Monitoring of Trace Metal Contamination in the Souss Estuary (South Morocco) Using the Clams <Emphasis Type="Italic">Cerastoderma edule</Emphasis> and <Emphasis Type="Italic">Scrobicularia plana</Emphasis>

Concentrations of seven metals (Cd, Cu, Cr, Pb, Ni, Zn, Hg) were monitored monthly during 2 years in two bivalves, Cerastoderma edule and Scrobicularia plana collected from the Souss estuary (South Morocco) before and after the commissioning of a sewage treatment plant in November 2002. According to trace metals, changes in concentrations were observed mainly in S. plana, characterised by a decrease of Cu, Hg and Pb when Cd was clearly increasing. Conversely, no clear changes were observed in C. edule during the same periods. This study suggests the use of S. plana in the monitoring of trace metal contamination of such coastal marine environments.     

Copper Accumulation and Tolerance in <Emphasis Type="Italic">Chrysanthemum coronarium</Emphasis> L. and <Emphasis Type="Italic">Sorghum</Emphasis><Emphasis Type="Italic">sudanense</Emphasis> L.

In the present study, the growth of Chrysanthemum coronarium L. and Sorghum sudanense L. and their copper accumulation were studied using hydroponic experiments. Results showed that the root elongation, dry biomass yield, and chlorophyll content in both plant species decreased significantly with the increasing level of Cu in solution. The concentrations of Cu in the two plants increased greatly with the increasing Cu level in the treatments. However, most of the Cu was accumulated in roots, and only a small portion was translocated into shoots. Compared with S. sudanense, the shoots of C. coronarium had a significantly higher concentration of Cu. The total amount and percentage of water-soluble Cu, and the nonprotein thiol were also higher in the shoots of C. coronarium. In the roots, however, S. sudanense accumulated more Cu than C. coronarium. The treatments with 5 to 50 μmol L⁻¹ Cu significantly increased the uronic acid content in the roots of S. sudanens, but did not have any significant effect for C. coronarium. Higher concentrations of Cu bound to the cell wall and uronic acid in the roots of S. sudanense were speculated to be the main reason to restrain Cu translocation from roots to shoots.     

Impact of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-Dimethylformamide from Domestic Effluents on River Waters

The impacts of N,N-dimethylformamide (DMF) from domestic effluents on rivers were evaluated. The hourly DMF concentrations in the inflows (0.21–0.52 μg/L in mean) and the outflows (0.18–0.62 μg/L in mean) of two sewage treatment plants did not show any characteristic variations, and DMF was not removed at both plants. The monthly variations of DMF in the outflows of four sewage treatment plants (0.16–0.62 μg/L in mean) and three rivers (0.06–0.11 μg/L in mean) into which the outflows of the plants were discharged did not show any significant variations. The domestic DMF load per person was calculated to be 0.25 mg/d/person. The percent DMF loads of domestic effluents in the rivers were estimated to be below (8%–32%).     

Comparison of Epigeic Moss (<Emphasis Type="Italic">Hypnum cupressiforme</Emphasis>) and Lichen (<Emphasis Type="Italic">Cladonia rangiformis</Emphasis>) as Biomonitor Species of Atmospheric Metal Deposition

In the present work epigeic moss (Hypnum cupressiforme Hedw.) and epigeic lichen (Cladonia rangiformis Hoffm.) samples were collected simultaneously in the Thrace region, Turkey according to a regular sampling grid. Whereas the moss was found at all 68 sampling sites, the lichen could be collected only at 25 of the sites, presumably because lichens are more sensitive than mosses with respect to air pollution and climatic variations. All elements showed higher accumulation in the moss than in the lichen whereas element inter-correlations were generally higher in the lichen. All considered the moss was judged to be a better choice than the lichen for biomonitoring of atmospheric deposition of metals in this case, and it is argued that mosses may be generally more suited than lichens for this purpose.     

Metal Content of the Gulf of California Blue Shrimp <Emphasis Type="Italic">Litopenaeus stylirostris</Emphasis> (Stimpson)

The blue shrimp Litopenaeus stylirostris is the main target species of the Gulf of California shrimping fleet, and its heavy metal content might be of concern for human health because of the increasing contamination of the Gulf. The Cd content of shrimp caught by commercial trawlers ranged from 0.38 to 1.05 μg/g and the mean value was significantly lower in the northern fishing grounds. Pb ranged from 3.19 to 9.59 μg/g and was significantly higher in the northern area. There were no significant geographic difference in the case of Cu and Zn (respective means = 25.4 and 57.8 μg/g).The mean values of all metals show that none is of particular concern for human health.     

