Behavior of Mercury in Soil Profiles: Impact of Increased Precipitation, Acidity, and Fertilization on Mercury Methylation
- Cite this article as:
- Matilainen, T., Verta, M., Korhonen, H. et al. Water, Air, & Soil Pollution (2001) 125: 105. doi:10.1023/A:1005220016761
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The behaviour of Hg in mineral pine forest (Pinussylvestris soil profiles (0–16 cm) was studied usinga lysimeter experimental design combined with thelabeling technique with 203HgCl2. Thelabeled surface soils were exposed to four differenttreatments: (i) normal precipitation (600 mma-1), (ii) four-fold precipitation, (iii) soilP-K fertilizing with normal precipitation, and (iv) the increased acidity in the rainwater with normalamount of precipitation. After the treatment period of97 days the 203Hg and methyl 203Hg weremeasured. The distribution of Hg in different soilmatrices was determined by extracting the soil withdistilled water, 1 M NH4-acetate, 1 M HCl, and 0.1 M NaOH.The results showed that the organic surface layer,especially the living moss (Pleuroziumschreberi), was the dominant scavenger of the added203Hg. Methyl 203Hg formation was mostintensive in this layer, too. Increased precipitationmobilized a part of the 203Hg from the moss layerto the deeper layers and leachate water. In thefertilized soil with increased pH, the accumulation ofboth total 203Hg and methyl 203Hg wasrecorded in the organic surface soil. A small increasein rainwater acidity had no clear effect on thebehavior of 203Hg in soil. 203Hg was mainlyassociated in the organic fraction (NaOH-extractable)whether in the living moss or humus layer. Thefertilized soil yielded the highest concentration ofwater extractable 203Hg. In view of the climatechange with increasing precipitation, the use offertilizers, in the watersheds should be minimal andwell-controlled. This is, because soil fertilizingseems to increase the availability of Hg formethylation, and because the mobilization of bothtotal Hg and methyl Hg from watershed soils to lakes,and probably to ground water, increases whenprecipitation increases.