Korean Journal of Environmental Agriculture Korean J Environ Agric. 2015;34(2):91-97. Korean Online ISSN: 2233-4173 Published online 2015 June 26. http://dx.doi.org/10.5338/kjea.2015.34.2.17 Print ISSN: 1225-3537 Research Article Open Access 유기성폐기물과밭토양에대한붉은줄지렁이와밭지렁이의섭식전후의분변토발생량및오염물질의함량변화 나영은 * 농촌진흥청연구운영과기후변화팀 Change of Cast Amount and Pollutant Contents before and after the Eating of the Organic Waste and Upland Soil with Earthworms, Eisenia andrei and Amynthas agrestis Young-Eun Na* (Climate Change Team, R&D Coordination Division, Rural Development Administration, Jeonju, 560-500, Korea) Received: 25 May 2015 / Revised: 5 June 2015/ Accepted: 23 June 2015 Copyright c 2015 The Korean Society of Environmental Agriculture This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract BACKGROUND: Earthworms are essential detritus feeders that play a vital role in the process of decomposition of organic matter and soil metabolism. The complex process of partial breakdown of organic matter and mixing with mucous and gut microbial flora in the form of earthworm cast results in the reduction of the toxicity. This study focused on the change of cast amount and pollutant contents before and after the eating of the organic waste and upland soil with the two species of earthworm. METHODS AND RESULTS: The two species of earthworms were compared to the cast production. In the upland soil material, the daily amount of worm s cast was 1.42 g in E. andrei and 0.40 g in A. agrestis. In the organic waste material, the cast of E. andrei was 0.78~0.83 g and the cast of A. agrestis. have not been collected because all earthworms died after the treatment. The heavy metals treated in the upland soil were evaluated the impact of the worm excretion. With the E. andrei, the cast production was decreased 0.1~0.8 times in zinc, 0.2~0.5 times in copper, *Corresponding author: Young-Eun Na Phone: +82 63 238 0756; Fax: +82 63 238 3823; E-mail: youngman99@korea.kr and 0.1~0.7 times in cadmium compared to the control treatment according to the levels of concentration. With A. agrestis, the cast amount was decreased 0.3~1.1 times in zinc, 0.2~0.3 times in copper, and 0.1~2.1 times in cadmium, respectively. The changes of pollutant contents before and after the eating of the organic wastes with E. andrei were studied. In the treatment of the Alcohol Fermentation Processing Sludge and the Fruit Juice Processing Sludge, heavy metal content of the cast was increased 0.7~53.3% compared