Toxic Environmental Releases from Medical Waste Incineration: A Review

Toxic releases from medical waste incineration comprising organic emissions such as polychlorinated dibenzo-dioxin/furan (PCDD/Fs) and polycyclic aromatic hydrocarbons (PAHs), inorganic emissions and ashes containing toxic metals have been reviewed. Attempts made by various investigators to reduce/eliminate emissions have also been included. Legislations concerning emission standards for medical waste incinerators have been discussed.     

Characterization of an urban landfill soil by using physicochemical analysis and solid phase microextraction (SPME)—GC/MS

We have aimed at characterizing top soil samples taken in-situ from five different locations of the unregulated dumping site in Eskişehir/Turkey for a period of six months. The study is the first attempt in the city and in Turkey, regarding particularly the SPME (Solid Phase Microextraction Technique) analysis method utilized. A comprehensive research has been conducted to produce critical soil data to be used for indicating current risks as well as the urgency of rehabilitating the site and establishing a sanitary landfill in the site. Conventional physicochemical analytical methods and SPME technique were used to analyze the samples. Physicochemical analyses were performed for determining the pH, total dried matter, volatile matter, total nitrogen, phosphorus, macro elements and heavy metals. Meteorological data were also recorded for the same period. SPSS.10.0 statistical program was used to determine the correlation between meteorological data and physicochemical analysis results. Mean values were used in the correlation analyses. These data indicated that the air temperature and precipitation have significant effects on soil characteristics. SPME, coupled with GC/MS, was used to identify eighty six volatile and semi-volatile organic compounds contained in soil samples. The samples were extracted by headspace SPME with heating (δHS-SPME). SPME analyses were conducted using a commercially available polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber having a film thickness of 65 μm (Supelco) as a capture medium. The experimentally optimized headspace sampling conditions were arranged (15 min. at 50^˚C) before a 30 min. sampling period.     

Ecological risk assessment of organic waste amendments using the species sensitivity distribution from a soil organisms test battery

Safe amendment rates (the predicted no-effect concentration or PNEC) of seven organic wastes were estimated from the species sensitivity distribution of a battery of soil biota tests and compared with different realistic amendment scenarios (different predicted environmental concentrations or PEC). None of the wastes was expected to exert noxious effects on soil biota if applied according either to the usual maximum amendment rates in Europe or phosphorus demands of crops (below 2 tonnes DM ha⁻¹). However, some of the wastes might be problematic if applied according to nitrogen demands of crops (above 2 tonnes DM ha⁻¹). Ammonium content and organic matter stability of the studied wastes are the most influential determinants of the maximum amendment rates derived in this study, but not pollutant burden. This finding indicates the need to stabilize wastes prior to their reuse in soils in order to avoid short-term impacts on soil communities.     

Comparison of solid-phase and eluate assays to gauge the ecotoxicological risk of organic wastes on soil organisms

Development of methodologies to assess the safety of reusing polluted organic wastes in soil is a priority in Europe. In this study, and coupled with chemical analysis, seven organic wastes were subjected to different aquatic and soil bioassays. Tests were carried out with solid-phase waste and three different waste eluates (water, methanol, and dichloromethane).Solid-phase assays were indicated as the most suitable for waste testing not only in terms of relevance for real situations, but also because toxicity in eluates was generally not representative of the chronic effects in solid-phase.No general correlations were found between toxicity and waste pollutant burden, neither in solid-phase nor in eluate assays, showing the inability of chemical methods to predict the ecotoxicological risks of wastes. On the contrary, several physicochemical parameters reflecting the degree of low organic matter stability in wastes were the main contributors to the acute toxicity seen in collembolans and daphnids.     

An alternative approach to reconstructing organic matter accumulation with contrasting watershed disturbance histories from lake sediments

A number of proxies, including carbon to nitrogen ratio (C:N) and stable isotopes (delta(13)C and delta(15)N), have been used to reconstruct organic matter (OM) profiles from lake sediments and these proxies individually or in combination cannot clearly discriminate different sources. Here we present an alternative approach to elucidate this problem from lake sediments as a function of watershed scale land use changes. Stable isotope signatures of defined OM sources from the study watersheds, Shawnigan Lake (SHL) and Elk Lake (ELL), were compared with sedimentary proxy records. Results from this study reveal that terrestrial inputs and catchment soil coinciding with the watershed disturbances histories probably contributed in recent trophic enrichment in SHL. In contrast, cultural eutrophication in ELL was partially a result of input from catchment soil (agricultural activities) with significant input from lake primary production as well. Results were consistent in both IsoSource (IsoSource version 1.2 is a Visual Basic program used for source separation, (http://www.epa.gov/wed/pages/models/isosource/isosource.htm) and discriminant analysis (statistical classification technique).     

