Maataloustieteellinen Aikakauskirja Vol. 59:57—62, 1987
Gaseous
health hazardsin livestock confinement buildings
JUHANI KANGAS, KYÖSTILOUHELAINEN and KAJ HUSMAN Kuopio Regional Institute
of
OccupationalHealth, P.O. Box 93 SF-70701 KUOPIO (Finland)Abstract. Gas concentrations weremeasuredon 16farms (eight cattle farms, five piggeries, three poultry yards) mainly during wintertime. The gases wereammonia,carbondioxide, methane,hydrogen sulfide, methylmercaptanand other sulfides.
Themeanconcentrations of ammonia varied between 8 —43cmVm3in the air of live- stock building.Inthe poultry yards the meanconcentration of ammoniawashighest; itwas lowerinpiggeriesand especiallyincowhouses. Carbon dioxide concentrationswere500—3500 cmVm3in cowhouses, 1000—4000 cm3/m3inhoghousesand600—4000cmVm3inpoultry yards.
Verylow concentrations of methane and sulfur compoundswerefound inthe livestockcon- finement buildings.
Itis obviousthatinnormal working situations only ammonia of the measured gasesex- ceeds the threshold limit value (25 cmVm3 ).High ammonia concentrations can be expected in the floortypepoultryconfinement buildings especially whenmanureis left onthe floor for several months.Insuchcaseseffective mechanical ventilation is the only way to keep the ammonia level acceptable.
Index words: farmers’gas exposure,ammonia,gases in livestock confinement buildings.
Introduction
Ammonia and hydrogen sulfide have been suspectedtobeanoccupational health hazard for farm workers in livestock confinement buildings. These gases have been identi- fied among the maincomponents of malodor- ous gases from swine and poultry manure (Spoelstra 1980). There is, however, little in- formationonoccupational hygienemeasure-
ments of gas concentrations in different live- stock buildings.
Ammonia, hydrogensulfide,carbon diox- ide and carbon monoxide were measured in swine producing farmsbyDonham and others (Donham & Popendorf 1985). They found that ammoniamost commonly exceeded the TLV (threshold limit value). According to theirmeasurementsother gases donotpresent an acute health hazard in normal situations.
JOURNAL OFAGRICULTURAL SCIENCEIN FINLAND
In the work of Batel (Batel 1975), ammonia was found toreach higher concentrations in piggeries than incowhouses. Ammoniacon- centrationswereI —3o cmVm3in normal barn farms and o—l20—12 cmVm3 in loose barn farms in Finland and themeanconcentrations of dif- ferentfarmswere4—9cmVm3 and I—91—9 cmVm3 respectively (Anon 1975, Karhunen et al.
1979).
Jonesetal. found ammonia levels of about 25 cmVm3in active workareasof poultrycon- finement buildings, but the levels could be much higher in areas with poor ventilation (Jones etal. 1984).
Ina turkey house ammoniawas found to be between 40 —50 cmVm3,when the ventila- tion functions properly (Aschbacher 1973).
In anormal work situation, theconcentration of hydrogen sulfide islow, but may rapidly reach toxic levels ifmanureis agitated (Don-
hametal. 1977, Donham etal. 1982, Osborn
& Crapo 1981) or the ventilation is off
(Aschbacher 1973).
The objective of this studywastomeasure concentrations ofammonia, methane, carbon dioxide and sulfur compounds in Finnish livestock confinement buildings.
Materials and methods
Concentrations of gaseswere measuredon 16farms (8 dairy cattlehouses,5 piggeries and 3 poultry yards) mainly during wintertime. In one piggery and in three poultry yards am- monia was measured also during summer.
Three of the piggeries had fattening pigs and twohad both fattening pigs and sows. Two of the poultry houseswerecooptypeunits and one was afloor poultry yard. Seven livestock confinement buildings had mechanical venti- lation withanexhaust volume of 800to8500 mVh during measurements. In farms with naturalventilation, the exhaust air volume varied from900to2300 m3/h duringmeasure- ments.
The outdoor temperature varied during measurementsfrom +2°Cto—2O°C in win- ter, and from +lo° to +2O°C in summer.
With the exception of carbondioxide, the gases were measured mainly by stationary sampling method with sampling time from 0.5 hto 2 hours.
