'Emerging Organic Contaminants and their Potential Significance for the Agricultural Recycling of Biosolids

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1 'Emerging Organic Contaminants and their Potential Significance for the Agricultural Recycling of Biosolids Stephen Smith & Bradley Clarke Department of Civil and Environmental Engineering

2 What s the problem? Over 50 million unique chemicals in CAS (Chemical Abstracts Service) database 143,000 registered in industrial use in Europe All potential biosolids contaminants that derive from industrial, urban and domestic sources Environmental and health concerns: Toxicity, mutagenicity, carcinogenicity, endocrine disruption, developmental toxins, ecotoxicity, antibiotic resistance

3 Strategic Reviews of OCs in Sludge Smith 1994 FWR Report Smith 1996 Agricultural Recycling of Sewage Sludge and the Environment. CAB INTERNATIONAL Smith 2000 Progress in Environmental Science 2 ICON 2001 Pollutants in Waste Water and Sewage Sludge, Final Report to European Commission Schowanek et al 2004 Reg Tox Pharm 40 Smith and Black 2006 Sources and Impacts of Past, Current and Future Contamination of Soil - Organic Contaminants, Final Report to DEFRA Schowanek et al 2007 Reg Tox Pharm 49 Jensen et al 2007 Chemosphere 69 Smith 2009 Philosophical Transactions of the Royal Society A 367,

4 Behaviour in Soil-Water-Plant System Toxic compounds present in trace amounts Three categories of behaviour: Rapid volatilisation Rapid biodegradation and no persistence Strong adsorption of persistent compounds Sludge Soil Plant Human (USEPA Pathway 1) bioconcentration in crops detected (<0.01) Negligible uptake = minimal human exposure

5 Trends in Environmental Exposure? Human Milk Concentrations DDT PCBs BDEs PFOS Concentrations ng g -1 lipid rén et al. (2000) Chemosphere 40, Karrman et al. (2007) Environ. Health Persp. 115, Hites (2004) Environ. Sci. Technol. 38, She et al. (2007) Chemosphere 67, S307-S317

6 Sensationalised badly designed biosolids research promotes negative public perception

7 Sensationalised badly designed biosolids research promotes negative public perception

8 Understanding the Risks Contaminant Pathway Receptor Human 1. Direct Exposure 2. Plant uptake 3. Animal uptake 4. Water contamination Ecological 1. Soil microbes 2. Soil organisms 3. Higher trophic animal 4. Define receptors Biosolids amended soil Food Chain Human Exposure

9 Key Questions Are there organic pollutants that may impact on the safe land application of biosolids? What are the likely candidates? How much research has been conducted internationally? What are the key research priorities to ensure the long-term sustainable management of biosolids?

10 List of Contaminants Reviewed Included Antibiotics and pharmaceuticals Benzothiazoles Bisphenol A Organotins (OTs) Polybrominated diphenyl ethers (PBDEs) Polychlorinated alkanes (PCAs) Polychlorinated naphthalenes (PCNs) Polydimethylsiloxanes (PDMS) Perfluorochemicals (PFCs) Phthalate acid esters (PAEs) Quaternary ammonium compounds (QACs) Steroids Synthetics musks Triclosan (TCS) & triclocarban (TCC) Excluded Chlorinated dioxins/furans (PCDD/Fs) Polyaromatic hydrocarbons (PAHs) Polychlorinated biphenyls (PCBs) nylphenol (NP) Linear alkyl benzene sulphonate (LAS)

11 Assessment Criteria Soil persistence Potential risks to human food chain Ecological bioaccumulation Soil ecotoxicity Extent and quality of the research Biosolids Conc. WWTP Soil Persistence Food Chain Bioaccumulation Ecotoxicity Mean (Range) mg kg -1 DS % Removal Half Life Possible, Uncertain or Yes, or Likely Yes, or Uncertain Numerous, Some or Few

12 Antibiotics & Pharmaceuticals Development of antibiotic resistance (human health) Ecological consequences Short residence time in aquatic environment Longer persistence in soil (i.e., carbamazapine 21 months, plant uptake) Many contain non-polar core and polar functional group rwegian Risk Assessment Identified 14 of 1400 for further research Sig. below PNEC US EPA Biosolids Survey 72 pharmaceuticals Drug Biosolids Conc. WWTP Soil Persistence Food Chain Bioaccumulation Ecotoxicity Low mg/kg Unchanged/Unknown Unknown; generally reported in days Possible Uncertain More required (mg kg -1 dry soil) Agricultural soil PEC Park areas PEC PNEC Mesalazin Ranitidin Sotalol Metoprolol Atorvastatin Tetracycline Ciprofloxacin Carisoprodol Gabapentin

