Aqua regia as an alternative extractor for the environmental diagnosis of areas impacted by industrial waste: case study Centres (Queimados, RJ)

ABSTRACT Metal contaminated areas lead to environmental and public health risks. In the 1980s, dangerous industrial waste storage was initiated in the CENTRES area in the municipality of Queimados, Rio de Janeiro, Brazil. The inadequate management of these wastes has promoted a large environmental impact to this region’s soils. The Brazilian legislation for diagnostics of contaminated areas limits the extraction of metals on soils to USEPA 3050-B and USEPA 3051-A methods. However, many researchers use the aqua regia method for extracting metals in soil, but there are few studies comparing concentrations of metals extracted by aqua regia and USEPA 3051A. Therefore, the objective of this work was to evaluate if the method of extracting metals in soils by aqua regia is statistically different from US EPA 3051A. The results showed that the Cd, Cr, Cu, Ni, Pb and Zn concentrations using both extractions were statistically similar. It was also observed that Cu, Ni, Pb and Zn concentrations were higher than the industrial investigation value which characterizes this area as highly contaminated and soil class 4.

摘要 金属污染区域会对环境及公众健康构成风险。20世纪80年代，巴西里约热内卢州凯马杜斯市（Queimados）的CENTRES区域启动了危险工业废物储存作业。此类废物的不当管理对该区域土壤造成了严重的环境影响。巴西污染区域诊断相关法规将土壤金属提取方法限定为美国环境保护署（USEPA）3050-B与USEPA 3051-A法。然而，诸多研究者常采用王水（aqua regia）法进行土壤金属提取，但针对王水法与USEPA 3051A法提取的金属浓度对比的研究较为匮乏。因此，本研究旨在评估王水法与USEPA 3051A法的土壤金属提取效果是否存在统计学差异。结果显示，两种提取方法得到的镉（Cd）、铬（Cr）、铜（Cu）、镍（Ni）、铅（Pb）及锌（Zn）浓度均无统计学显著性差异。研究同时发现，该区域土壤中铜、镍、铅、锌的浓度高于工业调查限值，据此可判定该区域为重度污染区域，土壤等级为4类。