Do ovarian scars persist with age in all Cetaceans: new insight from the short-beaked common dolphin (Delphinus delphis Linnaeus, 1758)

The determination of reproductive status and the reconstruction of individual reproductive histories are central to many ecological studies. In cetaceans, it has been assumed that ovarian scars accumulate with age and provide a lifetime record of female reproductive history. If ovarian scars persist, the number of scars should increase with age after puberty. To test this, we examined age, reproductive status and ovarian scars from 187 short-beaked common dolphins (Delphinus delphis) from the eastern North Atlantic. The number of Corpus Albicans (CA) present in ovaries did not increase with age after age at sexual maturity (ASM), suggesting that ovarian scars are not persistent and that their number at any one time would be a function of rates of ovulation and healing, the latter being defined here as the resorption or disintegration of CA tissue. Since female mammals stop ovulating when pregnant, inferences about healing rates could be made by using pregnant females. Pregnant females had ca. 40% fewer scars than non-pregnant females. This suggests that most CAs would heal quickly, with a half-life of less than 1 year, although larger scars may persist longer. Therefore, counting CAs would have limited potential for reconstructing individual reproductive lifetime histories in the common dolphin. A reassessment of the use of ovarian scars to reconstruct individual life reproductive histories in cetaceans is suggested.     

Degradation of isobutanal at high loading rates in a compost biofilter

Biofiltration has been increasingly used for cleaning waste gases, mostly containing low concentrations of odorous compounds. To expand the application area of this technology, the biofiltration of higher pollutant loading rates has to be investigated. This article focuses on the biodegradation of isobutanal (IBAL) in a compost biofilter (BF) at mass loading rates between 211 and 4123 g/m3/day (30-590 ppm(v)). At mass loading rates up to 785 g/m3/day, near 100% removal efficiencies could be obtained. However, after increasing the loading rate to 1500-1900 g/m3/ day, the degradation efficiency decreased to 62-98%. In addition, a pH decrease and production of isobutanol (IBOL) and isobutyric acid (IBAC) were observed. This is the first report showing that an aldehyde can act as electron donor as well as acceptor in a BF. To study the effects of pH, compost moisture content, and electron acceptor availability on the biofiltration of IBAL, IBOL, and IBAC, additional batch and continuous experiments were performed. A pH of 5.2 reduced the IBAL degradation rate and inhibited the IBOL degradation, although adaptation of the microorganisms to low pH was observed in the BFs. IBAC was not degraded in the batch experiments. High moisture content (51%) initially had no effect on the IBOL production, although it negatively affected the IBAL elimination increasingly during a 21-day time-course experiment. In batch experiments, the reduction of IBAL to IBOL did not decrease when the amount of available electron acceptors (oxygen or nitrate) was increased. The IBAL removal efficiency at higher loading rates was limited by a combination of nutrient limitation, pH decrease, and dehydration, and the importance of each limiting factor depended on the influent concentration.     

Characterization of Escherichia Coli Isolates from Different Fecal Sources by Means of Classification Tree Analysis of Fatty Acid Methyl Ester (Fame) Profiles

Microbial source tracking (MST) methods need to be rapid, inexpensive and accurate. Unfortunately, many MST methods provide a wealth of information that is difficult to interpret by the regulators who use this information to make decisions. This paper describes the use of classification tree analysis to interpret the results of a MST method based on fatty acid methyl ester (FAME) profiles of Escherichia coli isolates, and to present results in a format readily interpretable by water quality managers. Raw sewage E. coli isolates and animal E. coli isolates from cow, dog, gull, and horse were isolated and their FAME profiles collected. Correct classification rates determined with leaveone-out cross-validation resulted in an overall low correct classification rate of 61%. A higher overall correct classification rate of 85% was obtained when the animal isolates were pooled together and compared to the raw sewage isolates. Bootstrap aggregation or adaptive resampling and combining of the FAME profile data increased correct classification rates substantially. Other MST methods may be better suited to differentiate between different fecal sources but classification tree analysis has enabled us to distinguish raw sewage from animal E. coli isolates, which previously had not been possible with other multivariate methods such as principal component analysis and cluster analysis.     

Are consumers willing to pay for conservation agriculture? The case of white maize in the Democratic Republic of the Congo

Throughout the low-income world, agricultural producers have a motivation to slash-and-burn rainforests as they cannot afford inorganic fertilizers. Farmers in the Democratic Republic of the Congo (DRC), who are predominantly women, are often forced to walk long distances to cultivate more productive lands, when fertility near their villages is reduced. On their way and while working away from home, women become targets for rape. Adopting conservation agriculture (CA) could help mitigate deforestation and potentially create a safer environment for women. Limited knowledge about the benefits of CA across countries in Sub-Saharan Africa (SSA) has hindered its adoption. Taking these impediments into account, we estimate if consumers in the DRC are willing to pay (WTP) a premium for CA, using maize flour as the medium. By means of a double-bounded dichotomous choice valuation method, 600 consumers in Bukavu, DRC, were surveyed about their willingness-to-pay for CA-produced maize. Our study finds that only those consumers who identify themselves as farmers are WTP a premium. This study indicates that if CA adoption is to spread in the DRC, it will likely need to happen via increased yields or reduced costs before the farm gate and not premiums after the farm gate.     