Toxicity of Chiral Pesticide <Emphasis Type="Italic">Rac-</Emphasis>Metalaxyl and <Emphasis Type="Italic">R-</Emphasis>Metalaxyl to <Emphasis Type="Italic">Daphnia magna</Emphasis>

Chirality in pesticides has become a challenge because of enantiomers’ different toxicities to non-target organisms. Acute and chronic toxicities of Rac-metalaxyl and R-metalaxyl to Daphnia magna were determined and compared. The 48-h LC50 for Rac- and R-metalaxyl to Daphnia magna were 51.5 and 41.9 mg/L. In a 14-day chronic test, the lowest-observed-effective concentration (LOEC) and no-observed-effective concentration (NOEC) of Rac-metalaxyl were 2 and 1 mg/L, respectively, whereas those of R-metalaxyl were 1 and 0.1 mg/L. Body length, days-to-first-brood and number of broods per female were significantly (p < 0.05) affected by R-metalaxyl at >1.0 mg/L, but affected by Rac-metalaxyl at ≥2.0 mg/L.     

The Effects of Monocrotophos to Different Tissues of Freshwater Fish <Emphasis Type="Italic">Cirrhinus mrigala</Emphasis>

The histopathological effects of monocrotophos on the gill, kidney and intestine tissues of the Cirrhinus mrigala were determined by light microscopy. The changes in the gills were characterized by epithelial hyperplasia, aneurism, epithelial necrosis, desquamation, epithelial lifting, oedema, lamellar fusion and curling of secondary lamellae. Pycnotic nuclei in tubular epithelium, hypertrophied epithelial cells of renal tubules, contraction of the glomerulus and expansion of space inside the Bowman’s capsule were observed in the kidney tissues of fish after exposure to monocrotophos. In the intestine tissues of fish exposed to monocrotophos, oedema, necrosis and atrophy of epithelial cells were observed.     

Contamination of Metals in Tissues of <Emphasis Type="Italic">Ctenopharyngodon idella</Emphasis> and <Emphasis Type="Italic">Perca fluviatilis</Emphasis>, from Anzali Wetland,Iran

The objective of the present study was to investigate the levels of metals (Cd, Cu, Zn, Pb and Cr) in muscle, gill, liver, kidney and intestine of two freshwater fish, Ctenopharyngodon idella and Perca fluviatilis, in Anzali Wetland, Iran. The concentrations were different between the fish species as well as among the tissues of fish. Results showed that the metal concentrations in both fish species were in descending order of Zn > Cu > Pb > Cr > Cd. Results also showed that the Cd, Cu, Zn, and Pb concentrations in the muscle of both fish from Anzali Wetland are below levels of concern for human consumption.     

Effects of Pentachlorophenol on <Emphasis Type="Italic">Galba pervia</Emphasis>, <Emphasis Type="Italic">Tubifex sinicus</Emphasis> and <Emphasis Type="Italic">Chironomus plumousus</Emphasis> Larvae

The 24-h median lethal concentrations of pentachlorophenol to Chironomus plumousus, Tubifex sinicus and Galba pervia were 0.302, 0.977 and 0.293 mg/L, respectively. Bioconcentration factors of C. plumousus, T. sinicus and G. pervia to pentachlorophenol were 108, 367 and 85 at 0.02 mg/L pentachlorophenol, respectively. As pentachlorophenol concentration increased, the G. pervia egg hatching rates became lower, and the total hatched time became longer. Pentachlorophenol teratogenesis was demonstrated by observing the deformation of C. plumousus larvae mentum.     

Distribution of Metals in the Tissues of Benthic, <Emphasis Type="Italic">Euryglossa orientalis</Emphasis> and <Emphasis Type="Italic">Cynoglossus arel.</Emphasis>, and Bentho-Pelagic, <Emphasis Type="Italic">Johnius belangerii.</Emphasis>, Fish from Three Estuaries,Persian Gulf

Concentrations of Cd, Co, Cu, Ni, Pb, Fe and Zn were determined in the muscle, liver and gills of three commercial benthic and pelagic fish species (Johnius belangerii, Euryglossa orientalis and Cynoglossus arel) from three estuaries in the northwest Persian Gulf. Metals levels varied significantly depending on the tissues, species and locations. Generally, the results showed that liver accumulate higher concentrations of the metals in comparison to muscle and gills, except in few cases. Among the species, E. orientalis showed the highest levels of Co, Cu, Ni and Fe, while the highest concentrations of Pb and Zn were observed in C. arel. J. belangerii accumulated the highest level of Pb element.     

