水质净化功能是湿地的一个重要生态功能之一,本文以西藏拉萨河流域甲玛湿地作为研究对象,对湿地水的色度、浊度、pH值、水温、溶解氧和20种相对重要的金属元素的含量进行了初步研究。发现,西藏甲玛湿地水的pH值、DO值分别为7.40、8.07mg/L;甲玛湿地水中金属元素含量普遍较低,并且水中各种金属元素的含量也差异较大,它们的含量序列为:Ca〉As〉Mg〉Na〉K〉Fe〉Al〉Cu〉Mn〉Zn〉Mo〉Ni〉Cr〉Pb〉Sb〉Co〉Cd〉Se〉Hg〉Be。通过对进水和出水水质的比较发现甲玛湿地对色度、浊度和金属元素的去除效果比较明显。对色度、浊度的去除率分别达到了达到了65.1%、63.8%,对不同金属元素的去除效果不同,金属元素的去除率从高到低的顺序为:Be〉Al〉Pb〉Cu〉Cd〉Fe〉Se〉Co〉Mn〉Ni〉As〉Zn。其中对铍、铝、铅、铜、镉和铁六种金属元素的去除效果最明显,它们的去除率分别达到了73.33%、70.38%、67.95%、67.08%、66.30%、65.50%,对总硬度(Ca、Mg)、Na、Hg、K、Cr、Sb等几种金属元素的去除效率很差、几乎不能被去除。
Water purification is one of the important ecological functions of wetlands.Studies on the ecological functions of alpine wetlands,particularly on wetland water purification,seem to be inadequate,which is an obstacle for reasonably and effectively protecting alpine wetlands.In this study,analyses on water color,turbidity,pH,water temperature,and dissolved oxygen were performed in the Jama wetland in the Lhasa River basin in Tibet Autonomous Region,China.Also,contents of 20 types of heavy metals were determined by ICP-MS,ICP-OES and AFS.Results showed that:1)the range of water pH was from 6.56 to 7.75 and the average value was 7.40 in the Jama wetland,which was significantly lower than that of the total body of the Lhasa River basin ranging from 8.2 to 8.7.The range of dissolved oxygen(DO value)was from 6.58 mg/L to 10.1 mg/L with an average of 8.07 mg/L,indicating a relatively high water dissolved oxygen content in the wetland;2)water metal contents were generally lower in the Jama wetland compared with the background values of heavy metals in the surface water of the Tibet Plateau.The arsenic content was 112 times higher than the water quality standard of China's"drinking water health standards"(GB5749-2006),and the others were just 1%to 80.6%of the water quality standard values.In addition,the water contents of various metals varied greatly,with a decreasing sequence of galciumarsenicmagnesiumnatriumkaliumironaluminiumcuprummanganese zincmolybdenumnickelchromiumplumbumantimonycobaltcadmium seleniummercuryBeryllium;3)comparison between the influent and effluent qualities of the wetland showed that,the wetland had obvious removal effects on water color,turbidity and metal elements.The removal rates of water color and turbidity were found to be 65.1%and 63.8%,respectively.For various metal elements,the removal rates were different,suggesting a decreasing order of berylliumaluminiumplumbumcuprumcadmiumironseleniumcobalt manganesenickelarseniczinc.The removal effects of beryllium,aluminium,plum