Characterization of dissolved organic carbon and Humic substances in the well water of the Blackfoot disease area in Taiwan

Since the early 1960s, many investigators have reported that blackfoot disease, a peripheral vascular disease, observed in southwestern Taiwan is due to drinking the higher arsenic concentration in well water. However, recent studies indicated that the relationship with blackfoot disease is not only with arsenic but also humic substances. This paper presents some results concerning the characterization (such as fluorescence, elemental composition, molecular weight and carbon distribution) of humic substances isolated from the Fuhsing well water of the blackfoot disease area. For comparison, the dissolved organic carbon (DOC) and humic substances in the normal well water from Chiuying and the Nanwan coastal water were also analyzed. In general, in the well water of the blackfoot disease area, extremely high concentrations of DOC (18.5mg/L) and fulvic acid (7.54mg/L) with high fluorescence intensity (59.1, equivalent to 0.0282uM quinine sulfate solution) and high percentages (over 50%) of low molecular weights of less than 1,000 were obtained compared with those of normal waters. C‐13 Nuclear magnetic resonance spectroscopy showed a high content (37.2%) of aromatic carbon. These higher concentrations of DOC and fulvic acid with the higher content of aromatic carbon in well water might be one of the key factors causing the blackfoot disease in Taiwan.     

Photocatalytic oxidation of humic substances with TiO<Subscript>2</Subscript>-coated glass micro-spheres

The photocatalytic oxidation of humic substances in aqueous solutions and natural waters with TiO₂ attached to buoyant, hollow glass micro-spheres was studied. A maximum oxidation efficiency of 3.6 mg W^–1 h^–1 was achieved in neutral or alkaline media at a plane surface concentration of the catalyst attached to the micro-spheres of 25 g m^–2. Proceeding by different mechanisms in acidic and alkaline media, the photocatalytic oxidation efficiency did not benefit from an excessive presence of hydroxyl radical promoters, hydrogen peroxide and alkali.     

Huminstoffe in Sedimentporenwässern ausgewählter Bundeswasserstraßen

Humic substances are an important component of organic carbon in natural waters. Their character and properties are determined by the sources and the processes of their origin. Humic substances are not exclusively refractory compounds, but they are involved in several transformation processes in the water. It is not possible to directly analyze humic substances, therefore several methods were applied for their characterization. The presented LC-OCD-technique is a size-exclusion-chromatography with online UV- and carbon detection. Carbon fractions, e.?g. humic substances were differentiated by their molecular size. The portion of humic substances in sediment porewaters of the rivers Elbe, Rhine, Danube, Oder, Müritz-Elde-Waterway was determined. With only a few exceptions it ranges from 50 to 67?% of the dissolved organic carbon. The high molecular weight fraction accounts for 10 to 34?%, and the fraction of the low molecular weight substances was from 7 to 37?%. The ratio between the spectral absorption coefficient (254?nm) and the organic carbon is called SUVA (L/mg × m) and is an inidicator of the proportion of unsaturated bonds in the humic substances. Both high molecular herbal components (e.?g. cellulose, lignin) and biological degradiation products (e.?g. amino acids, sugar) are involved in sediment porewater transformation and degradiation processes. This demonstrates the distribution of the dissolved organic carbon between the fractions.     

Humic substances shorten human plasma prothrombin time

The prothrombin time of the normal human pooled plasma was shortened by Aldrich humic acid well water humic substances and lignin at final concentrations ranging from 5 × 10^–3 mg mL^–1 to 5 × 10^–2 mg mL^–1, with a maxmum effect at 1 × 10^–2 mg mL^–1. At this concentration the shortening was 5.5 s, 4.4 s, and 3.5 s by Aldrich humic acid, well water humic substances and lignin respectively. However, monomeric components of humic acid such as syringic acid, protocatechuic acid, pyrogallol, vanillic acid, gallic acid, resorcinol, ferulic acid, catechol, caffeic acid and p-coumaric acid did not have such ability to shorten prothrombin time at the same final concentration ranges. Certain reducing agents such as t-butanol (2.5 × 10^– –2.0 × 10^–2 mg mL^–1), glutathione (8.0 × 10^–2–1 .0 mg mL^–1), ascorbic acid (4.2 × 10^–2–5.0 × 10^–1 mg mL^–1) and dithiothreitol (1.0 × 10^–2–1.7 × 10^–1mg mL^–1) could prevent the shortening effects of humic substances or lignin on prothrombin time. These results suggested that humic substances and lignin with a polymerised structure had an ability to affect activities of some blood coagulating enzymes.     