13 Benzothiazoles Rubber vulcanizing agents Polymerisation of sulphur with rubber Proposed German limit MBT+OBT: 0.6 mg kg -1 DS Lack of empirical data specific reason why it was chosen? Aquatic toxicity Studies indicate that these compounds are biodegradable Biosolids Conc. Unknown WWTP Unknown Soil Persistence Unknown Food Chain Uncertain Bioaccumulation Ecotoxicity Uncertain Small 2-Mercaptobenzothiazole MBT 2-Hydroxybenzothiazole OBT

14 Bisphenol A Used in coatings of cans, plastics, dental fillings etc. Endocrine disruptor less than 17β-estrodiol Human exposure occurs in domestic environment Sig. reductions in WWTP Rapidly dissipated in soil Unlikely to pose issue for biosolids reuse Biosolids Conc ( ~ 325) WWTP Up to 99%, biodegradation Soil Persistence Foodchain Bioaccumulation Ecotoxicity 3 days Small Bisphenol A

15 Organotins Used since 1960s for industrial and agricultural purposes PVC stabliser Fungicides Insecticides Wood preservative High toxicity observed in aquatic environment Restricted use of TBT More research required Biosolids Conc (0.02 6) WWTP >80% sedimentation Soil Persistence Human Health Bioaccumulation Ecotoxicity < 2 months Uncertain Possible Yes Small Tributyltin TBT

16 Phthalates acid esters Concentration mg kg -1 dw Used since 1950s as a plasticizer Concern as EDC Degrades during WWTP Degrades in soil Unlikely to enter food chain Biosolids Conc. 58 ( ) WWTP Soil Persistence Foodchain Bioaccumulation Ecotoxicity Biodegradation (23 60%) <100 days Large DEHP

17 Polybrominated diphenyl ethers (PBDEs) Used as fire retardant Recently included as UN POP Electronics Environmental contaminant Lake Ontario Lake Michigan Lake Huron Biosolids Conc ( ) WWTP Sedimentation Soil Persistence 20 years Concentration ng g -1 lipid Food chain Bioaccumulation Ecotoxicity Yes Yes Uncertain Large PBDEs rstrom et al. (2002) Env. Sci. Techol. 36, rth American Great Lakes ecosystem in 2000 was determined by analysis of herring gull eggs analysing archived samples between 1981 and 2000

18 Polybrominated diphenyl ethers (PBDEs) Used as fire retardant Electronics Recently included as UN POP Environmental contaminant 4 Biosolids Conc ( ) Concentration mg kg -1 dw WWTP Soil Persistence Food chain Bioaccumulation Ecotoxicity Sedimentation 20 years Yes Yes Uncertain Large 0 PBDEs

19 Polychlorinated alkanes Produced since 1930s Class of industrial chemicals comprising chlorinated straight-chain hydrocarbons Applications include: Extreme pressure lubricant additives Plasticizers Flame-retardants Paint additives Analytical challenge 10,000+ isomers Extremely high concentrations reported Detected in humans Similarity to United Nations POPs Biosolids Conc. 910 ( ) WWTP Soil Persistence Food chain Bioaccumulation Ecotoxicity Unknown Unknown Yes Yes Uncertain Small Short chain PCAs C Medium chain PCAs C Long chain PCAs C Concentrations 1000 times higher than PCBs

20 Polychlorinated naphthalenes Used since early 1900s Precedes/parallels PCBs Applications include Dielectric fluids Engine oil additives Electroplating Wood preservatives Lubricant Dye production Voluntary phased out in USA in 1970s 1990s production ~ tonnes United Nations POPs candidate Dioxin-like toxicity Biosolids Conc ( ) WWTP Soil Persistence Food chain Bioaccumulation Ecotoxicity Unknown; sedimentation Unknown Yes Yes Uncertain Small

21 Polydimethylsiloxanes PDMS Man-made organosilicone polymer Widely used in industrial applications and consumers products including: Textiles treatment Household Personal care products Antifoam for food processing & WWTP Low toxicity Rapid abiotic degradation Largely removed through WWTP 94% unchanged Biosolids Conc. 632 ( ) WWTP Soil Persistence Food chain Bioaccumulation Ecotoxicity Sedimentation (94%) 28 days Good understanding n ranges between 100 and >10000

