Calidad del agua en estaciones seleccionadas del Lago Catemaco
	Concepto	Unidades	1990	1995	2000	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019
	Estación de medición
	Nombre		Catemaco	Catemaco	Catemaco	Catemaco	Catemaco	Catemaco	Catemaco	Catemaco	Catemaco	Catemaco	Catemaco	Catemaco	Catemaco	Catemaco	Catemaco	Catemaco	Catemaco
	Frecuencia de muestreo anual	Número	8	11	4	2	2	1	1	2	1	1	2	2	2	2	2	3	2
	Parámetros (mediana anual)
	Temperatura	°C	29	27	28.1	28.75	28.20	29.20	26.18	25.8	30.20	28	26.245	27.29	29.1	26.1	26.4	26.7	27.5
	Acidez	pH	6.00	7	8	8.32	8.01	8.31	8.76	8.08	8.60	8.21	7.805	7.74	7.7	8	8.25	7.3	8.35
	Oxígeno disuelto	mg O2 / l	7.755	7.58	7.44	6.57	7.42	5.11	nd	6.19	5.6	5.26	5.105	6.315	5.24	9.05	8.35	7.2	8.25
	Saturación de oxígeno	%	nd	nd	nd	nd	nd	nd	nd	nd	nd	nd	70.45	87.75	69.9	102.75	111.2	104.1	105.45
	DBO (20°C 5d)	mg O2/ l	4.28	4.18	5	<5	6.46	5.56	<5	<5	<5	4.26	3.8	2.85	4.5	3.4	3.195	<2	<2
	DQO (K2Cr2O7)	mg O2/ l	22	24.96	22.815	20.6	17.62	15.44	16.76	16.27	13.79	14.35	22.21	<10	24.535	26.76	<10	20.06	12.85
	Sólidos suspendidos	mg/ l	10	14	6.56	9.14	10.84	10	12	10.34	10.63	20	<10	<10	17	20	13.07	5	<10
	Sólidos disueltos	mg/ l	nd	84	89.36	72.87	76.17	76	70	91.67	79.37	372	72.96	87.68	87.04	92.8	142.72	170.88	129.6
	Nitrógeno total	mg N/ l	nd	2.912	nd	nd	nd	nd	nd	nd	nd	nd	0.586	0.7245	2.4995	1.3181	1.3198	1.0264	0.9300
	Nitratos	mg NO3/ l	<0.1	<0.01	0.06	0.26	0.44	0.16	0.15	<0.09	<0.09	0.09	0.018	0.002	0.3483	0.3855	0.0050	0.0125	0.0382
	Amonio	mg NH4/ l	nd	0.00265	nd	1.29	0.53	0.87	0.73	1.73	0.76	0.08	0.0371	0.1281	0.1569	0.1021	0.0525	0.0640	0.0265
	Fósforo total	mg P/ l	nd	nd	nd	nd	nd	nd	<0.09	<0.13	nd	0.14	0.026	0.068	0.0598	0.0517	0.0361	0.0397	0.0549
	Ortofosfatos	mg P/ l	nd	<0.01	nd	nd	nd	<0.09	<0.09	<0.15	<0.08	nd	0.018	0.02	0.0116	0.0213	0.0074	0.0306	0.0124
	Clorofila (en verano)	mg /m3	nd	nd	nd	nd	nd	nd	nd	nd	nd	nd	46.439	17	43.8808	27.6196	<0.1	7.1368	17.5072
	Coliformes fecales	NMP/100 ml	305	100	360	125	250	90	230	55	nd	2400	11	8.25	22	836	223	30	298.5
	Arsénico total	mg As/ l	nd	nd	nd	nd	nd	nd	nd	nd	nd	nd	<0.00139	<0.00139	<0.00139	<0.00139	<0.00139	<0.00139	<0.00139
	Cadmio total	mg Cd/ l	nd	nd	nd	nd	nd	nd	nd	nd	nd	nd	<0.0002	<0.0002	<0.0002	<0.0002	<0.0002	<0.0002	<0.00023
	Cromo total	mg Cr/ l	nd	nd	nd	nd	nd	nd	nd	nd	nd	nd	0.00272	0.00245	0.003347	0.0014795	<0.00088	<0.00088	<0.00088
	Plomo total	mg Pb/ l	nd	nd	nd	nd	nd	nd	nd	nd	nd	nd	<0.00154	<0.00154	<0.00154	0.0018465	<0.00154	<0.00154	<0.00154
	Mercurio total	mg Hg/ l	nd	nd	nd	nd	nd	nd	nd	nd	nd	nd	<0.00009	<0.00009	<0.00009	<0.00009	<0.00009	<0.00009	<0.00009
	Níquel total	mg Ni/ l	nd	nd	nd	nd	nd	nd	nd	nd	nd	nd	0.0013	0.0034	0.0010815	0.001106	<0.0002	<0.0002	<0.0002
	Notas:
	La fuente reporta los datos con medianas en vez de promedios debido a la alta sensibilidad de los promedios a los valores extremos.
	Ubicación geográfica de la estación de medición, Catemaco: 18° 24' 53'' lat. N; 95° 05' 08'' long. W.
	nd. No disponible
	Fuente:
	Comisión Nacional del Agua, Gerencia de Calidad del Agua, Junio 2020