Cytotoxicity and Genotoxicity Effects of a Magnetic Zeolite Composite in Daphnia magna (Straus, 1820).

Zeolite type 5A combined with the magnetic properties of maghemite nanoparticles facilitate the rapid absorption of heavy metals, which makes them an interesting proposal for the remediation of water contaminated with lead and arsenic. However, the physicochemical analysis related to concentration and size for the use of this magnetic zeolite composite (MZ0) in water bodies and the possible toxicological effects on aquatic fauna has not yet been carried out. The main objective of the research work is to determine lethal concentrations that cause damage to Daphnia magna based on LC50 tests, morphology, reproductive rate, and quantification of the expression of three genes closely involved in the morphological development of vital structures (Glass, NinaE, Pph13). To achieve this objective, populations of neonates and young individuals were used, and results showed that the LC50 for neonates was 11,314 mg L-1, while for young individuals, it was 0.0310 mg L-1. Damage to morphological development was evidenced by a decrease in eye size in neonates, an increase in eye size in young individuals, variations in the size of the caudal spine for both age groups, and slight increases in the heart size, body, and antenna for both age groups. The reproductive rate of neonates was not affected by the lower concentrations of MZ0, while in young individuals, the reproductive rate decreased by more than 50% from the minimum exposure concentration of MZ0. And for both ages, Glass gene expression levels decreased as the MZ0 concentration increased. Also, the MZ0 evidenced its affinity for the exoskeleton of D. magna, which was observed using both light microscopy and electron microscopy. It is concluded that MZ0 did not generate significant damage in the mortality, morphology, reproductive rate, or gene expression in D. magna at lower concentrations, demonstrating the importance of evaluating the possible impacts on different life stages of the cladoceran.

High incidence of lung cancer and malignant mesothelioma linked to erionite fibre exposure in a rural community in Central Mexico.

OBJECTIVE: To report the high incidence of lung cancer (LC) and malignant mesothelioma (MM) linked to environmental exposure to erionite fibres in a rural village of central Mexico. METHODS: This is a retrospective survey of clinical and mortality records from the years 2000-2012, accompanied by an environmental survey for nine Group-1 lung and pleura carcinogenic agents listed by the International Agency for Research on Cancer (IARC). RESULTS: Out of a total of 45 deaths between 2000 and 2012, 14 deaths correspond to different neoplasms of the lung, and at least four deaths to MM. The ages at diagnosis of MM were between 30 and 54 years. Annual age-standardised mortality rates per thousand due to LC and MM in the village (age >20 years) are 7.09 and 2.48 for males, and 4.75 and 1.05 for females, respectively. Erionite fibres were found in exposed rocks and soils, which can easily become airborne and be carried into streets and recreational areas near schools and homes. Other carcinogenic elements and minerals are found only in trace amounts, except for quartz dust and asbestos (chrysotile) cement sheeting, which are also present in the neighbouring villages. CONCLUSIONS: These results indicate that environmental exposure to erionite is the main cause of the high rates of MM mortality in the Village of Tierra Blanca, supporting previous similar reports for people exposed to erionite fibres in villages in Turkey.

The role of key genes and pathways involved in the tumorigenesis of Malignant Mesothelioma.

Malignant Mesothelioma (MM) is a very aggressive cancer with low survival rates and often diagnosed at an advanced stage. Several players have been implicated in the development of this cancer, such as asbestos, erionite and the simian virus 40 (SV40). Here, we have reviewed the involvement of erionite, SV40, as well as, the role of several genes (p16(INK4a), p14(ARF), NF2, LATS2, SAV, CTNNB1 and among others), the pathways (RAS, PI3K, Wnt, BCL and Hippo), and their respective roles in the development of MM.

Environmental occurrence, origin, physical and geochemical properties, and carcinogenic potential of erionite near San Miguel de Allende, Mexico.

Detailed geologic surveys and different microscopic and analytical techniques were conducted near Tierra Blanca de Abajo where lung cancer and malignant mesothelioma (MM) are the primary causes of death. Results show that erionite-K occurs as a diagenetic product in altered Oligocene-Miocene rhyolitic tuffs. The microscopic structure of erionite minerals shows concentrations of individual fibers in the range of 0.14-0.547 µm in diameter and 2.81-50 µm in length, with a few "bundles" about 0.2-2.5 µm wide by 10-50 µm long. Chemical properties of erionite show Si/Al in the range of 3.23-3.58 (at.%) and T Si in the range of 0.76-0.78 (at.%). Potassium is the dominant cation (K > Ca > Mg > Fe). Associated minerals are heulandite, clinoptilolite, quartz, sanidine, anorthite, smectite and opal. This mineral assemblage formed in the lower part of an open catchment, where bicarbonate-rich (T > 30 °C, pH > 8) groundwater discharge conditions prevailed in the past. The physical and chemical characteristics of erionite near San Miguel de Allende are similar to those of erionite from the Cappadocian region of Turkey where erionite is associated with MM. The presence of erionite and the type of respiratory diseases that occur in the village strongly suggest the need for detailed health-based studies in the region. Pliocene-Holocene fine-grain deposits, used in the past for the construction of adobe-houses and exposed in recreational areas, also contain erionite associated with erosion and alluvial transport from the rhyolitic tuffs, potentially affecting more than 13 villages located downstream toward the Allende Dam.

The impact of ammonia nitrogen concentration and zeolite addition on the specific methanogenic activity of granular and flocculent anaerobic sludges.

This work presents the effect of ammonia nitrogen concentration and zeolite addition on the specific methanogenic activity (SMA) of different anaerobic sludges with various physical structures (granular and flocculent), operating in batch conditions. Piggery, malting production and urban sludges derived from full-scale anaerobic reactors were tested in the experiment as the source of inoculum in batch digesters. It was found that piggery sludge was the most affected by the increase of ammonia nitrogen concentration while malting producing and municipal sludges were less affected. In general, the addition of zeolite at doses in the range of 0.01-0.1 g/g VSS reduced the inhibitory effect of N-NH(4)(+) for piggery sludge (P.S.). For this sludge, the propionic:acetic ratio increased when the concentration of N-NH(4)(+) increased, indicating that methanogenesis was affected. Finally, a study of the microbial population involved in this study for P.S. by using 16S rRNA based molecular techniques revealed a presence of microorganisms following the order: Methanococcaceae > Methanosarcina > Methanosaeta.