圣保罗州的主要土地利用/土地覆盖变化(LULCC)与人口增长和能源政策有关,巴西,自1970年以来。LULCC可以改变微量元素在不同环境系统中的行为,河床沉积物是微量元素的主要水库或水槽,从而成为关于时间变化的有价值的环境档案。因此,这项研究的主要目的是应用多示踪分析来估计亚热带流域河床沉积物污染的历史演变,Piracicaba河下游,圣保罗,巴西。在河流沉积物岩心样品上进行的210Pb测量允许在1971年至2001年之间估计9mmyr-1的沉积速率。锌是沉积物核心中含量最丰富的微量元素,其次是Cr,Cu,Ni,Pb,Sc和Cd。Cd的总浓度,Cr,Ni,Sc和Pb在沉积物岩心中几乎没有变化,连续过量约。0.27μgg-1yr-1的Cu和约。1971年至2001年之间的0.54μgg-1yr-1锌。过量的铜和锌与不稳定的部分有关,特别是与Zn结合的碳酸盐和与Cu结合的有机物。对痕量金属污染的评估表明,大多数微量元素都是地质成因,除了铜和锌。根据巴西使用的沉积物质量指南,Pb没有潜在的毒性作用,Cu,Cr和Zn处于阈值效应水平(TEL)和可能效应水平(PEL)的中间,并且Cd和Ni浓度高于PEL极限。对C和N以及C/N比的元素和同位素分析表明,在沉积物芯中发现的POM的人为起源主要与生活污水有关。
The main land use/land cover changes (LULCC) have been associated with population growth and energy policies in the São Paulo State, Brazil, since 1970. The LULCC can alter the behavior of trace elements in different environmental systems, with the riverbed sediments being the main reservoirs or sinks for trace elements, and thus become a valuable environmental archive on temporal changes. Thus, the main purpose of the study was to apply a multi-tracer analysis to estimate the historical evolution of pollution in riverbed sediment of a subtropical watershed, the lower course of the Piracicaba River, São Paulo, Brazil. 210Pb measurements done on river sediment core samples allowed estimating a sedimentation rate of 9 mm yr-1 between 1971 and 2001. Zn was the most abundant trace element in the sediment core, followed by Cr, Cu, Ni, Pb, Sc and Cd. The total concentrations of Cd, Cr, Ni, Sc and Pb presented practically no variations in the sediment core, with a continuous excess of ca. 0.27 μg g-1 yr-1 of Cu and of ca. 0.54 μg g-1 yr-1 of Zn between 1971 and 2001. The excess of Cu and Zn was associated with labile fractions, in particular with carbonate bound to Zn and organic matter bound to Cu. The assessment of trace metal pollution indicated that most of the trace elements were of geogenic origin, except for Cu and Zn. According to the sediment quality guidelines used in Brazil, Pb showed no potential toxic effect, Cu, Cr and Zn were intermediate to Threshold Effect Level (TEL) and Probable Effect Level (PEL) and the Cd and Ni concentrations were above the PEL limits. The elemental and isotopic analysis of C and N and the C/N ratio indicated that the anthropogenic origin of POM found in the sediment core is related mainly to domestic sewage.