Factors associated with impairment in gait speed in older people with clinically normal gait. A cross-sectional study.

BACKGROUND: Health professionals commonly use gait speed in the evaluation of functional status in older people. However, only a limited number of studies have assessed gait speed in the absence of disorders of gait, using confounding factors and exclusion criteria coming from studies conducted in younger people. Our study aims to analyse which factors are associated with gait speed in older people with normal clinical gait. METHODS: An observational cross-sectional study was conducted in 119 community-dwelling residents without relevant comorbidities (Charlson index < 2), preserved function (Barthel > 85) and normal gait by visual exploration. Exclusion criteria included suffering from any illness that could modify the characteristics of gait, terminal status or the presence of an acute medical illness in the past 3 months. We used a stepwise linear regression of several variables (sociodemographic characteristics, cognition, body composition, drugs, falls, sarcopenia, frailty and physical activity) on 6-metre gait speed. RESULTS: The mean age was 78 years (range 70-96 years) and 71.4% were women. Variables that remained associated with gait speed in the multivariate final model were age (B = - 0.020, p < 0.001); gender (B = - 0.184, p < 0.001); waist-to-height ratio (B = - 0.834, p = 0.002); number of falls (B = - 0.049, p = 0.003) and the number of Fried's frailty criteria (B = - 0.064, p = 0.019). CONCLUSION: Falls, frailty and the waist-to-height ratio modify gait speed in older people with normal gait. Studies analysing the potential effect of several factors on gait speed should consider them as confounding factors.

Life cycle assessment of carbon capture and utilization from ammonia process in Mexico.

Post-combustion CO2 capture (PCC) of flue gas from an ammonia plant (AP) and the environmental performance of the carbon capture utilization (CCU) technology for greenhouse gas (GHG) emissions to an enhanced oil recovery (EOR) system in Mexico was performed as case study. The process simulations (PS) and life cycle assessment (LCA) were used as supporting tools to quantify the CO2 capture and their environmental impacts, respectively. Two scenarios were considered: 1) the AP with its shift and CO2 removal unit and 2) Scenario 1 plus PCC of the flue gas from the AP primary reformer (AP-2CO2) and the global warming (GW) impact. Also, the GW of the whole of a CO2-EOR project, from these two streams of captured CO2, was evaluated. Results show that 372,426 tCO2/year can be PCC from the flue gas of the primary reformer and 480,000 tons/y of capacity from the AP. The energy requirement for solvent regeneration is estimated to be 2.8 MJ/kgCO2 or a GW impact of 0.22 kgCO2e/kgCO2 captured. GW performances are 297.6 kgCO2e emitted/barrel (bbl) for scenario one, and 106.5 kgCO2e emitted/bbl for the second. The net emissions, in scenario one, were 0.52 tCO2e/bbl and 0.33 tCO2e/bbl in scenario two. Based on PS, this study could be used to evaluate the potential of CO2 capture of 4080 t/d of 4 ammonia plants. The integration of PS-LCA to a PCC study allows the applicability as methodological framework for the development of a cluster of projects in which of CO2 could be recycled back to fuel, chemical, petrochemical products or for enhanced oil recovery (EOR). With AP-2CO2, "CO2 emission free" ammonia production could be achieved.

Inhibition of quorum-sensing-dependent virulence factors and biofilm formation of clinical and environmental Pseudomonas aeruginosa strains by ZnO nanoparticles.

