Soil pollution on agricultural fields and other land uses

The Global Symposium on Soil Pollution #GSOP18 | 2 - 4 May 2018 | FAO Hq

Mr. Steve McGrath, Rothamsted Research, UK

1. Steve McGrath Soil pollution and agriculture: status, drivers and challenges FAO GLOBAL SYMPOSIUM ON SOIL POLLUTION

2. What effects does soil pollution have? Phytoxicity , decreased yield Effects on soil biodiversity and microbial function Decreased food quality Decreased air and water quality Human and animal health

3. Preliminary remarks This talk concentrates on metals/metalloids in soils Contamination - any presence above “ background concentrations ” Pollution – presence of sufficient bioavailable substance to present harm , i.e. above a selected threshold value Non-essential substance Bioavailable concentration in soil Biological activity Essential substance Toxicity ̴Contamination Pollution NOAEC –No Observed Adverse Effect Concentration Smolders, Oorts, Sub-theme 4.1 Thursday

4. What are the sources of metals for agricultural soils? These are allowed to be added to soils but society can control them: – usually by imposing laws or codes of practice Graphic: Zhao, Ma, Zhu, Tang and McGrath, Environ Sci Technol. 2015, 750

5. Metal addition rates to agricultural land in E&W from various sources (g/ha/ yr ) Source Source Zn Cu Ni Pb Cd Atmospheric deposition Sewage sludge a 221.0 4557.0 57.0 3210.0 16.0 335.0 54.0 1256.0 1.9 19.0 Livestock manures a Dairy cattle slurry Beef cattle slurry Pig slurry Cattle FYM b Pig FYM Layer manure Broiler litter c 1063.0 1214.0 2321.0 718.0 2120.0 2734.0 1142.0 281.0 321.0 1679.0 168.0 1488.0 422.0 175.0 38.0 43.0 50.0 28.0 48.0 47.0 20.0 44.0 50.0 29.0 27.0 27.0 42.0 18.0 1.9 2.1 1.4 2.7 2.0 6.1 2.6 Inorganic fertilisers Nitrogen Phosphate Potash Lime d 2.2 34.0 0.5 53.0 1.6 4.9 0.4 12.0 0.2 3.3 0.1 25.0 0.7 0.5 0.2 10.0 0.1 1.6 0.0 1.4 Irrigation water Paper sludge 39.0 1380.0 16.0 1270.0 1.6 102.0 0.8 45.0 0.1 12.5 a Using application equivalent to 250 kg N/ha; b Includes sheep Farm Yard Manure; c Includes pullets and other poultry; d Typically applied 1/5 years to acid soils Nicholson et al, STOTEN, 311, 2003, 205-219

6. Metal addition rates to agricultural land in E&W from various sources (g/ha/ yr ) Source Source Zn Cu Ni Pb Cd Atmospheric deposition Sewage sludge a 221.0 4557.0 57.0 3210.0 16.0 335.0 54.0 1256.0 1.9 19.0 Livestock manures a Dairy cattle slurry Beef cattle slurry Pig slurry Cattle FYM b Pig FYM Layer manure Broiler litter c 1063.0 1214.0 2321.0 718.0 2120.0 2734.0 1142.0 281.0 321.0 1679.0 168.0 1488.0 422.0 175.0 38.0 43.0 50.0 28.0 48.0 47.0 20.0 44.0 50.0 29.0 27.0 27.0 42.0 18.0 1.9 2.1 1.4 2.7 2.0 6.1 2.6 Inorganic fertilisers Nitrogen Phosphate Potash Lime d 2.2 34.0 0.5 53.0 1.6 4.9 0.4 12.0 0.2 3.3 0.1 25.0 0.7 0.5 0.2 10.0 0.1 1.6 0.0 1.4 Irrigation water Paper sludge 39.0 1380.0 16.0 1270.0 1.6 102.0 0.8 45.0 0.1 12.5 a Using application equivalent to 250 kg N/ha; b Includes sheep Farm Yard Manure; c Includes pullets and other poultry; d Typically applied 1/5 years to acid soils Nicholson et al, STOTEN, 311, 2003, 205-219

