Prevention Of Environmental Pollution From Agricultural Activity

2 DIFFUSE AGRICULTURAL POLLUTIONDIFFUSE AGRICULTURALPOLLUTIONDOsDON'Ts1. All cropped land over the followingwinter must, where soil conditions afterharvest allow, have either: crop cover,grass cover, stubble cover, ploughedsurface or a roughly cultivated surface.Fine seedbeds must only be created veryclose to sowing. [GAEC measure 1]1. Don’t allow the runoff from roads,farmyards, hard standings and ring feederareas used by stock to discharge directly toa watercourse.2. Don’t allow livestock to have accessto watercourses. Instead, provide water atdrinking troughs wherever possible.2. Protect your soil by following theguidance in this Code regarding preventingdamage and erosion.3. Don’t employ any agriculturalcontractor or company involved inspreading organic waste to land unlessthey are competent and suitably trained,aware of legal requirements and arewilling to follow the guidance in this Code.3. Follow “The 4 Point Plan”, whichoffers guidance on how to:l reduce dirty water around the farm;l improve nutrient use;l carry out a land risk assessment forslurry and manure;l manage your water margins.4. Don’t use pesticides, veterinarymedicines or chemicals unless there is anidentified need.5. Don’t allow the rainwater frompoultry buildings that are ventilated to theroof to discharge directly to a watercourse.4. Use buffer strips and other measuresto reduce surface run-off from fields.5. Carefully plan all storage andhandling arrangements for livestockslurries and manures, animal feedstuffs,silage effluent, agricultural fuel oil, dirtywater, fertilisers, veterinary medicines,chemicals and pesticides at your farm.6. Don’t directly overspray awatercourse when using pesticides.7. Don’t hesitate to get involved incatchment partnerships to address diffuseagricultural pollution.8. Don’t forget that over-abstraction ofirrigation water from watercourses cancause downstream water pollution.6. Maintain a suitable distance from anywatercourse including ditches (e.g. 10m) ordrinking water supplies (e.g. 50m),especially when handling or applyingfertilisers, organic wastes, pesticides orother chemicals.7. Think about ways to protect andenhance your local environment, andhow to minimise the impacts of diffuseagricultural pollution of water, land and air.8. Account for every input, especially ofnutrients, pesticides and other chemicalsthrough careful planning.52

2 DIFFUSE AGRICULTURAL POLLUTIONDOs (cont.)9. Ensure that any biobed, reedbed,wetland or infiltration system installed toreduce the risk of diffuse pollution isdiscussed with SEPA before it is constructed.10. Obtain specialist advice whenconsidering using wetlands, ponds orinfiltration systems to treat contaminatedroof or dirty yard run-off at the farmsteading.11. Adopt “good housekeeping” andwaste minimisation practices that aim toprevent pollution at source.12. Minimise the area of farmyard androads over which animals can excrete andover which equipment transporting slurryis moved. Take steps to control the run-offfrom these areas.13. Ensure sprayer operators are fullytrained and posses certificates ofcompetence and that sprayers are properlymaintained and regularly tested.What is diffuseagricultural pollution?with farming practices and which can harmthe environment.2.1 For the purposes of this Code, diffuseagricultural pollution is contamination ofthe soil, air and water environmentsresulting from farming activities. Thispollution tends to arise over a widegeographical area and is dependent onwhat happens on the surface of the land.Although individually minor, such pollutionon a catchment scale can be significant,considering the cumulative effect whichthese separate discharges can have on theenvironment. Activities such as ploughing,seedbed preparation, crop spraying,fertiliser spreading and applying slurry mayall contribute to diffuse pollution. Run-offfrom farm roads and yards, the surface offields and dusty roofs after rainfall are allpotential sources of pollution. There istherefore a wide range of potential diffusepollution sources which are associatedWhy is it important?2.2 Maintaining a high qualityenvironment in Scotland is essential formarketing high quality agriculturalproducts. This link is one of Scotland’sstrengths and should be at the heart ofevery successful farming business.2.3 Water quality in Scotland is generallygood, and adherence to good agriculturalpractice is on the increase. Nevertheless,there are areas of concern. SEPA considersthat diffuse agricultural pollution is now themost significant cause of poor river qualityin certain parts of Scotland and that it willcontinue to be unless appropriate action istaken at individual farm and catchmentlevel to turn the situation around.6

