Removal of cadmium from scallop hepatopancreas by microbial processes.
A microbial process for removing cadmium from a homogenate of hepatopancreas, a waste of scallop processing, was devised to use this waste for value-added protein resources. Microorganisms were screened on the basis of the ability to remove cadmium from a medium with the initial concentration of 10 mg/l of cadmium. One soil isolate, identified as Xanthomonas sp. UR No. 2 by its taxonomical characteristics, removed 98% of the cadmium in the medium in 2 d. During cultivation of this strain in the homogenates of hepatopancreas digested by endopeptidases, 90% of cadmium was removed, while this strain had little effect on the simple non-digested homogenates. The mass balance of cadmium during homogenizations of the hepatopancreas tissues and cultivations in the protease-treated homogenate were examined. The content of crude proteins of culture supernatant treated by Xanthomonas sp. UR No. 2 was equivalent to those of various feedstuffs on the market. (+info
Evaluation of dehydrated restaurant food waste products as feedstuffs for finishing pigs.
Two dehydrated restaurant food waste (DFW) products were evaluated as potential feedstuffs for finishing pigs. For each product, fresh food wastes were obtained from food service operations at a resort complex in central Florida. The wastes were mostly leftover food and plate scrapings. The wastes were minced, blended with a feed stock (soy hulls and wheat flour [DFW1] or soy hulls and ground corn [DFW2]), pelleted, and dried. The dried product was then blended with additional minced fresh food wastes and dried; this process was then repeated. The final DFW products contained approximately 60% dried food wastes. The DFW1 and DFW2 products contained 11.4 and 8.4% moisture, 15.0 and 14.4% CP, 13.8 and 16.0% crude fat, 10.4 and 14.5% crude fiber, 5.8 and 4.7% ash, .63 and .64% lysine, .54 and .63% Ca, .34 and .38% P, .69 and .86% Cl, and .35 and .47% Na, respectively. Two feeding trials with 48 and 72 finishing pigs (56 to 112 kg), respectively, were conducted comparing diets without (control) or with the DFW product included at 40% of the diet (DFW1) for Trial 1 and 40 or 80% of the diet (DFW2) for Trial 2. Pigs fed the DFW diets in both trials had ADG that were similar (P > . 10) to and average gain:feed ratios that were superior (P = .06, Trial 1; P < .01; linear, Trial 2) to those for control pigs. Carcass lean content and lean quality scores were not reduced (P > . 10) by feeding pigs the DFW diets in either trial. Carcass fat became softer (P < .01; linear) with increasing amount of DFW2 in the diet in Trial 2. Thus, dehydrated restaurant food wastes have the potential to produce a nutritious feedstuff for pigs while offering a viable solid waste disposal option. (+info
Consumption and production waste: another externality of tobacco use.
OBJECTIVE: To describe the waste produced by and environmental implications of individual cigarette consumption (filter tips, packages, and cartons) and tobacco manufacturing. STUDY SELECTION: All available articles and reports published since 1970 related to cigarette consumption and production waste were reviewed. DATA SOURCES: Global cigarette consumption data were used to estimate cigarette butt and packaging waste quantities. Data from the Center for Marine Conservation's International Coastal Cleanup Project were used to describe some environmental impacts of tobacco-related trash. Data from the United States Environmental Protection Agency's (EPA's) Toxics Release Inventory and reported global cigarette consumption totals were used to estimate waste production from cigarette manufacturing. DATA EXTRACTION AND SYNTHESIS: In 1995, an estimated 5.535 trillion cigarettes (27,675 million cartons and 276,753 million packages) were sold by the tobacco industry globally. Some of the wastes from these products were properly deposited, but a large amount of tobacco consumption waste ends up in the environment. Some is recovered during environmental clean-up days. For the past eight years (1990-1997), cigarette butts have been the leading item found during the International Coastal Cleanup Project; they accounted for 19.1% of all items collected in 1997. The tobacco manufacturing process produces liquid, solid, and airborne waste. Among those wastes, some materials, including nicotine, are designated by the EPA as Toxics Release Inventory (TRI) chemicals. These are possible environmental health hazards. In 1995, the global tobacco industry produced an estimated 2262 million kilograms of manufacturing waste and 209 million kilograms of chemical waste. In addition, total nicotine waste produced in the manufacture of reduced nicotine cigarettes was estimated at 300 million kilograms. CONCLUSIONS: Laws against littering relative to cigarette butts could be better enforced. Additional taxes might be levied on cigarette products that would then be directed to environmental clean-up efforts. The tobacco industry should improve the biodegradability of filters, reduce packaging waste, and educate its customers. Worksites and public buildings should be encouraged or required to supply appropriate disposal mechanisms at all building entrances. Public awareness campaigns about the magnitude and prevention of cigarette consumption waste could be developed through partnerships among environmental groups, health organisations, and environmental protection agencies. Tobacco production waste should be a source of concern and regulation by governments throughout the world; it contains numerous chemicals which may be considered health hazards, not the least of which is nicotine produced in the manufacture of low-nicotine cigarettes. (+info
Domestic biomass fuel combustion and chronic bronchitis in two rural Bolivian villages.