UNLABELLED: Quorum quenching decreases Pseudomonas aeruginosa virulence factors and biofilm formation, alleviating infections in animal models. Nevertheless, it is usually performed in laboratory strains such as PAO1 and PA14, and studies involving clinical or environmental isolates are scarce. In this work, the effects of ZnO nanoparticles, a potent quorum and virulence quencher for the PAO1 strain, were tested in six clinical strains from cystic fibrosis patients, a furanone C-30 resistant clinical strain from urine, two PA14 gallium resistant mutants, a PA14 C-30 resistant mutant and four environmental isolates. ZnO nanoparticles effectively decreased elastase, pyocyanin, and biofilm formation for most of the strains; regardless their origin or their resistance against the canonical quorum quencher C-30 or the novel antimicrobial gallium. The data indicate ZnO nanoparticles may have a broad spectrum for the quorum quenching of relevant strains and that may be an alternative to treat Ps. aeruginosa recalcitrant infections. SIGNIFICANCE AND IMPACT OF THE STUDY: Virulence inhibition by quorum quenchers in Pseudomonas aeruginosa is usually tested in laboratory strains and studies of their effects in relevant clinical and environmental strains are scarce. This study is significant as the effects of ZnO nanoparticles in QS-dependent virulence factor production were tested in six clinical strains from cystic fibrosis patients, a C-30 resistant clinical strain from urine, two PA14 gallium resistant mutants, a PA14 C-30 resistant mutant, and four environmental isolates. ZnO nanoparticles decreased elastase, pyocyanin, and biofilms for most of the strains; indicating they have broad spectrum and may be an alternative to treat Ps. aeruginosa infections.

A European survey of older peoples' preferences, and perceived barriers and facilitators to inform development of a medication-related fall-prevention patient portal.

PURPOSE: Falls are a major and growing health care problem in older adults. A patient portal has the potential to provide older adults with fall-prevention advice to reduce fall-risk. However, to date, the needs and preferences regarding a patient portal in older people who have experienced falls have not been explored. This study assesses content preferences, potential barriers and facilitators with regard to using a patient portal, as perceived by older people who have experienced falls, and explores regional differences between European participants. METHODS: We conducted a survey of older adults attending an outpatient clinic due to a fall or fall-related injury, to explore their content preferences, perceived barriers, and facilitators with respect to a fall-prevention patient portal. Older adults (N = 121, 69.4% female, mean age: 77.9) were recruited from seven European countries. RESULTS: Almost two-thirds of respondents indicated they would use a fall-prevention patient portal. The portal would preferably include information on Fall-Risk-Increasing Drugs (FRIDs), and ways to manage other related/relevant medical conditions. Facilitators included a user-friendly portal, with easily accessible information and physician recommendations to use the portal. The most-commonly-selected barriers were privacy issues and usage fees. A family member's recommendation to use the portal was seemingly more important for Southern and Eastern European participants compared to the other regions. CONCLUSION: The majority of older people with lived falls experience expressed an interest in a fall-prevention patient portal providing personalized treatment advice to prevent further falls. The results will be used to inform the development of a fall-prevention patient portal. The fall-prevention patient portal is intended to be used in addition to a consultation with a physician. Future research is needed to explore how to prevent falls in older patients who are not interested in a fall-prevention patient portal.

Swallows as indicators of environmental pollution of the Rio Grande/Rio Bravo Basin: are persistent organic pollutants a concern?

Swallows from two locations in the Rio Grande/Rio Bravo Basin and one reference site located 500 km away were analyzed for organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). Of the OC pesticides, only p,p'-DDE was observed at levels of concern (carcass geometric mean range 642 to 8511 ng/g wet weight [ww]). DDE residues in carcass were significantly greater at El Paso than at other locations. PCBs were relatively low compared with locations in the northeastern United States and the Great Lakes. Geometric mean PBDE concentrations ranged from 18 to 258 ng/g ww (280 to 3395 ng/g lipid weight). PBDE congeners 47 and 99 comprised approximately 60% of total PBDEs. Concentrations of DDE measured in swallows from El Paso in 2000 and 2005 are among the highest observed in the last 20 years along the United States-Mexico border. The results from this study indicated that swallows are still being exposed to high concentrations of DDE, which could have adverse effects on reproduction or on predators that feed on swallows.

Potential effects of environmental contaminants on P450 aromatase activity and DNA damage in swallows from the Rio Grande and Somerville, Texas.

