Maturity degree of composts from municipal solid wastes evaluated by differential scanning calorimetry.

Differential scanning calorimetry (DSC) in association with chemical analysis was applied to assess the maturity reached by the organic fraction of Municipal Solid Wastes (MSW) subjected to composting processes with manual and fixed aeration and sampled at different composting times. Thermograms showed that the difference in the treatments, i.e., the manual aeration and the fixed aeration, had no relevant effect on the stabilization and maturation of OM in the substrates. Common thermal effects observed were: a low temperature endotherm assigned to dehydration and/or loss of peripheral polysaccharides chains; a medium temperature exotherm assigned to loss of peptidic structures, and a high temperature exotherm assigned to oxydation and polycondensation of aromatic nuclei of the molecule. Results obtained suggest that in the experimental conditions used, a shorter time of composting (about 30 d) appears adequate, in order to limit the extended mineralization of OM, whereas a prolonged composting time (up to 132 d) would produce a compost of poor quality with high ash content and low OM content.

Solid-phase extraction of sugar cane soot extract for analysis by gas chromatography with flame ionisation and mass spectrometric detection.

The incomplete combustion of biomass is one of the most important sources of emissions of organic compounds into the atmosphere, like polycyclic aromatic hydrocarbons (PAHs) which show genotoxic activity. Since environmental samples generally contain interferents and trace amounts of PAHs of interest, concentration and clean-up procedures are usually required prior to the final chromatographic analysis. This paper discusses the performance of Sep-Pak cartridges (silica gel and RP18) on clean-up of sugar cane soot extract. The best results were obtained with a silica Sep-Pak cartridge. The recoveries ranged from 79% (benzo[b]fluoranthene) to 113% (benzo[e]pyrene).

Serum concentrations of organochlorine compounds and K-ras mutations in exocrine pancreatic cancer. PANKRAS II Study Group.

BACKGROUND: Organochlorine compounds such as 1,1,1-trichloro-2,2-bis(p-chlorophenyl)-ethane (p,p'-DDT), 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (p,p'-DDE), and some polychlorinated biphenyls (PCBs) are carcinogenic to animals and possibly also to human beings. Occupational exposure to DDT may increase the risk of pancreas cancer. The high frequency of K-ras mutations in pancreatic cancer remains unexplained. We analysed the relation between serum concentrations of selected organochlorine compounds and mutations in codon 12 of the K-ras gene in patients with exocrine pancreatic cancer. METHODS: Cases were prospectively identified in five hospitals. Mutations in K-ras were analysed by PCR and artificial restriction fragment length polymorphism. Cases of pancreatic cancer with wild-type K-ras (n=17) were frequency matched for age and sex to cases of pancreatic cancer with a K-ras mutation (n=34, case-case study). These 51 cases were further compared with 26 hospital controls (case-control comparison). Serum organochlorine concentrations were measured by high-resolution gas chromatography with electron-capture detection and negative ion chemical ionisation mass spectrometry. FINDINGS: Serum concentrations of p,p'-DDT were significantly higher in pancreatic cancer cases with a K-ras mutation than in cases without a mutation (odds ratio for upper tertile 8.7 [95% CI 1.6-48.5], p for trend=0.005). For p,p'-DDE the corresponding figures were 5.3 (1.1-25.2, p for trend=0.031). These estimates held after adjusting for total lipids, other covariates, and total PCBs. A specific association was observed between a glycine to valine substitution at codon 12 and both p,p'-DDT and p,p'-DDE concentrations (odds ratio 15.9, p=0.044 and odds ratio 24.1, p=0.028; respectively). A similar pattern was shown for the major di-ortho-chlorinated PCBs (congeners 138, 153, and 180), even after adjustment for p,p'-DDE, but without a specific association with spectrum. Concentrations of p,p'-DDT and p,p'-DDE were similar among wild-type cases and controls, but significantly higher for K-ras mutated cases than for controls (p<0.01). INTERPRETATION: Organochlorine compounds such as p,p'-DDT, p,p'-DDE, and some PCBs could play a part in the pathogenesis of exocrine pancreatic cancer through modulation of K-ras activation. The results require replication, but they suggest new roles for organochlorines in the development of several cancers in human beings.

Organochlorine in the serum of inhabitants living near an electrochemical factory.