to the sludge materials. PAHs contents were decreased 50.1% in the cast of the Alcohol Fermentation Processing Sludge and 36.6% in the cast of the Fruit Juice Processing Sludge, respectively. CONCLUSION: In conclusion, although the A. agrestis was bigger than E. andrei in size and weight, the cast amount of A. agrestis was small. The two species of earthworm was less excretion with high concentration of heavy metals. While the heavy metals such as zinc, copper, and cadmium were considerably accumulated in the cast, the total compounds, PAHs were fairly decomposed. There results would provide us for restoring contaminated soil and cleaning organic wastes. Key words: Earthworm, Heavy metals, Organic waste, PAHs, Soil 91
92 Na Fig. 1. Earthworm species; Anynthas agrestis (top), Eisenia andrei (bottom). Table 1. Chemical properties of the upland soil ph (1:5) O.M (g kg -1 ) Av.P 2O 5 Cations (cmol kg -1 ) Heavy metals Ca Mg K Zn Cu Cd Texture 5.60 10 16.87 0.59 0.12 0.12 0.22 0.24 ND Sandy Loam 서론농업생태계내에서유해한오염물질의유입증가는국민건강과관련하여사회적문제로대두되고있으며농산물안전성에관련된여러국제기구에서도각종오염물질에대한규제기준을강화하고있는추세이다 (Holmgren et al., 1993; Smith, 1996; Vulava et al., 1997). 유기성폐기물의재활용에대한연구는 1970년대이전까지주로인축분뇨를대상으로작물의영양원과토양개량제로서의가치를평가하고적정사용기준을설정하였고그후 1980 년대의화학비료남용에따른토양비옥도저하문제가대두되고토양유기물의중요성이부각되어유기성폐기물의농업적활용에다한관심이커지면서유기성폐기물시용에따른토양환경변화를평가하기위한연구가활발하게수행되었다. 1990년대이후부터는폐기물의처리가사회문제화되어폐기물처리개념에서퇴비화가정책적으로장려되었다 (Lerch et al., 1990; Hernandez et al., 1997; Dar, 1997; Elsgaard et al., 2001; Petersen, 2001). 유기성폐기물은생산품의종류와제조공정등에따라중금속변이가크고함량이높아농경지에사용하는데제약요인이되는것으로보고되었다 (Smith et al., 1998). 이런문제를해결하기위하여지렁이사육을통한슬러지및오염물질을처리하는동시에지렁이도양식할수있는서로상호보완될수있는 Vermicomposting이라는개념이도입되는계기가마련되었다. 그러나지렁이종류에따른분변토량의차이, 중금속이지렁이에미치는영향, 지렁이활동에의한오염물질의변화특성을대한연구보고는부족한실정이다. 따라서밭토양과유기성폐기물에서지렁이의분변토발생량및오염물질 ( 중금속, PAHs) 의변화특성을밝히고자하였다. 재료및방법지렁이종류실험에사용된지렁이는 2종류이다 (Fig. 1). 낚시지렁이과 (Lumbricidae) 에속하는붉은줄지렁이 (Eisenia andrei) 와지렁이과 (Megascolecidae) 에속하는밭지렁이 (Amyntha agrestis) 이다. 이 2종류의지렁이는생태형과크기가아주달라서대표종으로선정했다. 붉은줄지렁이는주로퇴비더미와토양표층에서서식하는 10 cm 정도의크기인반면에밭지렁이는토양심층에서서식하는 25 cm 정도의크기이다. 붉은줄지렁이는제지슬러지및하수오니슬러지를이용하여국립농업과학원지렁이양식장에서지렁이환대가있고체중이 300~600 mg인개체를선별하여실험에사용하였다. 밭지렁이는토종지렁이로써휴경지밭에서환대가있는 1,000~ 3,000 mg인개체를채집하여사용하였다. 채집된지렁이는 2 주동안항온실 (20±2 ) 에서적응시킨후에본실험에공시생물로사용하였다. 밭토양과유기성폐기물의특성밭토양은야산에있는토양시료를채취하여 2 mm 체로선별한후밭토양을분석하였다 (Table 1). ph, 유기물, 양이온, 중금속의함량이적었고, 토성은사양토였다. ph만조절하여사용하면지렁이가서식하고섭식하는데문제가없는것으로판단했다. 유기성폐기물은주정슬러지와과즙슬러지를각각국내공장에서채취하여분석하였다 (Table 2). 주정슬러지와과즙슬러지는지렁이가서식하고섭식하기에 ph, 유기물, 질소, 인산, 가리함량이적정범위였으나, 중금속은아연과구리의함량이많은것이특징이었다.
