Toxicité du plomb et de ses dérivés

Toxic potential evaluation of liquid effluents discharged into nature by the university hospital centers (UHC) and mixed wastewater treatment station (WWTS) at Ouagadougou-Burkina Faso

In Burkina Faso, several investigations have raised suspicions that hospital liquid effluents are the source of contaminants in porbeagle-culture products and surface water in urban and peri-urban areas. This study aimed to evaluate the hygienic quality of hospital liquid effluents discharged into nature by the UHC Bogodogo (UHC-BOG), Yalgado Ouédraogo (UHC-YO), and the WWTS of Kossodo (WWTS-KOS). Thus, 15 samples of liquid effluents (five per site) discharged into nature were collected. Within the physicochemical parameters, the pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), suspended solids (TSS), conductivity, copper, iron, hafnium, silver, mercury, lead, and cadmium of these samples were determined using standard methods. The mean values of pH were 8.84 ± 0.42,8.06 ± 0.54, and 8.55 ± 0.53 for WWTS-KOS, UHC-BOG, and UHC-YO, respectively. Conductivity values were 1956.80 ± 81.30, 812.80 ± 45.22, and 956.00 ± 39.96 µS/cm, respectively. TSS were 338.20 ± 38.80, 45.00 ± 5.79, and 187.80 ± 27.58 mg/L, respectively. COD were 274.80 ± 20.46, 35.00 ± 5.52, and 139.80 ± 25.53 mg/L, respectively. BOD5 were 186.40 ± 68.68, 26.20 ± 4.82, and 81.80 ± 15.63 mg/L, respectively. Mercury values were 1.93 ± 0.38, 4.04 ± 0.38, and 14.37 ± 1.65 µg/L, respectively. Lead values were 434.70 ± 202.42, 310.50 ± 4.09, and 367.43 ± 94.01 µg/L, respectively. Cadmium values were 79.59 ± 19.48, 109.94 ± 8.43, and 80.26 ± 7.85 µg/L, respectively. Copper values were 27.66 ± 3.33, 30.84 ± 1.65, and 28.32 ± 2.36 mg/L, respectively. Iron was detected only on the STEP-KOS with an average of 71.01 ± 37.83 mg/L. Hafnium values were 50.27 ± 4.49 and 51.58 ± 4.61 mg/L for WWTS-KOS and UHC-BOG, respectively. Silver values were 34.26 ± 3.06 for WWTS-KOS. On the three sites, the differences found were significant (p < 0.05). Liquid hospital effluents from Ouagadougou discharged into nature on the whole do not compile with the Burkinabè normative values for the discharge of wastewater into the environment.

Development of a physiologically based toxicokinetic model for lead in pregnant women: The role of bone tissue in the maternal and fetal internal exposure

Epidemiological studies have shown associations between prenatal exposure to lead (Pb) and neurodevelopmental effects in young children. Prenatal exposure is generally characterized by measuring the concentration in the umbilical cord at delivery or in the maternal blood during pregnancy. To assess internal Pb exposure during prenatal life, we developed a pregnancy physiologically based pharmacokinetic (p-PBPK) model that to simulates Pb levels in blood and target tissues in the fetus, especially during critical periods for brain development. An existing Pb PBPK model was adapted to pregnant women and fetuses. Using data from literature, both the additional maternal bone remodeling, that causes Pb release into the blood, and the Pb placental transfers were estimated by Bayesian inference. Additional maternal bone remodeling was estimated to start at 21.6 weeks. Placental transfers were estimated between 4.6 and 283 L.day-1 at delivery with high interindividual variability. Once calibrated, the p-PBPK model was used to simulate fetal exposure to Pb. Internal fetal exposure greatly varies over the pregnancy with two peaks of Pb levels in blood and brain at the end of the 1st and 3rd trimesters. Sensitivity analysis shows that the fetal blood lead levels are affected by the maternal burden of bone Pb via maternal bone remodeling and by fetal bone formation at different pregnancy stages. Coupling the p-PBPK model with an effect model such as an adverse outcome pathway could help to predict the effects on children's neurodevelopment.

