Ameaças à integridade dos córregos urbanos na Amazônia Sul-Ocidental

Catâneo, Dayana Tamiris Brito dos Santos; Oliveira, Marcela Alvares; Matos, Najla Benevides; Costa, Anna Cristyna Tavares da; Pereira, Fabrícia Simões; Santos, Tauanne Alves Putumujú; Silveira, Maria Áurea Pinheiro de Almeida; Doria, Carolina Rodrigues da Costa

Resumo

Neste estudo, caracterizamos a integridade física, hidromorfologia e limnologia de dez igarapés urbanos da Amazônia Sul-Ocidental com diferentes graus de antropização, com o objetivo de investigar como essas características covariam e identificar as ameaças à saúde desses ecossistemas. A integridade física dos igarapés foi avaliada por um Índice de Integridade de Habitat (HII), a hidromorfologia com base na largura, profundidade, vazão e tipo de substrato, e a caracterização limnológica através de 14 parâmetros físico-químicos durante as estações seca e chuvosa. Três igarapés foram classificados como preservados, dois como intermediários e cinco como degradados. Alterações antrópicas foram observadas nas características hidromorfológicas, principalmente na largura, profundidade e tipo de substrato em diferentes categorias de integridade. A análise limnológica revelou que as demandas químicas e bioquímicas de oxigênio dissolvido, nitrogênio amoniacal, nitrato, ferro dissolvido e sulfetos ultrapassaram os limites estabelecidos pela regulamentação brasileira de qualidade da água (CONAMA 357/2005). A Análise de Redundância (RDA) indicou a influência de tipos específicos de substrato nos parâmetros dos igarapés degradados, enquanto os igarapés preservados mostraram correlação entre o oxigênio dissolvido e as condições da mata ciliar. A análise de cluster enfatizou a importância da integração de métricas ambientais, hidromorfológicas e limnológicas para uma avaliação abrangente da saúde do ecossistema. Dada a heterogeneidade dos ecossistemas aquáticos amazônicos, este estudo poderá contribuir para o estabelecimento de critérios baseados em características regionais para avaliação precisa e orientação de políticas públicas que visem proteger e garantir a integridade desses ecossistemas.

Palavras-chave:
análise microbiológica; características limnológicas; Porto Velho; urbanização

[1] ^*Corresponding author: Dayana Tamiris Brito dos Santos Catâneo, e-mail: daybrito65@gmail.com

Stream code	Micro-basin	Area	Latitude	Longitude	Characteristics of the studied excerpt
Ig01	Bate Estaca Stream	Urban	-8,804731	-63,907608	Left bank of the stream: few residences; domestic sewage disposal; garbage in the surrounding area and in the stream. Right bank: belongs to an Army Protection Area, absence of residences, medium-sized vegetation with an average height of 10m, strong presence of pioneer species. Close to an area of rural properties with small and medium size farms.
Ig02	Grande Stream	Urban	-8,777872	-63,900783	Many residences on both banks; garbage in the surrounding area and in the stream; dumping of domestic sewage, nearby gas stations and car washes; vegetation marked by large open areas where tree vegetation is discontinuous. Presence of individuals of exotic species and extensive graminoid stratum. Low floristic diversity.
Ig03	Belmont Stream	Periurban	-8,687056	-63,864361	Located inside a municipal conservation unit. Absence of residences, sewage, and garbage discharges. Huge area with well-preserved vegetation and high specific diversity.
Ig04	Bate estaca Stream	Urban	-8,808041	-63,890761	Many residences on both banks; domestic sewage disposal; garbage in and around the stream. Presence of extensive graminoid stratum. Low floristic diversity.
Ig05	Belmont Stream	Urban	-8,755018	-63,870291	Many residences on both banks, being larger on the right bank; the arboreal vegetation is discontinuous. Presence of individuals of exotic species. Presence of extensive graminoid stratum.
Ig06	Belmont Stream	Urban	-8,756044	-63,859701	Located within an environmental protection area; many residences in the surrounding area but absent on the banks; evidence of domestic and industrial sewage; presence of individuals of exotic species and extensive graminoid stratum. Low floristic diversity.
Ig07	Tancredo Neves Stream	Urban	-8,764679	-63,834249	Many residences on both banks; excess discharge of domestic and commercial sewage. Presence of extensive graminoid stratum. Low floristic diversity.
Ig08	Grande Stream	Urban	-8,769907	-63,901383	Right bank with many residences; left bank a Municipal park. Discharge of domestic sewage on both banks; presence of a gas station and car wash nearby. Presence of extensive graminoid stratum. Low floristic diversity.
Ig09	Garças River	Periurban	-8,810971	-63,839371	Located in a little altered permanent preservation area. Absence of residences on both banks and sewage discharges; presence of waste in low quantities. Vegetation with an average height of 12m, important presence of pioneer species.
Ig10	Bate estaca Stream	Periurban	-8,833167	-63,943667	Permanent preservation area present, but altered, rural property area - small and medium size farms, receives effluents from the municipal landfill upstream of the sampled section, vegetation with an average height of 13m and high specific richness.