22 Perfluorochemicals (PFOS & PFOA) Accumulating in humans Widely detected in environment Used to make products resistant to heat, oil, stains, grease and water Common applications include: n-stick cookware Breathable membranes Stain-resistant carpets & fabrics Fire fighting foams Surfactants Increases during WWTP Found in sediment and effluent Recently included as UN POP Restrictions introduced (PFOS - Directive 2006/122/EC and under review as WFD PHS) Biosolids Conc ( ) WWTP Soil Persistence Food chain Bioaccumulation Ecotoxicity Increasing; in effluent & sludge Unknown Yes Yes Uncertain More required Perfluorooctane sulphonate PFOS Perfluorooctanoic acid PFOA

23 Quaternary Ammonium Compounds Cationic surfactants (many) Commonly applications: Fabric softeners, hair conditioners, disinfectants, biocides, emulsifiers, wetting agents Source control of DTDMAC as aquatic toxin Relaced by DEEDMAC as more biodegradable Link to antibiotic resistance? DTDMAC Concentration mg kg -1 dw Biosolids Conc. WWTP Soil Persistence Food chain Bioaccumulation Ecotoxicity Mean (Range) Sedimentation & biodegradation days Few R1-4 represent alkyl or aryl substituent s DTDMAC: ditallow dimethyl ammonium chloride DEEDMAC: diethyl ester dimethyl ammonium chloride

24 Steroids Humans primary source to WWTP Natural and synthetic Released as inactive polar conjugates Female hormones degrade rapidly Hormone precursors regularly detected US EPA survey e.g. cholesterol Unlikely to be problematic for biosolids land application Analytical problems Biosolids Conc. WWTP Soil Persistence Human Health Bioaccumulation Ecotoxicity Varied High biodegradation Days Small 17α-oestradiol oestrone oestriol 17 α- ethinyloestradiol

25 Synthetic Musks Concentration mg kg -1 dw Inexpensive substitutes for natural musks used since 1930s Original nitromusks toxic (15%) Replaced with polycyclic musks (85%) PECs < PNECs Proposed German limits in sludge Biosolids Conc. 14 (1.9 81) WWTP Soil Persistence Food chain Bioaccumulation Ecotoxicity Sedimentation & biodegradation Unknown HHCB More required AHTN

26 Triclosan and Triclocarban Widely used antimicrobials in personal care products, including: Shampoos Soaps Cosmetics Skin-care lotions Creams Mouth rinses Toothpaste Typical concentration 0.1 to 0.3% (w/w) Biosolids Conc. 24 ( ) WWTP Soil Persistence Food chain Bioaccumulation Ecotoxicity Sedimentation & biodegradation <1 year Yes Yes Small mg kg -1 dw Triclosan Triclocarban Triclosan Triclocarban

27 Typical Concentrations POPs Bulk Chemical Personal Care Concentration mg kg -1 dw Higher than bulk chemicals 3 magnitudes higher than PCBs Relatively high concentrations compared to other POPs Very low concentrations

28 Assessment Matrix (somewhat subjective) Persistence Food chain Ecological Soil Ecotoxicity Score ( /11) 2 Yes 1 - Uncertain 0 2 Possible 1 - Uncertain Yes 1 - Possible Yes 1 - Uncertain Lack of data 2 - Few studies 1 - Consistent 0 - Many & similar Antibiotics Benzothiazoles Bisphenol A Organotins Phthalates PBDEs PCAs PCNs Siloxanes PFCs QACs Steroids Synthetic Musks Triclosan Triclocarban

29 Assessment Scores Score Contaminant 10 Perfluorochemicals (PFOS, PFOA) 9 PCAs; PCNs 7 Organotins; PBDEs; Triclosan; Triclocarban 6 Benzothiazoles 5 Antibiotics and pharmaceuticals 3 Synthetic musks 2 Bisphenol A; QACs; Steroids 1 Phthalates; Siloxanes

30 Key Recommendations 1. Long-term vigilance Assessment, monitoring and research 2. Empirical measurements Concentrations, fate and impacts 3. High concentration of PCAs Risk to health due to POP characteristics? 4. PFCs have a unique chemistry for a UN POP Potential environmental mobility?