A comparison of pesticide residues in soils from two highly technified agricultural valleys in northwestern Mexico.

A pesticide characterization is presented for two highly technified valleys in northwest Mexico: Culiacan Valley (CV) in Sinaloa and Yaqui Valley (YV) in Sonora. Approximately 250,000 kg of active ingredients are used every year, half of which are considered highly hazardous pesticides. Legacy pesticides are still present in the soils of these valleys. The aim of the present study was to identify and quantify a wide variety of pesticides in soils and correlate their concentrations with historical and current use. Agricultural soils from both valleys were sampled and analyzed using accelerated solvent extraction and subsequent quantification by gas chromatography with selective detectors. The most frequently detected pesticides (mean, µg g-1) in CV were organochlorines (0.1967), organophosphates (0.0928), synthetic pyrethroids (0.2565), organonitrogen (0.0552), and miscellaneous pesticides (0.1851). In YV, the most frequently detected pesticides were organochlorines (0.8607), organophosphates (0.0001), synthetic pyrethroids (0.0124), and miscellaneous pesticides (0.0009). The pesticides were more diverse in CV compared to those of YV, which was based on the types of crops produced. Both locations presented highly hazardous pesticides, including concentrations above the action levels established by the Canadian Soil Quality Guide. A follow-up risk assessment is recommended to assess potential effects.

Multiple biomarker approach in the fiddler crab to assess anthropogenic pollution in tropical coastal environments.

CONTEXT: Fiddler crabs are important to the ecology of estuarine systems around the world, however, few studies have incorporated them as bioindicators. Urias estuary represents one of the most urbanized lagoons in the Gulf of California region and received discharges from different sources: shrimp farm, thermoelectric plant, fish processing plants, and untreated domestic and sewage wastes. OBJECTIVE: Assess the effects on anthropogenic contamination on female fiddler crabs reproduction, survival and genetic stability. METHODS: Exposition of wild crabs from a less impacted (reference) site to naturally contaminated sediments on under controlled laboratory conditions. Reproductive parameters, levels of DNA damage and mortality rates were measured, together with chemical analyses of sediments. RESULTS: The most contaminated sediments corresponded to the site where fish processing plants were located and the integrated biomarker response analysis revealed that the most adverse effects were produced by exposure to sediments from this site; these crabs showed higher mortality (67%) and poorer ovarian development than those crabs exposed to sediments from other sites. CONCLUSIONS: Female crabs under pollution stress are able to trade-off reproduction for survival, and surviving animals were able to restore genetic stability possibly by activating DNA repair mechanisms. Multiple biomarker approach discriminates different coastal contamination scenarios.

Agrochemical loading in drains and rivers and its connection with pollution in coastal lagoons of the Mexican Pacific.

The state of Sinaloa in Mexico is an industrialized agricultural region with a documented pesticide usage of 700 t year-1; which at least 17 of the pesticides are classified as moderately to highly toxic. Pollutants in the water column of rivers and drains are of great concern because the water flows into coastal lagoons and nearshore waters and thereby affects aquatic organisms. This study was done in four municipalities in the state of Sinaloa that produce food intensively. To investigate the link between pollution in the lagoons and their proximity to agricultural sites, water was sampled in three coastal lagoons and in the rivers and drains that flow into them. Seawater from the Gulf of California, 10 km from the coast, was also analyzed. Concentrations of nutrients, organochlorines, and organophosphorus pesticides were determined. Nutrient determination showed an unhealthy environment with N/P ratios of <16, thus favoring nitrogen-fixing cyanobacteria. The organochlorine pesticides showed a clear accumulation in the coastal lagoons from the drains and rivers, with ΣHCH showing the highest concentrations. In the southern part of the region studied, pollution of the coastal lagoon of Pabellones could be traced mainly to the drains from the agricultural sites. Accumulation of OC pesticides was also observed in the Gulf of California. Tests for 22 organophosphates revealed only five (diazinon, disulfoton, methyl parathion, chlorpyrifos, and mevinphos); diazinon was detected at all the sites, although methyl parathion was present at some sites at concentrations one order of magnitude higher than diazinon.

[Osteological development of the vertebral column and caudal complex of Lujanus guttatus (Perciformes: Lutjanidae) larvae under rearing conditions]. / Desarrollo osteológico de la colUmna vertebral y del complejo caudal de larvas de Lutjanus guttatus (Perciformes: Lutjanidae) en condiciones de cultivo.