Photoreactivity of humic substances: relationship between fluorescence and singlet oxygen production

Humic substances are natural compounds abundantly present in the environment. They play a significant role in the natural attenuation of pollution in surface water due to their capacity to generate reactive species upon solar light excitation. Finding physico chemical parameters related to this property would be of a great help in the prediction studies of the organic pollutants fate. In this work, we investigated relationships between the ability of the humic substances to produce singlet oxygen and their fluorescence properties. For this, a series of sixteen humic acids, fulvic acids, and water-extractable organic matter from soils were studied. The steady-state singlet oxygen concentrations in the irradiated humic substances solutions were measured by monitoring the loss of furfuryl alcohol added as a singlet oxygen scavenger. The emission spectra of the sixteen samples were also recorded. Values of the steady-state singlet oxygen concentrations and the emission intensities showed significant variations among the humic samples and a parallel increase. Thus, here we demonstrate that the rate of singlet oxygen production and the emission intensity of the humic samples are correlated, the best correlation being obtained for emission wavelengths between 500 and 580 nm. This correlation which was never reported until now can be used to estimate the singlet oxygen-production capacity of the humic substances based on their fluorescent properties.     

Water hardness and cardiovascular mortality in Finland

In Finland, where mortality rates of cardiovascular diseases are as a rule among the highest in the world, significant areal differences in these figures are encountered especially between the eastern and western parts of the country. To test the hypothesis that these differences,( the reason of which has long been a subject for a lively debate in Finland), may result from geochemical factors such as variations in the hardness or calcium or magnesium content of well water a correlation analysis was carried out in which the geochemical properties in each of the country's individual administrative districts, or communes (444 in all, excluding Åland) were compared with the percentage of heart diseases among the causes of death from diseases in 1991. The results show a poor or extremely low correlation nation-wide (r ranging from –0.039 to +0.045), indicating a virtual absence of any causal relationship. On the other hand, taken pairwise, the extreme western and eastern provinces, Vaasa andNorthern Karelia, show marked differences both in their geochemical and mortality data, the percentage of deaths caused by cardiovascular diseases being markedly lower in the province of Vaasa, where the hardness and the magnesium content of well water (but not the calcium content) are significantly higher (p < 0.001 and 0.002 respectively). This inverse relationship is in line with the supposition that in addition to other factors, geochemical differences may have an effect on mortality.     

Arsenic in Drinking Water and Bladder Cancer: Comparison between Studies Based on Cancer Registry and Death Certificates

Associations between arsenic in drinking water and bladder cancer in an area along the southwest coast of Taiwan have been documented for decades. Several ecologic studies were conducted to assess the dose-response relationships. Some of them used the National Cancer Registry Program to identify cancer cases, and some used death certificates. Whereas the cancer registry collects information on all patients no matter if they died of bladder cancer or not, the case ascertainment might be incomplete due to the fact that reporting of cases is not mandatory. Reporting of death, on the other hand, is strictly enforced by law, but patients who did not die of bladder cancer might not be identified. In order to assess the problems with both approaches, we conducted a study using both case identification mechanisms. A total of 243 townships with measurements of arsenic in drinking water were included in the analysis of cancer registry data, and death certificates were collected from 10 of those townships. In both analyses, the same measurements of arsenic made by the mercuric bromide stain method were adopted. Due to limitation of the method, all levels below 0.04mg L^–1 were combined as a single exposure category. The results were very much alike; both approaches detected statistically significant associations between high arsenic levels in drinking water (above 0.64mg L^–1) and occurrence of bladder cancer but did not find such associations for arsenic exposures at lower levels.     

