Rosa M. Infanzón

Organochlorine pesticide residues in cow's milk and butter in Mexico.

This monitoring study of 355 samples of cows milk collected from the central region of Veracruz state and 448 samples of national butter brands was conducted to determine the contamination levels of organochlorine pesticides. The results obtained for mean HCH levels were 0.094 and 0.093 mg/kg on fat basis in cows milk and butter samples, respectively. The mean DDT levels were 0.159 and 0.049 mg/kg, respectively. In relation to cows milk, the total HCH levels in Veracruz state were higher but total DDT levels were comparable to those reported in other countries. On the other hand, organochlorine levels detected in national brand butter samples were lower than those found in other countries, where these pesticides are still used in sanitary actions. These results confirmed that dairy products in Mexico presented organochlorine pesticide residues (owing to their use in sanitary actions) indicating a human exposure through these food products.

Organochlorine pesticide residues in adipose tissue of Mexicans

Concentrations of organochlorine insecticide residues such as DDT, DDE, gamma- and beta-HCH were determined in human adipose tissue samples obtained during autopsies from urban and suburban areas of Veracruz city, the state of Veracruz and out-of-state areas, collected during 1988 and 1991. The mean levels of total DDT, which constitutes the predominant accumulated pesticide, decreased from 17.45 mg/kg in 1988 to 14.06 mg/kg in 1991. The highest levels of total DDT were determined in persons from suburban areas of Veracruz city and among persons over 51 years old with the highest levels of contamination observed in patients dying of cardiovascular disorders.

A rapid and low cost monitoring method for fluvalinate determination in honey

A simple analytical method for determining Fluvalinate residues in honey is described. Analyses were carried out by gas chromatography-electron capture detector (ECD), using a borosilicate glass column packed with 3% SP-2100. Fluvalinate residues were extracted from honey samples with n-hexane and acetic acid. Mean recoveries ranged from 98.1±6.9 to 101.9 ±7.6% with SD < 10 after standard addition of 20, 50 and 500 μg. No interferences of other pesticides were detected. ECD responses were linear within the range studied of 10-50 pg of Fluvalinate with a coefficient of determination 0.994, and a detection limit of 3 mg kg -1 was established. The use of a packed column allowed the exclusion of an expensive clean-up step. This fast, low-cost analytical method is adequate for monitoring studies of honey samples.

Organochlorine Pesticide Levels in Blood Serum Samples Taken at Autopsy from Auto Accident Victims in Veracruz, Mexico

Abstract Samples of human blood sera (N = 118) for the determination of organochlorine pesticide levels were obtained at autopsy from auto accident victims in Veracruz, Mexico, during the years 2000 and 2001. The presence of hexachlorobenzene (HCH), beta-hexachlorocyclohexane (β-HCH), 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (p,pǐ-DDE), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,pǐ-DDT), and o,pǐ-DDT was confirmed by gas-liquid-electron-capture detection chromatography. During the years 2000 and 2001, the respective mean levels of (a) HCB, (b) β-HCH, (c) p,pǐ-DDE, (d) o,pǐ-DDT, (e) p,pǐ-DDT, and (f) total DDT were (a) 2.1 ng/ml and 1.4 ng/ml, (b) 3.0 ng/ml and 3.6 ng/ml, (c) 21.1 ng/ml and 23.8 ng/ml, (d) 1.2 ng/ml and 0.8 ng/ml, (e) 3.3 ng/ml and 2.5 ng/ml, and, finally, (f) 25.4 ng/ml and 27.1 ng/ml, respectively. High levels of persistent organochlorine pesticides were—and continue to be—present in the blood of individuals who live in Mexico. Levels of insecticide metabolites (e.g., β-HCH, p,pǐ-DDE) in blood have increased during recent years (1997–2001), but levels of p,pǐ-DDT decreased in 2001 because the use of DDT for the control of malaria in Mexico was restricted.