The spotted rose snapper (Lutjanus guttatus) is an important commercial species in Mexico with good culture potential. The osteological study at early stages in this species is an important tool to confirm normal bone structure and for the detection of malformations that may occur during early development. This study was carried out in order to evaluate and describe the normal osteological development of the vertebral column and caudal complex of this species grown under controlled conditions. For this, a total of 540 larvae of L. guttatus, between 2.1 and 17.5 mm of total length (TL), were cultured during 36 days; culture conditions were 28 degrees C, 5.74 mg/L oxygen and 32.2 ups salinity with standard feeding rates. To detect growth changes, a sample of 15 organisms was daily taken from day one until day 36 of post-hatch (DPH). Samples were processed following standard techniques of clearing, and cartilage (alcian blue) and bone staining (alizarin red). Results showed that the vertebral column is composed of ten vertebrae in the abdominal region, and 14 vertebrae including the urostyle in the caudal region. The development of the axial skeleton starts with the neural arches and haemal arches at 3.8 mm TL. Caudal elements such as the hypurals and parahypural began to develop at 4.1 mm TL. Pre-flexion and flexion of the notochord and the formation of all hypurals were observed between 5.3 and 5.8 mm TL. Ossification of the vertebrae in the abdominal region and in some neural arches initiated at 9.5mm TL. In the caudal region, all the neural and haemal arches ossified at 10.2 mm TL. All the abdominal vertebrae and their respective neural arches and parapophyses ossified at 11.2 mm TL, while the elements of the caudal complex that ossified were the hypurals, parahypurals and modified haemal spines. All caudal fm rays, 12 neural spines and 3 haemal arches were ossified by 15.5 mm. The complete ossification process of this specie under laboratory culture conditions was observed when larvae reached 17.3 mm TL on 36 DPH. Detailed analysis of the osteological structures will allow a reference description to evaluate and detect malformations that may occur during the larval culture of the spotted rose snapper.

Desarrollo osteológico de la columna vertebral y del complejo caudal de larvas de Lutjanus guttatus (Perciformes: Lutjanidae) en condiciones de cultivo / Osteological development of the vertebral column and caudal complex of Lutjanus guttatus (Perciformes: Lutjanidae) larvae under rearing conditions

The spotted rose snapper (Lutjanus guttatus) is an important commercial species in Mexico with good culture potential. The osteological study at early stages in this species is an important tool to confirm normal bone structure and for the detection of malformations that may occur during early development. This study was carried out in order to evaluate and describe the normal osteological development of the vertebral column and caudal complex of this species grown under controlled conditions. For this, a total of 540 larvae of L. guttatus, between 2.1 and 17.5mm of total length (TL), were cultured during 36 days; culture conditions were 28ºC, 5.74mg/L oxygen and 32.2ups salinity with standard feeding rates. To detect growth changes, a sample of 15 organisms was daily taken from day one until day 36 of post-hatch (DPH). Samples were processed following standard techniques of clearing, and cartilage (alcian blue) and bone staining (alizarin red). Results showed that the vertebral column is composed of ten vertebrae in the abdominal region, and 14 vertebrae including the urostyle in the caudal region. The development of the axial skeleton starts with the neural arches and haemal arches at 3.8mm TL. Caudal elements such as the hypurals and parahypural began to develop at 4.1mm TL. Pre-flexion and flexion of the notochord and the formation of all hypurals were observed between 5.3 and 5.8mm TL. Ossification of the vertebrae in the abdominal region and in some neural arches initiated at 9.5mm TL. In the caudal region, all the neural and haemal arches ossified at 10.2mm TL. All the abdominal vertebrae and their respective neural arches and parapophyses ossified at 11.2mm TL, while the elements of the caudal complex that ossified were the hypurals, parahypurals and modified haemal spines. All caudal fin rays, 12 neural spines and 3 haemal arches were ossified by 15.5mm. The complete ossification process of this specie under laboratory culture conditions was observed when larvae reached 17.3mm TL on 36 DPH. Detailed analysis of the osteological structures will allow a reference description to evaluate and detect malformations that may occur during the larval culture of the spotted rose snapper.

El pargo flamenco (Lutjanus guttatus) es una especie de importancia comercial en México con un gran potencial para su cultivo. El estudio osteológico en estadios tempranos de esta especie bajo condiciones controladas, es una herramienta importante para el conocimiento de su estructura ósea normal y poder detectar las malformaciones que se puedan presentar. El objetivo del presente trabajo se realizó para conocer y describir el desarrollo osteológico normal de la columna vertebral y el complejo caudal de 540 larvas de 2.1 a 17.5mm de longitud total (LT) bajo condiciones de cultivo a 28°C, 5.74mg/L de oxígeno y 32.2UPS de salinidad. Diariamente se tomó una muestra de 15 organismos desde el día uno hasta el 36 después de la eclosión (DDE) y se procesaron con las técnicas de clareado y tinción de cartílago (azul aciano) y hueso (rojo alizarina) para llevar a cabo la descripción de las estructuras. La columna vertebral se divide en región abdominal con diez vértebras y región caudal compuesta por 14 vértebras incluido el urostilo. El desarrollo del esqueleto axial inicia con la formación de los arcos neurales y hemales a los 3.8mm de LT. A los 4.1mm de LT empieza la formación de los hipurales y parahipural que son elementos caudales. Entre los 5.3 y 5.8mm de LT se observó en pre-flexión y flexión del notocordio y la formación de todos los hipurales. La osificación de las vértebras en la región abdominal y en algunos arcos neurales inició a los 9.5mm de LT. A los 10.2mm de LT se osificó la región caudal y todos los arcos neurales y hemales. A los 11.2mm LT se osificaron todas las vértebras abdominales con sus respectivos arcos neurales y los parapófisis, mientras que los elementos del esqueleto caudal que se osificaron fueron los hipurales, parahipurales y las espinas hemales modificadas. A los 15.5mm de LT se osificaron los radios de la aleta caudal y 12 espinas neurales y 3 hemales. El proceso de osificación de las larvas de esta especie en condiciones de cultivo se completó a los 17.3mm LT o 36 DDE. El análisis detallado de las estructuras osteológicas, permitirá una descripción de referencia para evaluar y detectar las malformaciones que se puedan presentar durante el cultivo larvario.

