Abstract：
Understanding the geochemistry and contamination of rivers affected by anthropogenic activities is paramount to water resources management. The Asopos river basin in central Greece is facing environmental quality deterioration threats due to industrial, urban and agricultural activities. Here, the geochemistry of river sediments and adjacent soil in terms of major and trace elements (Al, Ca, Mg, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and the geochemical composition of surface water in terms of major ions, trace elements and nutrients along the Asopos river basin were determined. In addition, this study characterized potential nitrate sources through the analysis of stable isotope composition of NO3- (δ15Ν-ΝΟ3- and δ18Ο-ΝΟ3-). Results indicated that specific chemical constituents including nutrients (NO2-, NH4+, PO43-) and major ions (Na+, Cl-) were highest in the urban, industrialized and downstream areas. On the other hand, nitrate (NO3-) concentration in river water (median 7.9 mg/L) showed a decreasing trend from the upstream agricultural sites to the urban area and even more in the downstream of the urban area sites. Ionic ratios (NO3-/Cl-) and δ15Ν-ΝΟ3- values (range from +10.2 ‰ to +15.7 ‰), complemented with a Bayesian isotope mixing model, clearly showed the influence of organic wastes from septic systems and industries operating in the urban area on river nitrate geochemistry. The interpretation of geochemical data of soil and river sediment samples demonstrated the strong influence of local geology on Cr, Fe, Mn and Ni content, with isolated samples showing elevated concentrations of Cd, Cu, Pb and Zn, mostly within the industrialized urban environment. The calculation of enrichment factors based on the national background concentrations provided limited insights into the origin of geogenic metals. Overall, this study highlighted the need for a more holistic approach to assess the impact of the geological background and anthropogenic activities on river waters and sediments.
摘要：
了解受人为活动影响的河流的地球化学和污染对于水资源管理至关重要。希腊中部的Asopos河流域正面临着因工业、城市和农业活动。这里,河流沉积物和邻近土壤的主要和微量元素地球化学(Al，Ca,Mg,Cd,Cr,Cu,Fe,Mn,Ni,Pb和Zn）以及以主要离子表示的地表水地球化学组成，测定了Asopos河流域的微量元素和养分。此外,这项研究通过分析NO3-（δ15N-NO3-和δ18O-NO3-）的稳定同位素组成来表征潜在的硝酸盐来源。结果表明，包括营养物质(NO2-，NH4+,PO43-）和主要离子（Na+，Cl-）在城市中最高，工业化和下游地区。另一方面,河水中的硝酸盐（NO3-）浓度（中位数7.9mg/L）从上游农业站点到市区呈下降趋势，而市区下游站点则更多。离子比（NO3-/Cl-）和δ15N-NO3-值（范围从10.2‰到15.7‰），辅以贝叶斯同位素混合模型，清楚地表明了城市地区化粪池系统和工业中有机废物对河流硝酸盐地球化学的影响。土壤和河流沉积物样品的地球化学数据的解释表明了当地地质对Cr的强烈影响，Fe,Mn和Ni含量，分离的样品显示镉浓度升高，Cu,Pb和Zn,主要是在工业化的城市环境中。根据国家背景浓度计算富集因子对地质金属的起源提供了有限的见解。总的来说,这项研究强调需要更全面的方法来评估地质背景和人为活动对河流水域和沉积物的影响。
