TITLE:
Water Quality Assessment of a Tropical Mexican Lake Using Multivariate Statistical Techniques
AUTHORS:
Jessica Badillo-Camacho, Eire Reynaga-Delgado, Isela Barcelo-Quintal, Pedro F. Zarate del Valle, Ulrico J. López-Chuken, Eulogio Orozco-Guareño, Jorge Israel AlvarezBobadilla, Sergio Gomez-Salazar
KEYWORDS:
Multivariate Statistical Analysis, toxic Metals, Water Quality, Lake Pollution
JOURNAL NAME:
Journal of Environmental Protection,
Vol.6 No.3,
March
12,
2015
ABSTRACT: Water
quality of Mexican tropical lake Chapala was assessed through multivariate
statistical techniques, cluster analysis (CA) and principal component analysis
(PCA) at ten different monitoring sites for ten physicochemical variables and
six metals. This study evaluated and interpreted complex water quality data
sets and apportioned of pollution sources to get better information about water
quality. From descriptive statistics results, the highest concentrations of
metals occurred during the dry season, and this trend was explained by the fact
that an unusual rainy event occurred during the month of February 2009 and
brought metals into the lake by runoffs from nearby mountains. According to
international criteria for water consumption by aquatic organisms [USEPA], only
Zn concentration values were below these criteria whereas the values of Ni, Pb,
Cd and Fe were above the corresponding values set in these criteria (Ni: 52 μg·L-1,
Pb: 2.5 μg·L-1, Cd: 0.25 μg·L-1, and Fe: 1000 μg·L-1).
The correlations were observed by PCA, which were used to classify the samples
by CA, based on the PCA scores. Seven significant cluster groups of sampling
locations—(sites
4 and 5), (sites 3 and 9), (site 7), (site 10), (sites 2 and 6), (site 8) and
(site 1)— were detected on the basis of similarity of their water quality. The
results revealed that the stress exerted on the lake caused by waste sources
follows the order: domestic > agricultural > industrial.