Cliff swallows (Petrochelidon pyrrhonota) and cave swallows (P. fulva) were sampled during the breeding season at several locations in the Rio Grande, Texas, to evaluate the potential effects of environmental contaminants on P450 aromatase activity in brain and gonads and DNA damage in blood cells. The tritiated water-release aromatase assay was used to measure aromatase activity and flow cytometry was used to measure DNA damage in nucleated blood cells. There were no significant differences in brain and gonadal aromatase activities or in estimates of DNA damage (HPCV values) among cave swallow colonies from the Lower Rio Grande Valley (LRGV) and Somerville. However, both brain and gonadal aromatase activities were significantly higher (P < 0.05) in male cliff swallows from Laredo than in those from Somerville. Also, DNA damage estimates were significantly higher (P < 0.05) in cliff swallows (males and females combined) from Laredo than in those from Somerville. Contaminants of current high use in the LRGV, such as atrazine, and some of the highly persistent organochlorines, such as toxaphene and DDE, could be potentially associated with modulation of aromatase activity in avian tissues. Previous studies have indicated possible DNA damage in cliff swallows. We did not observe any differences in aromatase activity or DNA damage in cave swallows that could be associated with contaminant exposure. Also, the differences in aromatase activity and DNA damage between male cliff swallows from Laredo and Somerville could not be explained by contaminants measured at each site in previous studies. Our study provides baseline information on brain and gonadal aromatase activity in swallows that could be useful in future studies.

How nurses cope with death in the Paediatric Intensive Care Unit. / Afrontamiento de las enfermeras ante la muerte del paciente en la Unidad de Cuidado Intensivo Pediátrico.

The death of a child in the Paediatric Intensive Care Unit (PICU) is difficult, the loss generates feelings of sadness and pain; this study highlights the different coping strategies used by nurses to manage this situation and find the strength to provide care at the end of life. OBJECTIVE: Explore the strategies used by nurses in the PICU in coping with death. METHODS: Study conducted in the city of Manizales, Colombia, during the months of October, November and December. A qualitative, hermeneutical phenomenological approach was used. The method of intentional sampling for the selection of participating nurses (n=10) working in PICU, in-depth interviews were conducted for the construction of the information and the data were analyzed according to the procedures proposed by Cohen, Kahn and Steeves. RESULTS: Nurses use coping strategies focused on emotions: they inhibit their feelings towards the patient and their family; they use communication and prayer with the patient, as well as accompaniment to alleviate the suffering of the family. CONCLUSION: UCIP nurses develop coping strategies for end-of-life care using spiritual resources and communication with the family who require ongoing support, reflecting on death and accompanying the child in its transcendence.

EuGMS Task and Finish group on Fall-Risk-Increasing Drugs (FRIDs): Position on Knowledge Dissemination, Management, and Future Research.

Falls are a major public health concern in the older population, and certain medication classes are a significant risk factor for falls. However, knowledge is lacking among both physicians and older people, including caregivers, concerning the role of medication as a risk factor. In the present statement, the European Geriatric Medicine Society (EuGMS) Task and Finish group on fall-risk-increasing drugs (FRIDs), in collaboration with the EuGMS Special Interest group on Pharmacology and the European Union of Medical Specialists (UEMS) Geriatric Medicine Section, outlines its position regarding knowledge dissemination on medication-related falls in older people across Europe. The EuGMS Task and Finish group is developing educational materials to facilitate knowledge dissemination for healthcare professionals and older people. In addition, steps in primary prevention through judicious prescribing, deprescribing of FRIDs (withdrawal and dose reduction), and gaps in current research are outlined in this position paper.

EuGMS Task and Finish group on Fall-Risk-Increasing Drugs (FRIDs): Position on Knowledge Dissemination, Management, and Future Research.

Falls are a major public health concern in the older population, and certain medication classes are a significant risk factor for falls. However, knowledge is lacking among both physicians and older people, including caregivers, concerning the role of medication as a risk factor. In the present statement, the European Geriatric Medicine Society (EuGMS) Task and Finish group on fall-risk-increasing drugs (FRIDs), in collaboration with the EuGMS Special Interest group on Pharmacology and the European Union of Medical Specialists (UEMS) Geriatric Medicine Section, outlines its position regarding knowledge dissemination on medication-related falls in older people across Europe. The EuGMS Task and Finish group is developing educational materials to facilitate knowledge dissemination for healthcare professionals and older people. In addition, steps in primary prevention through judicious prescribing, deprescribing of FRIDs (withdrawal and dose reduction), and gaps in current research are outlined in this position paper.