Limnological parameters	Abbreviation	Unit
Hidrogenionic potential	pH	-
Electrical Conductivity	EC	mS/cm^-1
Temperature	TP	°C
Dissolved oxygen	DO	mg/L
Turbidity	TB	NTU
Total ammonia nitrogen	NH₄⁺	mg/L N
Chloridae	Cl	mg/L Cl
Dissolved iron	FeD	mg/L Fe
Chemical oxygen demand	COD	mg/L O²
Biochemical oxygen demand	BOD	mg/L O³
Nitrate	NO₃^-	mg/L N
Nitrite	NO₂^-	mg/L N
Sulfate	SO₄^2-	mg/L SO₄
Sulfide	H₂S	mg/L S

Limnological parameters	Seasonal period	Stream
		Preserved				Intermediate			Degraded
		Ig03	Ig09	Ig10	Mean	Ig01	Ig02	Mean	Ig04	Ig05	Ig06	Ig07	Ig08	Mean
Ph	Wet	6.10	7.54	7.10	6.91	7.00	7.76	7.38	7.83	6.58	6.72	7.46	7.12	7.14
Ph	Dry	6.74	6.68	6.60	6.67	7.14	7.48	7.31	8.12	7.18	7.64	8.02	6.82	7.56
EC	Wet	0.01	0.02	0.17	0.07	0.15	0.17	0.16	0.29	0.16	0.25	0.34	0.19	0.25
EC	Dry	0.02	0.01	0.35	0.13	0.34	0.28	0.31	0.65	0.23	0.46	0.53	0.22	0.42
TP	Wet	25.04	23.58	26.18	24.93	26.90	27.72	27.31	34.00	29.04	29.60	30.20	27.40	30.05
TP	Dry	24.20	25.40	25.18	24.93	28.20	27.54	27.87	26.78	24.86	29.50	30.54	28.70	28.08
TB	Wet	0.00	3.91	1.93	1.95	7.13	61.69	34.41	39.40	11.40	16.80	62.30	65.60	39.10
TB	Dry	0.00	9.90	3.90	4.60	10.30	14.80	12.55	25.70	8.10	17.30	36.40	4.09	18.32
DO	Wet	5.65	6.20	5.70	5.85	4.30*	4.90*	4.60	5.43	6.72	5.38	5.18	5.06	5.55
DO	Dry	5.36	6.66	5.60	5.87	5.70	5.50	5.60	4.80*	5.20	4.66*	4.47*	2.90*	4.41
COD	Wet	72.00*	56.00*	88.00*	72.00	284.00*	68.00*	176.00	118.20*	609.00*	780.00*	800.00*	66.00*	474.64
COD	Dry	284.99*	232.40*	184.48*	233.96	331.26*	88.22	209.74	1990.00*	20.70	3.68	77.41*	3.89	419.14
BOD	Wet	19.00*	14.80*	11.00*	14.93	120.00*	20.00*	70.00	82.80*	460.00*	516.00*	510.00*	33.00*	320.36
BOD	Dry	131.14*	38.66*	29.14*	66.31	132.64*	42.84*	87.74	461.50*	19.50*	414.40*	35.03*	804.80*	347.05
Cl	Wet	0.40	0.30	0.60	0.43	0.40	0.50	0.45	0.40	0.40	0.40	0.30	0.40	0.38
Cl	Dry	28.40	21.30	56.80	35.50	56.80	49.70	53.25	48.90	35.50	35.50	49.70	42.60	42.44
FeD	Wet	0.39*	0.66*	0.65*	0.57	1.90*	2.81*	2.36	1.55*	0.57*	0.81*	1.63*	1.17*	1.15
FeD	Dry	0.37*	5.52*	0.74*	2.21	1.00*	0.38*	0.69	2.61*	0.23	0.10	0.89*	0.38*	0.84
NH₄⁺	Wet	0.50	0.21	1.57	0.76	0.56	1.87	1.22	1.96	0.07	1.78	1.11	0.81	1.15
NH₄⁺	Dry	0.12	0.02	1.70	0.61	2.43	0.12	1.28	6.00*	0.02	0.12	2.04*	0.88	1.81
NO₃^-	Wet	0.21	0.01	0.26	0.16	0.16	0.20	0.18	0.13	0.30	0.43	0.19	0.19	0.25
NO₃^-	Dry	0.12	1.94	22.90*	8.32	11.60*	1.12	6.36	0.86	13.80*	9.50	35.03*	2.08	12.25
NO₂^-	Wet	0.16	0.03	0.08	0.09	0.08	0.12	0.10	0.12	0.01	0.48	0.21	0.09	0.18
NO₂^-	Dry	0.02	0.02	0.02	0.02	0.20	0.07	0.14	0.01	0.01	0.06	0.02	0.06	0.03
SO₄^2-	Wet	23.10	11.66	26.12	20.29	32.97	37.30	35.14	0.30	33.70	27.37	13.94	22.51	19.56
SO₄^2-	Dry	0.12	4.75	6.94	3.94	3.48	11.54	7.51	12.14	2.23	8.57	9.72	9.15	8.36
H₂S	Wet	0.10*	0.02*	0.09*	0.07	0.05*	0.35*	0.20	0.10*	0.02*	0.09*	0.13*	0.10*	0.09
H₂S	Dry	0.03*	0.12*	0.00	0.05	0.00	0.01*	0.01	0.01*	0.04*	0.01*	0.03*	0.00	0.02

Brasil

Brasil

Ameaças à integridade dos córregos urbanos na Amazônia Sul-Ocidental

Resumo