Contamination of the Conchos River in Mexico: Does It Pose a Health Risk to Local Residents?

Abstract

Presently, water contamination issues are of great concern worldwide. Mexico has not escaped this environmental problem, which negatively affects aquifers, water bodies and biodiversity; but most of all, public health. The objective was to determine the level of water contamination in six tributaries of the Conchos River and to relate their levels to human health risks. Bimonthly samples were obtained from each location during 2005 and 2006. Physical-chemical variables (temperature, pH, electrical conductivity (EC), Total solids and total nitrogen) as well as heavy metals (As, Cr, Cu, Fe, Mn, Ni, V, Zn, and Li) were determined. The statistical analysis considered yearly, monthly, and location effects, and their interactions. Temperatures differed only as a function of the sampling month (P < 0.001) and the pH was different for years (P = 0.006), months (P < 0.001) and the interaction years x months (P = 0.018). The EC was different for each location (P < 0.001), total solids did not change and total nitrogen was different for years (P < 0.001), months (P < 0.001) and the interaction years x months (P < 0.001). The As concentration was different for months (P = 0.008) and the highest concentration was detected in February samples with 0.11 mg L−1. The Cr was different for months (P < 0.001) and the interaction years x months (P < 0.001), noting the highest value of 0.25 mg L−1. The Cu, Fe, Mn, Va and Zn were different for years, months, and their interaction. The highest value of Cu was 2.50 mg L−1; for Fe, it was 16.36 mg L−1; for Mn it was 1.66 mg L−1; V was 0.55 mg L−1; and Zn was 0.53 mg L−1. For Ni, there were differences for years (P = 0.030), months (P < 0.001), and locations (P = 0.050), with the highest Ni value being 0.47 mg L−1. The Li level was the same for sampling month (P < 0.001). This information can help prevent potential health risks in the communities established along the river watershed who use this natural resource for swimming and fishing. Some of the contaminant concentrations found varied from year to year, from month to month and from location to location which necessitated a continued monitoring process to determine under which conditions the concentrations of toxic elements surpass existing norms for natural waters.

Coliform and Metal Contamination in Lago de Colina, a Recreational Water Body in Chihuahua State, Mexico

“…This effect is shown in Figure 10 where the mean of Ni before the Holy Week vacation period was 1.01 ppm, and this element increased to 1.77 ppm after the Holy Week vacation period. The values reported in this study relative to element Ni are higher than previously reported where it was found at 0.47 mg L –1 as the most contaminated location [19]. In addition, Ni values are higher than the findings of Holguin et al .…”

Development of a Water Quality Index (WQI) of an Artificial Aquatic Ecosystem in Mexico

“…Qian et al [11] found an increase in the physicalchemical variables during the rainy season, and consequently low levels of water quality. This is because some rain is acidic or can have more diluted contaminants [27]. Varnosfaderany et al [50] estimated a WQI for an ecosystem of an arid zone and found lower levels in August, which they attributed to agricultural activities that increase FC and DBO concentrations in water.…”

“…In the case of Mexico, there have been some studies concerning water pollution in the Conchos watershed, the Development of a Water Quality Index (WQI) of an Artificial Aquatic Ecosystem in Mexico 1297 most important watershed in the State of Chihuahua [24] as well as in tributaries like the San Pedro River [25]. The studies detected varying levels of pollution in the rivers and other water ecosystems in Chihuahua [26][27][28]. For instance, Gutierrez et al [29] determined contamination levels in the San Pedro River and the Francisco I Madero Dam.…”

Possibilities of High Resolution Inductively Coupled Plasma Optical Emission Spectrometry in the Determination of Trace Elements in Environmental Materials

“…Zn potential health concerns when detected in drinking water and in different aquatic environments [59][60][61][62]. The detection limits and the accuracy of analytical results are of prime importance.…”