Persistent environmental pollutants in eggs of aplomado falcons from Northern Chihuahua, Mexico, and south Texas, USA.

The northern aplomado falcon (Falco femoralis septentrionalis) disappeared from south Texas in the 1940s. Due to great success in the release of captive-reared aplomado falcons in south Texas, there are currently more than 40 established nesting pairs in the region. Addled eggs from aplomado falcons nesting in northern Chihuahua and south Texas were analyzed to determine organochlorine (OC) and inorganic element contaminant burdens and their potential association with egg failures and effects on reproduction. Among the OCs, DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] was present at the highest concentrations (range 262-21487 ng/g wet weight) followed by polychlorinated biphenyls (PCBs, range 88-3274 ng/g ww). DDE was greater (P=0.03) in eggs from El Sueco (Chihuahua, Mexico) than in those from Matagorda Island (Texas, USA). DDE concentrations in eggs of aplomado falcons from El Sueco were elevated; however, reproductive success in the two Chihuahuan populations did not seem to be affected by DDE. DDE and metals in potential avian prey of the aplomado falcon from Matagorda Island were very low and below levels in the diet at which some negative effects might be expected. Except for mercury (Hg), metal concentrations in eggs were fairly low and were not different among locations in Chihuahua and south Texas. Hg was somewhat elevated and was greater (P<0.001) in Texas than in the Chihuahua locations. Periodic monitoring of Hg concentrations in addled eggs of aplomado falcons in south Texas is recommended to continue evaluating potential negative effects on their recovery.

Regional variation and relationships between the contaminants dde and selenium and stable isotopes in swallows nesting along the Rio Grande and one reference site, Texas, USA.

Cave swallows (Petrochelidon fulva) and cliff swallows (P. pyrrhonota) nest in numerous colonies throughout the Texas portion of the Rio Grande along the U.S. border with Mexico. We collected swallows during 1999 and 2000 from eight locations along the Rio Grande to determine if delta15N and delta13C values could be used to predict 1,1-di-(p-chlorophenyl-)2,2-dichloroethene (DDE) and selenium (Se) contaminant burdens in insectivorous birds nesting across a geographic gradient in the Texas-Mexico border and to discern if stable isotopes could help discriminate between local versus nonlocal acquisition of contaminants. We analysed delta15N and delta13C in liver and muscle and DDE and Se in swallow carcasses. Within individuals, delta15N was higher in liver than in muscle of both species by an average of 1.34%, whereas delta13C was 0.145% higher in muscle than in liver. Significant differences occurred among locations in delta15N and delta13C values in liver and muscle of both species. Cave swallows from three locations in the Lower Rio Grande Valley were more enriched in delta15N than swallows from other sites. In general, swallows nesting in more northern latitudes along the Rio Grande had lower delta15N and delta13C values than those nesting farther south. Concentrations of DDE were significantly greater in swallows from El Paso, Llano Grande, and Pharr than in those from Brownsville, Falcon Lake, Laredo, Del Rio, and a reference site outside the Rio Grande. All swallows (n = 21) from El Paso, Llano Grande, and Pharr had DDE concentrations > or = 3 microg g(-1) wet weight (ww), a value three times greater than the estimated threshold in avian prey that could cause potential reproductive failures in raptors. Concentrations of Se also were significantly greater in El Paso and Del Rio than at other locations. Most Se concentrations were not of concern for direct effects on birds or their predators. Principal component analysis indicated some positive correlations between delta15N and delta13C values in tissues and contaminant concentrations in carcass; however, analysis of covariance suggested a stronger effect of location on concentrations of DDE and Se. At the local level (Llano Grande and Pharr) there was a significant positive correlation between delta15N in liver and DDE concentrations in swallow carcasses; however, Se concentrations were not significantly correlated with isotopes even at the local level. Our results provide a good database of delta15N and delta13C values for insectivorous birds nesting along the Rio Grande. Similar ecologies for cave and cliff swallows and their abundance and wide distribution along the Rio Grande make them ideal indicators of environmental pollution of this portion of the Texas-Mexico border.

