Environmental diagnosis of metals in streams near sugarcane cultivation areas: current and historical analysis in the central region of the State of São Paulo

Abstract

In Brazil, innumerable regions of native landcover have been removed and replaced by agricultural cultivation, especially of sugarcane. In this culture, the application of fertilizers containing metals has caused impacts on the water resources causing contamination of stream sediments and occasioning bioaccumulation of metals in aquatic invertebrates. In the year of 2006, an environmental diagnosis of metals in sediments of streams located near sugarcane cultivation areas and in streams located in preserved areas, was published. That study pointed to high concentrations of metals in stream sediments in agricultural areas. These streams have been monitored over the last 10 years conducting analyses of metals and monitoring possible changes in land use. In the present paper, a historical comparison of metals contamination in the sediments of the same streams is conducted, aiming to present a status of 10 years later, analyzing 5 metals (Zn, Cd, Mn, Cr and Fe) found in the sediments of 8 streams, five located in areas of sugarcane cultivation and three located in preserved areas. This study also shows that there is higher concentration of metals in the sediments of streams near sugarcane cultivation than in preserved areas. The temporal historical evaluation showed high concentrations of Cd in 2016 when compared to the year 2006 for streams near sugarcane cultivation.

Sugarcane/peanut intercropping system improves the soil quality and increases the abundance of beneficial microbes

“…Crop rotation helps alleviate soil compaction in sugarcane cultivation systems [40]. As sugarcane cultivation may worsen estuarine water quality [8] in streams [41] as well as estuaries in the tropical marine protected area [42], we suspected that intercropping systems could help achieve the full usage of water and nutrients in sugarcane planting systems. Peanut is a model plant for intercropping [13], because intercropping reduces the populations of microbes that decrease peanut yield under continuous cropping [11].…”

The relationship between sediment metal concentration and Odonata (Insecta) larvae assemblage structure in Cerrado streams

“…In general, metals are essential to the biota. Organisms require trace quantities of some metals, such as cobalt, copper, manganese, zinc and iron to complete vital functions in the body (Mertz, 1986, Melo et al, 2012, Corbi et al, 2018. However, some metals have reference values that indicate toxicity if exceeded.…”

Impact of urbanization on the water quality of the Uberaba River and tributaries

“…Cadmium is extremely toxic to humans; this metal can lead to death even at low concentrations. It can derive from rechargeable batteries used in calculators and in similar devices, from the electrolytic coating of metals, from the discharge of industrial effluents resulting from galvanization processes or from rainwater leachate fertilizers (CORBI et al, 2018). All sampling sites recorded values higher than the one recommended by CONAMA 357/2005, with emphasis on sites B, C, E and F.…”

“…Toxic metals from agriculture, mining and industries are carried to water bodies from leaching sediments. High concentrations of heavy metals cause considerable damage to the environment due to the effectiveness of accumulation in the environment, as in sediments, plants and animals (CORBI et al, 2006;CORBI et al 2018). Thus, the analysis of the concentration of metals shows the degree of contamination of the aquatic environment (LUOMA;RAINBOW, 2008).…”