= 6 mg/day Recommended limit (under tox criteria): <10% ADI: 6*10/100= 0.6 mg Assuming 2L consumption: =0,6/2 = 0,3 mg/L = 300 ug/L

EXAMPLE: A PESTICIDE for post-harvest thiabendazol, NOAEL =10 mg /Kg/day UF=100.

One experts suggested adding an additional safety factor of 3

• r 10 due to some uncertainty in the carcinogenicity study but

it was not agreed by most other experts.

In that worse case: F=300 or 1000 ADI= 10/1000 = 0,01 mg/Kg/day

0,6 mg/day (adult 60 Kg)

Recommended limit (under tox criteria): <10% ADI: 0,6*10/100= 0.06 mg =0,06mg/2L = 0,03 mg/L = 30 ug/L Then the conclusion is between Worse case : 30 ug/L Stardard criteria: 300 ug/L

SOME CRITERIA for limits in water (1) SAFETY (1). Based on a threshold. Establishing: · Safety dose (no effect NOAEL) · safety factor (AF, UF) · acceptable daily intake (IDA) =NOAEL/AF) ·Accepted allocation of water (10% and 2 L daily water consumption in adult 60Kg) (2) (3) (4) (5) (6)

Most of recommended guide values of WHO Most of water quality parameter in European Directive Are based in this criteria:

WHAT IS SAID IN THE EUROPEAN DIRECTIVE? Our estimation is 300 g/Litro

(by toxicological criteria under treshold)

The regulation is 3,000 time lower

OBVIOUSLY OTHER CRITERIA IS USED FOR PESTICIDES All pesticides has the same máximum limit:

0,1 g/Litre

examples of guide values by WHO

Guideline value (μg/litre)

aldicarb 10 aldrin/dieldrin 0.03 atrazine 2 bentazone 300 carbofuran 7 chlordane 0.2 chlorotoluron 30 cyanazine 0.6 DDT 2 propanilo 20 methoxychlor 20 lindane 2 permethrina 20 DICHLORPROP 100 2,4-DB 90 FENOPROP 9 Simazina 2

WHO guides

Values per individual substance (Toxicology criteria) Values in the range of units to hundreds g/L (except 3 not used with 0,03 g/L)

European Directive

All pesticides the same limit

0,1 g/L

(based in analític criteria)

PESTICIDE IN EUROPE

Very simple:  No function in water, no needed in water  It is possible to avoid by good agricultural practice Consequently:

European citizens DO NOT want pesticides in drinking water.

(Criteria based in SOCIAL SENSITIVITY) How controlling concentration = CERO? Legal limit: Based on a limit of detection/quantification (Technical criteria based on analytical chemistry)

METHODS FOR ANALYTICAL CONTROL The methosd should be able to:  Detect and measuring <10 % de legal limit  With a error <10% For a limit of 0,1 ug/L (plaguicidas) The analytical method with error <0,001 ug/L (1ppt) (LD<0,01; LQ<0,02 ug/L)

SOME CRITERIA for limits in water (1) SAFETY (1). Based on a threshold. (2) SEGURIDAD-2. (3) ANALYTICAL CRITERIA. Based on limit of quantification (4) SOCIOECONOMICAL (1): Social Sensitivity (5) (6)

special cases of

Carcinogens (by genotoxic mechanism)

 Scientifically consensus: NO THRESHOLD  Lower dose  less probability BUT no cero, any dose has a probability Acceptable risk? OMS

acepta riesgo de

1 / 100.000

EUROPA

acepta riesgo de

1 / 1.000.000

 Risk 1/10,000 to 1/100,000 is considered of concern  Risk higher that 1/10,000 unacceptable

SOME CRITERIA for limits in water (1) SAFETY (1). Based on a threshold. (2) SAFETY(2). Probabilístic carcinogens by genotoxic mechanism (mutagenic) Excess of Risk <1/100,000 (3) ANALYTICAL CRITERIA. Based on limit of quantification (4) SOCIOECONOMICAL (1): Social Sensitivity (5) (6)

ACRILAMIDE, BENCENE and other

Level regulated EU and WHO guide with probability of excess of risk <1/100.000

ARSENIC

10 μg/L (as WHO) (probability of excess on skin cancer 6/10.000) (unacceptable?) No lethal cancer, The lung cancer Risk is lower than 1/million Severe problem in India-Bangla Desh Problems in Mexico and Chile In the future should be revised, BUT