Total mercury, organic mercury and selenium in liver and kidney of a South American coastal dolphin

Selenium and total and organic mercury were determined in the liver and kidney of franciscana dolphin (Pontoporia blainvillei) incidentally caught in fishing nets along two Brazilian coastal areas (southeast and south). Regional differences in the concentrations of these contaminants were observed in P. blainvillei. Liver showed the highest organic and total mercury. In general, samples of individuals collected at the southern of Brazil had the highest concentrations of selenium and total and organic mercury. No significant gender differences were observed. Growth stage influenced the accumulation of these contaminants in both organs, and hepatic concentrations increased with the body length, according to the sampling area. Molar mercury and selenium concentrations in liver were significantly correlated, with a Se:Hg ratio close to 4. The among-site differences we found may be related to differences in preferred prey, bioavailability in the marine environment, environmental conditions, or these individuals may belong to distinct populations.     

The use of clays to sequestrate organic pollutants. Leaching experiments

Leaching experiments are performed from clay-pollutant systems in order to evaluate the capability of clays to sequestrate organic pollutants from wastewaters. Reference kaolinite KGa-1b, montmorrillonite SWy-2 and reference soil BCR^®-700 are the sorbent materials. 2,4,6-trichloroaniline (2,4,6-TCA) and 4-chlorophenol (4-CP) are the typical pollutants, sorbed at amounts of 10.0 mg g⁻¹ and 5.8 mg g⁻¹ on SWy-2 and 7.3 mg g⁻¹ and 2.2 mg g⁻¹ on KGa-1b, respectively.The leaching agents are ultrapure water and model solutions of acid rain and surface waters that simulate meteoric leaching. 1.0 mM HNO₃, 1.0 mM H₂SO₄ solutions and a methanol/water 50/50 (v/v) mixture simulate leaching agents of industrial source.The results are compared and the preferential capability of the clays to sequestrate the more lipophilic 2,4,6-TCA is evidenced.The bond interactions are discussed and explained through preferential adsorption reactions. For montmorrillonite also a simultaneous intercalation in the phyllosilicate interlayer is proposed.     

Molecular indicators for pollution source identification in marine and terrestrial water of the industrial area of Kavala city, North Greece

Eight terrestrial and four marine water samples were collected from the industrial section of the city of Kavala in northern Greece to determine the occurrence and distribution of organic contaminants, as well as to identify the molecular markers of different emission sources. The samples were analyzed by means of non-target screening analyses. The analytical procedure included a sequential extraction of the samples, GC-FID, GC/MS analyses, and additional quantitative analyses of selected pollutants. The results show a wide variety of compounds including halogenated compounds, technical additives and metabolites, phosphates, phthalates, benzothiazoles, etc. A close relationship between many of the contaminants and their emission sources was determined based on their molecular structures and information on technical applications.     

Effect of application of phosphate and organic manure-based fertilizers on arsenic transformation in soil columns

The mobility of arsenic in Cambisol under the influence of added barnyard manure and application of a phosphate solution to the soil was described on the basis of column experiments. A soil sample containing 126 mg/kg total As and 3.72 mg/kg specifically-sorbed As was extracted using demineralized water (DIW) or a 28 μmol/l phosphate solution in a column containing untreated soil and in a column with added barnyard fertilizer. The pH, Eh, alkalinity, main components, including DOC, and selected trace elements (Al, Mn, Pb, Cu, Zn, Cd, Cr, Co, Ni, Ba and As) were determined in the extracts. Hydrodynamic tests of the flow and transport of the substances in the columns were carried out. The addition of barnyard manure was manifested in elevated concentrations of the main inorganic components, DOC and Al and a decrease in the Eh value and Mn concentration. Application of a phosphate solution was manifested in a decrease in the NO₃ and SO₄ concentrations, probably as a result of the effect of increased biological fixation. The As concentration in extracts varied from 8.8 to 15.5 μg/l and was not dependent on the composition of the extracting solution or the addition of barnyard fertilizer.     

牛粪与小麦秸秆混合高温堆肥的腐熟进程研究

通过研究牛粪与小麦秸秆混合高温堆肥的腐熟进程,寻求最佳的堆肥体积比,旨在为农业废弃物快速资源化利用提供科学依据。将牛粪与小麦秸秆分别按体积比10∶0、8∶2、6∶4、4∶6、2∶8混合,高温堆肥64d,研究各种处理下堆肥进程。结果表明,与纯牛粪高温堆肥相比,添加小麦秸秆可以加快堆肥升温速度,抑制高温堆肥前期pH的升高和氨气挥发,减少氮素损失,加速堆肥内有毒有害物质分解,加快C/N降低速率。其中牛粪和小麦秸秆以6∶4的体积比混合高温堆肥时效果最好,堆肥结束时有机质和速效氮下降幅度最小,分别为31.84%和18.18%,全氮、全磷、全钾、速效磷和速效钾的提高幅度最大,分别为15.86%、13.64%、9.42%、22.73%和29.30%。若以种子发芽指数80%作为堆肥腐熟的评价指标,牛粪和小麦秸秆按6∶4体积比混合高温堆肥43d即可腐熟,比纯牛粪腐熟提前了12d。综合判断,实际应用中牛粪与小麦秸秆按6∶4体积比进行高温堆肥较为适宜。