Ammonia samples were collected into im- pinger flasks containing 10 ml of 0.1 M sul- furic acid.Ammonium ionwasdetected with an ion selective electrode (Orion Research).
The detection limitwas0.01 cmVm3. Methane sampleswerecollected in41 laminated plastic bags and analyzed with agaschromatograph (Hewlett Packard
5370
A) equipped with a flame ionization detector. The column was packed with Carbowax20M, with pure nitro- gen (40 ml/min)asthe carrier gas and column temperature 60°C. The detection limit for methane was 1.0 cmVm3.Hydrogen sulfide was collected into im- pinger flasks containing 30 ml of 0.02 M CdS04 solution. Collected hydrogen sulfide was determined by methylene blue method (Jacobs, 1967). The detection limit for hy- drogen sulfide was 0.01 cmVm3.
On each farm, air samples were collected into a4 1 plastic laminated bag in order to analyze theconcentrationof the principal sul- fur compounds. The stability of samples in plastic laminated bags has been tested earlier (Kangas etai. 1986).
The samples in the bagswereinjected into agaschromatograph (Analytical Instruments Development, Model 621 —l9) equipped with a flame photometric detector. A Teflon columnwasused packed with Chromosorb T 60/80 coated witha mixture of polyphenyl- ether and orthophosphoric acid. The oven temperature was60°C,andanoptimum flame in the detectorwas achieved by purging with hydrogen (55 1/min) and air (85 1/min). Pure nitrogen servedasthe carried gas (20 1/min).
This procedure yielded a good separation of the principal sulfur compounds with detection limits for hydrogen sulfideat0.005 cmVm3,
for methyl mercaptan at 0.005 cmVm3, for dimethyl sulfide at 0.03 cmVm3 and for dimethyl disulfideat 0.05 cmVm3 .
Standards were prepared by permeation tube technique. The permeation rates of the
standard gases aredependenton the ambient temperature. The permeation tube is placed inathermostaticchamberand the permeated gas is diluted withnitrogen. By altering the carrier gas flow andtemperature, the standard gas concentrations canbe changed.
Carbon dioxidewasdetermined by Draeger indicator tubes with Draeger hand pump (Drä- gerwerk AG Liibeck).
Results
Withoneexception, the ammoniaconcen- trations in cow houses were below the TLV (25 cmVm3). In piggeries and especially in poultry yards, the ammonia concentrations occasionally reached very high levels (Table 1). Inone piggery and in three poultry yards ammonia levels were measured during both winter and summer.Duringsummerthecon- centration of ammoniawas three times high- erthan in wintertime. In poultry yards theam- monia level in ambient airwas lower insum- mer than in winter.
The exposure of farmers to hydrogen sul- fideonFinnish farmswas found tobe mini- mal normal working situations (Table 2).
When manure was agitated, hydrogen sulfide wasliberated and concentrations rising to27 cmVm3were measured. Organic sulfurcom- pounds (methylmercaptan, dimethyl sulfide and dimethyl disulfide) in ambient air remain- ed under the respective detection limit of the method used for analysis. Methaneconcen- trationswerehighestoncattlefarms,35—290 cmVm3 and lower in piggeries and poultry yards (Table 2). The concentration of carbon
Table 1. Ammonia concentrationsin cowhouses,pig- geriesand poultry yards, cmVm1.
cow piggeries poultry yards
houses ; ;
winter summer winter summer winter
mean 7.8 17.8 35.8 38.0 43.0
SD 6.6 11.2 16.0 33.0 13.0
min 0.2 4.7 16.4 3.0 23.7
max 35.0 34.6 57.4 138 67.2
N 50 42 4 33 8
Table 2. Concentrations of hydrogen sulfide (H2S), methane (CH4 )and carbon dioxide (CO2) in cow houses, piggeries and poultry yards, cmVm3.
cow piggeries poultry
houses yards
mean 0.4 0.02 0.5
SD 0.8 0.01 0.3
H2S min 0.01 0.01 0.3
max 2.9 0.02 1.2
N 11 10 5
mean 170 12 3
SD 75 9
CH4 min 35 5 3
max 290 30 3
N 8 6 3
mean 1520 2000 1900
SD 850 920 910
C02 min 500 1000 600
max 3500 4000 4000
dioxidewassimiliar in differenttypesof build- ings and all resultswerebelow the TLV (5000 cmVm3)(Table 2).
