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根据广西北海近岸表层沉积物取样测试结果,通过统计方法分析了研究区表层沉积物粒度特征、重金属Cr分布及其相互关系。结果表明,Cr含量为5.2×10~(-6)~66.7×10~(-6),在不同沉积物显示出不同统计特征;由于波浪淘选作用,表层沉积物砂分布最为广泛,粒级主要在~0.5mm到~0.25mm之间;砂由于颗粒较粗,其粒级与Cr关系较为分散,但总体上仍然存在着线性关系,且随着粒级变细相关性提高。黏土质砂的粒级与Cr线性关系明显改善,吸附粒级拐点在~0.125mm至~0.063mm之间;Cr含量与分选和平均粒径为线性关系,与偏态、峰态为聚类关系,并划分出五类聚类类型;有机质随沉积物颗粒变细而升高,变化范围为0.02%~1.29%,在黏土质砂中与Cr为显著线性正相关,且高、低值分段拟合关系稳定。Cr/Org比值变化很大,在(43~419)×10~(-6)/%之间,高、低值段Cr与有机质关系均表现稳定。长石/石英比值为0.03~0.08表明化学风化尚在初级阶段,Cr与该比值的关系尚不明显;以最小二乘法线性拟合参数|k|·R~2来综合表示沉积物组分、成分和粒级对Cr之影响性,砂沉积物中以砂组分影响力最大,砂质黏土中,砂组分含量大为降低,有机质权重最高。
According to the sampling results of surface sediment near the bank of Beihai in Guangxi Province, the grain size characteristics of surface sediments and the distribution of Cr in heavy metals were analyzed by statistical methods. The results show that the Cr content is 5.2 × 10 -6 -6.7 × 10 -6, showing different statistical characteristics in different sediments. Due to the wave panning, the surface sediment sand is the most widely distributed, Mainly between ~ 0.5mm and ~ 0.25mm. Due to the coarse grains, sand has a relatively scattered relationship with grain size. However, there is still a linear relationship between grain size and grain size. The linear relationship between grain size and Cr content of clay sand was improved obviously. The inflection point of adsorption grain size was between ~ 0.125mm and ~ 0.063mm. Cr content was linear with sorting and average grain size, And divided into five types of clustering types. The organic matter increased with the grain size of the sediment becoming thinner, ranging from 0.02% to 1.29%. It had a significant linear positive correlation with Cr in clay sand and the high and low value points Section fitting relationship is stable. The ratio of Cr / Org varied greatly, and the relationship between Cr and organic matter was stable at (43 ~ 419) × 10 -6 /%. The feldspar / quartz ratio of 0.03 to 0.08 indicates that the chemical weathering is still in its infancy, and the relationship between Cr and this ratio is not obvious. The sediment composition is expressed by the least squares linear fitting parameter | k | · R ~ 2, The influence of composition and grain size on Cr is the most influential for the sand composition in the sand sediments. The content of sand components in the sandy clay is greatly reduced and the weight of the organic matter is the highest.