OBJECTIVES: To measure the impact of occupational and lifestyle factors on concentrations of organochlorine compounds in a general population sample living near an electrochemical factory with a high airborne concentration of hexachlorobenzene (HCB). METHODS: Serum samples from 608 people (328 selected from a random sample) were collected in 1994. Information on lifestyles, occupation, and medical condition was obtained by questionnaire. RESULTS: HCB and polychlorinated biphenyls (PCBs) were detected in all samples (means 36.7 ng/ml and 4.3 ng/ml respectively), followed by dichlorodiphenyl dichloroethane (DDE) and beta-hexachlorocyclohexane (beta-HCH), found in 98.7% and 87.3% of the samples respectively (means 4.6 ng/ml and 2.5 ng/ml, respectively). Concentrations of HCB were the highest ever reported. Occupation in the factory was the main determinant of the variation in concentrations of HCB (regression coefficients 1.52 (SEM 0.14) in 1n (HCB) for workers in the production department, and 2.13 (0.23) for workers in maintenance department) and explained the highest concentrations of HCB found in men of middle age. In retired workers, concentrations of HCB declined with time since retirement. The PCBs, dichlorodiphenyl trichloroethane (DDT), and beta-HCH were independent of the occupation and concentrations were similar to those found in other populations. Concentrations of beta-HCH and DDE in the whole population, and HCB among non-workers, were higher in women than in men. Concentrations of all measured organochlorine compounds increased with age and body mass index. Consumption of locally caught fish was an independent determinant of HCB and PCB concentrations. CONCLUSIONS: This population incorporated HCB directly through occupation in the electrochemical factory, by airborne pollution, and consumption of locally caught fish. Concentrations of other common organochlorine compounds were not higher than expected. Environmental exposures to these compounds deserve attention due to their persistence and potential health effects.

Urinary porphyrin excretion in a human population highly exposed to hexachlorobenzene.

BACKGROUND: Data from an epidemic reported in Turkey (1955-1959) is the only information about the relationship between hexachlorobenzene (HCB) intake and porphyria cutanea tarda in humans. No information is available on the HCB threshold exposure level to induce porphyria cutanea tarda. OBJECTIVES: To study HCB serum levels and urinary porphyrin excretion in the inhabitants of a village located near an organochlorine compound factory with high HCB concentrations in the air and to detect possible alterations in urinary porphyrin excretion and examine their relationship with HCB serum levels. DESIGN: Cross-sectional study. SETTING: Unit of Porphyrias of a tertiary care facility in Barcelona, Spain. PARTICIPANTS: Six hundred four inhabitants of the village who were older than 14 years provided serum and urine samples (185 participants were factory workers). MAIN OUTCOME MEASURES: Serum HCB was analyzed by gas chromatography coupled to electron capture detection. Quantification of urinary total porphyrins was performed by spectrofluorimetry. Porphyrin profile was determined by high-pressure liquid chromatography. RESULTS: Hexachlorobenzene was detected in all serum samples (mean, 39.8 ng/mL; range, 1.1-1616.0 ng/mL), and levels were higher in factory workers. Mean +/- SD level urinary total porphyrin average concentration was 98 +/- 69 nmol/L (range, 9-1009 nmol/L). Only the urine sample with the highest porphyrin concentration showed an increase of highly carboxylated porphyrins, with a typical profile of porphyria cutanea tarda. In the remaining 603 urine samples, coproporphyrin was the predominant fraction. CONCLUSION: The airborne exposure to and increased body burden of HCB in the Flix village population are not enough to trigger a significant alteration of the heme biosynthesis pathway.

Health effects of chronic high exposure to hexachlorobenzene in a general population sample.

Hexachlorobenzene, an organochlorine compound that accumulates in humans, is widespread throughout the environment. In this study, we describe the health status of inhabitants of a rural village that surrounds an electrochemical factory characterized by high levels of hexachlorobenzene in the air. During 1994, we conducted a cross-sectional study of 1 800 inhabitants in the south of Catalonia, Spain, who were older than 14 y of age. We obtained information on lifestyles and occupational and medical histories via questionnaire. Self-reported health outcomes were validated against clinical records and cancer registry data. Serum levels of hexachlorobenzene were very high in males who worked in the electrochemical factory (geometric mean = 54.6 ng/ml in randomized participants). Levels were lower among subjects who had never worked in the electrochemical factory (females, 14.9 ng/ml; males, 9.0 ng/ml). Levels of other organochlorine compounds (i.e., beta-hexachlorocy-clohexane, 2,2-bis[p-chlorophenyl]-1,1-dichloroethylene) were in the same range found in other communities. Perceived health, prevalence of self-reported common chronic conditions, and porphyria cutanea tarda, thyroid pathology, Parkinson's disease, cancer, and reproductive outcomes were within the ranges observed in other studies. Employment in the plant, however, was associated with having any of the a priori selected health outcomes that were potentially related to exposure to hexachlorobenzene (odds ratio for cancer prevalence = 1.9; 95% confidence interval = 0.5, 7.6). Our population of workers and nonworkers had the highest levels of hexachlorobenzene ever described. The results suggest that exposure to hexachlorobenzene did not affect the general health status of the this population, but it was associated with specific health effects of the most highly exposed subjects.

