Rural and Urban Streams: Anthropogenic Influences and Impacts on Water and Sediment Quality

Abstract

The Pirapó river watershed (Paraná State, Brazil) compounds a relatively industrialized and urbanized region, undergoing great pressure from the discharge of industrial, agricultural and domestic wastes. We evaluated the environmental quality of ten streams belonging to this watershed in April and June 2008 by performing acute and chronic toxicity tests with Daphnia similis and Ceriodaphnia silvestrii from water and sediment samples. We tested the hypothesis that the streams located in urban areas are more exposed to the influence of pollutants, than those outside the city limits. In addition, we obtained the measures of physical and chemical parameters, and identified the main polluted sources. Contrary to what was expected, the rural streams were more toxic than those located in urban area. These results demonstrate that the water bodies located in rural areas are being affected by the pollution of aquatic ecosystems as far as those found in urban areas, requiring the same attention of environmental managers in relation to its monitoring. IntroductionThe increasing contamination of aquatic, terrestrial and atmospheric environments with substances from human activities has attracted attention from political organizations and environmental managers, as well as from society as a whole. Many researchers have searched for solutions through effluent treatment, solid waste recycling and clean energy production. In spite of their efforts, many counties still do not possess sewage collection networks that include all inhabitants or suitable local systems for garbage disposal. Hence, some domestic discharges and industrial effluents reach watercourses untreated, causing environmental damage.Due to the complexity and variability of organic and inorganic compounds that enter water bodies and because little information about the interactions between these substances is known, it is not possible to establish allowable discharged concentrations using only the physical and chemical analyses commonly performed by environmental managers. The char- acterization of aquatic systems needs to go beyond routine analyses to evaluate the overall effects of pollutants on the environments and organisms. The evaluation of effects on the biological components through biomonitoring and toxicity tests is a more effective tool for predicting or detecting several types of impacts (COSTA and ESPÍNDOLA, 2000).Toxicity tests are widely used, but a great majority is restricted to aquatic compartment, even though the importance of sediment to aquatic ecosystems is now recognized (COSTA and ESPÍNDOLA, 2000). Although tests with surface water, groundwater, industrial and domestic wastewater, are responsible for the detection of toxic substances and control the level of pollutants entering the aquatic ecosystems, monitoring should also include sediment, because it has a high ability to accumulate compounds that may eventually be released to the water column due to changes (physical, chemical and biological -bioturbation) in environmental condit...

Effect of land use on the composition, diversity and abundance of insects drifting in neotropical streams

“…With a catchment area of approximately 5,076 km 2 , the Pirapó River covers an extension of 168 km to its mouth in the Paranapanema River, approximately 50 km from the city of Maringá, being responsible for the water supply of the municipality (SANEPAR, 2002). The climate in the region is Subtropical Humid Mesothermal, with average annual temperature of 20 °C, with dry winters and concentration of rainfall in the summer months (Kuhl et al, 2010).…”

“…The Nazaré stream (23° 24' 04,64" S; 51° 58' 03,57" W) is located in the urban perimeter, with 34.8% of impervious surfaces and 100% of urbanization, affected by storm sewer, domestic sewage and surface leaching. The Remo stream (23° 21' 39,26" S; 52° 01' 02,48" W) is located in rural area with 0.5% of impervious surfaces and 0.5% of urbanization, having agricultural effluents as a source of pollution (Kuhl et al, 2010;Cunico et al, 2012).…”

Does the habitat structure control the distribution and diversity of the Odonatofauna?

“…The studied streams are continuously altered by human activities, with variation in the major sources of pollutants. The urban streams receive primarily domestic sewage, and rural streams receive effluents mainly from agriculture (Kühl et al, 2010).…”

Protozoa ciliates community structure in urban streams and their environmental use as indicators

“…Such studies have focused on the diverse effects of human activities on these environments (Kühl et al, 2010;Camargo and Velho, 2011;Cunico et al, 2012).…”