Technical-economical difficulties to be reduced

SOME CRITERIA for limits in water (1) SAFETY (1). Based on a threshold. (2) SAFETY(2). Probabilístic – carcinogens) (3) ANALYTICAL CRITERIA. Based on limit of quantification (4) SOCIOECONOMICAL (1): Social Sensitivity (5) SOCIOECONOMICAL (1): technical and economical viability (6)

HALOMETHANES (HALOFORMS) and OTHER HALOGENATED

Formed by reaction organic material and chlorine (CHLORINATION) Due to potential carcinogenicity level should be convenient to reduce Legal limit considered higher than convenient BUT We cannot eliminate chlorination Future strategy for decreasing organic material CRITERIUM: Other priority measures for public health should not be compromised (WE NEED GURANTY OF MICROBIOLOGICAL HYGIENE IN WATER) (We need chlorination)

SOME CRITERIA for limits in water (1) SAFETY (1). Based on a threshold. (2) SAFETY(2). Probabilístic-carcinogens (3) ANALYTICAL CRITERIA. Based on limit of quantification (4) SOCIOECONOMICAL (1): Social Sensitivity (5) SOCIOECONOMICAL (1): technical and economical viability (6) COMPATIBLE WITH OTHER PUBLIC HEALTH MEASURES (as chlorination for disinfection)

RISK MANAGEMENT AND COMMUNICATION.

What to do if the level detected is > 0,1 g/Litro?

(case A) level higher to level of risk (case B) level higher than the legal but no health risk

Escenarios: i) Tap water in a city/tawn of

• a. <1000 inhabitanys
• b. Between 1000 and 100,000 inhabitants
• c. 100,000 -1 million
• d. Magapoli of more that 1 million

ii) Bottle water iii) Wáter in a food industry

New chemicals EC Directive 67/548/EEC Data requirement Directivae92/32/EEC Principles (Criteria for evaluation) Directive 93/67/EEC Technical Guidance Documents TGD, EC, 1993

A basic concept is that it should be based on the evaluation of data that are required and must be submitted by the “Notifier” (producer/importer that aims to put it on the European market for a given application) Not in the European Inventoy of Existing Substance (EINECS) by Sept de 1981

Existing chemicals

EC Reg. Consejo 793/93 Risk assessment principles EC Reg 1488/94 TGDs TGDs for EC Reg 1488/94 TGDs package for harmonization of the evaluation of News and Existing Chemicals TGDs EC, 1996

Those in the European Inventory (EINECS) by Sept de 1981 (n=100.106 substances)

Sustancias con normativas específicas

Nombre Nombre en ingles Referencia Directiva de Plaguicidas Directive of Pesticides (or PPP Directive) EC Directiva 91/414/EEC Medicamentos veterinarios Veterinary drugs EC Regulacion 2377/90 Aditivo alimentarios Feed additives EC Directiva 70/524/EEC Aditivos de alimentos Food additives 89/107/EEC Cosméticos Cometics SCP/803/90 Materiales de embalaje Packaging materials EC Directiva CSIPM/1025 Biocidas Biocides EC Directiva 98/8/EEC TGDs en preparación

The concept of "EXISTING" and "NEW" Europe It is applied in various fields (any chemical, pesticides, biocides, cosmetics, food) Different security requirement would be applied temporarily NEW substances: inmediate application of the new regulation EXISTING substances: A calendar for adaptation to new regulation TRANSIENT PERIOD

Critical date

EXISTING BEFORE CRITICAL DATE NEWS

Authorization needs PREVIOUSLY to demonstrate safety and efficacy The authorization to continue marketing remains. Industry is required to demonstrate their safety and effectiveness to continue commercialization It is only deactivated if AFTER the evaluated a risk is deduced

Limit of Notification Date Directive or Regulation

FIELD Fecha crítica Directiva o norma europea Chemicals 1967 y 1981 Directive 92/32/CEE (mod Dir 67/548)

(Dir 2001/58 28 mod)

Pesticides (agricuture) 1991 91/414/CCE Biocides 2000 98/3/CE Cosmetics 1976 y 2003 Dir 2003/15/CE (7ª modif Dir 76/768/CEE) Foods 1997 Regulation (CE) 258/97 1829/2003 y 641/2004