Allelopathic Effects of <Emphasis Type="Italic">Myriophyllum aquaticum</Emphasis> on Two Cyanobacteria of <Emphasis Type="Italic">Anabaena flos-aquae</Emphasis> and <Emphasis Type="Italic">Microcystis aeruginosa</Emphasis>

Allelopathy has been proposed as a sustainable means to control undesired algal growth and to reduce blooms threatening freshwater systems worldwide. In this study, the allelopathic effects of Myriophyllum aquaticum and its exudate on two typical bloom-forming cyanobacteria, Microcystis aeruginosa and Anabaena flos-aquae, were investigated under laboratory conditions. The growth of the cyanobacteria was strongly inhibited by live M. aquaticum while the primary addition of M. Aquaticum exudates had a significant inhibitory effect on the growth of M. aeruginosa but not A. flos-aquae. The results suggested that the persistent release of allelochemicals from live M. aquaticum was needed to effectively constrain the growth of A. flos-aquae. Analysis of cyanobacterial physiological indexes indicated that M. aquaticum produced an inhibitory effect on SOD enzyme activity of A. flos-aquae, while it affected membrane lipid peroxidation in M. aeruginosa. The results show the potential of M. aquaticum to mitigate cyanobacterial blooms in coexistence systems.     

<Emphasis Type="Italic">Chlamydia</Emphasis><Emphasis Type="Italic">trachomatis</Emphasis> and placental inflammation in early preterm delivery

Chlamydia trachomatis may infect the placenta and subsequently lead to preterm delivery. Our aim was to evaluate the relationship between the presence of Chlamydia trachomatis and signs of placental inflammation in women who delivered at 32 weeks gestation or less. Setting: placental histology and clinical data were prospectively obtained from 304 women and newborns at the Erasmus MC-Sophia, Rotterdam, the Netherlands. C. trachomatis testing of placentas was done retrospectively using PCR. C. trachomatis was detected in 76 (25%) placentas. Histological evidence of placental inflammation was present in 123 (40%) placentas: in 41/76 (54%) placentas with C. trachomatis versus 82/228 (36%) placentas without C. trachomatis infection (OR 2.1, 95% CI 1.2–3.5). C. trachomatis infection correlated with the progression (P = 0.009) and intensity (P = 0.007) of materno-fetal placental inflammation. C. trachomatis DNA was frequently detected in the placenta of women with early preterm delivery, and was associated with histopathological signs of placental inflammation.     

Comparative Studies on the Toxicokinetics of Benzo[<Emphasis Type="Italic">a</Emphasis>]pyrene in <Emphasis Type="Italic">Pinctada martensii</Emphasis> and <Emphasis Type="Italic">Perna viridis</Emphasis>

Research on the kinetics of Benzo[a]pyrene (B[a]P) bioaccumulation in the clam Pinctada martensii and mussel Perna viridis showed that the initial rate of uptake was directly related to the PAH concentrations in the ambient environment. The uptake and depuration rate constants were different at the four B[a]P exposure levels, which indicated that the toxicokinetic rate constants mainly depended on the exposure levels of pollutants to the environment. In addition, the uptake rate constants of B[a]P were higher than the depuration rate constants in the entire experiment. The comparison demonstrated that mussels release B[a]P more rapidly than clams. The bioconcentration factors (BCFs) of B[a]P varied from 3335 to 12892 in the clam and 2373–6235 in the mussel. These findings on the bioaccumulation kinetics for petroleum hydrocarbons, in association with the critical body residue, will be valuable when choosing sensitive organisms to assess the potential ecotoxicological risk to the marine environment.     

