Assessment of water quality and concentration of heavy metals in fishes in the estuary of the Perizes River, Gulf of Maranhão, Brazil.

The present study evaluated physicochemical and microbiological variables of the water in the estuary of the Perizes River in the state of Maranhão, Brazil, heavy metal levels in the muscle tissue of fish species (Genyatremus luteus, Macrodon ancylodon, Sciades herzbergii and Mugil curema). Data were collected bimonthly between Nov 2017 and May 2018. Physicochemical variables of the water (pH, salinity, conductivity, dissolved oxygen and turbidity). The microbiological analysis of the water was performed using the multiple-tube method. Atomic absorption spectrophotometry was used for the determination of heavy metals in muscle tissue of the fishes. The results revealed minor fluctuations in the environmental variables, with the exception of turbidity. The microbiological quality of the water was associated with acceptable bacterial levels. Regarding heavy metals, acceptable concentrations were found of Al, Cu, Fe, Mn, Zn, Ni and Hg, whereas Cr and Pb were found at concentrations higher than the maximum.

Determination of metals in estuarine fishes in a metropolitan region of the coastal zone of the Brazilian Amazon.

The aim of the present study was to determine concentrations of cadmium, copper, chromium, manganese and iron in fishes in the São Marcos (SMB), São Jose (SJB) and Arraial (AB) Bays. Metal concentrations were determined using inductively coupled plasma optical emission spectrometry. Mean Cd and Cr levels were above the permissible limits set by different international or national guidelines in all three bays, whereas copper levels were well below the maximum acceptable limit. High concentrations of iron were found in all species analyzed, whereas high concentrations of manganese were found, especially in specimens caught in SJB. Spatial analysis indicated significant differences among the elements investigated. Copper was correlated more with SMB and AB as well as the species Macrodon ancylodon (carnivore) and Sciades herzbergii (omnivore). Cadmium and iron were strongly associated with AB and SJB, while manganese was only associated with SJB, mainly in carnivorous and herbivorous species.

Anthropogenic litter on the macrotidal sandy beaches of the Amazon region.

Coastal zones, which are strategic points of considerable importance to the tourism industry, are among the environments most affected by anthropogenic debris. Thus, it is crucial to monitor and implement management programs to provide immediate solutions. Here, we aimed to evaluate anthropogenic litter along 21 macrotidal sandy beaches in the Amazon region. Indices and multivariate statistical analyses were used to identify spatial patterns of pollution, as well as sources and lifetime of the items. A total of 20,286 items were collected, with an average density of 0.19 items/m2 and a predominance of plastics. Litter was associated with tourist and recreational activities. The lifetime of most items was <1 year. All beaches had intermediate levels of pollution. The analyses identified varying patterns of anthropogenic litter related to the cleaning frequency and waste item typologies. In conclusion, pollution of macrotidal beaches in the Amazon region is an emerging problem that requires measures to prevent and mitigate the impacts on this ecosystem and to reconsider the form of production and consumption of plastic waste.