Developing Sustainable Cancer Education Programs: Training Public Health Students to Deliver Cancer 101 in Puerto Rico.

The use of promotores to educate Hispanic communities about different health topics has been proven successful, albeit with limitations in program sustainability. The goal of this study was to develop a sustainable train-the-trainer model to train graduate public health (PH) students to disseminate cancer education among communities in Puerto Rico (PR). Graduate students (n = 32) from Ponce Health Sciences University's (PHSU) PH program participated in a 2-day Cáncer 101 training, where they learned how to deliver nine cancer modules to the community. Cancer knowledge was assessed before and after the training via 54 items measuring discussed concepts. Participants also assessed the training's effectiveness by completing a training evaluation informed by social cognitive theory (SCT) constructs of self-efficacy, outcome expectations, facilitation, and observational learning. Participants were mainly female (78.1 %), 26.7 ± 3.9 years old, and enrolled in a Masters-level program (81.3 %). Participants reported an average 11.38-point increase in cancer knowledge after attending the training [t(31) = 14.88, p < .001]. Participants also evaluated the training favorably upon completion, reporting satisfactory comments in the open-ended responses and high scores on measured SCT constructs. The Cáncer 101 training program effectively prepared students to deliver cancer education to local communities. Training graduate PH students to educate communities about health issues is an innovative, and potentially sustainable, way to reach underserved populations.

Serum P-glycoprotein level: a potential biomarker of DMARD failure in patients with rheumatoid arthritis.

OBJECTIVES: To evaluate the utility of elevated serum P-glycoprotein (P-gp) as a risk marker of therapeutic response failure in rheumatoid arthritis (RA) patients treated with disease-modifying antirheumatic drugs (DMARDs). METHODS: A cross-sectional study was conducted in 151 RA patients. Patients were classified into two groups according to the response achieved in terms of the disease activity score (DAS)28 after ≥ 6 months: (1) patients with a therapeutic response to DMARDs, with DAS28 < 3.2; and (2) patients without a response to DMARDs, with persistent DAS28 ≥ 3.2. We explored a wide group of clinical factors associated with therapeutic resistance. Serum P-gp levels were measured by ELISA. The risk of P-gp elevation as a marker of failure to achieve a therapeutic response to DMARDs was computed using multivariate logistic regression. RESULTS: Serum P-gp levels were significantly higher in RA patients (n = 151) than in the controls (n = 30) (158.70 ± 182.71 ng/mL vs. 14.12 ± 8.97 ng/mL, p < 0.001). The P-gp level was correlated with the DAS28 score (r = 0.39, p < 0.001). RA patients with DMARD failure had higher serum P-gp levels than patients with a therapeutic response (206 ± 21.47 ng/mL vs 120.60 ± 15.70 ng/mL; p = 0.001). High P-gp levels increased the risk of DMARD failure (OR 3.36, 95% CI 1.54-7.27, p = 0.001). After adjusting for confounding variables, elevated P-gp remained associated with DMARD failure (OR 2.64, 95% CI 1.29-5.40, p = 0.01). CONCLUSION: Elevated serum P-gp is associated with DMARD failure. The P-gp level can be considered a clinical tool for evaluating the risk of DMARD failure in patients; however, future prospective studies should be performed to evaluate the utility of this marker in predicting long-term responses.

Reproductive cycle and maternal-embryonic nutritional relationship of shovelnose guitarfish Pseudobatos productus in the Gulf of California.

Samples of the shovelnose guitarfish Pseudobatos productus were collected on board a vessel and at landings of artisanal commercial fisheries in the Gulf of California from May 2004 to June 2007. Samples of 650 females, 2047 embryos and 484 uterine eggs were examined. The reproductive cycle is annual, ovulation and parturition occur in July, the uterine eggs are in diapause for 9 months (July-March) before an accelerated growth of embryos of 3 months. Histological analyses of the uterine wall of pregnant females suggested that no secretions were used for embryo nourishment. The standard percentage of water content was 48·6% in fertilized eggs and 80·75% in full-term embryos. Dry mass loss during embryonic development was 16·3% and the chemical balance of development was 0·84. This indicates that P. productus is a strictly lecithotrophic, viviparous species, that makes no maternal contribution of nutrients during embryonic development.

Diagnostic reference levels and complexity indices in interventional radiology: a national programme.