2 DIFFUSE AGRICULTURAL POLLUTIONalso affect groundwater or large waterbodies, especially lochs which have lowlevels of plant nutrients naturally.2.4 Losses of nutrients or agrochemicalsto land or water represent not only afinancial loss to farming but can alsodamage the environment. By applyingthese inputs in the right amounts and atthe right time both farmers and theenvironment can benefit. Excess nutrients,such as nitrogen and phosphorus, canharm soils, rivers, lochs and estuaries bycausing algal blooms and by changing thenatural balance of plants, insects and otherlife. In the wrong place, pesticides can killriver insects and fish and can remain inriver sediments for many years. Run-offfrom dirty yards, roads and grazing fieldsor land that has been spread with livestockslurries can also contribute to the bacterialcontamination of inland and coastal watersand the failure of environmental qualitystandards. Fellow farmers downstream mayexperience poor quality water or incurextra expense in dealing with the effects ofdiffuse pollution including the possibility ofdisease transmission. In addition,groundwater (i.e. water held below thesurface of the land; an important source ofdrinking water in rural areas) can be put atrisk as a result of the leaching orpercolation of nutrients and pesticidesfrom the surface of the land. Groundwateris also important in maintaining river flowand for other aquatic environments. If itbecomes polluted, surface waters are alsoat risk.2.6 Measures to reduce the risk ofpollution at the farm steading (forexample, improved collection and storageof silage effluent, slurry, fuel oil andpesticides) have successfully reduced therisk of direct discharges to rivers. Attentionis now increasingly being focused on theactivities being carried out in the fields.What legislation must becomplied with?2.7 The Water Framework Directive wasagreed in December 2000 and acomprehensive and co-ordinatedprogramme has begun to be implementedto protect and improve the waterenvironment in Scotland. This Directivedovetails with the requirements of thoseDirectives that are not repealed by it, suchas the EC Nitrates Directive. The Directivewas transposed into Scottish primarylegislation through the Water Environmentand Water Services (Scotland) Act 2003.Secondary legislation, the WaterEnvironment (Controlled Activities)(Scotland) Regulations, is being developedunder this Act to give effect to the range ofcontrols necessary to protect the waterenvironment.2.8 The new regime will be underpinnedby a participative river basin managementplanning process, under which the fullrange of potential threats to the aquaticenvironment will be considered. A seriesof risk-based controls will be graduallyintroduced during 2006 and 2007 whichwill address diffuse pollution; point-sourcepollution; abstraction; impoundment andriver engineering. Many of the standardsthat farmers will be expected to followwill be based on existing Codes, such asthis PEPFAA Code, and on recognisedgood practice.2.5 The total effect of a number ofindividually minor sources ofcontamination can be highly significantover an entire catchment area. If thesources of water for a river arepredominately contaminated, then thewhole river is likely to be polluted. Smallwatercourses, with little dilution, are morelikely to be adversely affected by diffusepollution than larger rivers. Overabstraction of irrigation water fromwatercourses can exacerbate this problemby lessening the potential for dilution.However, diffuse sources of nutrients can7

2 DIFFUSE AGRICULTURAL POLLUTIONWhat types of diffuseagricultural pollutants are there?Pesticides, sheep dips andother toxic chemicals2.9 Diffuse agricultural pollution isprincipally associated with:lsoil particles;lpesticides and other potentially toxicchemicals, including veterinarymedicines;lnutrients, principally nitrogen andphosphorus;lpathogens, for example, bacteria fromlivestock slurries and manures spreadon land and run-off associated withintensive grazing practices;lgases such as ammonia.2.12 Pesticides can exert damaging effectson river habitats and water resources.Should pesticides be required, seekspecialist advice on the options that areavailable. Once it is determined that apesticide is to be applied, the labelrecommendations must be followed. Theadoption of Crop Protection ManagementPlans (CPMPs) or precision farming canassist in optimising inputs and minimisingrisks.2.13 If poorly managed or controlled,pesticides in tank rinse waters from thecleaning of protective clothing, or fromresidues in bags or containers, can causepollution. Due to the particular risks thatarise during pesticide handling andwashdown operations, considerationshould be given to the installation of apurpose-built or specially designed areathat drains to, or that is situated directlyover, a biobed. Guidance on the design ofsuch areas is available from the CropProtection Association (CPA) under “TheVoluntary Initiative” (VI).Soil particles2.10 Soil is effectively a non-renewableresource due to the time it takes to beformed. It should therefore be protectedfrom damage or loss in order to sustainagricultural production, as well as for thelife it supports in itself. In addition, soil andwater quality are very closely linked.Eroded soil from grazed or cultivated land,muddy run-off from farm roads or yardsand via field drains can causeenvironmental problems such asdestroying gravel riffles on the bed ofwatercourses. These riffles are an essentialhabitat requirement for many aquaticinsects and provide spawning areas for fish.2.14 It is also essential to avoid sprayingpesticides in conditions or circumstanceswhere drift can occur. Buffer strips orunsprayed headlands should be consideredprior to spraying fields bordered bywatercourses or ditches. Farmers andcontractors should never directly overspraywatercourses. Farmers must carry out a“Local Environmental Risk Assessment forPesticides” (LERAP) if they want to reducethe 5m aquatic buffer strip. This isdependent upon:lthe size of the watercourse borderingthe land being sprayed (in respect ofhorizontal boom sprayers);lthe pesticide being applied usingcertain nozzle types and/or reduceddoses; andlwhether the product qualifies for theLERAP scheme.2.11 Soil particles are also importantbecause they can carry more seriouspollutants. For example, some pesticidesbind firmly onto soil particles and aretherefore liable to contaminatewatercourses when soil is lost from fields.Similarly, mud on farmyards and roads maycarry oily residues. Phosphorus can be lostfrom farmland to water and can causepollution. In excess, certain trace elementstransported with the soil can also damagethe aquatic environment. It should also beremembered that erosion very ofteninvolves the loss of the most fertile soilfrom a field.8