Effects of arsenic on osmoregulation in the tilapia Oreochromis mossambicus reared in seawater

The effects of arsenic (As₂O₃) on plasma osmolarity, Na and K concentrations, the activity of gill Na–K-ATPase, and on the ultrastructure of gill chloride cells were compared between seawater tilapia (Oreochromis mossambicus) and freshwater tilapia in the Institute of Zoology, Academia Sinica, between 1989 and 1991. Arsenic was found to be more lethal in seawater tilapia [96 h LC₅₀ (median lethal concentration): 26.5 ppm] than in freshwater ones (71.7 ppm). No significant effect was found on plasma ion concentrations and osmolarity, enzyme activity or the ultrastructure of chloride cells in freshwater tilapia after 96 h exposure to 70 ppm arsenic. In contrast, 96 h exposure to 15 ppm arsenic caused evident effects in seawater tilapia: an increase in plasma osmolarity and activity of gill Na–K-ATPase, as well as better development of the chloride cell tubular system. These data suggest that the lethal effect of arsenic may be partially attributed to a hydromineral disturbance in seawater tilapia, but in freshwater tilapia arsenic perhaps causes destruction in some physiological mechanisms other than osmoregulation. The activation of gill Na–K-ATPase and chloride cells in seawater tilapia appears to indicate an adaptation in the osmoregulatory mechanism to arsenic exposure, i.e., to enhance secreting ions or arsenic in the gills.     

The arsenic content of bottled mineral waters

The arsenic levels of 23 mineral waters on sale to the public in the United Kingdom were measured. The arsenic content of most waters was below 1 g L^–1 but the statutory limits of 50 ug L^–1 for natural mineral waters and 100 g L^–1 for non-alcoholic beverages were exceeded by the French mineral water, Vichy Célestins (220 ug L^–1). Regular consumption of mineral water of such elevated concentration could make a significant contribution to the intake of the more toxic inorganic species of arsenic, with possible adverse long-term effects on the health of some individuals. The general need for analytical speciation studies of dietary arsenic is emphasised.     

成都东郊稻田水中砷形态的测定及分布特征

采用氢化物发生-原子荧光光谱法测定了成都东郊4块稻田水中砷的形态.研究发现,该区域稻田表面水砷浓度平均值为3.15—7.9μg.L-1,土壤孔隙水为18.71—53.71μg.L-1,除4号稻田土壤孔隙水外,其余各稻田表面水及土壤孔隙水中砷浓度的平均值均未超出国家农田灌溉水质标准.垂直方向上,土壤孔隙水中各形态砷的浓度均比稻田表面水中的高,且都在水-土界面或接近界面处最大,然后依次向下呈递减趋势.水平方向上,各形态砷的浓度因所处稻田条件的不同而分布各异.各形态砷在所研究稻田水中的分布皆呈现出可溶态砷>颗粒态砷、三价砷>五价砷的特征.     

荧光猝灭法测定菲、苊、芘与腐殖酸的结合常数

用荧光猝灭法测定了胡敏酸（Fluka）与苊、菲和芘相互作用的结合常数（KDOC），其lgKDOC值分别为4．4，4．48和4．89．用同样方法测得长江水生FA以及黑龙江水生FA和HA的KDOC之间有显著差别．HA的KDODC一般高于FA．黑龙江水生FA的KDOC高于长江．对同一来源的腐殖酸，三种多环芳烃的KDOC与KOW呈线性相关．     

Community structure and vertical distribution of cyclopoid copepods in the Red Sea

The species abundance, vertical distribution and diurnal vertical migration of cyclopoid copepods was analyzed in the central Red Sea in October–November 1980. Samples were taken to a depth of 450 m with a multiple opening — closing plankton net with 0.1-mm mesh-size. Selected important species were allocated to five different groups according to their depth distributions during daytime. The greatest number of species (9) was found in the lower epipelagic zone (40 to 100 m), below the strong seasonal thermocline. The lowest number of species (1) occurred in the upper part of the upper mesopelagic zone (100 to 250 m), which is characterized by a strong dissolved oxygen gradient. Five species had a bimodal vertical distribution, with dual peak abundances in the epipelagic and upper mesopelagic zones. Distinct differences in distribution patterns were noted between sexes and/or developmental stages. The vertical range of diurnally migrating species was small, usually less than 50 to 100 m. Characteristic diurnal changes in the vertical succession of dominant species occur within the epipelagic zone (0 to 100 m). Species-specific vertical distribution patterns are compared with published data from other areas. A conspicuous difference in the proportion of carcasses was noted between species: small species (<0.5 mm in length) had a much higher proportion of carcasses, usually between 20 and 40% of the total standing stock, than larger ones (<5%). The potential causes of this phenomenon, which may be due to (1) methodological bias, (2) a lower sinking velocity of small carcasses, or (3) a higher mortality rate of small species, are discussed.     

