Bioaccumulation of metal(loid)s in Cardisoma crassum and pollution assessment in a mangrove protected area in Mexico.

The bioaccumulation of several elements in "mouthless crabs" (Cardisoma crassum) and their concentrations in environmental samples were assessed in a mangrove forest within a natural protected area located in the middle of Puerto Vallarta, Mexico. The concentrations of Al, As, Ba, Cd, Cr, Cu, Fe, Ni, Pb, Sr, Si, V, and Zn in sediments, mangrove litterfall, and pore water and their bioaccumulations in the muscle and shell tissue of C. crassum were determined during rainy and dry seasons.

Effect of mono and divalent salts on the conformation and composition of a humic acid and on atrazine adsorption.

We investigated the effects of sodium and calcium chlorides on the conformation and composition of a purified Aldrich humic acid (PAHA), as well as on the adsorption of atrazine. The PAHA was treated with 1, 10, and 100 mM NaCl, CaCl, or a mixture of NaCl and CaCl (molar ratio 5:1) at pH 7.5 and 8.

Assessment of heavy metals in sediment of Aguamilpa Dam, Mexico.

The Aguamilpa Dam is part of the reservoir cascade system formed by four reservoirs in the middle and lower part of the Santiago River. For decades, this system has received urban and industrial wastewater from the metropolitan area of Guadalajara and the runoff of agricultural fields located in the river basin. The present study was carried out to obtain a preliminary assessment on the concentration distribution of heavy metals (Al, Ba, Cd, Cr, Cu, Fe, Hg, Mg, Ni, Pb, and Zn) in surface sediments of the Aguamilpa reservoir collected from 10 sampling stations.

Accumulation and regulation effects from the metal mixture of Zn, Pb, and Cd in the tropical shrimp Penaeus vannamei.

Environmental metal pollution is one of the major problems faced by humankind. This type of pollution affects aquatic systems (estuaries, coastal lagoons, etc.), which are very dynamic systems, therefore making the study of the effects on the organisms that inhabit them an essential issue.

Pollution by organochlorine pesticides in Navachiste-Macapule, Sinaloa, Mexico.

The lagoon system of Navachiste-Macapule is located in northern Mexico, in the state of Sinaloa, with an area of 24,000 ha. The main economic activity in the area is agriculture, and the lagoon lies next to the irrigation district ID-063 which covers 116,615 ha. The purpose of this study is to evaluate the levels of pollution generated by organochlorine pesticides (OC) in the surface sediments of the lagoon and in the agricultural drains of the ID-063 that are supposedly transported into the system as a result of agricultural activities and runoff from adjacent land.

Induction of morphological deformities and moulting alterations in Litopenaeus vannamei (Boone) juveniles exposed to the triazole-derivative fungicide tilt.

A tropical marine bioassay was developed with juveniles of Pacific white shrimp, Litopenaeus vannamei, in order to test the acute and sublethal toxicity of Tilt, which is the commercial formulation of the fungicide propiconazole. A 10-d acute toxicity and a 32-d sublethal test were performed. A median lethal concentration (LC50) was determined for different exposure times, resulting in a 24-h LC50 of 1167 (1101-1386) microg/L (concentration based on active ingredient propiconazole), and reaching a threshold LC50 (72-h) at 1043 (1018-1068) microg/L.