An intense erosive process has recently caused progressive hydrogeomorphological changes in the mouths of two large rivers belonging to the Amazon River Delta, on the estuarine coast of Amapá State, namely: Araguari and Amazonas. Consequently, Araguari River was captured by the Amazon River and it influenced the sediment and water quality dynamics when two tidal channels expanded in opposite directions; this process affected both hydrographic basins and blocked Araguari River mouth. The aim of the current study is to analyze the space-seasonal variations of hydrodynamic and water quality parameters influenced by the following factors: location (channels connected to Araguari and Amazonas rivers), seasonality (dry/rainy) and spring tidal phase (flood/ebb). The herein adopted methodological stages comprised a) flow measurement with Doppler current profiler; b) water sampling (physicochemical and suspended sediments); c) suspended solids transport estimates; and d) multivariate statistical analysis of parameters. Results have indicated significant space-seasonal variation in these parameters (p<0.05). Water balance in the dry period has shown that Urucurituba Channel absorbs 100% of Araguari River flow, distributes 29% of it in the floodplain and discharges 71% of Araguari River flow into the Amazon River. This channel received 86% of Araguari River flow and absorbed 14% of the flow deriving from the floodplain in the rainy season, which totaled 100% of its flow at Amazon River mouth-solid discharge was proportional to 107,982 t of tidal cycle-1. Multivariate analyses have shown significant variations in 90% of the investigated parameters, which were influenced by such as location, seasonality and tidal phase (p<0.05). It was possible concluding that the recent channels have significantly affected the hydrodynamics, sediment transport processes and water quality of both basins. This phenomenon is currently in intense and irreversible hydrogeomorphological evolution, and it mainly affects the Araguari River estuary Evolution of erosive and hydrodynamic impacts on water quality in tidal channels at the mouths of the Araguari and Amazon rivers

The present work aims to determine the spatial distribution pattern of Protium Burm. f and the diametric structure of these species in a dense tropical submontane rainforest along the Sustainable Development Reserve (SDR) of the Iratapuru river. The area of study was divided into three plateau compartments called Mane Preto Sierra, Banco Grande Sierra and Alaska Sierra. In each plateau compartment it was settled a single area transect with 1,000 x 20 m, where DAP ≥ 10 cm of the entire Protium population within the transects was measured. The data was processed in the specific software Mata Nativa 2. There were inventoried Protium tenuifolium, Protium altsoni, Protium polybotryum subsp. blackii and Protium paniculatum var. riedelianum. Most individuals concentrated in smaller diametric classes, decreasing progressively to a lesser extent in larger classes. It can be concluded that the population has medium size and its vertical structure is characterized by the presence of three strata, however, its phytocenoses is defined by two clear constants: the first groups individuals of up to 15 m of height and forms the uniform and dominant stratum; the second is composed by emerging up to 35 m high and whose diameter structure shows a population in dynamic balance.

A disposição final inadequada dos resíduos sólidos é um problema comum na maioria das cidades brasileiras, reflete a precariedade do sistema de saneamento básico, em especial dos serviços de limpeza urbana e manejo de resíduos sólidos, gerando grandes impactos socioeconômicos e ambientais no país. A região norte do Brasil apresenta os piores dados de cobertura de saneamento básico e disposição correta de resíduos sólidos com grandes possibilidades de contaminação dos ambientes por conta dessa problemática. Dessa forma, o objetivo do presente trabalho foi avaliar os parâmetros físico-químicos e bacteriológicos das águas superficiais e subterrâneas do aterro sanitário do município de Macapá e do antigo lixão do município de Santana, localizados no Estado do Amapá, para aferir se atendem aos padrões estabelecidos nas Resoluções CONAMA nº 357/2005 e nº 274/2000. Avaliou-se ainda os níveis e a distribuição de onze metais pesados no solo dessas áreas. As amostras de solo e água foram coletadas em outubro de 2020 e, posteriormente, realizadas as análises desses parâmetros em laboratório. Os resultados obedeceram aos valores determinados pela Resolução CONAMA 420/2009, mostrando que a maioria dos parâmetros estavam dentro da normalidade com exceção de alguns pontos que apresentaram alta DBO, cor e turbidez. O trabalho representou um instrumento básico para subsidiar tomada de decisão dos gestores municipais quanto a intervenções/melhorias nessas áreas de disposição final de resíduos sólidos, objetivando minimizar os impactos desses depósitos na qualidade da água e do solo e, consequentemente, apresentar padrões em conformidade com a legislação ambiental sobre o tema.