Assessment of the treatment efficiency of an urban stormwater pond and its impact on the natural downstream watercourse.

During the last few decades, stormwater ponds have become an alternative management practice in order to avoid flooding and to contain rainwater and runoff in urban areas where impervious land cover has increased. A second purpose of stormwater ponds is to improve the quality of runoff water that is usually contaminated with nitrogen, phosphorus, metals and organic micropollutants. Processes used are based on natural methods such as settlement and contribute to minimize the impact of these inputs to the natural aquatic system. This study aims to better understand the behavior of a wet stormwater pond, Heron Lake (33 ha) located in the city of Villeneuve d'Ascq in northern France through various indicators [trace metals, PAHs, PCBs, caffeine (CAF), carbamazepine (CBZ), nutrients and pathogens]. For that purpose, water quality was monitored for 1 year, mainly at the entrance and at the outlet of the lake. Sampling have also been done in the downstream aquatic environment, the Marque River. Sediments were sampled in the lake to evaluate the pollution trapped during sedimentation. Our results of both water and sediment sampling highlight: (i) the wastewater input into the Heron Lake is estimated to be equivalent to that of roughly 3800 inhabitants; (ii) the removal rates observed at the outlet, relative to concentrations at the entrance channel, vary as follows for these dissolved species: 24% for NO3- and PO43-, 28% for CBZ, 35% for Cu, 63% for Pb, 78% for CAF, 84% for Zn and up to 93% for NH4+; (iii) there are high levels of sediment contamination with metals, PAHs and PCBs at the entrance channel; (iv) the eutrophication of this pond is attributed to persistent high nutrient concentrations in both water and sediment, and has contributed to the development of an invasive macrophyte, the Elodea nuttallii; and (v) there appears to be only a negligible impact of the discharge from the lake to the natural watercourse, contributing annual loads of <2 up to 6% of the total amount of Cu, Pb, Zn, CAF, CBZ and nutrients measured in the Marque River, and having a slight diluting effect on concentrations in the Marque River.

Water quality assessment of a small peri-urban river using low and high frequency monitoring.

The biogeochemical behaviors of small rivers that pass through suburban areas are difficult to understand because of the multi-origin inputs that can modify their behavior. In this context, a monitoring strategy has been designed for the Marque River, located in Lille Metropolitan area of northern France, that includes both low-frequency monitoring over a one-year period (monthly sampling) and high frequency monitoring (measurements every 10 minutes) in spring and summer. Several environmental and chemical parameters are evaluated including rainfall events, river flow, temperature, dissolved oxygen, turbidity, conductivity, nutritive salts and dissolved organic matter. Our results from the Marque River show that (i) it is impacted by both urban and agricultural inputs, and as a consequence, the concentrations of phosphate and inorganic nitrogen have degraded the water quality; (ii) the classic photosynthesis/respiration processes are disrupted by the inputs of organic matter and nutritive salts; (iii) during dry periods, the urban sewage inputs (treated or not) are more important during the day, as indicated by higher river flows and maximal concentrations of ammonium; (iv) phosphate concentrations depend on oxygen contents in the river; (v) high nutrient concentrations result in eutrophication of the Marque River with lower pH and oxygen concentrations in summer. During rainfalls, additional inputs of ammonium, biodegradable organic matter as well as sediment resuspension result in anoxic events; and finally (vi) concentrations of nitrate are approximately constant over the year, except in winter when higher inputs can be recorded. Having better identified the processes responsible for the observed water quality, a more informed remediation effort can be put forward to move this suburban river to a good status of water quality.

Urinary DNA as an indicator of nephrotoxicity caused by endotoxin and gentamicin in mice.

Extracellular DNA is a non-specific marker of cell death. Urinary DNA, as an indicator of nephrotoxicity, was investigated in endotoxin/gentamicin-injected mice. In mice injected both with endotoxin (15 mg/kg) and gentamicin (80 mg/kg), urinary DNA concentration was markedly increased for several days; in contrast, there was at most a slight and transient excretion of DNA in mice receiving gentamicin or endotoxin alone. Plasma DNA concentrations increased for 24-48 h in endotoxin-injected mice, then decreased rapidly. Mice injected with gentamicin and endotoxin showed widespread and severe kidney lesions with tubular cell necrosis and intraluminal casts while mice receiving gentamicin or endotoxin alone showed at most few and mild lesions. In mice receiving lower doses of endotoxin (5-10 mg/kg) and 80 mg/kg gentamicin, urinary DNA peaked at 72-96 h, at a time when plasma DNA had returned to normal concentrations. Maximal urinary DNA concentrations depended upon endotoxin dose. In conclusion, urinary DNA is a marker of definite cell death occurring in the urinary tract and could represent a new indicator of nephrotoxicity in clinical and experimental situations.

