Stagličić Nika, Violić Ivana, Bojanić Varezić Dubravka, Tutman Pero
Institute of Oceanography and Fisheries, Šetalište I. Meštrovića 63, 21000 Split, Croatia.
University of Dubrovnik, Department of Applied Ecology, Ćira Carića 4, 20000 Dubrovnik, Croatia.
Mar Pollut Bull. 2025 Nov;220:118459. doi: 10.1016/j.marpolbul.2025.118459. Epub 2025 Jul 18.
Rivers are major transporters of land-based litter to coastal environments, yet the extent to which river flow and distance from the river mouth shape beach litter accumulation remains insufficiently understood. The Neretva River, the largest river system in the eastern Adriatic, and Mali Ston Bay, a semi-enclosed coastal area into which it flows, were used as a case study to investigate the influence of seasonal river discharge and spatial proximity to the river mouth on beach litter dynamics. Monthly surveys conducted over two years (2021-2022) at beaches located near and far from the river mouth quantified litter abundance, weight, and composition in relation to seasonal hydrological conditions. Increased river discharge during the wet season led to a significant rise in beach litter loads, with both abundance and weight more than doubling compared to the dry season. Proximity to the river mouth also played a key role in debris distribution, with higher litter loads at deltaic beaches than those farther away in the bay. Plastics dominated the litter composition across all sites and seasons, with single-use plastics particularly prevalent. Despite pronounced seasonal and spatial variability, interannual litter accumulation remained stable, suggesting persistent pollution sources. These findings emphasize the importance of upstream waste management, riverine litter interception, and seasonally targeted beach cleanups, particularly near river mouths, as well as the need for regulatory actions, such as restrictions on single-use plastics, and long-term monitoring to mitigate river-driven coastal litter pollution.
河流是将陆源垃圾输送到沿海环境的主要载体，但河流水量和与河口的距离对海滩垃圾堆积的影响程度仍未得到充分了解。亚得里亚海东部最大的河流系统内雷特瓦河及其流入的半封闭沿海区域马里什通湾被用作案例研究，以调查季节性河流流量和与河口的空间距离对海滩垃圾动态的影响。在两年（2021 - 2022年）期间，对靠近和远离河口的海滩进行了月度调查，量化了与季节性水文条件相关的垃圾丰度、重量和组成。雨季河流流量增加导致海滩垃圾负荷显著上升，丰度和重量相比旱季均增加了一倍多。与河口的距离在垃圾分布中也起着关键作用，三角洲海滩的垃圾负荷高于海湾中距离更远的海滩。在所有地点和季节，塑料在垃圾组成中占主导地位，一次性塑料尤为普遍。尽管存在明显的季节性和空间变异性，但年际垃圾堆积保持稳定，这表明污染源持续存在。这些发现强调了上游废物管理、河流垃圾拦截以及季节性针对性海滩清理（特别是在河口附近）的重要性，以及采取监管行动（如限制一次性塑料）和进行长期监测以减轻河流驱动的沿海垃圾污染的必要性。
