Shah Vikaskumar G, Dunstan R Hugh, Geary Phillip M, Coombes Peter, Roberts Timothy K, Rothkirch Tony
School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia.
Water Res. 2007 Aug;41(16):3655-66. doi: 10.1016/j.watres.2007.02.052. Epub 2007 Apr 10.
In this study, 12 catchments sites located along the north coast of New South Wales in Australia were grouped into the four categories of septic, cattle, sewage treatment plant (STP) and forested sites via cluster analysis based on their land use patterns. Water samples from all these sites were collected between October 2004 and June 2006 at a regular monthly interval and within 48 h of rain events. The samples were analyzed for bacterial counts including faecal coliform and total coliform; faecal sterols including coprostanol, epicoprostanol, cholesterol, cholestanol, 24-ethylcoprostanol, campesterol, stigmasterol and beta-sitosterol; and the elements including Na, Rb, Sr, Ag, Cd, Sn, Cs, Ba, Hg, Tl, Pb, Bi, U, Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, K, As, Se, P and Mo. Over the course of the sampling period, the STP site had the highest average coprostanol level of 1693+/-567 ng/L which was significantly higher (p<0.05) than the septic sites (190+/-71 ng/L), the cattle sites (163+/-94 ng/L) and forested sites (14+/-4 ng/L). As expected, the forested sites had significantly lower average level of faecal coliforms (373+/-87 cfu/100 mL) compared with the STP (1395+/-574 cfu/100 mL), septic (1243+/-494 cfu/100 mL) and cattle sites (535+/-112 cfu/100 mL). The concentrations of coprostanol were not correlated with the numbers of faecal coliform bacteria when the entire data set was evaluated. The forested sites generally had the lowest average levels of elemental compositions, with significantly lower levels noted for Na, U, Mg, V, Cu, Sr, K, As, P and Mo, whereas Fe was the only element notably higher in the forested sites. Temporal and rain events analyses of the data set revealed that elevated levels of both coprostanol and faecal coliforms were not exclusive to rain events. The average coprostanol levels in rain event samples at each site were not significantly different compared with the corresponding dry event samples. Conversely, faecal coliform numbers increased by 2-4 times in rain events samples from septic, cattle and forested sites, but did not alter in the STP site. Multivariate analyses identified coprostanol and Sr as major contributing factors for the discrimination of septic, cattle, STP and forested sites for both rain and dry events samples. It was clear that each land use type of catchment could be characterized by biochemical, bacteriological and elemental parameters.
在本研究中，澳大利亚新南威尔士州北海岸的12个集水区站点根据其土地利用模式通过聚类分析被分为化粪池、养牛场、污水处理厂（STP）和森林覆盖站点四类。2004年10月至2006年6月期间，每月定期且在降雨事件发生后48小时内从所有这些站点采集水样。对样本进行细菌计数分析，包括粪大肠菌群和总大肠菌群；粪便固醇分析，包括粪甾醇、表粪甾醇、胆固醇、胆甾烷醇、24-乙基粪甾醇、菜油甾醇、豆甾醇和β-谷甾醇；以及元素分析，包括钠、铷、锶、银、镉、锡、铯、钡、汞、铊、铅、铋、铀、镁、钒、铬、锰、铁、钴、镍、铜、锌、钾、砷、硒、磷和钼。在采样期间，污水处理厂站点的粪甾醇平均水平最高，为1693±567 ng/L，显著高于（p<0.05）化粪池站点（190±71 ng/L）、养牛场站点（163±94 ng/L）和森林覆盖站点（14±4 ng/L）。正如预期的那样，与污水处理厂站点（1395±574 cfu/100 mL）、化粪池站点（1243±494 cfu/100 mL）和养牛场站点（535±112 cfu/100 mL）相比，森林覆盖站点的粪大肠菌群平均水平显著较低（373±87 cfu/100 mL）。当评估整个数据集时，粪甾醇浓度与粪大肠菌群数量不相关。森林覆盖站点的元素组成平均水平通常最低，钠、铀、镁、钒、铜、锶、钾、砷、磷和钼的水平显著较低，而铁是森林覆盖站点中唯一显著较高的元素。对数据集的时间和降雨事件分析表明，粪甾醇和粪大肠菌群水平升高并非降雨事件所特有。每个站点降雨事件样本中的粪甾醇平均水平与相应的干旱事件样本相比无显著差异。相反，化粪池、养牛场和森林覆盖站点降雨事件样本中的粪大肠菌群数量增加了2至4倍，但污水处理厂站点没有变化。多变量分析确定粪甾醇和锶是区分降雨和干旱事件样本中的化粪池、养牛场、污水处理厂和森林覆盖站点的主要贡献因素。很明显，每个集水区的土地利用类型都可以通过生化、细菌学和元素参数来表征。
