Ahn Jong Ho, Grant Stanley B
Department of Chemical Engineering and Materials Science, Henry Samueli School of Engineering, University of California, Irvine, California 92697, USA.
Environ Sci Technol. 2007 Feb 1;41(3):695-702. doi: 10.1021/es061960+.
In this paper we define seasonal and along-shore variations in suspended particle size distributions (PSDs) at two marine bathing beaches in southern California, using a low-angle light scattering instrument (LISST). Empirical Orthogonal Function (EOF) analysis of the LISST data set (n = 55 651) identified three particle size modes that collectively account for > 90% of the variance in the de-meaned PSD data at six sites along the shoreline at Huntington Beach and Newport Beach: a dinoflagellate mode, a large particle mode, and a small particle mode. These three modes exhibit distinct seasonal patterns, and along-shore distributions, reflecting both the sources of particles and environmental factors that trigger their occurrence. Comparison of volume-based PSDs generated from the LISST and from image analysis of optical micrographs indicates that the LISST performs well when measuring the size distribution of particles associated with dinoflagellate blooms. However, LISST measurements on stormwater-impacted samples consistently yield a rising tail at small particle sizes that may be an artifact arising from the non-spherical nature of inorganic particles in terrestrial runoff. The results presented here demonstrate that PSDs measured by light scattering instruments such as the LISST represent a new data resource for assessing water quality, and managing human health risk, at marine bathing beaches.
在本文中，我们使用低角度光散射仪（LISST）定义了南加州两个海水浴场海滩悬浮颗粒大小分布（PSD）的季节性变化和沿岸变化。对LISST数据集（n = 55651）进行的经验正交函数（EOF）分析确定了三种颗粒大小模式，它们共同解释了亨廷顿海滩和纽波特海滩沿岸六个地点去均值PSD数据中超过90%的方差：一个甲藻模式、一个大颗粒模式和一个小颗粒模式。这三种模式呈现出不同的季节性模式和沿岸分布，反映了颗粒来源以及引发其出现的环境因素。对LISST生成的基于体积的PSD与光学显微镜图像分析生成的PSD进行比较表明，LISST在测量与甲藻水华相关的颗粒大小分布时表现良好。然而，对受雨水影响样本的LISST测量在小颗粒尺寸处始终产生一个上升的尾部，这可能是陆地径流中无机颗粒的非球形性质导致的假象。本文给出的结果表明，通过诸如LISST等光散射仪器测量得到的PSD代表了一种用于评估海水浴场海滩水质和管理人类健康风险的新数据资源。
