Temporal distribution and ecological risk assessment for pesticides in water from the north-central coastal zone of Sinaloa, Mexico.

Water contamination with pesticides is one of the major pollution problems in northwestern Mexico, and this is due to the extensive use of pesticides in agriculture. In this research, water samples of ten sampling sites (fishing grounds, beaches, and both) were analyzed in the search for 28 pesticides (organochlorines, organophosphates, pyrethroids, carbamates, among other chemical classes), supplemented with a calculation of the resulting potential environmental risk. Pesticides were separated from the matrix by liquid-liquid extraction and quantified by gas chromatography coupled to electron micro-capture (organohalogenated) and pulsed flame photometric detectors (organophosphates).

Spatio-temporal variation of nitrate based on Landsat 8 in Playa Colorada bay, Sinaloa, Mexico.

Characterizing water quality in coastal waters through spatial observations is challenging, due to spatial and temporal variations in water composition. Nitrate, an important compound for water quality assessment, has received little attention in estimates made from satellite measurements, even though it can be estimated using models generated from multispectral images. Since nitrate is a non-optically active parameter that can be correlated with optically active parameters, it was related to bands of the visible and infrared spectrum, captured in Landsat-8 images, and used to generate empirical models to estimate the spatio-temporal variation of nitrate concentration in the Playa Colorada Bay, in the state of Sinaloa Northwest Mexico.

Chlorpyrifos and Dimethoate in Water and Sediments of Agricultural Drainage Ditches in Northern Sinaloa, Mexico.

In northern Sinaloa state, Mexico, little is known on organophosphate pesticide transport and fate in agricultural drainage systems. Spatial and temporal variation of chlorpyrifos and dimethoate was assessed in two agricultural drainage ditches (Buenaventura and Burrión) and risk for aquatic life was estimated. Analysis was made by high performance liquid chromatography and risk estimates were determined following international reference frameworks.

Evaluation of contaminants in agricultural soils in an Irrigation District in Colombia.

This study evaluated the concentration and distribution of heavy metals (HM) (Cr, Ni, Pb, Cd, Hg, and Zn) and pesticides (organochlorine and organophosphorus) and the relationship of these pollutants with the physicochemical properties of agricultural soils in an Irrigation District (ID) in Colombia. Soils samples were analyzed for pH, humidity, organic matter, P total, N total, electric conductivity (EC), cation exchange capacity, and texture (% sand, clay and silt). Canonical correlation was used to determined relationship between soil properties and HM.

Contamination Level and Spatial Distribution of Heavy Metals in Water and Sediments of El Guájaro Reservoir, Colombia.

Heavy metals have become a subject of special concern worldwide, mainly due to high persistence in the environment, toxicity, biogeochemical recycling and ecological risk. Therefore, the objective of this investigation was to analyze the spatial-temporal distribution of heavy metals in water and sediments to determine the environmental status of El Guájaro Reservoir, where such studies have not been developed. Two measurement campaigns (dry and wet period) were carried out and eight sampling stations were selected.