2 DIFFUSE AGRICULTURAL POLLUTIONmust be taken and statutory obligationscomplied with. Analysis of the waste beforeuse, assessing the land suitability prior tospreading, calculation of the growing croprequirements, soil sampling and nutrientbudgeting can all reduce the risk of diffuseagricultural pollution occurring. The wasteproducer or their contractor may carry outsome, or all, of this work for farmers.Anyone wishing to apply industrial wastesto agricultural land must demonstrate inadvance, and to SEPA’s satisfaction, thatsuch an application will result in benefit toagricultural or ecological improvement.Note that the statutory controls on theapplication of sewage sludge to agriculturalland must be complied with to be eligiblefor the Single Farm Payment.2.15 A very wide range of chemicalcompounds are used as pesticides andeach of these interacts with soils and waterdifferently. Some will move through soilquite easily and enter groundwater. Suchwater may then be abstracted for use inpublic or private drinking water supply, orin food processing etc. Once present ingroundwater, pesticides can be present formany years and are very costly to remove.It is therefore important that suchchemicals are prevented from enteringgroundwater in the first place.2.16 The chemicals used in sheep dip arealso highly toxic, and can have potentiallydevastating effects on aquatic life over largedistances. They can also pollutegroundwaters. Each aspect of the dippingoperation must be planned in advance, allpossible pollution risks must be identifiedand action must be taken to minimisethese risks as far as possible. Farmersshould take note of the guidance on goodsheep flock management given in section 8of this Code. Staff should be suitablytrained in the correct use of dips anddipping practice. SEERAD has issuedguidance for those involved in dippingsheep, in the form of “The Sheep DippingCode of Practice for Scottish Farmers,Crofters and Contractors” under theGroundwater Regulations 1998 (availablefrom SEERAD and also via the ScottishExecutive’s website). Waste sheep dipdisposal may only be undertaken inaccordance with an authorisation issued bySEPA. It is also possible for dip to bedisposed of off farm, through a licensedwaste contractor. Note that theGroundwater Regulations 1998 must becomplied with to be eligible for the SingleFarm Payment.2.18 Particular risks may arise whenorganic wastes are injected into drainedland, especially over gravel backfill.Nutrients2.19 If leached in excessive amounts,nutrients such as nitrogen (N) andphosphorus (P) can cause severe problemsfor rivers, lochs, estuaries and coastalwaters by, for instance, contributing to thedevelopment of toxic algal blooms or foulsmelling mats of algae on our coastline.Nutrients can be lost from manures andslurries as well as from other organicwastes spread on land, and significantlosses can also be associated with fertilisersand soil. Advice must be tailored to theparticular farm and catchment area inorder to prevent such losses and reducethe risk of pollution.2.20 Nitrogen-based fertilisers are used insignificant amounts in both arable andlivestock farming. Water passing throughthe soil dissolves salts, nutrients andorganic substances. When these materialsare carried out of root range by waterdraining through the soil, they are said tohave “leached”. Nitrate (from inorganicnitrogen fertilisers or derived from organic2.17 Sewage sludge or industrial wastescan contain potentially toxic substancessuch as heavy metals and persistentorganic chemicals which may contaminatesoil and pollute rivers. Certain precautions9

