Surface water quality assessment of the main tributaries in the lower São Francisco River, Sergipe

Britto, Fábio Brandão; Vasco, Anderson Nascimento do; Aguiar Netto, Antenor de Oliveira; Garcia, Carlos Alexandre Borges; Moraes, Gilsia Fabiane Oliveira; Silva, Marinoé Gonzaga da

doi:10.1590/2318-0331.231820170061

Acessibilidade / Reportar erro

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Scientific/Technical Article • RBRH 23 • 2018 • https://doi.org/10.1590/2318-0331.231820170061 copy

Surface water quality assessment of the main tributaries in the lower São Francisco River, Sergipe

Avaliação da qualidade da água superficial dos principais afluentes do baixo rio São Francisco em Sergipe

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

Contamination of water body by diffuse and point sources in springs has caused concerns mainly due to restrictions on its quality. The problem becomes more serious when contamination affects water for human consumption, as occurs in the river São Francisco, which supplies several municipalities of Sergipe. In this sense, the objective of the study was to evaluate water quality in eleven tributaries of the São Francisco river in its low course in the period from 2013 to 2014, in order to subsidize decision making by public management bodies operating in the region. For this purpose, it was used the Water Quality Index (WQI) and the Trophic State Index (TSI), as well the hierarchical grouping techniques associated to the samples to compare the different causes of contamination of each source. The lowest WQI values were observed in the rivers Betume and Jacaré and they were associated with high concentrations of coliforms related to the disposal of domestic effluents from the riverside cities. It was observed a tendency to eutrophication in the Jacaré stream, Santo Antônio, Pilões, Papagaio and Capivara rivers demonstrated by the high TSI in the rainy season. The results of the cluster analysis were close to their Euclidean distance, and showed that there were similarity relationships between the different water sources related to their parameters of water quality. In this piece of work, we also used the Factor Analysis resulted in the selection of five factors of water quality indicators which are mainly related to mineral content, organic matter, surface runoff and the level of pollution. Thus, it is concluded that the water quality of the São Francisco river tributaries is at a strong tendency towards contamination and that its tributaries need a constant monitoring for the environmental management decisions to be the most adequate for the sustainable survival of the riverside communities.

Keywords:
Environmental monitoring; Eutrophication; Factorial analysis and clustering

Parameters	Methodology	L.Q	Unity
OD	SMEWW, 2012, 4500-O C	−	mg O_2.L^-1
Thermophilic Coliforms	SMEWW9221B	−	NMP.100mL^-1
pH	SMEWW, 2012, 4500 H+ B	−	−
DBO	SMEWW, 2012, 5210-D	−	mg O_2.L^-1
Temperature	Multiparameter probe HANNA - HI9829	-	°C
N-amoniacal	Ion Chromatography (US EPA 300.0)	0.039	mg NH₃.L^-1
Nitrate	Ion Chromatography (US EPA 300.0)	0.011	mg N^-NO₃.L^-1
Total phosphorus	SMEWW,4500-P E	0.010	mg P.L^-1
Turbidity	SMEWW, 2012, 2130 B	−	UT
STD	SMEWW, 2012, 2510 A	−	mg.L^-1
Total hardness	SMEWW, 2012, 2340 B	−	mg CaCO₃.L^-1
Chlorophyll-a	Spectrophotometric determination	0.001	µg.L^-1
Sulfates	Ion Chromatography (US EPA 300.0)	0.050	mg SO₄.L^-1
Total iron	AAS	0.023	mg Fe.L^-1
Sodium	AAS	0.044	mg Na.L^-1
Chloride	SMEWW,4500-CL B	2.420	mg Cl^-.L^-1
Conductivity	Multiparameter probe HANNA - HI9829	−	µS.cm^-1

Water quality parameters	Weight (w)
OD	0.17
Thermophilic Coliforms	0.15
pH	0.12
BOD	0.10
Water temperature	0.10
Total Nitrogen	0.10
Total Phosphorus	0.10
Turbidity	0.08
TDS	0.08

Category	Weighting
Great	100 ≥ IQA ≥ 80
Good	80 ≥ IQA > 52
Acceptable	52 ≥ IQA > 37
Bad	37 ≥ IQA > 20
Terrible	20 ≥ IQA > 0

Category	Weighting
Ultra oligotrophic	IET ≤ 47
Oligotrophic	47 < IET ≤ 52
Mesotrophic	52 < IET ≤ 59
Eutrophic	59 < IET ≤ 63
Super eutrophic	63 < IET ≤ 67
Hyper eutrophic	IET > 67

Component	1	2	3	4	5
C. E	0.98	0.04	0.09	0.15	-0.03
Chloride	0.97	-0.09	0.10	0.13	-0.08
Sodium	0.96	-0.11	0.02	0.14	-0.11
STD	0.96	0.17	0.03	0.15	0.00
Hardness	0.95	-0.08	0.00	0.20	-0.08
Sulfate	0.80	-0.01	0.51	0.06	-0.06
pH	-0.02	0.97	-0.01	-0.02	0.09
OD	-0.02	0.95	0.01	-0.04	-0.13
DBO	-0.04	0.94	-0.03	-0.09	0.23
Ammonia	0.18	-0.06	0.91	0.01	0.02
C. T	0.09	-0.12	0.88	0.17	0.08
Nitrate	0.00	0.47	0.73	-0.13	0.01
Chlorophyll a	0.21	-0.16	-0.20	0.91	-0.06
TSI	0.15	-0.05	0.08	0.88	0.23
P	0.35	0.02	0.31	0.84	-0.04
WQI	0.04	-0.04	-0.19	-0.29	-0.86
Turbidity	-0.11	0.43	0.02	-0.24	0.71
Iron	-0.25	-0.46	-0.23	0.07	0.56

Associação Brasileira de Recursos Hídricos Av. Bento Gonçalves, 9500, CEP: 91501-970, Tel: (51) 3493 2233, Fax: (51) 3308 6652 - Porto Alegre - RS - Brazil
E-mail: rbrh@abrh.org.br

Acompanhe os números deste periódico no seu leitor de RSS

[1] E-mails: brandaobritto@hotmail.com (FBB), anderovasco@yahoo.com.br (ANV), antenor.ufs@gmail.com (AOAN), cgarcia@ufs.br (CABG), gislane.rocha.18@gmail.com (GFOM), marinoegonzaga@gmail.com (MGS)