OBJECTIVES: To propose national diagnostic reference levels (DRLs) for interventional radiology and to evaluate the impact of the procedural complexity on patient doses. METHODS: Eight interventional radiology units from Spanish hospitals were involved in this project. The participants agreed to undergo common quality control procedures for X-ray systems. Kerma area product (KAP) was collected from a sample of 1,649 procedures. A consensus document established the criteria to evaluate the complexity of seven types of procedures. DRLs were set as the 3rd quartile of KAP values. RESULTS: The KAP (3rd quartile) in Gy cm2 for the procedures included in the survey were: lower extremity arteriography (n = 784) 78; renal arteriography (n = 37) 107; transjugular hepatic biopsies (THB) (n = 30) 45; biliary drainage (BD) (n = 314) 30; uterine fibroid embolization (UFE) (n = 56) 214; colon endoprostheses (CE) (n = 31) 169; hepatic chemoembolization (HC) (n = 269) 303; femoropopliteal revascularization (FR) (n = 62) 119; and iliac stent (n = 66) 170. The complexity involved the increases in the following KAP factors from simple to complex procedures: THB x4; BD x13; UFE x3; CE x3; HC x5; FR x5 and IS x4. CONCLUSIONS: The evaluation of the procedure complexity in patient doses will allow the proper use of DRLs for the optimization of interventional radiology. KEY POINTS: • National DRLs for interventional procedures have been proposed given level of complexity • For clinical audits, the level of complexity should be taken into account. • An evaluation of the complexity levels of the procedure should be made.

Association between -174G/C and -572G/C interleukin 6 gene polymorphisms and severe radiographic damage to the hands of Mexican patients with rheumatoid arthritis: a preliminary report.

Several interleukin 6 gene (IL6) polymorphisms are implicated in susceptibility to rheumatoid arthritis (RA). It has not yet been established with certainty if these polymorphisms are associated with the severe radiographic damage observed in some RA patients, particularly those with the development of joint bone ankylosis (JBA). The objective of the present study was to evaluate the association between severe radiographic damage in hands and the -174G/C and -572G/C IL6 polymorphisms in Mexican Mestizo people with RA. Mestizo adults with RA and long disease duration (>5 years) were classified into two groups according to the radiographic damage in their hands: a) severe radiographic damage (JBA and/or joint bone subluxations) and b) mild or moderate radiographic damage. We compared the differences in genotype and allele frequencies of -174G/C and -572G/C IL6 polymorphisms (genotyped using polymerase chain reaction-restriction fragment length polymorphism) between these two groups. Our findings indicated that the -174G/C polymorphism of IL6 is associated with severe joint radiographic damage [maximum likelihood odds ratios (MLE_OR): 8.03; 95%CI 1.22-187.06; P = 0.03], whereas the -572G/C polymorphism of IL6 exhibited no such association (MLE_OR: 1.5; 95%CI 0.52-4.5; P = 0.44). Higher anti-cyclic citrullinated peptide antibody levels were associated with more severe joint radiographic damage (P = 0.04). We conclude that there is a relevant association between the -174G/C IL6 polymorphism and severe radiographic damage. Future studies in other populations are required to confirm our findings.

When a Common Language Is Not Enough: Transcreating Cancer 101 for Communities in Puerto Rico.

In Puerto Rico (PR), cancer is the leading cause of death. Previous research has identified the need for cancer education in PR. Using culturally adapted cancer curricula to train local health educators may effectively increase cancer education and reduce health disparities. This article describes the three-phase process used to transcreate the Cancer 101 curriculum to train Master of Public Health (MPH) students to educate PR communities. First, an expert panel collaboratively reviewed the curriculum for content, legibility, utility, and colloquialisms. Recommendations included incorporating local references and resources, replacing words and examples with culturally relevant topics, and updating objectives and evaluation items. Subsequent focus groups with 10 MPH students assessed the adaptation's strengths, weaknesses, and utility for future trainees. Participants were satisfied with the curriculum's overall adaptation, ease of use, and listed resources; further improvements were suggested for all modules. Final expert panel revisions highlighted minor feedback, with the final curriculum containing nine transcreated modules. The transcreation process identified the need for changes to content and cultural translation. Changes were culturally and literacy-level appropriate, represented PR's social context, and were tailored for future trainees to successfully deliver cancer education. Findings highlight the importance of adapting Spanish educational materials across Hispanic sub-groups.

Metals in the caudal scutes of Morelet's crocodile (Crocodylus moreletii) from the southern Gulf of Mexico.