Discussion
Ammonia is formed through the hydrolysis of urea (Spoelstra 1980). Our results con- firm earlier findings that ammonia is themost abundant gas in active areas of thelivestock confinement buildings when comparedtotheir threshold limit values. Especially in floor poultry yards high ammonia concentrations weremeasured during wintertime(maximum
138 cmVm3 ).The reasons for these high am- monia levelswerethat manure is kepton the floor for several months during wintertime and therewas no mechanical ventilation in these poultry yards, and the inlet ducts were tightly closed in orderto maintain the airtem- perature comfortable for the hens.
Mechanical ventilation is neededto lower the ammonia concentration in poultry yards.
Thiswasnoted during the summerwhen lower concentrations of ammonia were measured while doors and windows were kept open, even though the microbial hydrolysis ofurea into ammonia ismoreactiveduring thewarm
season. The influence of the outdoor tem- perature onthe hydrolysis of urea was seen in theresults of ammoniameasurements in piggeries with mechanical ventilation. In win- tertime the concentration of ammonia was lower than insummer. The difference in the ammonia concentrations between the floor and cooptypepoultry yards noted during win- tertimewas not noted in summer. This was probably due tothe more effective natural ventilation in summer.
The high level of ammonia in poultrycon- finement buildings might be lowered by using somegasabsorbing material such as a litter;
for example peat could be effective for this purpose. The observed concentrations ofam- monia in the poultry confinement buildings are so high that irritation of the eyes and mucous membranesare expected among the exposed farmers. According to our earlier measurementsthe piggeries and poultry yards were very dusty workplaces (Louhelainen etal. in press). Ammonia may also adsorbto the dust particles, and by thiswayreach high local concentrationsatthe depositionareasof the farmers’ lungs. This might partly explain the observed high prevalence of chronic bron- chitis among Finnishfarmers (Terho etai. in press).
Methane reached highest concentrations in the dairy houses (35 —290 cmVm3). In pig- geries and in poultry confinement buildingswe measured clearly lower levels. In the nearly anaerobicconditions ofcow rumen carbohy- drate is fermented almost entire by into fatty acids and methane. This ismostprobably the mainsource of methane incow houses (Kay 1983). In general, methane is the final product ofmicrobial degradation of organic material.
Methane in poultry yards and piggeries origi- natesfrom this source(Stevens&Cornforth
1974).However, methane concentrationsare at such a low level that they donot provide anoccupational healthorsafety hazardtothe farmers in their active working areas.
Sulfur compounds are formed from the microbial degradation of sulfate-containing material in themanure. Sulfate-reducing bac- teria produce mainly hydrogen sulfide but also other malodorous sulfur gases (mercaptans) can be foundas aresult of reduction of sul- fur compounds inwastes(Hatchikian 1976).
We detected only hydrogen sulfide in the live- stock confinement buildings andthe concen- trationwaslow. Wecanconclude that during normal working situations (no agitation of the manure) there is norisk of excessive hydro- gen sulfide exposure on the Finnish farms.
The situation is quite different when thecon- tainer of the liquidmanureis pumped dry and thefarmerhastoworknearthe pitorthe slur- ry tank (Donham etal. 1977,Donham etal.
1982, Osborn & Crapo 1981).
Carbon dioxide is one of the main com- ponents of the breathing gases of the animals but it is also formed by microbial degradation of carbonaceous material (Stevens & Corn-
forth 1974). The level of carbon dioxidere- mained below TLV in allmeasurements. It has often been mentionedtobeanindicator of in- door air quality. According to our measure- ments, therewas no correlation betweencar- bon dioxide and ammoniaormethane. How- ever, this would need further investigation focusing mainly on thecorrelation between the carbon dioxiode concentration and the ventilation in the livestock building. We believe that the concentration of carbon dioxide could bearough indicator of the ef- ficiency of ventilation in livestock confine- ment buildings.
References
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tiedote 24/75, Vakola, Helsinki. 23: 267—272.