BACKGROUND: Chronic bronchitis is an important public health problem worldwide. A study was undertaken to examine the association between exposure to air pollution from domestic biomass fuel combustion and chronic bronchitis in two rural Bolivian highland villages: a village in which cooking is done exclusively indoors and a village in which cooking is done primarily outdoors. Apart from this difference, the villages were virtually identical in terms of socioeconomic status, climate, altitude, access to health care, and other potential confounders. METHODS: Pollution exposure was assessed by combining information on concentrations of particulate matter of <10 microm diameter (PM(10)) in 12 randomly selected households in each village in all potential microenvironments of exposure with time allocation information. The prevalence of chronic bronchitis was assessed using the British Medical Research Council's questionnaire on individuals >20 years of age in both villages (n = 241). RESULTS: Daily pollution exposure was significantly higher in the indoor cooking village (range for adults: 9840-15 120 microg-h/m(3)) than in the outdoor cooking village (range for adults: 5520-6240 microg-h/m(3)) for both seasons and for men and women. The overall prevalence of chronic bronchitis was 22% and 13% for the indoor and outdoor cooking villages, respectively. Logistic regression analysis, which excluded the few smokers present in the population, showed a 60% reduced risk of chronic bronchitis in the outdoor cooking village compared with the indoor cooking village (OR 0.4; 95% CI 0.2 to 0.8; p = 0.0102) after adjusting for age and sex. Individuals aged >40 years were 4.3 times more likely to have chronic bronchitis than the younger age group (OR = 4.3; 95% CI 2.0 to 9.3; p = 0.0002). There was no significant difference in the prevalence of chronic bronchitis in men and women. CONCLUSIONS: The results of this study suggest an association between chronic bronchitis and exposure to domestic biomass fuel combustion, but further large scale studies from other areas of the developing world are needed to confirm the association. Results from this and other studies will assist the development of culturally acceptable and feasible alternatives to the high exposure cooking stoves currently being used by most people worldwide. (+info
Succession of microbial communities during hot composting as detected by PCR-single-strand-conformation polymorphism-based genetic profiles of small-subunit rRNA genes.
A cultivation-independent technique for genetic profiling of PCR-amplified small-subunit rRNA genes (SSU rDNA) was chosen to characterize the diversity and succession of microbial communities during composting of an organic agricultural substrate. PCR amplifications were performed with DNA directly extracted from compost samples and with primers targeting either (i) the V4-V5 region of eubacterial 16S rRNA genes, (ii) the V3 region in the 16S rRNA genes of actinomycetes, or (iii) the V8-V9 region of fungal 18S rRNA genes. Homologous PCR products were converted to single-stranded DNA molecules by exonuclease digestion and were subsequently electrophoretically separated by their single-strand-conformation polymorphism (SSCP). Genetic profiles obtained by this technique showed a succession and increasing diversity of microbial populations with all primers. A total of 19 single products were isolated from the profiles by PCR reamplification and cloning. DNA sequencing of these molecular isolates showed similarities in the range of 92.3 to 100% to known gram-positive bacteria with a low or high G+C DNA content and to the SSU rDNA of gamma-Proteobacteria. The amplified 18S rRNA gene sequences were related to the respective gene regions of Candida krusei and Candida tropicalis. Specific molecular isolates could be attributed to different composting stages. The diversity of cultivated bacteria isolated from samples taken at the end of the composting process was low. A total of 290 isolates were related to only 6 different species. Two or three of these species were also detectable in the SSCP community profiles. Our study indicates that community SSCP profiles can be highly useful for the monitoring of bacterial diversity and community successions in a biotechnologically relevant process. (+info
Increase in bacterial community diversity in subsurface aquifers receiving livestock wastewater input.