Comparative involvement of 5-HT1, 5-HT2 and 5-HT3 receptors in stress-induced colonic motor alterations in rats.

The role of 5-HT1, 5-HT2 and 5-HT3 receptors in the genesis of colonic motor alterations induced by emotional stress was evaluated in rats equipped with implanted nickel/chrome electrodes on the proximal colon and a catheter into the lateral ventricle of the brain. In control rats the frequency of colonic spike bursts increased from 7.6 +/- 1.3 to 16.8 +/- 1.3 per 10 min when the rats were placed in a test cage in which they had previously received electric footshocks. I.p. injection of methysergide (0.1 mg/kg) reduced by 54% the emotional stress-induced increase of colonic spike burst frequency, while a higher dosage (1 mg/kg) of methysergide had no effect. The i.p. injection of ketanserin (a 5-HT2 receptor antagonist, 0.1 and 1 mg/kg) or granisetron (a 5-HT3 receptor antagonist, 0.1 and 1 mg/kg) had no effect on emotional stress-induced colonic hyperkinesia. The i.p. injection of the 5-HT1A receptor agonists, buspirone (1 mg/kg) or 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino(tetralin) (0.05 and 0.1 mg/kg) or benzodiazepine (clonazepam, 1 mg/kg) significantly reduced or suppressed the emotional stress-induced increase of colonic spike bursts. Injected i.c.v., buspirone, but not 8-OH-DPAT, also reduced the emotional stress-induced hyperkinesia. Pretreatment with devazepide receptor (1 microgram/kg) antagonized the inhibitory effects of buspirone and 8-OH-DPAT injected i.p. on emotional stress-induced colonic hyperkinesia but did not alter the effects of clonazepam (1 mg/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma DNA as cell death marker in elderly patients.

Plasma DNA increases where cell death occurs in vivo. To investigate its significance in elderly patients, plasma DNA was assayed in 79 institutionalized patients over 68 years of age. The patients were divided into two groups: group I comprises 39 patients suffering from various acute or chronic illnesses; group II comprises 40 patients without chronic disease, and free of any clinical or biological symptoms of any infectious or inflammatory process. Plasma DNA was higher in group I than in group II (p < 0.0001) and in group II than in a control group of middle-aged subjects (p < 0.05). In group I, increase in plasma DNA concentration was found in various pathological situations associated with cell death phenomena, including infections, cancers with metastasis, hepatitis, irreversible cardiac failure, severe respiratory insufficiency and thrombophlebitis. Plasma DNA concentrations were not correlated with erythrocyte sedimentation rate, fibrinogen concentration, hemoglobin concentration or leukocyte count. In group I, as well as in the overall population, survival after 1 month was significantly reduced in patients with increased concentrations of plasma DNA. In conclusion, plasma DNA as a marker of cell death phenomena occurring in vivo, could be helpful for follow-up and management of elderly patients.

The beta-blocker acebutolol down modulates the spontaneous polyclonal activation of lymphocytes in NZB X NZW lupus mice.

Acebutolol is a beta blocking agent that induces in C57Bl/6 mice a polyclonal activation of lymphocytes (PAL). In this study, its effect on cellular parameters of spontaneous PAL and lupus disease in NZB x NZW female mice is investigated. A significant reduction of PAL is found in 10-week-old mice after only five injections of 50 mg/kg/day of acebutolol. This effect is also observed in 7- and 9-month-old mice after 12 weeks of treatment. In these chronically treated mice, a significant decrease in incidence and levels of proteinuria as compared with untreated mice is found. No statistically significant increase in survival is observed. In conclusion, acebutolol down modulates the spontaneous PAL which characterizes the NZB x NZW mouse lupus disease and might prevent to some extent the development of nephritis.

Quantitation of blood plasma DNA as an index of in vivo cytotoxicity.

Cell death triggers the release into extracellular spaces of products of chromatin catabolism, particularly of DNA. A sensitive DNA assay has been used to investigate in the mouse whether the quantitation of plasma DNA may be used as an index of in vivo cytotoxicity. It has been found that toxic doses of bacterial lipopolysaccharide, HgCl2, CCl4, cyclophosphamide and hydroxyurea, are responsible for the release of extracellular DNA in plasma, in a dose dependent relationship. In conclusion, quantitation of extracellular DNA may be used for investigating in vivo cell death phenomena induced by toxic agents and drugs. Such a method could be applied to toxicological studies in animals and man.