Nasopharyngeal colonization in Costa Rican children during the first year of life.

BACKGROUND: The establishment of the nasopharyngeal flora was followed in Costa Rican children from birth to 1 year of age. METHODS: Nasopharyngeal cultures were obtained at 1 (n = 413), 3 (n = 393), 6 (n = 376) and 12 months (n = 356) of age from children representative of the population in the Puriscal district. Weekly cultures were obtained from a subcohort of these children (n = 101). Mother-infant diads (n = 95) and preschool children (n = 208) attending day-care centers were also studied. RESULTS: The estimated proportion of colonized children in the population differed markedly depending on the frequency of culture. Quarterly cultures showed a slow increase in carrier rates from 3.9% for Haemophilus influenzae, 3.1% for Streptococcus pneumoniae and 6.5% for Moraxella catarrhalis at 1 month of age to 10.1% carrying H. influenzae and 19.4% carrying S. pneumoniae by the end of the first year. By quarterly culture the proportion of children colonized at least once was 36% for S. pneumoniae, 26% for H. influenzae and 28% for M. catarrhalis. In contrast weekly sampling showed that 95 to 100% of the children were colonized at least once during the first year of life with H. influenzae, S. pneumoniae or M. catarrhalis. Nasopharyngeal carriage of H. influenzae, S. pneumoniae and M. catarrhalis was low in the mothers, and very few mother-infant pairs carried identical bacteria at the same time. In contrast carrier rates were high in the siblings attending day care (H. influenzae 27.9%, S. pneumoniae 39.4%, both organisms 26.6%). Infants with siblings had significantly higher bacterial carriage at all ages than infants without siblings. CONCLUSIONS: Quarterly nasopharyngeal cultures showed that Costa Rican infants acquire their nasopharyngeal flora at a rate comparable with that for infants in developed countries and that siblings are an important source of the bacteria. Weekly samplings showed that virtually all children were colonized at least once during the first year of life.

Opposite roles of D1 and D5 dopamine receptors in locomotion revealed by selective antisense oligonucleotides.

Contralateral rotations induced by the D1-like agonist SKF 38393 in unilaterally 6-hydroxydopamine-lesioned rats were completely prevented by the administration of the D1-like antagonist SCH 23390. A similar result was obtained after intracerebroventricular administration of an antisense oligodeoxynucleotide for the D1 receptor (D1R-as). Contrariwise, administration of a D5R-as potentiated the effects of SKF 38393, showing a 60% increase in the rotational scores. Both effects were reversible upon cessation of D1R-as or D5R-as treatment and were also specific since rotational scores in rats treated with vehicle or with a randomly designed oligodeoxynucleotide were not modified. These results suggest that whereas D1 receptors play a facilitatory role in locomotion, D5 receptors exert an inhibitory effect.

Therapeutic efficacy of interferon alfa-2b in infants with life-threatening giant hemangiomas.

BACKGROUND: Because of their size and the possibility of complications, giant hemangiomas represent a therapeutic challenge. Various forms of treatment have been used, with variable results, including surgery, embolization, lasers, pentoxifylline, and corticosteroids. Interferon alfa has been used successfully to treat life-threatening hemangiomas, possibly by means of its antiangiogenic activity. OBSERVATIONS: We treated 7 infants with organ-interfering and/or life-threatening giant hemangiomas with subcutaneous injections of 3 million U/m2 per day of interferon alfa-2b during the first month and subsequently every 48 to 72 hours, depending on the evolution in each case. The treatment lasted from 3 to 12 months. In 2 patients, interferon alfa-2b was administered while prednisone therapy was being tapered. In all 7 patients, there was considerable reduction of the volume of the hemangiomas and remission of their complications. All patients presented with fever, neutropenia, and an increase in serum aminotransferase levels. The patients who received interferon alfa-2b and prednisone seemed to improve at a faster rate. CONCLUSIONS: Interferon alfa-2b is a good option for the treatment of patients with steroid-resistant, organ-interfering and/or life-threatening giant hemangiomas. In our experience, the adverse effects were transient and minor and did not require the interruption of the treatment.

