As a trace heavy metal, lead (Pb) has many anthropogenic applications but also produces many environmental pollution problems because of its high toxicity. In this study, we combined two in situ high-resolution sampling techniques – high-resolution dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) – with the DGT-induced fluxes in sediment (DIFS) model to explore the mechanism of Pb release and resupply between sediments and pore water in the lower reaches and estuary of the Jiuxi River and the adjacent coast. An analysis of the chemical forms of Pb in the sediments showed that the content of the acid-extractable fraction (F1) was higher at the coastal site than at the other sampling sites, which indicates that Pb in the coastal sediments had greater activity and was more likely to cause Pb pollution. The apparent diffusion fluxes of Pb across the sediment-water interface (SWI) in the lower reaches, estuary and coastal zone are negative, and the absolute value of Pb flux in the estuary is several times higher than that in the other two stations, indicating a strong downward Pb diffusion trend, which may be due to water pollution caused by the nearby sewage outlet. As an insensitive element to redox, Pb did not exhibit an obvious correlation with Fe. In particular, the high Pb concentration and strong downward diffusion trend of the overlying water in the estuary caused the significant negative correlation between Pb and Fe. The calculated results of the DIFS model show that the reduced layer in the intertidal zone along the coast has the highest R value, the highest desorption rate (k₋₁) and the shortest response time (T_c), indicating that sediment particles in the coastal intertidal zone supply Pb to the pore water at the fastest rate; consequently, Pb pollution in the coastal zone is worthy of further attention.

铅（Pb）作为痕量重金属，具有许多人为用途，但由于毒性高，还产生许多环境污染问题。在这项研究中，我们结合了两种原位高分辨率采样技术–高分辨率透析（HR-Peeper）和薄膜中的扩散梯度（DGT）–与DGT诱导的沉积物通量（DIFS）模型进行了探讨溪河下游及邻近海域河口和沉积物与孔隙水之间铅的释放和补给量 对沉积物中Pb的化学形式的分析表明，酸提取部分（F1）的含量在沿海地点要高于其他采样地点，这表明沿海沉积物中的Pb具有更大的活性，并且更可能导致铅污染。在下游，河口和沿海地区，Pb在沉积物-水界面（SWI）的表观扩散通量为负值，并且Pb通量的绝对值比其他两个站高出几倍，表明铅的向下扩散趋势很强，这可能是由于附近污水出口造成的水污染。作为一种对氧化还原不敏感的元素，Pb与Fe没有明显的相关性。特别是河口上覆水的高Pb浓度和强烈的向下扩散趋势导致Pb和Fe之间显着负相关。DIFS模型的计算结果表明，沿海岸带潮间带的还原层具有最高的R值，最高的解吸速率（k 河口Pb通量的绝对值比其他两个站高出几倍，表明Pb的向下扩散趋势很强，这可能是由于附近排污口造成的水污染所致。作为一种对氧化还原不敏感的元素，Pb与Fe没有明显的相关性。特别是河口上覆水的高Pb浓度和强烈的向下扩散趋势导致Pb和Fe之间显着负相关。DIFS模型的计算结果表明，沿海岸带潮间带的还原层具有最高的R值，最高的解吸速率（k 河口Pb通量的绝对值比其他两个站高出几倍，表明Pb的向下扩散趋势很强，这可能是由于附近排污口造成的水污染所致。作为一种对氧化还原不敏感的元素，Pb与Fe没有明显的相关性。特别是河口上覆水的高Pb浓度和强烈的向下扩散趋势导致Pb和Fe之间显着负相关。DIFS模型的计算结果表明，沿海岸带潮间带的还原层具有最高的R值，最高的解吸速率（k 这可能是由于附近的排污口造成的水污染。作为对氧化还原不敏感的元素，Pb与Fe没有明显的相关性。特别是河口上覆水的高Pb浓度和强烈的向下扩散趋势导致Pb和Fe之间显着负相关。DIFS模型的计算结果表明，沿海岸带潮间带的还原层具有最高的R值，最高的解吸速率（k 这可能是由于附近的排污口造成的水污染。作为一种对氧化还原不敏感的元素，Pb与Fe没有明显的相关性。尤其是河口上覆铅的高Pb浓度和强烈的向下扩散趋势导致Pb与Fe之间显着负相关。DIFS模型的计算结果表明，沿海岸带潮间带的还原层具有最高的R值，最高的解吸速率（k_{− 1}）和最短响应时间（T _c），表明沿海潮间带的沉积物颗粒以最快的速度向孔隙水供应Pb；因此，沿海地区的铅污染值得进一步关注。