Variations in heavy metal contamination of stream water and groundwater affected by an abandoned lead–zinc mine in Korea

This study evaluated variations in heavy metal contamination of stream waters and groundwaters affected by an abandoned lead–zinc mine, where a rockfill dam for water storage will be built 11 km downstream. For these purposes, a total of 10 rounds of stream and groundwater samplings and subsequent chemical analyses were performed during 2002–2003. Results of an exploratory investigation of stream waters in 2000 indicated substantial contamination with heavy metals including zinc (Zn), iron (Fe) and arsenic (As) for at least 6 km downstream from the mine. Stream waters near the mine showed metal contamination as high as arsenic (As) 8,923 μg L⁻¹, copper (Cu) 616 μg L⁻¹, cadmium (Cd) 223 μg L⁻¹ and lead (Pb) 10,590 μg L⁻¹, which greatly exceeded the Korean stream water guidelines. Remediation focused on the mine tailing piles largely improved the stream water qualities. However, there have still been quality problems for the waters containing relatively high concentrations of As (6–174 μg L⁻¹), Cd (1–46 μg L⁻¹) and Pb (2–26 μg L⁻¹). Rainfall infiltration into the mine tailing piles resulted in an increase of heavy metals in the stream waters due to direct discharge of waste effluent, while dilution of the contaminated stream waters improved the water quality due to mixing with metal free rain waters. Levels of As, Cu and chromium (Cr) largely decreased after heavy rain but that of Pb was rather elevated. The stream waters were characterized by high concentrations of calcium (Ca) and sulfate (SO₄), which were derived from dissolution and leaching of carbonate and sulfide minerals. It was observed that the proportions of Ca and SO₄ increased while those of bicarbonate (HCO₃) and sodium and potassium (Na+K) decreased after a light rainfall event. Most interestingly, the reverse was generally detected for the groundwaters. The zinc, being the metal mined, was the most dominant heavy metal in the groundwaters (1758–10,550 μg L⁻¹) near the mine, which far exceeded the Korean standard of 1000 μg L⁻¹ for drinking water. The decreases in the heavy metals contents in the groundwaters associated with reduced rainfall were quite different from the increases observed for the stream waters, which is not clearly understood at this time and warrants further investigation.     

Environmental geochemistry study of arsenic in Western Hunan mining area,P.R. China

The geochemical characteristics of arsenic in the soil of the Western Hunan mining area of P.R. China were systematically studied. The results show that the strata of Western Hunan are rich in arsenic and that Western Hunan is a geochemically abnormal region for arsenic. The experimental study on speciation in the strata also indicates that the speciation of arsenic in the Neoproterozoic-Cambrian strata are mainly easily transferred speciation (exchangeable, carbonate-bound, sulfides-bound), which are approaching or exceed 60%. Arsenic content in the main soil of Western Hunan is in the range of 8.8–22.8 μg g⁻¹, the mean value is 16.1 μg g⁻¹, which is larger than the arsenic background value of Hunan soil. The distribution of rock with high arsenic content or high easily transferred arsenic speciation is consistent with the distribution of high arsenic content soil. In the mining region, part soils and river/brook waters were polluted by mine tailings and mining/smelting waste water. The arsenic content in polluted paddy soils and river/brook water is 46.26–496.19 μg g⁻¹, 0.3–16.5 mgL⁻¹, respectively. The positive abnormality and pollution of arsenic in the soil and water affects the arsenic content of the crop and the inhabitants’ health.     