7. Metal addition rates to agricultural land in E&W from various sources (g/ha/ yr ) Source Source Zn Cu Ni Pb Cd Atmospheric deposition Sewage sludge a 221.0 4557.0 57.0 3210.0 16.0 335.0 54.0 1256.0 1.9 19.0 Livestock manures a Dairy cattle slurry Beef cattle slurry Pig slurry Cattle FYM b Pig FYM Layer manure Broiler litter c 1063.0 1214.0 2321.0 718.0 2120.0 2734.0 1142.0 281.0 321.0 1679.0 168.0 1488.0 422.0 175.0 38.0 43.0 50.0 28.0 48.0 47.0 20.0 44.0 50.0 29.0 27.0 27.0 42.0 18.0 1.9 2.1 1.4 2.7 2.0 6.1 2.6 Inorganic fertilisers Nitrogen Phosphate Potash Lime d 2.2 34.0 0.5 53.0 1.6 4.9 0.4 12.0 0.2 3.3 0.1 25.0 0.7 0.5 0.2 10.0 0.1 1.6 0.0 1.4 Irrigation water Paper sludge 39.0 1380.0 16.0 1270.0 1.6 102.0 0.8 45.0 0.1 12.5 a Using application equivalent to 250 kg N/ha; b Includes sheep Farm Yard Manure; c Includes pullets and other poultry; d Typically applied 1/5 years to acid soils Nicholson et al, STOTEN, 311, 2003, 205-219 McLaughlin Theme 1 This afternoon

8. Metal addition rates to agricultural land in E&W from various sources (g/ha/ yr ) Source Source Zn Cu Ni Pb Cd Atmospheric deposition Sewage sludge a 221.0 4557.0 57.0 3210.0 16.0 335.0 54.0 1256.0 1.9 19.0 Livestock manures a Dairy cattle slurry Beef cattle slurry Pig slurry Cattle FYM b Pig FYM Layer manure Broiler litter c 1063.0 1214.0 2321.0 718.0 2120.0 2734.0 1142.0 281.0 321.0 1679.0 168.0 1488.0 422.0 175.0 38.0 43.0 50.0 28.0 48.0 47.0 20.0 44.0 50.0 29.0 27.0 27.0 42.0 18.0 1.9 2.1 1.4 2.7 2.0 6.1 2.6 Inorganic fertilisers Nitrogen Phosphate Potash Lime d 2.2 34.0 0.5 53.0 1.6 4.9 0.4 12.0 0.2 3.3 0.1 25.0 0.7 0.5 0.2 10.0 0.1 1.6 0.0 1.4 Irrigation water Paper sludge 39.0 1380.0 16.0 1270.0 1.6 102.0 0.8 45.0 0.1 12.5 a Using application equivalent to 250 kg N/ha; b Includes sheep Farm Yard Manure; c Includes pullets and other poultry; d Typically applied 1/5 years to acid soils Nicholson et al, STOTEN, 311, 2003, 205-219

9. What is the extent of soil pollution?

10. Cadmium concentrations in agricultural topsoils GEMAS: Geochemical Mapping of Agricultural and Grazing land Soil Birke et al. J Geochem Expl 173 (2017) 13–30 Reimann et al. / App Geochem 88 (2018) 302-318

11. How many soils have unusually high metal concentrations? Reimann et al, Fig 3. Appl Geochem, 88, 302-318, 2018 Red = N Europe; Black = S Europe; SGV = a range of European Soil Guideline Values; Vertical lines = 99%ile; green lin es = upper whisker of boxplot 20 Answer: 161 of 2,108 agricultural soils exceed the upper whisker = 7.6%*

12. Risks for Cd concentrations in European topsoils *RCR = PEC/PNEC, using PNECsoil = 0.9 mg Cd/kg Predicted Environmental Concentration Birke et al. J Geochem Expl 173 (2017) 13–30 Predicted No Effect Concentration Risk Characterisation Ratios (RCR*) for Cd in European agricultural soils n P%10 Median P%90 GEMAS 2218 0.07 0.20 0.48 Countries Min 0.03 0.09 0.17 Max 0.21 0.63 2.53 But we must also take into account bioavailability And whether this is natural or anthropogenic