Distribution of pesticides and PCBs in sediments of agricultural drains in the Culiacan Valley, Sinaloa, Mexico.

Agriculture is one of the most important economic activities in Sinaloa, Mexico. The Culiacan Valley is an extensive agricultural region characterized by a variety of crops with high-yield productions. In this study, concentrations of organochlorine (OCPs) and organophosphorus (OPs) pesticides and polychlorobiphenyls (PCBs) were determined in sediments of the agricultural drainage system of Culiacan Valley. Overall, 32 compounds were detected, with concentrations widely ranging from 0.03 to 1 294 ng g(-1) dry weight. OCP concentrations (15) ranged from 0.1 to 20.19 ng g(-1) dw. OP concentrations (8) ranged from 0.03 to 1294 ng g(-1) dw, and diazinon was the compound with the highest concentration. PCB concentrations were also determined and varied from 0.05 to 3.29 ng g(-1) dw. Other compounds detected included permethrin, triadimefon, and fipronil. The central zone registered the higher concentrations and the greatest number of compounds, which could be related to the occurrence of horticultural fields in this zone. According to sediment quality guidelines, the compounds exceeding the probable effect level were γ-HCH, p,p'-DDT and p,p'-DDE, while the pesticides above the maximum permissible concentration were endosulfan, azinphos methyl, diazinon, dichlorvos, and permethrin. Although Sinaloa is an important agricultural crop producer in northwest Mexico, there are not many studies dealing with pesticide distribution in agricultural areas.

Follicular apoptosis in the mussel (Mytella strigata) as potential indicator of environmental stress in coastal ecosystems.

Follicular apoptosis in the tropical mussel Mytella strigata was assessed in three coastal lagoons located in the southern Gulf of California, Mexico. Mussels were collected from three coastal lagoons associated with different scenarios of anthropogenic stress during one year. The gonad of each mussel was dissected, weighed, and sampled for histology and apoptosis analysis by TUNEL labeling. Two apoptotic indices were used: the apoptotic index of cells (AIC) based on the number of follicular cells in apoptosis in one thousand cells counted per gonad, and the apoptotic index of follicles (AIF) based on the number of follicular cells per follicle per gonad. Both indices showed high association with each other for all developmental stages, although AIF seemed to better discriminate among sites. Higher AIF and AIC were observed at the Urias Estuary (1.6 and 1.5 respectively) ranked as highly polluted, followed by Ensenada del Pabellon (0.82 and 0.95 respectively), ranked as moderately polluted, and the Teacapan Estuary (0.57 and 0.76 respectively) ranked as slightly polluted. Our data indicate that the apoptotic index in tropical mussels could be a useful indicator of environmental stress in coastal ecosystems; however, the ecological relevance of follicular apoptosis in polluted environments needs further investigation.

Heat-shock protein (Hsp70) and cytochrome P-450 (CYP1A) in the white mullet Mugil curema (Pisces:Mugilidae) as biomarkers to assess environmental quality in coastal lagoons.

Biomarkers have been useful tools to monitor some effects of pollution in coastal environments. Hepatic expression of heat-shock protein 70 (Hsp70) and cytochrome P450 1A (CYP1A) were analyzed in white mullet (Mugil curema) by RT-PCR from July, 2005 until July, 2006 in three coastal lagoons located in the southern Gulf of California, Mexico. These three coastal systems receive contaminants derived from local anthropogenic activities. Heat-shock proteins function to maintain protein integrity in the presence of stressors (such as heat or chemicals) and can be used as biomarkers of homeostatic alterations in polluted environments, whereas cytochrome P450 family members participate in steroid hormone synthesis and metabolism, and in xenobiotic transformation as a detoxification mechanism. The expression levels of both genes showed consistency in time and space, and presented a high overall correlation (r = 0.731, P < 0.001). Regardless of a high individual variability, both genes presented higher expression levels in the Urias Estuary (P < 0.001 and P < 0.05 for CYP1A and Hsp70, respectively), which was considered the most polluted among the three systems, especially during the rainy season (summer to fall). Gene expression levels were significantly associated with non-halogenated hydrocarbon concentrations in sediments during the sampling period (r = 0.686, P = 0.019 for CYP1A and r = 0.91, P < 0.001 for Hsp70), suggesting that both genes respond to chemicals in the environment. The results indicate that Mugil curema is a good candidate species to implement biomonitoring programs in tropical coastal environments.