3D-printed flow system for determination of lead in natural waters

The development of 3D printing in recent years opens up a vast array of possibilities in the field of flow analysis. In the present study, a new 3D-printed flow system has been developed for the selective spectrophotometric determination of lead in natural waters. This system was composed of three 3D-printed units (sample treatment, mixing coil and detection) that might have been assembled without any tubing to form a complete flow system. Lead was determined in a two-step procedure. A preconcentration of lead was first carried out on TrisKem Pb Resin located in a 3D-printed column reservoir closed by a tapped screw. This resin showed a high extraction selectivity for lead over many tested potential interfering metals. In a second step, lead was eluted by ammonium oxalate in presence of 4-(2-pyridylazo)-resorcinol (PAR), and spectrophotometrically detected at 520nm. The optimized flow system has exhibited a linear response from 3 to 120µgL^-1. Detection limit, coefficient of variation and sampling rate were evaluated at 2.7µgL^-1, 5.4% (n=6) and 4 sampleh^-1, respectively. This flow system stands out by its fully 3D design, portability and simplicity for low cost analysis of lead in natural waters.

Screening for childhood lead poisoning in the industrial region of Fez, Morocco

The study objectives were to estimate lead poisoning prevalence among children living next to an industrial area, to compare it to that in a control population, and to establish clinical and biological follow-up of the poisoned children. This is a descriptive cross-sectional study including 150 children (exposed and unexposed) performed between January 2012 and April 2013. It was meant to determine blood lead levels (BLLs) in children considered to be an exposed population (EP N 90), living in the industrial area Ain Nokb Fez compared with BLLs of children of other areas belonging to the same city supposed to be unexposed [UP (N = 60)]. A sociodemographic questionnaire was obtained, and a blood lead analysis was performed. Clinical and biological follow-up has been performed of poisoned children. The sample consisted of 90 EP children with an average age of 6.82 ± 3.32 years and male-to-female sex ratio (SR) of 1.5 and 60 UP children with an average age of 6.45 ± 3.29 years and an SR of 1.2. Among the 150 children recruited, the average of BLLs was 58.21 ± 36 µg/L (18-202.3 μg/L). The average of BLLs in EP children (71 ± 40 µg/L) was statistically greater (p < 0.0001) than that registered in UP children (38 ± 13 µg/L). All poisoned children belonged to the EP group at a prevalence of 21.1 %. The clinical and biological examinations of poisoned children showed a few perturbations such as anemia, hypocalcaemia, and deficiencies in magnesium and iron. No renal disease or objective neurological disorders were observed. In the follow-up of the children with BLL ≥100 µg/L (19 cases). BLL monitoring showed a significant decrease in average of blood concentration ranging from 136.75 ± 32.59 to 104.58 ± 32.73 µg/L (p < 0.0001) and in lead poisoning prevalence (p < 0.001), which decreased to 7.8 % from 21.1. Our study showed a high prevalence of lead poisoning (21.1 %) in EP children. The relocation of the industrial site associated with corrective and preventive measures has contributed to a decrease of exposure and lead poisoning prevalence in the aforementioned population.

[Lead poisoning by fishing sinker ingestion]

INTRODUCTION

Lead colic is a rare cause of abdominal pain. The diagnosis of lead poisoning is most often mentioned in at risk populations (children, psychotic patients).

CASE REPORT

We report a 21-year-old man who presented with colicky abdominal pain. Abdominal plain radiograph showed multiple intracolonic metallic bodies. Markedly elevated lead and zinc protoporphyrin serum levels confirmed the diagnosis of lead poisoning. The patient reported that he commonly chewed fishing lead sinker and may sometimes swallow them during the preparation of fishing rod. Clinical outcome was favourable with chelation therapy.

CONCLUSION

Lead poisoning following fishing sinker ingestion is very uncommon. Diagnosis may be discussed in the presence of foreign metallic bodies on plain abdominal radiograph and confirmed by high serum level of lead. A prompt treatment with chelation therapy and digestive emptying is usually effective.

Responses of wild small mammals to a pollution gradient: host factors influence metal and metallothionein levels

We investigated how host factors (species, age, gender) modulated Cd, Pb, Zn, and Cu concentrations, metallothionein levels (MTs) and their relationships in 7 sympatric small mammal species along a pollution gradient. Cd concentrations in liver and kidneys increased with age in all species. Age effect on other metals and MTs differs among species. Gender did not influence metal and MT levels except in the bank vole. Three patterns linking internal metal concentrations and MTs were observed along the gradient: a low metal accumulation with a (i) high (wood mouse) or (ii) low (bank vole) level of MTs accompanied by a slight or no increase of MTs with Cd accumulation; (iii) an elevated metal accumulation with a sharp increase of MTs (common and pygmy shrews). In risk assessment and biomonitoring perspectives, we conclude that measurements of MTs and metals might be associated because they cannot be interpreted properly when considered separately.