Threshold of dopamine content and D1 receptor stimulation necessary for the expression of rotational behavior induced by D2 receptor stimulation under normo and supersensitive conditions.

We measured the minimum amount of endogenous dopamine (EDA), necessary for the expression of rotational behavior induced by D2 receptor stimulation in striatal or medial forebrain bundle (MFB) lesioned rats. We correlated these results with the minimum dose of D1 receptor agonists needed to substitute EDA in its permissive role for D2 motor effects to take place. Rats with unilateral quinolinic acid (QA) striatal or 6-hydroxydopamine (6-OHDA) MFB lesions were given increasing doses of the tyrosine hydroxylase inhibitor alpha-methyl-para-tyrosine (AMPT) in combination with a fixed dose of the D2 receptor agonist quinpirole (trans-(-)-4aR-4,4a,5,6,7,8,8a,9-Octahydro-5-propyl-1H-pyrazolo(3, 4-g) quinoline hydrochloride) and tested for rotational behavior. The animals were later sacrificed and striata removed; EDA was measured by high performance liquid chromatography (HPLC). Rotational responses were abolished by increasing doses of AMPT inducing a stepwise depletion of EDA. EDA content and rotational behavior to D2 stimulation showed a high degree of correlation. There was an abrupt reduction in rotational behavior at dopamine levels of 50-60% of controls in both animal models. In addition, striatal or MFB lesioned rats which were maximally depleted of dopamine by AMPT pretreatment received a fixed dose of quinpirole and then challenged with increasing doses of a D1 receptor agonist SKF 38393 ((+/-)-1-Phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrochloride). Rotational behavior was restored by SKF 38393 in both animal models in a dose-dependent fashion. Our results confirm the need for simultaneous D1/D2 stimulation in the generation of rotational behavior in both animal models. Moreover, they demonstrate the existence of a threshold level of D1 stimulation necessary to exert its permissive role on D2 mediated responses.

DDE mercury, and selenium in Biota, sediments, and water of the Rio Grande-Rio Bravo Basin, 1965-1995.

An assessment of contaminant stressors on biota of the Rio Grande was conducted to identify relevant contaminant issues, assess exposure and ecological effects, identify data gaps, and determine potential risks. Most contaminant data were from studies conducted during 1965-1995 in the Lower Rio Grande, on the Texas side of the river, within a 100-km boundary from Falcon Dam to the mouth. Contaminants most frequently reported were organochlorine compounds (OCs) and trace elements. The number of records for OCs and trace elements was at least twofold greater for fish than for birds, mammals, or reptiles. Of the OCs, p,p'-DDE was the most commonly reported. Among the trace elements, Hg was one of the most frequently reported; however, Se, As, Pb, Cu, and Zn were also common. The highest concentrations of OCs and trace elements were reported predominantly from Lower Rio Grande Valley locations, with approximately 68% of the highest values detected from Falcon Dam to the mouth of the river. Twenty-six (20%) of the locations with maximum concentrations corresponded to portions of Llano Grande Lake and the Arroyo Colorado. Recent analyses of birds and fish indicate that levels of DDE are currently much lower than in the 1970s or 1980s in Rio Grande wildlife. This apparent decline does not apply to Hg and Se levels in birds and fish, which have remained more or less constant, but may have increased over the years in some locations. Hg was of particular concern because of high levels found recently in addled eggs of aplomado falcons and in their potential prey. Hg was elevated in fish from the Big Bend area. Also, Se in fish sampled in 1993 and 1994 was near or above the threshold for potential effects in fish-eating wildlife. Future investigations should evaluate the potential impacts of Hg and Se on aquatic and terrestrial species from selected sites of concern.

Treatment of superior and inferior vena cava syndromes of malignant cause with Wallstent catheter placed percutaneously.