Caudal scutes were collected from 92 Morelet's crocodiles (Crocodylus moreletii) between May and August 2012, in three Wildlife Management and Use Units (UMAs, from its name in Spanish) and three wild sites in Campeche, Mexico. The UMAs are intensive, with an ex situ approach to manage crocodiles in captivity. The concentrations of arsenic, mercury, lead, nickel, cadmium and chromium were analyzed in each sample. As and Pb were detected in all samples, Hg in 86 and Ni in 74. The metal concentrations estimated were higher than most of the concentrations reported for skin, tail tip and caudal scutes in other crocodilians around the world. The concentration of As, Pb and Ni was significantly greater in the free-ranging groups than in the captive groups in UMAs (p < 0.05). Negative linear relationship was estimated between the snout-vent length and the concentration of Pb (in five groups) and Ni (in three groups). In this region C. moreletii is exposed to metals contamination and more studies are necessary to establish if represents a risk to their populations.

Strategic Plan for the Spanish Academy of Dermatology and Venerology (AEDV): FuturAEDV 2013-2017.

BACKGROUND: The Spanish Academy of Dermatology and Venereology (AEDV) has decided that a Strategic Plan is needed to help the association adapt to new circumstances and anticipate future developments. OBJECTIVES: 1) To position the AEDV as a medical association that can exert an influence in everything related to dermatology. 2) To contribute to the development of the specialty, strengthening the prestige and reputation of dermatology and dermatologists. 3) To establish a model for operating and strategic thinking that can be handed on to successive Boards of Directors and will enable the Academy to identify future challenges. METHODS: The approach used to develop the Strategic Plan was as follows: analysis of trends in the health care system; assessment of the current situation of AEDV and of dermatology in general through an internal analysis based on surveys and interviews with academics; analysis of strengths, weaknesses, opportunities, and threats; preparation of a mission statement; and identification, development, and implementation of a strategy map prioritizing strategic lines of action. RESULTS: The strategy map set out 16 general goals grouped into 4 main topics (achieving the vision, internal and external customers, internal processes, and innovation) and detailed in an action plan with 19 initiatives, each with specific actions. The plan will be monitored by the Strategic Plan Monitoring Committee, which is made up of the members of the Standing Committee and the chairs of the 9 Technical Committees responsible for implementing the initiatives. COMMENT: The Functional Plan should guide the management of AEDV until 2017, and its implementation will enable the association to contribute to the development and prestige of the specialty and position itself as a reference in terms of its functional model.

Pulmonary function in ankylosing spondylitis: association with clinical variables.

To evaluate the association between pulmonary function and clinical variables in ankylosing spondylitis (AS) and to compare the pulmonary function of patients with AS with that of healthy controls, 61 AS patients and 74 healthy controls were included. In AS, we assessed clinical disease indices (BASDAI, BASFI, BASG), morning stiffness, number of hypersensitive entheses, metrology measures, 6-min walking test, acute phase reactants, radiological presence of "bamboo spine," and severity of radiological involvement in sacroiliac and vertebral joints. AS and healthy controls had similar age and gender. All the parameters of pulmonary function were significantly diminished in AS than in healthy controls (p < 0.001), with a higher proportion of restrictive pattern (57.4 vs. 5.4 %). In AS, pulmonary function correlated negatively with BASDAI, BASFI, BASG, morning stiffness, number of hypersensitive entheses, occiput-wall distance, and ESR, and positively with 6-min walking test. There was no association between pulmonary function with radiological stage of vertebral joints and sacroiliac joints, "bamboo spine," disease duration, or chest expansion. A higher frequency of AS patients had a decreased pulmonary function and results of the 6-min walking test. These abnormalities in AS were more related with disease activity than with mobility limitation.

Antibody and cytokine responses in BALB/c mice immunized with the excreted/secreted proteins of Giardia intestinalis: the role of cysteine proteases.