2 DIFFUSE AGRICULTURAL POLLUTIONmanures) is leached especially rapidlybecause it is very soluble. This isparticularly the case during rainfall ifnitrogen fertiliser has been over-appliedand the soils themselves are free draining.In areas where there are sandy soilsoverlying permeable rocks, there areparticular risks of nitrate leaching intogroundwater.the health of your fellow farmers’ livestockdownstream if they drink thiscontaminated water. Wherever possible,install water troughs and fence offwatercourses to eliminate this problem. Itis essential to ensure that public andprivate drinking water supplies areprotected from grazing animals andlandspreading activities.2.21 The key to preventing diffusepollution by nitrate is to ensure that allinputs are carefully accounted for and thatany applications are made to meet therequirements of the growing crop. Farmersin the Nitrate Vulnerable Zones (NVZs) areobliged to comply with an ActionProgramme, including limits on nutrientapplications, adherence to closed periodsand record keeping. These requirementsmust also be complied with to be eligiblefor the Single Farm Payment.2.25 Field middens must also be sited atleast 10 metres from a watercourse and notwhere they can contaminate field drains.2.22 Soil erosion is usually the majorcontributory factor to losses of phosphorus(P) to freshwater. Phosphorus can alsoreach rivers as dissolved P from field drainsand as suspended solids in some soils. It isimportant therefore not to allow soils tobecome excessively high in this nutrient.Soil sampling is recommended to assess Plevels prior to determining the applicationrate of fertilisers and manures.Manures and slurries2.23 Livestock slurries and manures, andother organic wastes, are valuable materialsfor improving soil fertility and can save onfertiliser costs. However, they are highlypolluting if spread at the wrong time or inthe wrong place. They can also beassociated with the microbiologicalcontamination of rivers and groundwater ifinsufficient precautions are taken.2.26 The area of farmyard and roads overwhich animals can excrete, and equipmentoperates to transport slurry, should beminimised.2.27 In vulnerable locations, the drainagefrom stored manures and slurries or theseepage from housed livestock units canbe highly polluting to surface andgroundwaters.2.24 Adverse effects can also arise fromallowing livestock access to watercoursesby direct excretion and damage toriverbanks by poaching. This could affect10

2 DIFFUSE AGRICULTURAL POLLUTION2.28 Apart from the nutrient content andhigh organic loading, the possibility ofmicrobiological contamination can threatenrivers, bathing waters and individualgroundwater sources and affect compliancewith environmental quality standards oftenassociated with EC Directives.forms of plant life to produce anundesirable disturbance to the balance oforganisms present in the water and to thequality of the water concerned”). Rainwaterfrom poultry buildings that are ventilatedto the roof should never be allowed todischarge directly to a watercourse (due tothe deposition of dust, feed residues andanimal/bird excreta).2.29 To address all of the pollution risksassociated with manures, slurries andgrazing animals, it is essential to follow theguidance in “The 4 Point Plan”, theindividual components of which are:lminimising dirty water around thesteading;lbetter nutrient use;la risk assessment for manure andslurry; andlmanaging water margins.2.33 Once emissions to air have beenprevented, for example by covering a slurrystore (if safe and practicable), it is essentialthat effective use is then made of theincreased nutrient content of the slurrywithout increasing the risk to rivers andgroundwater from application to land.Intensive pig and poultry installationsexceeding the thresholds in the PollutionPrevention and Control (Scotland)Regulations 2000 as amended (the PPCRegulations) will require a permit from SEPA.2.30 Guidance on “The 4 Point Plan” isavailable from the existing farm advisorynetwork and copies are available free fromSEERAD Area Offices (see Annex A).Treatment systems2.34 Normally, the practices described inthis section should be sufficient to preventor at least minimise the risk of diffuseagricultural pollution. In some cases,however, it may be necessary to considerthe installation of some form of treatmentsystem near the source of potentialpollution. It may be possible, for example,to install a wetland, pond or infiltrationsystem to deal with contaminated roof ordirty yard run-off at the farm steading.Specialist advice should be sought on the

preventing pollution of water, relevant sections have a statutory base under Section 51(1) of the Control of Pollution Act 1974 (as amended). This means that although contravention of this Code does not in itself give rise to any criminal or civil liability, it may be taken into account in any legal proceeding involving a water pollution .