Despite intensive studies of microbial-community diversity, the questions of which kinds of microbial populations are associated with changes in community diversity have not yet been fully solved by molecular approaches. In this study, to investigate the impact of livestock wastewater on changes in the bacterial communities in groundwater, bacterial communities in subsurface aquifers were analyzed by characterizing their 16S rDNA sequences. The similarity coefficients of restriction fragment length polymorphism (RFLP) patterns of the cloned 16S ribosomal DNAs showed that the bacterial communities in livestock wastewater samples were more closely related to those in contaminated aquifer samples. In addition, calculations of community diversity clearly showed that bacterial communities in the livestock wastewater and the contaminated aquifer were much more diverse than those in the uncontaminated aquifer. Thus, the increase in bacterial-community diversity in the contaminated aquifer was assumed to be due to the infiltration of livestock wastewater, containing high concentrations of diverse microbial flora, into the aquifer. Phylogenetic analysis of the sequences from a subset of the RFLP patterns showed that the Cytophaga-Flexibacter-Bacteroides and low-G+C gram-positive groups originating from livestock wastewater were responsible for the change in the bacterial community in groundwater. This was evidenced by the occurrence of rumen-related sequences not only in the livestock wastewater samples but also in the contaminated-groundwater samples. Rumen-related sequences, therefore, can be used as indicator sequences for fecal contamination of groundwater, particularly from livestock. (+info
Health and environmental implications of using composted household and yard waste bedding in a cattle feedlot.
A study was conducted to determine the safety and feasibility of using municipal solid waste compost (MSWC) as a bedding material for cattle feedlots. Two pens in an open-front pole barn were bedded with either corn stalks or MSWC in each of two feeding periods (blocks) with two pens (23 x 34 m) per block. Block 1 used 336 heifers (initial BW, 398 kg) during a 104-d period (summer), and Block 2 used 276 steers (initial BW, 412 kg) during a 92-d period (winter). Blood concentrations of regulated elements (Cd, Cu, Mo, Pb, Ni, and Zn), electrolytes, glucose, or liver and kidney enzymes were unaffected (P > .05) by use of either bedding material. Polychlorinated biphenyls in perirenal fat were not detectable (< .5 ppm) in cattle bedded with either material. At slaughter, kidney Cu and kidney and liver Pb concentrations were greater (P < .05) for cattle bedded with MSWC. Despite this, tissue concentrations of these elements were well within those considered normal for healthy cattle. Regulated element concentrations of feed did not differ (P > .05) between diets within period, and neither did DMI or DM digestibility; therefore, cattle bedded with MSWC were likely inhaling additional amounts of these elements and excreting them through feces. More MSWC than corn stalks was required to supply a dry bed per animal daily (P < .05). Soiled bedding (manure as-is) output was similar (P > .05) for both bedding materials. On a DM basis, more manure (P < .05) was removed from the pen bedded with MSWC in Block 2. Total manure N and P removed was similar for both bedding materials. Nitrogen and P concentrations in manure were lower (P < .05) during Block 2, but total manure N removed was greater (P < .05) during Block 2. Total manure P removed from the pens was not affected by season. Under the conditions of this study, MSWC seemed to be a safe and effective bedding material for cattle feedlots. (+info
Cell wall adaptations to multiple environmental stresses in maize roots.
A municipal solid-waste bottom slag was used to grow maize plants under various abiotic stresses (high pH, high salt and high heavy metal content) and to analyse the structural and chemical adaptations of the cell walls of various root tissues. When compared with roots of control plants, more intensive wall thickenings were detected in the inner tangential wall of the endodermis. In addition, phi thickenings in the rhizodermis in the oldest part of the seminal root were induced when plants were grown in the slag. The role of the phi thickenings may not be a barrier for solutes as an apoplastic dye could freely diffuse through them. The chemical composition of cell walls from endodermis and hypodermis was analysed. Slag-grown plants had higher amounts of lignin in endodermal cell walls when compared to control plants and a higher proportion of H-type lignin in the cell walls of the hypodermis. Finally, the amount of aliphatic suberin in both endo- and hypodermal cell walls was not affected by growing the plants on slag. The role of these changes in relation to the increase in mechanical strengthening of the root is discussed. (+info