基于水质梯度的海水主要营养盐及石油类监测方法适用性研究

Study on the Applicability of Monitoring Methods for Major Nutrients and Petroleum in Seawater Based on Water Quality Gradients

摘要: 我国近岸海域水质类别的跨度很大，一类至劣四类水质区域均有分布。《海洋监测规范》中部分方法在适应性和检测效率上的局限性愈发凸显。本研究基于实验数据和6个典型沿海城市的长期监测数据，对比传统方法与HJ系列的连续流动比色法、气相分子吸收光谱法的技术参数与适用性。引入GUM法不确定度评估模型，量化合成相对标准不确定度，模拟标准曲线拟合误差随浓度梯度的变化特征，并建立“人为操作引入不确定度次数”量化模型，以分析各种检测方法的适用性。结果表明：传统方法测量范围较窄、操作步骤繁琐，用于低浓度样品测定时必须辅以严格的质控以评估其不确定度是否在可接受范围；气相分子吸收光谱法和连续流动比色法测量范围宽，自动化程度高，人为误差引入次数少。研究提出了基于检测目标水质梯度的具体监测方法推荐方案，为实验室方法选择提供数据支撑。

Abstract: The water quality categories in China’s coastal waters span a wide range, with Class I through inferior Class IV water quality areas all being distributed. The limitations of certain methods in the Marine Monitoring Specifications in terms of adaptability and detection efficiency have become increasingly prominent. Based on experimental data and long-term monitoring data from six typical coastal cities, this study compares the technical parameters and applicability of traditional methods with the continuous flow colorimetry and gas-phase molecular absorption spectrometry of the HJ series. The GUM method uncertainty evaluation model is introduced to quantify the combined relative standard uncertainty, simulate the variation characteristics of standard curve fitting errors with concentration gradients, and establish a quantitative model of “number of uncertainty introductions caused by human operation” to analyze the applicability of various detection methods. The results show that traditional methods have narrow measurement ranges and cumbersome operating procedures, and when used for low-concentration samples, strict quality control must be supplemented to assess whether their uncertainty is within an acceptable range; gas-phase molecular absorption spectrometry and continuous flow colorimetry have wide measurement ranges, high degrees of automation, and fewer introductions of human-induced errors. The study proposes a specific monitoring method recommendation scheme based on the gradient of target water quality for detection, providing data support for the selection of laboratory methods.