Integrated assessment of metal contamination in sediments from two tropical estuaries.
In order to evaluate if sediment metal contamination is responsible for benthic degradation and identify possible reference sites in Todos os Santos Bay (TSB), comparisons between a highly impacted (Subaé) and less impacted (Jaguaripe) estuarine systems were made based on (i) field assessment of macrobenthic assemblage, (ii) sediment metal concentrations and (iii) chronic toxicity test with the tropical copepod Nitokra sp. Data were integrated by multivariate analysis (BIOENV and PCA) and the ratio-to-mean (RTMe) approach. Estuaries were divided into four different salinity zones to avoid misclassification of benthic conditions. Salinity was the main variable correlated to the benthic distribution in both estuaries, indicating that categories based on salinity features seem to be suitable in TSB. Correspondence among lines of evidence differed in low and high metal contaminated systems. Chronic toxicity was found along both the entire systems, being considerably higher in Jaguaripe. However, there was no clear evidence of metal contamination and benthic alteration in most stations of Jaguaripe. Although the concentrations of Sr and Cu were correlated to the benthic assemblage in Jaguaripe, it is unlikely that toxicity has been caused by these elements. The benthic assemblage distribution of Jaguaripe seems to be rather related to natural stressful conditions of transitional waters. Even though the Jaguaripe estuary might not be pristine, it can be used as a reference estuary for benthic assessment in TSB. Regarding the Subaé estuary, toxicity and Zn were also correlated to the benthic assemblage and most stations showed signs of benthic alteration and metal contamination. All lines of evidence were in agreement providing evidences that metal contamination might be responsible for benthic degradation in Subaé.
Laboratório de Ecologia Bentônica, PPGEcoBio, Instituto de Biologia, Rua Barão de Geremoabo s/n., Campus Ondina, Universidade Federal da Bahia, CEP 40170-115 Salvador, BA, Brazil. Electronic address: marcoskpl@gmail.com.
Marcos
M
Krull
Núcleo de Estudos sobre Poluição e Ecotoxicologia Aquática, UNESP, Campus Experimental do Litoral Paulista, São Vicente, SP, Brazil. Electronic address: dmabessa@clp.unesp.br.
Denis M S
DM
Abessa
Laboratório de Oceanografia Química, Instituto de Química, Universidade Federal da Bahia, INCT de Ambientes Marinhos Tropicais, Salvador, BA, Brazil. Electronic address: vanessahatje@gmail.com.
Vanessa
V
Hatje
Laboratório de Ecologia Bentônica, PPGEcoBio, Instituto de Biologia, Rua Barão de Geremoabo s/n., Campus Ondina, Universidade Federal da Bahia, CEP 40170-115 Salvador, BA, Brazil. Electronic address: franciscobarros.ufba@gmail.com.
Francisco
F
Barros
D000818:Animals; D004784:Environmental Monitoring; D063366:Estuaries; D019015:Geologic Sediments / Q000737:chemistry*; D007448:Invertebrates / Q000187:drug effects; D008670:Metals / Q000032:analysis* / Q000633:toxicity; D015999:Multivariate Analysis; D054712:Salinity; D014329:Tropical Climate; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
D008670:Metals; D014874:Water Pollutants, Chemical
Jaguaripe; Nitokra; Reference sites; Sediment quality triad; Subaé