title: Ecotoxicological risks of calcium nitrate exposure to freshwater tropical organisms: Laboratory and field experiments.
abstract: This study aimed to analyze laboratory and field data to assess the ecotoxicological risks of calcium nitrate exposure to freshwater tropical biota. Short-term laboratorial tests resulted in estimated EC₅₀ values of 76.72 (67.32-86.12)mg N-NO₃₋ L(-1) for C. silvestrii and 296.46 (277.16-315.76) mg N-NO₃₋ L(-1) for C. xanthus. Long-term laboratorial tests generated IC₂₅ values of 5.05 (4.35-5.75) and 28.73 (26.30-31.15) mg N-NO₃₋ L(-1) for C. silvestrii and C. xanthus, respectively. The results from in situ mesocosm experiments performed in the Ibirité reservoir (a tropical eutrophic urban water body located in SE Brazil) indicated that C. silvestrii and C. xanthus were not under severe deleterious acute impact due to the treatment because the higher nitrate concentrations determined were 5.2 mg N-NO₃₋ L(-1) (t=24 h; sediment-water interface) and 17.5 mg N-NO₃₋ L(-1) (t=600 h; interstitial water). However, an abrupt decrease in the densities of Cyanophyceae members and other benthic taxa was observed. In summary, the present work contributes greatly to the toxicity data linked to two taxonomically distinct organisms that have never been screened for calcium nitrate sensitivity. Furthermore, considering the problem of the management and restoration of eutrophic environments, our study reports a comprehensive field assessment that allows the elucidation of the possible toxic impacts caused by the addition of calcium nitrate (a remediation technique) on aquatic and benthic organisms as well as the implications on the aquatic ecosystem as a whole, which may greatly allow expanding the current knowledgebase on the topic.
authors: Laboratório de Biogeoquímica Ambiental/ Núcleo de Estudos, Diagnósticos e Intervenções Ambientais, Departamento de Química, Universidade Federal de São Carlos, Caixa Postal 676, Rodovia Washington Luiz, km 235, CEP 13565-905 São Carlos, SP, Brazil. Electronic address: asueitt@gmail.com.
authors: A P E
authors: AP
authors: Sueitt
authors: Laboratório de Biogeoquímica Ambiental/ Núcleo de Estudos, Diagnósticos e Intervenções Ambientais, Departamento de Química, Universidade Federal de São Carlos, Caixa Postal 676, Rodovia Washington Luiz, km 235, CEP 13565-905 São Carlos, SP, Brazil.
authors: T M
authors: TM
authors: Yamada-Ferraz
authors: Laboratório de Biogeoquímica Ambiental/ Núcleo de Estudos, Diagnósticos e Intervenções Ambientais, Departamento de Química, Universidade Federal de São Carlos, Caixa Postal 676, Rodovia Washington Luiz, km 235, CEP 13565-905 São Carlos, SP, Brazil.
authors: A F
authors: AF
authors: Oliveira
authors: Centro de Recursos Hídricos e Ecologia Aplicada, Universidade de São Paulo, São Carlos, SP, Brazil.
authors: C M R
authors: CM
authors: Botta
authors: Laboratório de Biogeoquímica Ambiental/ Núcleo de Estudos, Diagnósticos e Intervenções Ambientais, Departamento de Química, Universidade Federal de São Carlos, Caixa Postal 676, Rodovia Washington Luiz, km 235, CEP 13565-905 São Carlos, SP, Brazil.
authors: P S
authors: PS
authors: Fadini
authors: Laboratório de Poços de Caldas, Comissão Nacional de Energia Nuclear, Poços de Caldas, MG, Brazil.
authors: M R L
authors: MR
authors: Nascimento
authors: Centro de Pesquisas Leopoldo Américo Miguez de Mello/Petrobras, Rio de Janeiro, RJ, Brazil.
authors: B M
authors: BM
authors: Faria
authors: Laboratório de Biogeoquímica Ambiental/ Núcleo de Estudos, Diagnósticos e Intervenções Ambientais, Departamento de Química, Universidade Federal de São Carlos, Caixa Postal 676, Rodovia Washington Luiz, km 235, CEP 13565-905 São Carlos, SP, Brazil.
authors: A A
authors: AA
authors: Mozeto
mesh_terms: D000818:Animals; D059001:Aquatic Organisms; D001938:Brazil; D017610:Calcium Compounds / Q000633:toxicity*; D033361:Cladocera; D017753:Ecosystem; D054750:Ecotoxicology; D005618:Fresh Water; D009566:Nitrates / Q000633:toxicity*; D012306:Risk; D018675:Toxicity Tests; D014329:Tropical Climate
chemical_list: D017610:Calcium Compounds; D009566:Nitrates; C059948:calcium nitrate
keywords: Acute toxicity; Chronic toxicity; Eutrophication; Remediation; Water pollution