The mechanisms involved in the induction of the immune response in humans or experimental hosts infected with Giardia intestinalis are not well understood. The results of previous studies indicate that the parasite induces a mixed Th1/Th2 response and that, in experimentally infected mice, the parasite's excreted/secreted (E/S) proteins contain cysteine proteases that are recognised by the murine immune system. In the present study, the possible effects of the E/S proteases of G. intestinalis on the host's humoral and cellular immune responses were investigated in BALB/c mice immunized with the parasite's E/S proteins. High titres of specific IgG(1), IgG(2a) and IgE antibodies were detected after immunization with native E/S proteins. Spleen cells stimulated with such proteins in vitro showed a significant antigen-specific proliferative response accompanied by the production of high concentrations of interleukin-4 (IL-4), interleukin-5 (IL-5) and interleukin-10 (IL-10) but little secretion of interferon-gamma (IFN-gamma). When, before use, the proteases in the E/S proteins were inhibited, by heat treatment or the addition of E-64, they elicited much lower titres of specific IgG(1) and IgE in mice while, in splenocytes in vitro, they triggered much lower production of IL-4, IL-5 and IL-10 and reduced antigen-specific proliferation. Since E-64 only inhibits cysteine proteases, these results indicate that the excreted/secreted cysteine proteases of G. intestinalis may be involved in the induction and regulation of a specific immune response in the infected host.

Initial poor function in the age of old donors: prognostic factors.

INTRODUCTION: The current donor selection criteria have changed from the past years. Primary nonfunction is a serious complication after liver transplantation, but initial poor function (IPF), which occurs from 2% to 23%, also has an increased morbidity and mortality. We analyzed prognostic factors associated with IPF. MATERIALS AND METHOD: This retrospective study of 551 liver transplants performed from January 2000 to December 2005 excluded retransplantations and transplants by classic surgery. The study cohort was attentified according to the presence or the absence of IPF. The variables included were (1) donor age, gender, cause of death, length of stay in Critical Care Medicine, noradrenaline use, sodium levels, and cardiorespiratory arrest, (2) from the standpoint of surgery: we included ischemia time (IT), intervention time, units of packet red cells (PRC), volume of blood autotransfusion (VBA), postreperfusion syndrome (PRS), and vasoactive drugs within the surgery procedure (VAD); (3) from the recipient's: view we examined age, gender, etiology, functional state, and covermittant pathology; (4) During the postoperative period we noted the presence of postoperative hemorrhage. Statistical analysis used chi-square test, Student t test, multiple logistic regression with significance set at P < .05. RESULTS: Differences were found in IT (P = .001), VBA (P = .001), PRS (P = .012), VAD (P = .03), fulminant hepatic failure as the cause the transplantation (P = .002), and chronic obstructive pulmonary disease (P = .007). A regression model retained the following variables: IT, VBA, PRS, fulminant hepatic failure, and chronic obstructive pulmonary disease. CONCLUSIONS: The prognostic factors for IPF need to be modified together with donor selection criteria in liver transplantation.

Temporal evolution of polycyclic aromatic hydrocarbons (PAHs) in sludge from wastewater treatment plants: comparison between PAHs and heavy metals.

This paper presents results on the presence and temporal variability of the 16 PAHs recommended by the EPA in primary, secondary and digested sewage sludge over a year. The sewage sludges originated from the Guadalete wastewater treatment plant (WWTP) site in Jerez de la Frontera (Cádiz, Spain). These organic pollutants have been extracted from the sewage sludge by microwave energy. High performance liquid chromatography coupled with diode array (HPLC-DAD) or fluorescence (HPLC-FL) detectors have been used. The results showed that total PAHs concentration varied between 1,945 ng g(-1) dry matter (DM) for primary sludges collected in March and 10,100 ng g(-1) DM for primary sludge collected in June. Generally, concentrations of PAHs were higher in compost and digested sludge than in fresh one. On the other hand, the highest concentration of PAHs were found on summer. This thing is associated to the traffic increase from inland zones to the coast (Jerez de la Frontera is very near to beaches). Finally, this paper present a comparative study of the American an European legislation concluding that the limits of concentrations established are not exceeded. In addition heavy metals were analysed. The origin of PAHs and heavy metals seems to be different.

Minimally invasive distal limb bypasses. Techniques and results.

As endovascular procedures increasingly become the procedures of choice for limb salvage, a subset of patients remains that requires open arterial reconstruction due to anatomic or pathologic reasons. Traditional greater saphenous vein harvest performed during open bypass for peripheral occlusive arterial disease is associated with long surgical incisions, increased operative times devoted to wound closure, and wound complications such as infection and dehiscence. Endoscopic conduit harvest, used with excellent results in coronary artery bypass surgery, can also be used in minimally invasive arterial bypass for limb salvage with certain technical modifications. These approaches to complex limb salvage procedures may result in shortened operating room time, shorter length of stay, reduced readmissions for wound complications, and ultimately, decreased costs to the health care system. The treating surgeon must continue to stay up to date with these approaches and be aware of pertinent issues regarding open and minimally invasive arterial interventions, as well as endovascular approaches.

