Hazards related to biological contaminants. Possible deleterious effects on human health caused by micro-organisms

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Frederick Ford
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1 Hazards related to biological contaminants Possible deleterious effects on human health caused by micro-organisms Infectious diseases (ingestion, cutaneous contact or inhalation) Immunoallergic, inflammatory or toxic effects (cutaneous contact or inhalation of endotoxins, glucans, allergenic fungi, mycotoxins, protozoa) Mutagenic/carcinogenic effects (some mycotoxins, viruses such as Hepatitis) Animal health : infectious diseases and toxins (Listeria monocytogenes, Aspergillus and Fusarium spp ), parasites Plant health 24 Direction du végétal et de l environnement

2 Inactivation of biological contaminants Pathogens are supposed to be either drastically reduced or eradicated by the treatments applied to raw material However, true sterilisation processes are not the rule Process Inactivation of microorganisms Eradication of pathogens Very efficient processes Incineration Dry heating total complete Efficient processes High under following conditions : Pasteurisation >70 C for 30 min Thermophilic digestion >55 C for 10 days Drying bed for > 200 days incomplete Composting >55 C for 2 weeks Liming ph>12 and stored for 20 days Other processes Weak except if : Psychrophilic digestion for 90 days Mesophilic digestion for > 50 days incomplete From Cadiergues (2000) 25 Direction du végétal et de l environnement

3 Inactivation of biological contaminants It is impractical to determine for each process and each type of product the inactivation rate for all pathogens that may be present Use of indicators to measure the extent of destruction of selected micro-organisms exposed to the process : Consistently present in raw materials in large numbers Not more resistant than the pathogens they represent Easy enough to identify and quantify The relevance of those indicators should be reassessed on a regular basis Possible evolution during storage 26 Direction du végétal et de l environnement

4 Fate of biological contaminants 2009, September 9 Transfer In soil Most pathogens would stay on the soil surface Viruses more mobile To water Few data on transfer to groundwaters and surface waters, but some cases of contamination reported (Campylobacter spp., Listeria spp., Cryptosporidium spp., E. Coli producing Shiga-toxins), related to heavy rains To the air (bioaerosols) Few data, on some bacteria only Cannot be excluded for bacteria, viruses and products (endotoxins, mycotoxins and glucans) To crops (spraying, dusts) 27 Direction du végétal et de l environnement

5 Fate of biological contaminants 2009, September 9 Survival in soil Under favorable conditions (temperature, medium), could survive for months and even years (Salmonella spp.) Some microorganisms are specially adapted to resist : spores-forming bacteria (Clostridium spp.), viruses with envelope, eggs of parasites (helminths) Salmonella spp. reported to grow again (Gibbs 1997) To be considered vs natural or fertilisation-stimulated presence Survival on crops Pathogens Survival on crops Bacteria (Salmonella spp., E. Coli spp.) <100 days (often <20 days) Viruses (enteroviruses) <60 days (often <15 days) Protozoaires (Entamoeba histolytica) <10 days (often <2 days) Helminthes (Ascaris spp., Taenia saginata) <60 days (often <30 days) 28 Direction du végétal et de l environnement

6 Main issues raised by biological contaminants 2009, September 9 Pathogens causing very severe diseases can be present in the products Contagiousness Users, workers and possibly neighbours may be significantly exposed by contact and inhalation For consumers and neighbours eating garden plants, special attention should be given to crops which can be eaten raw Contribution to the dissemination of pathogens into cattle and into the environment (ex : rotavirus and Hepatitis E virus pathogenic for human and carried by pigs, ruminants ) 29 Direction du végétal et de l environnement

7 Example of biological contamination by organic fertilisation 2009, September 9 Contamination of spinach crops in California in 2006 With E. coli O157:H7 Case reports 1 death 27 people with severe kidney failure 88 hospitalisations Compost process used questionable Shows the need for assessment and controls 30 Direction du végétal et de l environnement

8 Metallic chemical contaminants Examples Cadmium Copper Nickel Zinc Chrome Mercury Lead Selenium Controls - Current regulatory rules for threshold not based enough on risk assessment - Speciation and changes in speciation should be taken into account Need to take into account the natural presence in the environment 31 Direction du végétal et de l environnement