Change of Cast Amount and Pollutant Contents with Earthworm 93 Table 2. Chemical properties of the organic wastes Wastes ph OM T-N P 2O 5 K 2O Heavy metals (1:5) (g kg -1 ) (g kg -1 ) (g kg -1 ) (g kg -1 ) Zn Cu Cd Alcohol fermentation processing sludge 7.3 791 74.6 40.8 7.0 332.9 80.3 1.36 Fruit juice processing sludge 7.0 611 29.9 46.1 6.2 202.1 147.9 0.43 Table 3. Cast amount of earthworm species for 12 days in the upland soil Species Eisenia andrei Amyntha agrestis Replication Fresh wt. Total of cast amount for 12 days (g) per fresh wt. (g g -1 ) 1 0.33 5.91 0.49 1.48 2 0.29 3.96 0.33 1.14 3 0.33 4.50 0.38 1.14 4 0.28 5.25 0.44 1.56 5 0.44 9.02 0.75 1.71 mean±sd 0.33±0.06 5.73±1.98 0.48±0.17 1.41±0.26 1 0.88 2.63 0.22 0.25 2 0.85 2.29 0.19 0.22 3 0.79 4.19 0.35 0.44 4 0.29 2.16 0.18 0.62 5 0.99 5.49 0.46 0.46 mean±sd 0.76±0.27 3.4±1.44 0.28±0.12 0.40±0.16 분변토발생량및오염물질분석분변토의발생량및중금속이분변토발생에미치는영향을평가하기위하여밭토양 90% 에피트모스 10% 를혼합하여섞고, 증류수를부어토양수분함량이 50% 가되게만들었으며, ph는탄산칼슘 (CaCO 3) 을첨가하여 6.0±0.5 범위가되도록조절하여만들었다. 또한중금속함량에따라분변토발생량을조사하기위하여아연은 zinc nitrate(zn(no 3) 26H 2O), 구리는 copper nitrate(cu(no 3) 23H 2O), 카드뮴은 cadmium nitrate(cd(no 3) 24H 2O) 을시약으로구입하여밭토양에지렁이치사에영향없는무영향농도 (Spurgeon, 1994) 와무영향농도의 2, 4, 8배를감량하여밭토양과혼합한후지렁이 3마리를각각처리하였고, 자세한절차및실험방법은 Na(2000) 문헌을따라했다. 오염물질 ( 중금속, 유기화합물 ) 분석중금속은마이크로웨이브전처리장비 (Mars-X, CEM) 를이용하여시료 0.5 g을마이크로웨이브 vessel에취하여분해액인왕수 (HNO 3:HCl=1:3) 12 ml를가한다음미국 EPA -method 3051a법에근거한분해조건으로분해하였고, 분해된시료는초순수를가하여 50 ml로채워분석용시료로사용하였다. 수용성화학성분및중금속분석은폐기물공정시험법인용출시험법을응용하여증류수로침출한후여과하여분석용시료로사용하였다. PAHs 는 US EPA 의우선감시물질목록에포함된 14가지 PAHs (Naphthalene, Acenaphthene, Fluorine, Phenanthrene, Anthracene, Fluoranthene, Pyrene, Benzo(a)anthracene, Chrysene, Benzo(b)fluoroanthene, Benzo(k)fluoroanthene, Benzo(a)pyrene, Dibenzo(a,h)anthracene, Bbenzo(g,h,i) perylene) 를분석하였다. 시료 5 g을무수황산나트륨 20~50 g과혼합하여시료내수분이제거된상태에서원통여과지에넣고 Soxhlet에장착하여열판에서 16시간동안추출하였다. 이때사용된추출용매는 dichloromethane 200 ml이었다 (US EPA, 1994). 결과및고찰 지렁이종류에따른분변토발생량비교밭토양에서붉은줄지렁이한마리가하루에 0.33~0.75 g 의분변토를배설했고, 밭지렁이는 0.18~0.46 g의분변토를만들어냈다 (Table 3). 붉은줄지렁이생체무게 1 g에평균 1.41 g의분변토를만든반면에밭지렁이는 1 g에평균 0.40 g의분변토를만드는것으로분석되었다. 붉은줄지렁이는자기체중보다 1.40배많은분변토를만들었고, 밭지렁이는 0.4 배로적게분변토를만들었다. Choi(1992) 는붉은지렁이 (rumbricus rubellus) 의생체무게 1 g에 0.18 g의분변토가발생한다고보고했다. 이것은붉은줄지렁이보다 7.8배적고, 밭지렁이보다 2.2배적은분변토량이다. 이와같이분변토량이크게차이가나는것은지렁이종류와먹이가각각서로달랐기때문이라고판단된다. 유기성폐기물에서붉은줄지렁이한마리가하루에 0.25