Chronic Effects of <Emphasis Type="Italic">Pinus radiata</Emphasis> and <Emphasis Type="Italic">Eucalyptus globulus</Emphasis> Kraft Mill Effluents and Phytosterols on <Emphasis Type="Italic">Daphnia magna</Emphasis>

Two kraft pulp mill effluents were compared in terms of their chronic toxicity to Daphnia magna. One resulted from pulping Pinus radiata and the other came from a parallel processing of Pinus radiata and Eucalyptus globulus (mixed kraft pulp mill effluent). The concentration of phytosterols found in the mixed kraft pulp mill effluent was higher than in the effluent from Pinus radiata, with values of 0.1082 and 0.02 μg/L, respectively. The phytosterols per se are responsible for 12.9% and 8.1% of the deviation from the natural shape, while the kraft pulp mill effluents account for 25.6%–27.8% of shape deviation. The role of β-sitosterol and stigmasterol is discussed in relation to endocrine disruption.     

Toxicity of Sediment-Associated Pesticides to <Emphasis Type="Italic">Chironomus dilutus</Emphasis> and <Emphasis Type="Italic">Hyalella azteca</Emphasis>

Two hundred sediment samples were collected and their toxicity evaluated to aquatic species in a previous study in the agriculturally dominated Central Valley of California, United States. Pyrethroid insecticides were the main contributors to the observed toxicity. However, mortality in approximately one third of the toxic samples could not be explained solely by the presence of pyrethroids in the matrices. Hundreds of pesticides are currently used in the Central Valley of California, but only a few dozen are analyzed in standard environmental monitoring. A significant amount of unexplained sediment toxicity may be due to pesticides that are in widespread use that but have not been routinely monitored in the environment, and even if some of them were, the concentrations harmful to aquatic organisms are unknown. In this study, toxicity thresholds for nine sediment-associated pesticides including abamectin, diazinon, dicofol, fenpropathrin, indoxacarb, methyl parathion, oxyfluorfen, propargite, and pyraclostrobin were established for two aquatic species, the midge Chironomus dilutus and the amphipod Hyalella azteca. For midges, the median lethal concentration (LC₅₀) of the pesticides ranged from 0.18 to 964 μg/g organic carbon (OC), with abamectin being the most toxic and propargite being the least toxic pesticide. A sublethal growth endpoint using average individual ash-free dry mass was also measured for the midges. The no–observable effect concentration values for growth ranged from 0.10 to 633 μg/g OC for the nine pesticides. For the amphipods, fenpropathrin was the most toxic, with an LC₅₀ of 1–2 μg/g OC. Abamectin, diazinon, and methyl parathion were all moderately toxic (LC₅₀s 2.8–26 μg/g OC). Dicofol, indoxacarb, oxyfluorfen, propargite, and pyraclostrobin were all relatively nontoxic, with LC₅₀s greater than the highest concentrations tested. The toxicity information collected in the present study will be helpful in decreasing the frequency of unexplained sediment toxicity in agricultural waterways.     

Antibiotics for the treatment of Cholera, <Emphasis Type="Italic">Shigella</Emphasis> and <Emphasis Type="Italic">Cryptosporidium</Emphasis>in children

Background

Diarrhea is a major contributor to the burden of morbidity and mortality in children; it accounts for a median of 11% of all deaths among children aged less than 5 years, amounting to approximately 0.8 million deaths per year. Currently there is a dearth of literature exploring the effectiveness of antibiotics for diarrhea due to Cholera, Shigella and cryptosporidiosis in children.

Methods

We reviewed the literature reporting the effect of antibiotics for the treatment of diarrhea due to Cholera, Shigella and Cryptosporidium in children under five years. We used a standardized abstraction and grading format and performed meta-analyses to determine the effect of the treatment with various antibiotics on mortality and rates of clinical and bacteriological/parasitological failure. The CHERG Standard Rules were applied to determine the final effect of treatment with antibiotics on diarrhea morbidity and mortality.

Results

For Cholera; the evidence was weak to recommend any effect on mortality. For Shigella; there was no data on mortality; either all-cause or cause specific, hence we used clinical failure rates as a proxy for Shigella deaths and propose that treatment of Shigella dysentery with antibiotics can result in a 82% reduction in diarrhea mortality due to Shigella. For cryptosporidiosis; there was data on all-cause mortality but the evidence was weak hence we used clinical failure rates as a proxy for mortality to estimate that antimicrobial treatment of diarrhea due to cryptosporidiosis can result in a 54% reduction in mortality.

Conclusions

There is evidence to recommend antibiotic use for reduction of morbidity and mortality due to Cholera, Shigella and Cryptosporidium. We recommend that more clinical trials should be conducted to evaluate the efficacy and safety of first- and second- line drugs currently in use for treatment for diarrhea and dysentery in both developing and developed countries.