13. Other regions?

14. Threats to soil function: condition and trend Table 8 Condition: Very poor Poor Fair Good Very good http://www.fao.org/documents/card/en/c/39bc9f2b-7493-4ab6-b024-feeaf49d4d01/

15. Soil contamination in China In 2014 the Ministry of Environmental Protection (MEP): current status of soil contamination in China Surface (0−20 cm) soil samples from 8 × 8 km grids and analysed for: As, Cd, Co, Cr, Cu, F, Hg, Mn, Ni, Pb , Se, V and Zn [3 types of organic contaminants (hexachlorocyclohexane, dichlorodiphenyltri-chloroethane , and polyaromatic hydrocarbons)] Of all the samples analysed, 16% exceed the environmental quality standard set by the MEP and 19% of agricultural soils (equivalent to approximately 26 million ha) Contamination by As, Cd, Cr, Cu, Hg, Ni, Pb and Zn accounted for the majority (82.4%) of the soils classified as being contaminated Amongst those, Cd ranked first in the percentage soil samples (7.0%) exceeding the MEP limit Zhao, Ma, Zhu, Tang and McGrath, Environ Sci Technol. 2015, 750-759

16. Soil Cd concentration in China: 90 th Percentile for different provinces Hunan Guangxi Guizhou Chinese element background values in soil , 1990

17. Geographical patterns of rice Cd concentrations in China Chen et al 2018. Environ. Pollut . Chinese Limit 0.2 mg/kg

18. As toxicity in soils of irrigated rice in SE Asia >70% groundwater is used for irrigation of paddy rice in the dry season Irrigation adds >1000 t arsenic to topsoils in Bangladesh / yr IRRI arsenite arsenite arsenite Groundwater

19. Africa? Mining, industry, urbanisation mg/kg Predicted topsoil (0-20 cm) extractable Zn GeoSurvey – crowdsource MobileSurvey – sampling app Dry spectroscopy techniques Blue or light blue – crop Zn deficiency Faster, cheaper methods needed for local measurement and for gathering data for large areas Hengl et al, Nutr Cycl Agroecos (2017) 109: 77-102

20. I can reveal: The solution to pollution? Prevention! Soil Protection FAO (2015) Status of the World's Soil Resources

21. Legislation Types of laws Air pollution prevention laws Water pollution prevention laws Soil pollution prevention laws Food quality rules (SANCO, WHO/CODEX) Legislation on the production and use of chemicals Waste disposal laws Results? Decreasing concentrations in air, water, materials added to soils Decreasing build-up in soils

22. Metal concentrations in sewage sludge are decreasing as a result of emission controls Zn and Cd in sewage sludge from Nottingham STW, UK during the period 1978 – 1999 From: Pollutants in Urban Waste Water and Sewage Sludge, EC, 2001 ↓ x 4 ↓ x40

23. UK metal emissions: National Atmospheric Emissions Inventory Metal emissions are declining http://naei.defra.gov.uk/ Different patterns in other regions

24. Conclusions and future challenges We must promulgate a unified terminology around contamination/pollution Where anomalously high metal concentrations occur, they are normally due to either natural geochemical hot spots, or mining, smelting, urbanization* and other industries. Diffuse pollution of agricultural soils cannot be detected at large scale Investigations need to be local, and based on soil properties, bioavailability and local background concentrations, i.e. specific risk assessment Monitoring over time can demonstrate anthropic inputs, but this is almost non-existent Cheaper methods for sampling and analysis are needed for site assessment and monitoring Pollution control is the solution; decontamination of large areas is expensive Harmonised methods for sampling and analysis need to be used obtain comparable regional/global information A common generic framework for the derivation of bioavailability-based risk values needs to be used * Urban or peri-urban agriculture often takes place on contaminated soils