Aschbacher, P.W. 1973. Airpollutionresearch needs: Batel, W. 1975.Messungenzur Staub-, und Geruschs-
belastunganArbeitsplätzeninder Landvirtschaflichen Produktion und WegezurEntlastung Ertster Bericht.
GrundlagenLandlechnik Bd 25: 135—157.
Donham, K.J.&Popendorf,W.J. 1985.Ambient levels of selected gases inside swine confinement buildings.
Am. Ind. Hyg. Assoc. J. 46: 658 —661.
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Donham, K.J., Rubins, M., Thedell, T.D.,Kannermeyer, J. 1977.Potential health hazards to agricultural workers in swine confinement buildings. J. Occup. Med. 19:
383—387.
Hatchikian,E.C., Chaigneau,M.andLeGall J. 1976.
Analysisof gas production by growing cultures of three speciesof sulfate-reducingbacteria. In: H.G. Schlegel, G. Gottschalkand N.Pfennig(Eds.), Microbial Pro- duction and Utilization of Gases.E.Goltze, K.G. Got- tingen, 109—118.
Jacobs,M.B. 1967.The analytical toxicology of indus- trial inorganic poisons pp. 545 —548. Interscience Publishers John Wiley&Sons, New York (Sydney) London.
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&Hickey, J. 1984. Environmental study of poultry
confinement buildings.Am. Ind. Hyg. Assoc. J.45:
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pumpingstations. The Sci Total Environ. 57: 49 —55.
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Msreceived March 2, 1987
SELOSTUS
Kaasumaiset ilman epäpuhtaudet tuotantorakennuksissa
Juhani Kangas, Kyösti Louhelainen, Kaj Husman
Kuopion aluetyöterveyslaitos, PL 93, 70701Kuopio
Tutkimuksessa mitattiin ilman kaasupitoisuuksia 16 maatilalla (kahdeksan navettaa, viisi sikalaa jakolme ka- nalaa) pääasiassa talviaikaan.Kaasutolivat ammoniak- ki, hiilidioksidi, metaani,rikkivety, metyylimerkaptaani jasulfidit.
Työsuojeluhallituksen antamat 8 tunnin HTP-arvot (haitalliseksi tunnetut pitoisuudet) eri kaasuille ovat:am- moniakki25 cmVm’,rikkivety 10cmVm',metyylimer- kaptaani0,5cmVmJjahiilidoksidi5000cmVm1 .Metaa- nille ja muille rikkiyhdisteille tällaisia arvoja ei ole.
Keskimääräiset ammoniakkipitoisuudet olivat navetois- sa7,8cmVm1(vaihtelu0,2—35cmVm'), sikaloissa 17,8 cmVm1(4,7—34,6 cmVm1)jakanaloissa 38,0 cmVm1 (3,0—138cmVm!)talvella. Kesällä tehdyissä mittauksissa yhdessä sikalassa ammoniakkia oli keskimäärin 35,8 cmVm' (16,4—57,4cmVm1 )jakolmessa kanalassa 43,0 cmVmJ(23,7—67,2 cmVm!).
Rikkivetypitoisuudet olivat alhaisetkaikissatuotanto- rakennuksissa normaalin työnaikana. Sekoitettaessa lie- telantaa lantakourussa rikkivetypitoisuus nousi 27
cmVm3 . Muiden rikkiyhdisteiden (metyylimerkaptaani, dimetyylisulfidi ja dimetyylidisulfidi)olivat alle analyy- silaitteen määritysrajan (alle0,05cmVm3). Metaanipitoi- suudet olivat alhaiset ja niiden työhygieeninen merkitys vähäinen.
Hiilidioksidipitoisuudetolivat navetoissa 500—3500 cmVm1 ja kanaloissa cmVm3, sikaloissa
600—4000cmVm1.
1000—4000
Tutkimustulosten mukaan ammoniakkionmitatuista kaasuista haitallisin kotieläinrakennuksissa. Suurimmat pitoisuudet(maksimi 138cmVm1) mitattiin lattiakana- loissa talvella. Syinä korkeaan ammoniakkipitoisuuteen ovat mm. lattialla oleva lanta ja vähäinen ilmanvaihto- määrä. Muiden kaasujen pitoisuudet olivat alle HTP- arvojen.