The -174G/C Interleukin-6 Gene Promoter Polymorphism as a Genetic Marker of Differences in Therapeutic Response to Methotrexate and Leflunomide in Rheumatoid Arthritis.

Objective. To evaluate the association of -174G/C IL-6 polymorphism with failure in therapeutic response to methotrexate (MTX) or leflunomide (LEF). This prospective, observational cohort included 96 Mexican-Mestizo patients with moderate or severe rheumatoid arthritis (RA), initiating MTX or LEF, genotyped for IL-6 -174G/C polymorphism by PCR-RFLP. Therapeutic response was strictly defined: only if patients achieved remission or low disease activity (DAS-28 < 3.2). Results. Patients with MTX or LEF had significant decrement in DAS-28 (p < 0.001); nevertheless, only 14% and 12.5% achieved DAS-28 < 3.2 at 3 and 6 months. After 6 months with any of these drugs the -174G/G genotype carriers (56%) had higher risk of therapeutic failure compared with GC (RR: 1.19, 95% CI: 1.07-1.56). By analyzing each drug separately, after 6 months with LEF, GG genotype confers higher risk of therapeutic failure than GC (RR = 1.56; 95% CI = 1.05-2.3; p = 0.003), or CC (RR = 1.83; 95% CI = 1.07-3.14; p = 0.001). This risk was also observed in the dominant model (RR = 1.33; 95% CI = 1.03-1.72; p = 0.02). Instead, in patients receiving MTX no genotype was predictor of therapeutic failure. We concluded that IL-6 -174G/G genotype confers higher risk of failure in therapeutic response to LEF in Mexicans and if confirmed in other populations this can be used as promissory genetic marker to differentiate risk of therapeutic failure to LEF.

Mortality risk factors in critical post-surgical patients treated using continuous renal replacement techniques.

OBJECTIVE: To determine the influence of demographics, medical, and surgical variables on 30-day mortality in patients who need continuous renal replacement therapy (CRRT). MATERIALS AND METHODS: A retrospective-following study was conducted using the data of 112 patients admitted to the postoperative intensive care unit who required CRRT, between August 2006 and August 2011, and followed-up for 30 days. The following information was collected: age, gender, history of HBP, DM, cardiovascular disease, and CKD, urgent surgery, surgical speciality, organic dysfunction according to the SOFA scale, the number of organs with dysfunction, use of mechanical ventilation, diagnostic and origin of sepsis, type of CRRT, and 30-day mortality. General linear models were used for estimating the strength of association (relative risk [RR], and 95% confidence interval [CI] between variables and 30-day mortality. RESULTS: In the univariant analysis, the following variables were identified as risk factors for 30-day mortality: age (RR 1.04; 95% CI 1.01-1.06; P=.0005), and history of cardiovascular disease (RR 1.57; 95% CI 1.02-2.41; P=.039). Among the variables included in the multivariable analysis (age, history of cardiovascular disease, sepsis, and number of organs with dysfunction), only age was identified as an independent risk factor for 30-day mortality (RR 1.03; 95% CI 1.00-1.05; P=.007). CONCLUSION: Thirty-day mortality in postoperative, critically ill patients who require CRRT is high (41.07%). Age has been identified as an independent risk factor, with renal failure as the most common indication for the use of these therapies.

Minimal deviation melanoma.

Minimal deviation melanomas (MDM) are poorly characterized, uncommon naevomelanocytic tumours that are thought to represent part of the continuum from benign atypical naevi to frank malignant melanomas. Exactly where on that continuum they stand and who is most affected remains controversial. The few studies classifying MDM pointed to a less aggressive nature. Furthermore, it is thought that MDM affects patients in the fourth and fifth decades of life. In a recent review conducted at our institution, medical records of all patients with melanoma diagnosed at a tertiary care university medical center between January 1997 and May 2000 were reviewed to identify those with MDM. Those with MDM were examined to determine subtype, age and sex distributions, and location of tumour and findings were compared to those in the published literature. Unlike previous studies, the mean age of patients with MDM was 27 years with 20/31 being under 30 years old. Our results support prior findings that MDM is less aggressive than typical malignant melanomas in that only 1/5 undergoing lymphatic mapping had a positive node. Despite its description more than 30 years ago, MDM remains a poorly understood pathologic entity. Further study in such techniques as sentinel lymph node mapping and determination of angiogenesis factors is warranted to give insight as to what features predict an aggressive nature and to identify prognostic factors.

