ABSTRACT
La deposición de nutrientes por vía atmosférica tiene graves impactos sobre la ecología de bosques y cuerpos de agua templados. Sin embargo, su importancia en cuerpos de agua neotropicales casi no ha sido estudiada. En este artículo se cuantifica la contribución de nitrógeno inorgánico disuelto (NID, [NO3--N + NH4+-N]) y fósforo inorgánico soluble (FIS, [PO4-3-P]) depositados en bulto sobre superficies húmedas por vía atmosférica hacia el lago Atitlán (Guatemala). Las cargas estimadas de NID y FIS consecuencia de la deposición atmosférica directa (depositada sobre la superficie del lago) fueron de 151.2 ton/año y 5.6 ton/año, respectivamente. Con estos resulta-dos, se estima que el aporte de FIS por deposición atmosférica al lago Atitlán es comparable al de sus principales ríos tributarios, y de casi el doble para el ingreso de NID. Las estimaciones para el lago Atitlán son mayores que lo reportado para otros lagos. Nuestro estudio proporciona información básica para entender la eutrofización del lago Atitlán, enfatizado en la importancia de la deposición atmosférica como contribuyente al deterioro de este cuerpo de agua. Además, demuestra la necesidad de extender este tipo de estudio a otras cuencas neotropicales y la importancia de minimizar este impacto.
Atmospheric nutrient deposition has serious impacts on the ecology of forests and temperate water bodies nevertheless its importance in Neotropical water bodies has hardly been studied. Here we quantify the contribution of bulk atmospheric deposition on wet surfaces of dissolved inorganic nitrogen (DIN,[NO3--N + NH4+-N])and soluble inorganic phosphorus (SIP, [PO4-3-P])into Lake Atitlán (Guatemala). The estimated NID and SIP loads from this direct deposition on the lake surface were respectively, 151.2 tons/year and 5.6 tons/year. With these results, we estimated that the SIP input from atmospheric deposition to Lake Atitlán is comparable to that from the lake's main tributary rivers, whereas for DIN entry this is almost twice as much. Estimates for Lake Atitlán are higher than those reported for many lakes. Our study provides basic information towards understanding the eutrophication of Lake Atitlán, emphasizes the importance of atmospheric deposition in this process and the need for additional studies to document the process in neotropical watersheds.
Subject(s)
Humans , Phosphorus/analysis , Lakes/analysis , Nitrogen/analysis , Rain/chemistry , Temperature , Wind , Basins , Nutrients , EutrophicationABSTRACT
O presente trabalho objetivou analisar a contaminação de águas superficiais e de chuvas por agrotóxicos em dois municípios do estado do Mato Grosso, Lucas do Rio Verde e Campo Verde, situados entre os maiores produtores de soja, milho e algodão do estado e do país. A metodologia analítica combinou o uso de técnicas cromatográficas em amostras de água superficial e de chuva com análises ecotoxicológicas do impacto da contaminação por agrotóxicos sobre espécies bioindicadoras. Resultados das análises mostraram a presença de resíduos de diferentes agrotóxicos nas amostras de águas superficiais e de chuva coletadas nos dois municípios. Associados a estes dados, resultados das análises ecotoxicológicas mostraram a presença de anomalias em uma espécie de anfíbio anuro coletado em uma das duas localidades, compatíveis com exposição a agrotóxicos. Os resultados aqui apresentados e discutidos apontam para a degradação da qualidade de recursos hídricos da região, causada pelo uso intensivo de agrotóxicos na agricultura, incluindo fontes de água de consumo humano e de chuvas, amplificando o risco de contaminação para além das áreas de plantio.
