RESUMEN
We report the occurrence of plastics and associated persistent organic pollutants (POPs) in surface waters from Northern Chilean Patagonia. A total of 200 particles were found during the conducted survey. The highest number of particles found was 0.6 item m-3. We found that 53 % of the collected particles corresponded to plastic, with an average of 0.19 ± 0.18 item m-3. Microplastics (68 %) were the dominant size found in the area, followed by macroplastics (18 %) and mesoplastics (14 %). Most plastic particles were white (55 %) while others were <10 % each. Black and light blue represented 9 %; red, dark blue, and other colors 7 %; and green 6 %. Fragments were the most frequent shape of plastic debris (38 %), followed by Styrofoam (30 %) and fiber (27 %). Higher PBDE levels were found in the central zone, and those were higher than DDT, PeCB, HCB, and PCB levels. This study is the first report on POP occurrence in marine plastic debris from Chiloé Sea in the Northern Chilean Patagonia.
Asunto(s)
Contaminantes Ambientales , Contaminantes Químicos del Agua , Plásticos , Contaminantes Químicos del Agua/análisis , Chile , Monitoreo del Ambiente , MicroplásticosRESUMEN
Mercury (Hg) is known as one of the major contaminants in the Amazon. The Tapajós River basin, in the Brazilian Amazon, has diverse anthropogenic activities which increase Hg concentrations in the aquatic ecosystem. Moreover, high concentrations of Hg are naturally found in this basin. Distribution of total (THg) and methyl (MeHg) mercury were assessed in unfiltered water (nâ¯=â¯47), suspended particulate matter (SPM, nâ¯=â¯30), superficial sediment (BS, nâ¯=â¯29), plankton (nâ¯=â¯28) and fishes (nâ¯=â¯129) from the Tapajós River basin. Suspended particles were the main carrier of Hg in the water column and sediment. Increased erosion, prompted by anthropic activities, led to higher Hg concentrations in water from the most impacted areas. Hg is transported mainly in particulate matter; thus, anthropic disturbances influence Hg concentrations downstream. Limnological parameters such as organic matter content influenced MeHg concentrations in water, plankton and sediment of the Tapajós basin. Hg methylation in total plankton was more efficient in lakes (13-66%) than in Tapajós River main channel (2-14%). Biotic and abiotic factors interact in a complex way in the aquatic ecosystem, making Hg concentrations to vary in food web. Gold mining and deforestation probably increase Hg levels in the Tapajós basin. Thus, in addition to Hg monitoring, prevention and remediation efforts should be focused on soil and sediment erosion control.
Asunto(s)
Monitoreo del Ambiente , Compuestos de Metilmercurio/análisis , Contaminantes Químicos del Agua/análisis , Animales , Brasil , Ecosistema , Peces/metabolismo , Cadena Alimentaria , Lagos , Mercurio/análisis , Compuestos de Metilmercurio/metabolismo , Minería , Plancton/química , Ríos/química , Alimentos Marinos , Suelo , Agua , Contaminantes Químicos del Agua/metabolismoRESUMEN
This work aimed to evaluate associated risks of fish consumption to human health, concerning mercury (Hg) and selenium (Se) concentrations in fish species largely consumed in the Tapajós River basin in the Brazilian Amazon. Total mercury (THg), methylmercury (MeHg) and Se concentrations were measured in 129 fish specimens from four sites of the Tapajós River basin. Estimated daily intake (EDI) of Hg and Se were reported regarding fish consumption. EDI were compared with the reference value of provisional tolerable daily intake proposed by the World Health Organization (WHO). Se:Hg ratios and selenium health benefit values (Se HBVs) seem to offer a more comprehensive fish safety model. THg concentrations in fishes ranged from 0.03 to 1.51⯵gâ¯g-1 of wet weight (w.w.) and MeHg concentrations ranged from 0.02 to 1.44⯵gâ¯g-1 (w.w.). 80% of the samples were below the value of Hg recommended by the WHO for human consumption (0.5⯵gâ¯g-1 w.w.). However, Hg EDI exceeded the dose suggested by the United States Environmental Protection Agency (0.1⯵gâ¯kg-1â¯day-1), due to the large level of fish consumption in that area. Se concentrations in fishes ranged from 0.02 to 0.44⯵gâ¯g-1 w.w. An inverse pattern was observed between Hg and Se concentrations in the trophic chain (highest levels of Se in the lowest trophic levels). The molar ratio Se:Hg and Se HBVs were higher in iliophagous and herbivorous fishes, which is noteworthy to reduce toxic effects of Hg contamination. For planktivores, the content of Se and Hg was almost equimolar. Carnivorous fishes - with the exception of Hemisorubim platyrhynchos and Pseudoplatystoma fasciatum -, showed Se:Hg ratios <1. Thus, they do not act as a favorable source of Se in the diet. Therefore, reduced intake of carnivorous fishes with preferential consumption of iliophages, herbivores and, to some extent, even planktivores should be promoted as part of a healthier diet.