Environmental quality assessment by multiple biogeochemical indicators of an intertidal flat under anthropogenic influence from the southwest of Buenos Aires (Argentina)

Abstract

Chemical measures combined with biological data (biomarkers) are recommended in monitoring programs of marine environments. In the present research, the use of multiples biogeochemical indicators allowed interrelating different environmental measurements to deepen the knowledge of the quality/status of the intertidal flat from Puerto Rosales (Bahía Blanca estuary, Argentina) subjected to anthropogenic pressure. The sediments from this site presented a eutrophic status and high organic matter concentration with high nutritional value for the benthic community. The TPR/TCH ratio (~ 10) would evidence the untreated sewage discharge contribution and increments in protein content due to the complexation of nitrogen during phytodetritus accumulation and degradation. Trace metals levels in the fine sediments were lower than those recommended by international guides for uncontaminated sites. In the sediments, except Cu, all metals analyzed were rarely associated with adverse biological effects. Finally, metallothioneins levels in the burrowing crab Neohelice granulata were lower than those found in the literature and significantly higher in females than in males. Even though the different analyses and indices performed indicate that this intertidal flat is in good environmental condition, the wastewater discharge influenced it. Thus, it is advisable to continue with this kind of study by applying multi-combined proxies in this and other impacted tidal flats.