94 Na Table 4. Cast amount of earthworm species for 12 days in the organic wastes Species Replication Fresh wt. Total of cast amount for 12 days (g) per fresh wt. (g g -1 ) Alcohol fermentation processing sludge Eisenia andrei 1 0.43 4.03 0.34 0.78 2 0.30 3.01 0.25 0.84 3 0.33 2.96 0.25 0.75 4 0.35 3.12 0.26 0.74 5 0.41 3.90 0.33 0.79 mean±sd 0.36±0.05 3.40±0.52 0.28±0.04 0.78±0.04 Fruit sewage sludge 1 0.35 3.80 0.32 0.90 2 0.46 4.32 0.36 0.78 3 0.36 3.54 0.30 0.82 4 0.31 3.09 0.26 0.83 5 0.40 3.94 0.33 0.82 mean±sd 0.38±0.06 3.74±0.46 0.31±0.04 0.83±0.04 Amyntha agrestis 0* *The casts have not been collected because all earthworms were died after the treatment. Table 5. Effect of earthworm s cast amount with levels of heavy metals in the upland soil Zn Cu Cd Species Levels of treatment. per fresh wt. (g g -1 ) Levels of treatment. per fresh wt. (g g -1 ) Levels of treatment. per fresh wt. (g g -1 ) 36.1 1.15±0.15 26.3 0.66±0.09 37.5 0.97±0.08 72.3 0.74±0.06 52.5 0.22±0.02 75.0 0.50±0.05 Eisenia andrei 144.5 0.59±0.12 105.0 0* 150.0 0.19±0.01 289.0 0.07±0.05 210.0 0* 300.0 0.05±0.03 Control 1.39±0.22 36.1 0.36±0.04 26.3 0.30±0.05 37.5 0.78±0.13 72.3 0.42±0.09 52.5 0.20±0.06 75.0 0.43±0.07 Amyntha agrestis 144.5 0.20±0.06 105.0 0* 150.0 0.02±0.02 289.0 0.13±0.04 210.0 0* 300.0 0* Control 0.38±0.12 *The casts have not been collected because all earthworms were died after the treatment. ~0.36 g의분변토를배설했고, 밭지렁이는모두죽어서분변토를얻지못했다 (Table 4). 붉은줄지렁이생체무게 1 g에주정슬러지분변토 0.78 g, 과즙슬러지분변토 0.83 g를각각만드는것으로분석되었다. 이는붉은줄지렁이체중보다적게분변토를만들었다. 이것은밭토양에서자기체중보다많이만든것과는대조적이다. 붉은줄지렁이는분변토를적게만들고밭지렁이는모두죽은이유는유기성폐기물의오염물질들이영향을미친것으로생각된다. 중금속이분변토발생량에미치는영향밭토양에중금속을농도별로처리한후 2종류의지렁이분변토발생량을조사했다 (Table 5). 아연처리구의분변토발생량은붉은줄지렁이 0.07~1.15 g, 밭지렁이 0.13~0.42 g 이었고대조구와비교하면중금속농도가높을수록대체로분변토발생량이적었다. 구리는붉은줄지렁이 0.22~0.66 g, 밭지렁이 0.20~0.30 g이었고무영향농도의 2배 (105 mg kg -1 ) 와 4배 (210 mg kg -1 ) 을감량한처리구에서는지렁이가모두죽어서분변토를조사하지못했다. 카드뮴은붉은줄지렁
Change of Cast Amount and Pollutant Contents with Earthworm 95 Table 6. Change of heavy metal content before and after the eating of organic wastes with earthworm, Eisenia andrei Heavy metal content Organic wastes Alcohol fermentation processing sludge Fruit juice processing sludge Zn Cu Cd Zn Cu Cd Before the treatment (materials) 332.9 80.3 1.36 202.1 147.9 0.52 After the treatment (cast) 410.8 123.1 1.63 250.6 148.9 0.67 Ratio (A%) 23.4 53.3 21.3 24.0 0.7 29.9 Table 7. Change of PAHs content before and after the eating of organic wastes with earthworm, Eisenia andrei PAHs content(ug kg -1 ) Compounds Alcohol fermentation processing sludge Before the tr. (materials) After the tr. (Cast) Ratio (%) Fruit juice processing sludge Before the tr. (materials) After the tr. (Cast) Ratio (%) Naphthalene 63.5 70.8-11.5 99.9 38.1 +61.9 Acenaphthene 7.3 4.4 +39.7 10.3 4.3 +58.3 Fluorene 183.7 60.7 +67.0 242.1 117.6 +51.4 Phenanthrene 425.1 13.7 +96.8 974.2 386.4 +60.3 Anthracene 45.3 n.d.