Testing non-linearity and directedness of interactions between neural groups in the macaque inferotemporal cortex.

Information processing in the visual cortex depends on complex and context sensitive patterns of interactions between neuronal groups in many different cortical areas. Methods used to date for disentangling this functional connectivity presuppose either linearity or instantaneous interactions, assumptions that are not necessarily valid. In this paper a general framework that encompasses both linear and non-linear modelling of neurophysiological time series data by means of Local Linear Non-linear Autoregressive models (LLNAR) is described. Within this framework a new test for non-linearity of time series and for non-linearity of directedness of neural interactions based on LLNAR is presented. These tests assess the relative goodness of fit of linear versus non-linear models via the bootstrap technique. Additionally, a generalised definition of Granger causality is presented based on LLNAR that is valid for both linear and non-linear systems. Finally, the use of LLNAR for measuring non-linearity and directional influences is illustrated using artificial data, reference data as well as local field potentials (LFPs) from macaque area TE. LFP data is well described by the linear variant of LLNAR. Models of this sort, including lagged values of the preceding 25 to 60 ms, revealed the existence of both uni- and bi-directional influences between recording sites.

Iodine-131 treatment of thyroid papillary carcinoma in patients undergoing dialysis for chronic renal failure: a dosimetric method.

Until recently, the therapeutic protocol widely accepted for ablation of the thyroid remnant and for metastases of thyroid papillary carcinoma was the administration of 131I after surgery. However, at present, some data question the usefulness of such treatment in patients considered low risk. The treatment with radioiodine in patients suffering from end-stage renal disease (ESRD) undergoing hemodialysis requires controlled dosages and individualized administration guidelines. The need to include these patients on the waiting list for a renal transplantation, once they have overcome the disease, and the higher prevalence of thyroid carcinoma in ESRD patients makes this an increasingly significant problem. The cases reported in the literature are few and the therapeutic models followed are very difficult. In this paper we propose a therapeutic model that provides the highest thyroid ablative dosage, minimizing radiation exposure to the rest of the organs. The main difference between our protocol and that already described is the performance of daily hemodialysis during the first 5 days of treatment, as well as the administration of a dose of 131I equivalent to that administered to patients who show normal renal function.

Spectrofluorimetric determination of cisatracurium and mivacurium in spiked human serum and pharmaceuticals.

Spectrofluorimetric methods to determine cisatracurium and mivacurium are proposed and applied to the determination of both substances in human serum and to the determination of mivacurium in pharmaceuticals. The fluorimetric methods allow the determination of 5-500 ng ml(-1) of mivacurium in aqueous solutions and 5-500 ng ml(-1) of cisatracurium in water-acetonitrile solutions, both containing acetic acid-sodium acetate buffer (pH 5.5) with lambda(exc)=230 nm and lambda(em)=324 nm.

Speciation as a screening tool for the determination of heavy metal surface water pollution in the Guadiamar river basin.

The Guadiamar river basin has traditionally received pollutants from two main sources: in its northern section of mining origin, and in its southern section (next to Doñana National Park) from urban-industrial and agricultural sources. In April 1998, the spill of 6 million m3 of mining wastes (acidic waters and sludge) severely polluted the Guadiamar river basin with heavy metals, which caused serious damage to the local ecosystem. There is a direct association between the physicochemical speciation of an element and its toxicity, biological activity, bioavailability, solubility, etc. This work describes a distribution study of the metals Zn, Cd, Pb and Cu by speciation analysis of surface waters in eleven sampling points of the Guadiamar river basin. Four metal fractions were determined using anodic stripping voltammetry: labile metal forms, H+ exchangeable metal forms, strongly inert forms (associated with organic and inorganic matter in solution), and forms associated with suspended matter. Total concentrations in surface waters followed the trend Zn > Cu > Pb > Cd. The speciation study showed that Zn and Cd were present to a large extent in available forms (labile and H+ exchangeable), while Pb and Cu were found mostly in the less available forms (strongly inert). Moreover, the available forms were found in the northern section (mining pollution) and the strongly inert forms in the southern section (urban, industrial and agricultural pollution). These results can illustrate the potential value of speciation to discern between different sources of pollution.