Enhanced sensitivity in the analysis of trace organochlorine compounds by negative-ion mass spectrometry with ammonia as reagent gas.

A comparison of the performances of ammonia and methane as reagent gases for the analysis of trace organochlorine compounds by gas chromatography coupled to negative-ion chemical ionization mass spectrometry is performed in the present study. Examples of standard mixtures and human blood samples analyzed with both reagents in scan and selected-ion monitoring mode are shown. Important advantages are observed as a consequence of the use of ammonia. These concern detection and quantitation limits and the lower dependence of sensitivity on the degree of chlorine substitution of the compounds.

Hexachlorocyclohexanes in human blood serum.

A simplified method allowing the determination of trace concentrations (ng/ml) of hexachlorocyclohexanes in human sera suitable for the analysis of large numbers of samples has been developed. Comparison of acid (conc. H2SO4,) and basic (5 M KOH) digestion has shown that good recoveries are obtained with the former when an internal standard, 1,2,4,5-tetrabromobenzene (TBB), is used to correct for volatilization losses. Good separation between alpha-, beta- and gamma-HCH isomers, TBB, hexachlorobenzene and some interfering compounds is obtained with DB-5 columns. The use of electron-capture detection (ECD) or negative ion chemical ionization mass spectrometry (NICI-MS) in the selected ion monitoring mode (m/z 71) provides sufficient sensitivity for quantitative determination. ECD is the most sensitive method for beta-HCH and NICI-MS for the other isomers. GC-NICI-MS is needed for the unambiguous determination of delta-HCH due to the coelution with one interfering compound. The method has been successfully applied to the analysis of a series of 625 samples collected in a population situated near the effluents of an organochlorinated solvent factory. The results have shown that beta-HCH is selectively accumulated in human sera and prompt to the preferential investigation of the toxic effects of this isomer in humans and mammals.

Metabolism of hexachlorobenzene in humans: association between serum levels and urinary metabolites in a highly exposed population.

Serum and urine from 100 subjects of a general population highly exposed to airborne hexachlorobenzene (HCB) were analyzed to obtain new insights into the metabolism of this ubiquitous compound. HCB was detected in all serum samples with concentrations ranging between 1.1 and 953 ng/ml. The major known metabolites of HCB were investigated in urine collected over 24 hr. Pentachlorophenol (PCP) was detected in all urines with values ranging between 0.58 and 13.9 micrograms excreted in 24 hr [mean +/- standard deviation (SD), 2.52 +/- 2.05; geometric mean, 2.05]. A sulfur derivative that, after hydrolysis, yielded pentachlorobenzenethiol (PCBT) could also be identified and quantified in all the urines with values ranging between 0.18 and 84.0 micrograms of PCBT excreted in 24 hr (mean +/- SD, 3.47 +/- 10.8; geometric mean, 1.39). The sulfur derivative assessed as PCBT appeared to be the main metabolite, with urinary concentrations surpassing those of PCP in the subjects with higher HCB accumulation (HCB in serum > 32 ng/ml). PCBT concentration in urine collected over 24 hr showed a very strong association with HCB concentration in serum; the association was stronger in males than in females. An increase of 1 ng/ml of HCB in serum led to an increase of 2.12 micrograms of PCBT excreted in urine collected over 24 hr in males (95% CI, 1.82-2.44) and to an increase of 0.67 microgram of PCBT in females (CI, 0.33-1.09). A weaker association was found between PCP in urine and HCB in serum, which was only statistically significant in males (an increase of 1 ng/ml of HCB in serum led to an increase of 0.63 microgram of PCP excreted in urine collected over 24 hr; (CI, 0.34-0.95). These results show that the formation of the cysteine conjugate is a quantitatively more important metabolic pathway in humans than the formation of PCP. Moreover, the association found suggests that PCBT is a good urinary marker of HCB internal dose and glutathione-mediated metabolism.