9 Metallic chemical contaminants : main hazards 2009, September 9 Considered* as carcinogenic or probably carcinogenic (Cd, Cr VI, Cr III, Ni compounds) Considered as toxic or probably toxic for reproduction (Cd, Ni, Pb, (Met)Hg compounds) Causing immunological disturbances or allergenic reactions (Ni, Cr III or VI, Cu) Displaying toxicity for : Brain and nervous system (Cd, Se, Pb,(Met)Hg) Kidney (Cd, Cu, Pb) or liver (Cu) Respiratory tract (Cr III or VI, Ni) Gastro-intestinal tract (Cr III or VI, Cu, Se) * IARC or Regulation (EC) N 1272/ Direction du végétal et de l environnement

10 Organic chemical contaminants HOC halogenated organic compounds LAS linear alkylbenzene sulfonates DEHP bis(2-éthylhexyle) phthalate NPE nonylphenols PAH Polycyclic aromatic hydrocarbons (acenaphthene, benzo(a)pyrene) PCB Polychlorinated biphenyls PCDD/PCDF dioxins Green wastes and wood by-products : pesticides, biocides Sludges from paper industry : ink, pigments Residues of medicinal drugs (for human or veterinary use) 33 Direction d végétal et de l environnement

11 Organic chemical contaminants : main hazards Considered* as carcinogenic or probably carcinogenic (Benzo(a)pyrene, PCB) Considered as toxic or probably toxic for reproduction (Benzo(a)pyrene, DEHP) Endocrine disruptors (NPE, PCB) Displaying toxicity for : Brain and nervous system (PCB) Kidney (Fluoranthene, benzo(a)pyrene) or liver (PAH, PCB, DEHP) Heart (dioxines) Respiratory tract (PCB) Gastro-intestinal tract (PCB) * IARC or Regulation (EC) N 1272/ , September 9 34 Direction du végétal et de l environnement

12 Chemical contaminants Degradation of metallic elements No degradation Degradation of organic chemical compounds Group of compounds total HAP Benzo(a)pyrene DEHP PCB PCDD/PCDF From A. Coftier (2005) 35 Direction du végétal et de l environnement Estimation for degradation rate decrease by >80% after 20 years strongly adsorbed in soil by organic components weak capacity for leaching 60% remaining after 30 years (25 applications) 50% remaining after 1 year very persistant, half-life of several years strongly adsorbed in soil by organic components weak capacity for leaching very persistant, half-life of several years strongly adsorbed in soil by organic components weak capacity for leaching

13 Fate of chemical contaminants Example : Cd in Denmark & " # ' # $" %! "# ( ' ) # (g ha -1 year -1 ) from Hovland, 1981

14 Fate of chemical contaminants Transfer To crops Could be estimated with a Bioconcentration Factor for each substance and each crop, determined from experimental studies (values proposed by INERIS*) From crops to cattle Could be estimated with a Bioaccumulation Factor for each substance and each species (values proposed by INERIS*) To soil, terrestrial, aquatic organisms Factors to be determined Secondary poisoning and bioaccumulation Contaminants and factors to be discussed and harmonised at EU level * From A. Coftier (2005) 37 Direction du végétal et de l environnement

15 Issues raised by chemical contaminants Some very persistant compounds of known human toxicity Possible long-term presence and accumulation in the environment Exposure coming from fertilisers added to many others Carcinogenic effects : no threshold Ecotoxicity to be assessed Cu and toxicity to worms with secondary poisoning PCB and toxicity to fishes, with possible impact to anglers and families 38 Direction du végétal et de l environnement

16 Main concerns regarding assessment of fertilisers Mineral fertilisers doses and eutrophication Synthetic components E-fate often unknown, putative toxicity or ecotoxicity Organic fertilisers Major issues possible due to pathogens Distribution in the environment of micro-organisms harmful for human, animal or plant health Chemical contaminants, persistant and potentially carcinogenic, showing toxicity for human and possibly for other organisms 39 Direction du végétal et de l environnement

17 Conclusion (I) 2009, September 9 To protect human health and the environment, risk assessment is necessary for new products and probably for some products already known (new hazards or routes of exposure identified) Need of harmonised regulation, at least within EU Methods for risk assessment specific to fertilisers should be developed 40 Direction du végétal et de l environnement

18 Conclusion (II) 2009, September 9 Tasks to discuss further : hazards, routes of exposure (duration taken into account), methods for assessing risks to grade the possible risks and match the data requirements with the level of risk and concerns to identify data gaps and prioritise how to address them by appropriate research Afssa is very willing to collaborate with Agencies of other Member States to make progress in the assessment of fertilisers 41 Direction du végétal et de l environnement s

Identification of health and environmental issues related to the use of fertilisers and growing media

Identification of health and environmental issues related to the use of fertilisers and growing media Pascale Robineau 9 September 2009 Types of products The Fertiliser family Nutrient providers, usually