The concept of "EXISTING" and "NEW" Europe It is applied in various fields

REgulation REACH

Registration

• f

CHemicals Evaluation Autorization

REACH

1 Protection of human health and the environment

• 2. Competitivity of the chemical industry
• 3. Avoid fragmentation of the market
• 4. Increase transparency
• 5. International integration
• 6. Promotion of non-animal tests.
• 7. Accordance with international obligations of the EU

Objetives REACH

Table 1.1 The proposed schedule for the registration of 30,100 existing substances (6) Number of substances Volume (tonnes per annum) Deadline for registration 2600 >1000 end of 2005 2900 100-1000 end of 2008 4600 10-100 end of 2012 20,000 1-10 end of 2012

REACH

Asignación de responsabilidad a la industria

Cambio drástico de planteamiento Los ensayos costará >2.100 M€

Assignment of responsibility to industry. Drastic change of approach Testing industry cost > 2,100 M€ Important change

REACH

Toxicity in animal models and human data No observed effect adverse effect level

(NOAEL) Acceptable daily intake

(IDA = NOAEL/UF)

Margen de Seguridad IDA/(Ingesta diaria) (MOS) (<1 hay riesgo) (>1 no riesgo)

Source and route of exposure

Contribution to daily intake Daily exposure

EXPOSURE ASSESSMENT EFFECT ASSESSMENT RISK CHARACTERIZATION

RISK ASSESSMENT TO HUMANS

Extrapolation

(Uncertainty factor UF) (Evaluationn factor)

Base set minus: 4 5 (partly ) 6b,c,d,e 7a-d 8 Base set minus: 4 (partly ) 5 (partly ) 6d, 1genotoxtest 7a,b,c 8 Base set plus: Reproductive toxicity Subchronic /chronic toxicity Extended genotoxicity Toxicokinetics Chronic ecotoxicity Terrestrial ecotoxicity Extended fate tests Othertestsconsidered necessary for a full risk assessment

• 1. Identitydata,methodsof

analysis

• 2. Quantity

, functions , applications

• 3. Precautionary measures

, emergency measures

• 4. Physical properties
• 5. Chemical properties
• 6. Toxicological properties

:

• a. acute

toxicity(2 routes)

• b. skin/

eye irritation c.sensitization d.subacute toxicity e.genotoxicity (2 tests)

• 7. Ecotoxicological properties
• a. acute

toxicity(algae , fish , Daphnia ) b.inhibition bacteria c.ready biodegradability d.hydrolysis

• 8. Methods rendering

the substance harmless

Base set minus: 4 5 (partly ) 6b,c,d,e 7a-d 8 Base set minus: 4 (partly ) 5 (partly ) 6d, 1genotoxtest 7a,b,c 8 Base set plus: Reproductive toxicity Subchronic /chronic toxicity Extended genotoxicity Toxicokinetics Chronic ecotoxicity Terrestrial ecotoxicity Extended fate tests Othertestsconsidered necessary for a full risk assessment

• 1. Identitydata,methodsof

analysis

• 2. Quantity

, functions , applications

• 3. Precautionary measures

, emergency measures

• 4. Physical properties
• 5. Chemical properties
• 6. Toxicological properties

:

• a. acute

toxicity(2 routes)

• b. skin/

eye irritation c.sensitization d.subacute toxicity e.genotoxicity (2 tests)

• 7. Ecotoxicological properties
• a. acute

toxicity(algae , fish , Daphnia ) b.inhibition bacteria c.ready biodegradability d.hydrolysis

• 8. Methods rendering

the substance harmless

The need for development of alternative methods is highlighted by dividing the research needs in two sections:

• Development of Alternative Methods
• Other priorities of research

Research and Validation

REACH

Supported regulation on animal protections. Animal should be replaced as possible

Lago Maiore. Ispra. ECVAM, ECB

http://tox.umh.es http://remanet.net RED ESPAÑOLA DE METODOS ALTERNATIVOS A LA EXPERIMENTACION ANIMAL

EFFECT ASSESSMENT

Toxicity in vitro and animal models

Toxicological properties. HAZARD IDENTIFICATION Acceptable daily intake

(ADI/IDA = NOAEL/UF)

Extrapolation

(Uncertainty/safety/factor, UF) No effect level (NOAEL) Dose effect relationship

CLASSSIFICATION and LABELING Directive 67/548

• Reg. 1272/2008

RESTRICTIONS (independently of risk ESTABLISHING CONCENTRATION LIMITS