AbstractAnthropogenic organic pollution in Galician estuariesconstitutes a growing threat to the health of coastalecosystems, driven by the intensive use of fertilizers,urban growth and inefficient wastewater management.Thus, determining the value of organic pollution is essentialto maintain control over the quality of the coastalecosystem. In this study, the human impact on theRamallosa estuary (Vigo estuary) was evaluated byanalyzing δ¹5N and %N in the brown algae Fucus vesiculosusand organic matter in sediments, selecting threestrategic areas based on their distance from the mouthof the Miñor River. The results obtained, from differentstatistical analyses (Levene’s Test, Shapiro-Wilk/Kolmogorov-Smirnov Test and parametric ANOVA), revealedsignificant differences in %N of algae, but not inδ¹5N or in organic matter of the sediment, suggestingthat there are no significant differences in pollution betweenthe three areas. ResumoA contaminación orgánica de orixe antropoxénica nas ríasgalegas constitúe unha ameaza crecente para a saúde dosecosistemas costeiros, impulsada polo uso intensivo defertilizantes, o crecemento urbano e a xestión ineficientede augas residuais. Así, determinar o valor da contaminaciónorgánica resulta indispensable para manter o controlsobre a calidade do ecosistema costeiro. Neste estudo,avaliouse o impacto humano no esteiro da Ramallosa (ríade Vigo) mediante a análise de δ¹5N e %N na alga pardaFucus vesiculosus e a materia orgánica en sedimentos,seleccionando tres zonas estratéxicas en función da súadistancia á desembocadura do río Miñor. Os resultadosobtidos, a partir de diferentes análises estatísticas (Testde Levene, Test de Shapiro-Wilk/Kolmogorov-Smirnov eANOVA paramétrico), revelaron diferenzas significativasna %N das algas, pero non no δ¹5N ou na materia orgánicado sedimento, suxerindo que non hai diferenzas significativasde contaminación entre as tres zonas.