* n.d.* 53.9 17.5 +67.5 Fluoroanthene n.d.* n.d.* n.d.* n.d.* n.d.* n.d.* Pyrene n.d.* 97.7 n.d.* 82.5 83.4-1.1 Benzo(a)anthracene 13.8 21.1-52.9 9.2 57.4-523.9 Chrysene 116.6 32.5 +72.1 63.8 227.9-257.2 Benzo(b)fluoroanthene 17.3 20.1-16.2 7.8 22.6-189.7 Benzo(k)fluoroanthene 7.3 5.1 +30.1 5.4 13.6-151.9 Benzo(a)pyrene 8.4 10.4-23.8 10.5 19.9-89.5 Dibenzo(a,h)anthracene 22.5 19.3 +14.2 15.4 30.7-99.4 Benzo(g,h,i)perylene 152.1 182.0-19.7 109.3 166.2-52.1 Total 1465.2 731.0 +50.1 2248.8 1424.9 +36.8 *Non detected 이 0.05~0.97 g으로대조구보다농도가높을수록분변토발생량이적었고, 밭지렁이 0.02~0.78 g으로대조구 (0.38 g) 보다무영향농도 2배감량 (150 mg kg -1 ) 에서 0.02 g으로현저히적었으나, 4배감량와 8배감량처리구에서는오히려많은분변토가발생했고무영향농도에서는지렁이가모두죽었다. Spurgeon et al. (1994) 은붉은줄지렁이와비슷한종류인줄지렁이 (Eisenia fetida) 의치사에영향이없는농도즉무영향농도 (NOEC, no observed effect concentrations) 가아연 289, 구리 210, 카드뮴 300 mg kg -1 로보고하였지만, 구리의무영향농도와 2배감량농도 (105 mg kg -1 ) 에서붉은줄지렁이와밭지렁이가모두죽었고카드뮴의무영향농도에서밭지렁이가모두죽었다. 2종류의지렁이모두중금속농도 높을수록분변토발생량이적은것은중금속이지렁이에게악영향을미치는것으로판단된다. 지렁이가적게먹고적게배설하는것은다양한원인이있을수있으므로피부자극, 섭식장해, 장내미생물활성등어떤부분에영향을미쳤는지는더면밀한실험이필요하다고본다. 지렁이섭식전후의중금속과 PAHs (polycyclic aromatic hydrocarbons) 함량변화유기성폐기물 ( 주정슬러지, 과즙슬러지 ) 에대한붉은줄지렁이의섭식전후의중금속 (Zn, Cu, Cd) 함량의변화를조사했다 (Table 6). Table 4에서조사된것처럼밭지렁이는유기성폐기물에서모두죽기때문에제외했다. 붉은줄지렁이분변
96 Na 토의중금속함량은지렁이가먹은슬러지보다 0.7~53.3% 까지더증가했다. 주정슬러지에서는아연 23.4%, 구리 53.3%, 카드뮴 21.3% 가증가했고, 과즙슬러지는아연 24%, 구리 0.7%, 카드뮴 29.9% 가증가했다. PAHs의함량변화는 Table 7과같다. 주정슬러지에서 14종류유기화합물의총량은 1,465 μg kg -1 이었으나붉은줄지렁이가섭식하고배설한분변토에서는 731 μg kg -1 로서 50.1% 가감소했다. 과즙슬러지도 2,249 μg kg -1 에서 1,423 μg kg -1 으로 36.6% 가감소했다. 두종류의슬러지에서지렁이의섭식후에분해되어함량이적어진유기화합물은 Acenaphthene, Fluorene, Phenanthrene, Anthracene로 4종류였다. 반대로지렁이의섭식후에농축되어함량이많아진유기화합물은 Benzo(a)anthracene, Benzo(b)fluoroanthene, Benzo(a)pyrene, Benzo(g,h,i)perylene으로 4종류였다. Nam et al. (2002) 은우리나라하수슬러지의총 PAHs 함량이 142~20,102 μg kg -1 으로평균 3,289 μg kg -1 으로보고한것과비교하면주정슬러지와과즙슬러지는우리나라평균치보다상당히적은함량을가지고있었다. 지렁이에의해서 PAHs가분해되거나농축되는현상과분해에대한기작구명은추후더면밀한실험이진행되어야할것으로사료된다. 요약 지렁이는토양의물리화학성변화에중요한역할을한다. 본연구는밭토양과유기성폐기물에서지렁이의분변토발생량및오염물질 ( 중금속, PAHs) 의변화특성을밝히고자하였다. 지렁이종류에따라분변토발생량을비교하면, 밭토양에서는붉은줄지렁이생체무게 1 g 에평균 1.41 g 의분변토를만든반면에밭지렁이는 1 g 에평균 0.40 g 의분변토를만들었고, 유기성폐기물에서는붉은줄지렁이생체무게 1 g 에주정슬러지분변토 0.78 g, 과즙슬러지분변토 0.83 g 를각각만든반면에밭지렁이는모두죽어서분변토를얻지못했다. 중금속이분변토발생량에미치는영향을조사한결과, 붉은지렁이의분변토량은대조구와비교해서아연이 0.1~0.8 배, 구리가 0.2~0.5 배, 카드뮴이 0.1~0.7 배감소했다. 밭지렁이의분변토량은아연이 0.3~1.1 배, 구리가 0.2~0.3 배, 카드뮴이 0.1~2.1 배감소했다. 지렁이섭식전후의중금속과 PAHs 의함량변화을분석한결과, 유기성폐기물 ( 주정슬러지, 과즙슬러지 ) 에대한붉은줄지렁이분변토의중금속 (Zn, Cu, Cd) 함량은지렁이가섭식전슬러지보다 0.7~53.3% 까지증가했다. PAHs 의함량은주정슬러지에서 1,465 μg kg -1 에서 731 μg kg -1 로 50.1% 가감소했다. 