Superior vena cava syndrome (SVCS) and inferior vena cava syndrome (IVCS) represent a severe symptomatic complication of some malignant tumors. Although radiation therapy and chemotherapy are elective, symptomatic relief takes 7-10 days to be achieved, and poor symptomatic benefit can be obtained in relapsed or resistant tumors. We report on a palliative approach using Wallstent catheters placed percutaneously in a series of 16 patients. Results obtained in relief of symptoms were excellent (complete response of cephalea, jugular enlargement, and collateral circulation achieved in 100% [16/16] of patients; complete response of edema obtained in 93% [15/16] of patients). Achievement of symptomatic response was obtained for all symptoms during the first 24 h poststenting, except for edema and dyspnea. Mean duration of patency of the stents was 6.4 months (range 2-17 months). Rates of morbidity and complications were very low. Dyspnea was a quite resistant symptom, and only four of 13 patients (31%) obtained complete response, while partial improvement was obtained in the other nine (79%). However, placement of the stents does not preclude the use of radiation therapy or chemotherapy. We think that these results and those from other studies warrant larger multicentric trials.

A comparative assessment of contaminants in fish from four resacas of the Texas, USA-Tamaulipas, Mexico border region.

A recent survey of contaminant information for the Lower Rio Grande Valley (LRGV), Texas, has shown that little is known about contaminants and their impacts on biota of resacas (oxbows) along the US-Mexico border. In 1996, fish were collected from four resacas in the Texas-Tamaulipas border region to assess contaminant loadings and their impacts on fish and birds. Tissue residue concentrations in fish were analyzed and also compared to two histopathological bioindicators of unhealthy environmental conditions. Of the organochlorine insecticides measured, DDE was the most common and was present at relatively high concentrations (10 microg/g w/w) at some sites. DDE concentrations were nearly 20 times greater in fish from resacas in Texas than from resacas in Tamaulipas, although the limited sample sizes obtained precluded statistical comparisons. DDE concentrations in fish from the two Texas resacas were also greater than those reported in fish from nearby areas during the 1980s and 1990s. Most trace element concentrations were similar among resacas from Texas and Tamaulipas. Arsenic, however, was two to six times greater in fish from a downtown resaca in Matamoros than in fish from other resacas in Tamaulipas and Texas. The bioindicators, pigment accumulation, and macrophage aggregates (MAs), in general, reflected the contamination indicated by the tissue residues for each site. Overall, it appears that some resacas of the US-Mexico border region are contaminant sinks and could pose potential health or reproductive problems for fish and wildlife, and humans that consume fish from those sites.

Persistent organochlorine pollutants in eggs of colonial waterbirds from Galveston Bay and East Texas, USA.

Eggs of neotropic cormorants (Phalacrocorax brasilianus), black-crowned night herons (Nycticorax nycticorax), and great egrets (Ardea alba) nesting on several locations in Galveston Bay (TX, USA) and at two control sites outside the bay were collected during April-May 1996 and analyzed for chlorinated pesticides, PCBs, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans. Additionally, concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQs) were determined by use of relative potency factors (TEQs) or the H4IIE-luc bioassay TCDD-EQs. Concentrations of 1,1,-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) were greater in eggs of neotropic cormorants from Alexander Island (mean = 1,040 ng/g wet wt) in the Houston Ship Channel (Houston, TX, USA) and in those from Telfair Island (mean = 1,460 ng/g wet wt), a reference location outside the bay, than in most locations inside the bay (mean range = 119-453 ng/g wet wt). Mean PCB concentrations were greater in eggs of neotropic cormorants from Alexander Island (mean = 5,720 ng/g wet wt) than in eggs of cormorants from areas farther away from the ship channel, including two reference sites outside the bay (mean range = 404-3,140 ng/g wet wt). The TCDD was the main dioxin congener detected in eggs from all locations within Galveston Bay. Instrumental TEQs in eggs ranged from 67 pg/g wet weight at control sites to 452 pg/g wet weight at Alexander Island. Concentrations of TCDD-EQs determined in the H4IIE assay were correlated with instrumental TEQs and were greater in eggs of cormorants from islands within the bay, although these were farther away from the ship channel. Overall, concentrations of DDE, PCBs, TCDD, and TCDD-EQs were less than the threshold levels known to affect reproduction. However, some eggs contained concentrations of total PCBs or DDE greater than what would elicit adverse effects on birds. No identifiable deformities or abnormalities were detected in embryos collected from all sites.