This study sought to analyze groundwater and rainwater contamination by pesticides in two municipalities (Lucas do Rio Verde and Campo Verde) of Mato Grosso state. The area is Brazil's mid-west situated among the major soybean, corn and cotton producers in the state and the country. The analytical methodology combined chromatographic techniques on groundwater and rainwater samples with eco-toxicological analyses of the impacts of contamination by pesticide on bio-indicator species. The results revealed the presence of different pesticide residues in the groundwater and rainwater samples collected in the two municipalities. In conjunction with this data, results of the eco-toxicological tests revealed the presence of anomalies in a bio-indicator species collected in one of the two study sites compatible with exposure to pesticides. The results presented and discussed here highlight the degradation of water resources in the region, caused by the intensive use of pesticides in agriculture, including the contamination of drinking water sources and rain, broadening the risk of contamination beyond the cultivated areas.
Subject(s)
Agriculture , Groundwater/chemistry , Pesticide Residues/analysis , Pesticides/analysis , Rain/chemistry , Water Pollutants, Chemical/analysis , Water Pollution, Chemical , BrazilABSTRACT
Six storm periods were monitored from November 2002 to September 2005 at two stations of a receiving pond of the stormwater runoff from a small urban catchment of the city of Santa Fe, Argentina. Weekly samples were taken before and after rain events under different conditions of temperature, pluvial precipitation, and duration of the previous dry period. A sampling station was established at the outlet of the catchment (S1) and another one near the outlet of the receiving pond (S2). Both stations differed significantly in their dissolved oxygen (DO) concentration, temperature, transparency, and zooplankton composition. The concentrations of nutrients and BOD5 values indicated permanently eutrophic condition at both stations. After rainstorms, the concentrations of lead, zinc and suspended solids showed a marked increase. The zooplankton composition at S1 was characterized by the abundance of protozoans (Dexiostoma campylum (Stokes) Didinium nasutum Muller, Plagyopila cf nasuta, and Bdelloidea rotifers (Philodina sp and Rotaria sp), while Monogononta rotifers and small cladocerans were dominant at S2. The most abundant species were the rotifers Platyias quadricornis (Ehrenberg), Mytilina ventralis (Ehrenberg) and Lepadella ovalis (Muller), and the cladoceran Chydorus pubescens Sars.
Subject(s)
Animals , Argentina , Biodiversity , Biological Assay , Cities , Daphnia/drug effects , Fresh Water/chemistry , Rain/chemistry , Toxicity Tests , Waste Disposal, Fluid , Water Pollutants, Chemical/analysis , Water Supply , Zooplankton/classificationABSTRACT
The purpose of this study is to analyze the chemical composition of wet precipitation in samples collected at three stations in the Candiota region in the Brazilian state of Rio Grande do Sul (RS). Samples were collected in 2004. Variables analyzed in wet precipitation were pH, conductivity, and concentration of Cl-, NO3-, SO4(2-) F-, Na+, Ca2+, Mg2+, K+, NH4+, Cu, Zn, Fe, Mn, Pb, Ni, Cd, Co, and Cr. SO2 and NO2 distribution over the time were also evaluated. Results have showed that pH < 5.6 are found mostly at Candiota airport (85 percent), followed by Aceguá (72 percent) and Três Lagoas (65 percent). Enrichment Factor of the studied ions in wet deposition revealed higher Ca2+ and SO4(2-) enrichment in Três Lagoas. Factor Analysis applied to metals and major ions allowed identifying the major sources. While Cl-, Na+, Mg2+ are of marine origin, SO4(2-), NO3-, NH4+ ,F- come from anthropogenic sources. Except for Fe and Mn originating from the soil dust, the metals studied showed to have anthropogenic influence The average SO2 and NO2 concentration, as well as SO4(2-) and NO3- in wet precipitation in the Candiota region showed higher concentrations during the warmer months.