과즙슬러지도 2,249 μg kg -1 에서 1,423 μg kg -1 으로 36.6% 가감소했다. 따라서이러한결과들은향후유기성폐기물처리및오염토양복원에있어서지렁이종류선택및처리방법에대한연구에도움이될것으로기대된다. Acknowledgment This study was carried out with the support of Research Program for Agricultural Science & Technology Development (Project No. PJ008608), National Academy of Agricultural Science, Rural Development Administration, Republic of Korea. References Dar, G. H. (1997). Impact of lead and sewage sludge on soil microbial biomass and carbon and nitrogen mineralization. Bulletin of Environmental Contamination and Toxicology, 58(2), 234-240. Elsgaard, L., Petersen, S. O., & Debosz, K. (2001). Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 2. Effects on soil microbiology as influenced by sewage sludge and incubation time. Environmental Toxicology and Chemistry, 20(8), 1664-1672. Hernández, T., Moreno, J. I., & Costa, F. (1991). Influence of sewage sludge application on crop yields and heavy metal availability. Soil Science and Plant Nutrition, 37(2), 201-210. Holmgren, G. G. S., Meyer, M. W., Chaney, R. L., & Daniels, R. B. (1993). Cadmium, lead, zinc, copper, and nickel in agricultural soils of the United States of America. Journal of Environmental Quality, 22(2), 335-348. Lerch, R. N., Barbarick, K. A., Westfall, D. G., Follett, R. H., McBride, T. M., & Owen, W. F. (1990). Sustainable rates of sewage sludge for dryland winter wheat production II. Production and income. Journal of Production Agriculture, 3(1), 66-71. Na, Y. E., Han, M. S., Lee, S. B., Kim, S. G., & Park, H. M., (2000). Establishment of disposing method for dairy cow manure by vermiculture. Korean Journal of Soil Zoology, 5(2), 125-131. Nam, J. J., Lee, S. H., Kwon, S. I., Hong, S. Y., Lim, D. K., Koh, M. H., & Song, B. H. (2004). Toxicity assessment of the soil by bioassay following a long-term application of sewage sludge. Korean Journal of Environmental Agriculture, 23(4), 258-263. Petersen, J. (2001, March). Review of Danish field experiments with sewage sludge and composted household refuse as a fertilizer source. (ed : Dhir, et al.), pp. 175-189. Recycling and Reuse of Sewage Sludge. Proceedings of the International Symposium at University of Dundee, Scotland, UK. Smith, S. R. (1996). Agricultural Recycling of Sewage Sludge and the Environment, WRC Marlow Buckinghamshire UK. Spurgeon, D. J., Hopkin, S. P., & Jones, D. T. (1994). Effects of cadmium, copper, lead and zinc on growth,
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