Mercury speciation in the Persian Gulf sediments

The concentrations of total mercury (Hg) and methyl mercury (MMHg) were determined in 78 marine sediments in the Iranian coastal waters of the Persian Gulf along nine transects perpendicular to the coastline. Total Hg ranged from 10 to 56 ng g( - 1)d.w. and MMHg from 0.1 to 0.4 ng g( - 1) d.w. The fraction of methyl mercury accounted from 0.3% to 1.1% of the total mercury amount. The organic carbon (OC) content ranged from 0.4% to 1.8%. The present study indicates that the levels of Hg in the sediments of the Iranian coast of the Persian Gulf were all in the concentration range of unpolluted areas regarding Hg (<100 ng g( - 1)). The concentrations of total Hg, methyl mercury and organic carbon were generally higher in the deeper stations. Total Hg and MMHg were significantly correlated, but no significant correlations could be found between the Hg and OC levels.     

Dietary exposure to dioxin-like compounds in three age groups: results from the Flemish environment and health study

Lipophilic contaminants are present in the environment and bioaccumulate in the food chain. Therefore, their intake via animal fat of various sources was assessed for three age groups of the Flemish population, participating in a large biomonitoring program of the Flemish government. In total, 1636 adolescents (14-15 years), 1186 mothers (18-44 years), and 1586 adults (50-65 years) participated in the study and completed a semi quantitative food frequency questionnaire. Individual consumption data were combined, via a so-called simple distribution approach, with recent data on polychlorinated dibenzo-p-dioxins/furans and dioxin-like polychlorinated biphenyls, measured via the chemical-activated luciferase gene expression (CALUX) bio-assay in food items available on the Flemish market. The median (95th percentile) estimated intakes of dioxin-like contaminants were 2.24 (4.61), 2.09 (4.26), and 1.74 (3.53) pg CALUX-TEQ kg(-1) bw d(-1) for, respectively adolescents, mothers and adults. These data are in the same range as those found in other European studies. The CALUX-TEQ results of respectively 59.8%, 53.7% and 36.2% of the adolescent, mother and adult population exceed the tolerable weekly intake (TWI) of 14 pg WHO-TEQ kg(-1) bw w(-1), as derived by the Scientific Committee on Food [Scientific Committee on Food, 2001. Opinion of the Scientific Committee on Food on the Risk Assessment of Dioxins and Dioxin-like PCBs in Food, CS/CNTM/DIOXIN/20 final Brussels, Belgium]. The main contributors of dioxin-like substances are fish and seafood (25-43% of the total intake), added fats (22-25% of the total intake) and dairy products (17-20% of the total intake).     

Biocatalytic dechlorination of lindane by nano-scale particles of Pd(0) deposited on Shewanella oneidensis

A new approach for the removal of the pesticide lindane (gamma-hexachlorocyclohexane or gamma-HCH) makes use of catalytic reduction of HCH to benzene over a metal catalyst, namely Pd(0). Since specific surface area plays an important role in reactivity of catalysts, this study investigated the use of bioPd(0), i.e. nano-scale Pd(0) particles precipitated on the biomass of Shewanella oneidensis, for the removal of lindane. It was demonstrated that bioPd(0) has catalytic activity towards dechlorination of gamma-HCH, with the addition of formate as electron donor, and that dechlorination with bioPd(0) was more efficient than with commercial powdered Pd(0). The biodegradable compound benzene was formed as reaction product and other HCH isomers could also be dechlorinated. Subsequently bioPd(0) was implemented in a membrane reactor technology for the treatment of gamma-HCH polluted water. In a fed-batch process configuration with formate as electron donor, a removal percentage of 98% of gamma-HCH saturated water (10 mg l(-1)) was achieved within 24h. The measured chloride mass balance approached the theoretical value. The results of this work showed that a complete, efficient and fast removal of lindane was achieved by biocatalysis with bioPd(0).     

Assessment of heavy metal distribution and contamination in the sediment of the Ciujung Watershed,Banten Province,Indonesia

Journal of Material Cycles and Waste Management - The present study examined the distribution and severity of heavy metal contamination in the sediments of the Ciujung Watershed and its tributaries...