O objetivo deste estudo é analisar a composição química da precipitação úmida em amostras coletadas em três estações na região de Candiota no Estado do Rio Grande do Sul (RS) Brasil. Amostras foram coletadas em 2004. Variáveis analisadas na precipitação úmida foram pH, condutividade e concentração de Cl-, NO3-, SO4(2-) F-, Na+, Ca2+, Mg2+, K+, NH4+, Cu, Zn, Fe, Mn, Pb, Ni, Cd, Co e Cr. Distribuição no tempo de SO2 e NO2 também foi avaliada. Resultados mostraram que pH < 5,6 são encontrados em sua maioria no aeroporto de Candiota (85 por cento), seguidos pelo Aceguá (72 por cento) e Três Lagoas (65 por cento). Fator de Enriquecimento dos íons estudados na deposição úmida revelou maior enriquecimento de Ca2+ e SO4² em Três Lagoas. Análise Fatorial aplicada aos metais e íons maiores permitiu identificação de fontes maiores. Enquanto Cl-, Na+, Mg2+ são de origem marinha, SO4(2-), NO3-, NH4+, F- são provenientes de fontes antropogênicas. Exceto Fe e Mn originários de poeira do solo, os metais estudados mostraram ter influência antropogênica. A média da concentração de SO2 e NO2, bem como SO4(2-) e NO3- na precipitação úmida na região de Candiota mostrou maiores concentrações durante os meses mais quentes.
Subject(s)
Environmental Monitoring/methods , Metals, Heavy/analysis , Rain/chemistry , Brazil , Factor Analysis, Statistical , SeasonsABSTRACT
The study was conducted to assess the physico-chemical and bacteriological quality of stored rain water in the ferrocement tanks of Alappuzha District, Kerala (India). Representative water samples were collected on random basis from ten stations (S1 to S10) with rain water harvesting facility during the periods January 2006 and April 2006. The present study revealed that the physico-chemical characteristics of stored rain water analysed during the winter and summer seasons were within the permissible drinking water standard limits prescribed by W.H.O. Microbiological analysis showed that most of the stored rainwater samples had microbial contamination in both winter and summer seasons and the bacterial count was above the permissible standards for drinking water. Faecal coliforms were also detected in the stored rain water samples collected from eight stations during the summer season. The present study revealed that the quality of stored rain water is suitable for drinking purpose in terms of physical and chemical characteristics. However, disinfection is necessary to make the water microbially safe for drinking purposes.
Subject(s)
Environmental Monitoring , Fresh Water/chemistry , India , Rain/chemistry , Seasons , Water Pollutants/analysisABSTRACT
OBJECTIVE: Test the resistance to antibiotics and heavy metals of E. coli strains isolated from storm sewer water and adjacent seawater samples from three beaches (Meio, Area Preta and Ponta Negra) in the city of Natal/RN/Brazil, and determine the association among those characteristics. METHODS: A total of 98 strains of E. coli, 50 from storm sewers and 48 from the seawater were analyzed resistance to several antimicrobials by disk diffusion and agar dilution and to heavy metals by dilution in plates with aqueous solutions of CuSO4 incorporated to Mueller Hinton agar in concentrations of 100, 150, 200 and 250 ig/mL and HgCl2 in concentrations of 5, 10, 20, 30, and 50 ig/mL. Standard strains were used as control. RESULTS: Among the twelve antimicrobials tested, 28 (28.5%) of E. coli strains showed resistance to different antimicrobials drugs to seven. The greatest resistance rate was to tetracycline (46.4%), ampicillin (39.3%) and cephalothin (32.1%), with the remainder (nitrophurantoine, nalidixic acid, sulfatomexazol-trimethoprin and chloramphenicol) at lower percentages. Among the heavy metals, all the strains (100%) were resistant to zinc and to copper in the largest concentration (250 ig/mL), and 18.4% were resistant to HgCl the 50 ig/mL. Ten (55.5%) of the E. coli strains resistant to Hg were associated to resistance to antibiotics. CONCLUSION: These results suggest the existence of extra chromosomal genes in E. coli strains isolated from storm sewer water and adjacent seawater, which encoders of the resistance to antibiotics and heavy metals.