Life-history patterns in two forms of Macrophthalmus japonicus (Crustacea: Brachyura)

Two behaviorally distinct forms — courtship signal — (Form L and V) of Macrophthalmus japonicus (De Haan) are known. Monthly samples of each form were collected from two areas in Japan: Form L from Amakusa, western Kyushu, between April 1985 and February 1986; Form V from Fukuoka, northern Kyushu, between November 1982 and December 1983. Life-history traits were compared between two populations and discussed. Individuals from the Amakusa population grew more slowly and matured at a smaller size than those from the Fukuoka population. Maturation period and longevity did not differ significantly. In the first year of reproduction, females in the Fukuoka population produced more, and larger broods than those in the Amakusa population and crab mortality was higher in every age group. Egg size did not differ significantly. The major environmental factors — air-temperature, nitrogen content of the surface mud and period of aerial exposure were similar in both areas, and it is suggested that the differences in life-history exhibited by these crabs are genotypic, and perhaps related to their different form.     

A seasonal study of arsenic in groundwater,Snohomish County,Washington, USA

A series of arsenic poisonings near Granite Falls in Snohomish County, Washington, were identified during 1985–87. An initial investigation revealed the source of arsenic exposure to be high levels of arsenic in well water. A large number of wells in eastern Snohomish County were tested, residents were interviewed and sources of contamination, both natural and man-made, were investigated. More than 70 private drinking-water wells were found to contain elevated levels of arsenic . One well contained 33 mg As L^–1. The finding of elevated arsenic levels in a previously approved drinking-water well for a restaurant, plus suggestions of symptoms consistent with arsenic poisoning among people with wells with no detectable arsenic, raised concern over possible temporal variation in arsenic levels. To evaluate this temporal variation, a 12-month study of arsenic in groundwater was conducted in selected wells near Granite Falls. The 12-month study of 26 wells, conducted between February 1988 and January 1989, found arsenic levels for individual wells to vary from one to 19 fold over time. Because of this variability, four out of the eight wells with arsenic levels close to the Maximum Contamination Level (MCL) of 0.050 mg As L^–1 would have been considered safe on the basis of a single sample, but would have exceeded the MCL at another time of the year.In areas with a high occurrence of arsenic contaminated drinking water, approval of well water prior to the sale of a house or issuance of a building permit which is based on a single arsenic test may result in later findings of unacceptable drinking water. When the arsenic is near the MCL, it may be prudent to follow well-water arsenic concentrations over time to assure that the arsenic level remains within acceptable bounds. If lower arsenic standards are adopted for drinking water, the issue of temporal variation around the standard will become a matter of more widespread concern.To whom correspondence should be addressed. The contents of this paper do not necessarily reflect the views and policies of the US Environmental Protection Agency.     

The molecular composition of humic substances extracted from green composts and their potential for soil remediation

Humic substances play empirically several essential functions in biogeochemical cycles such as storage of carbon, pollutants, nutrients and water, yet the underlying mechanisms remain poorly known because their precise molecular structure is largely unknown so far. Here, we extracted humic substances from biomass waste of bell pepper, fennel, artichoke, coffee ground, coffee husks, and nursery residues. We analyzed humic extracts by ultra-high resolution Orbitrap Fusion Lumos Tribrid 1 M mass spectrometry, using both positive photoionization and negative electrospray ionization modes, and by ¹³C cross polarization/magic angle spinning nuclear magnetic resonance spectroscopy. We identified 5000–7000 unique organic compounds in humic substances by integrating photoionization with electrospray ionization. The chemical distribution of all components was depicted by nuclear magnetic resonance. Humic substances from green composts are composed by a wide variety of hydrophilic and hydrophobic moieties, thus providing the required biosurfactant properties for effective soil washing capacities, with carboxyl-rich alicyclic molecules, fatty acids, and phenolic acids as major constituents. Overall, our findings provide a major insight in the molecular structure of humic substances, thus opening research on mechanisms ruling the origin, fate and behavior of humic substances.

     

Recovering humic substances from the dewatering effluent of thermally treated sludge and its performance as an organic fertilizer

The biologic treatment of the dewatering effluent from thermally treated sludge is difficult due to the high concentration of refractory humic substances. On the other hand, humic substances are an important source of organic fertilizer. In this study, a novel process using ferric coagulant was developed to recover humic substances from dewatering effluent for use as an organic fertilizer. When ferric coagulant was applied to raw dewatering effluent, up to 70% of humic substances were enmeshed by hydrolyzed ferric ions at an optimum pH of 4.5. The proper mass ratio of iron ions to humic substances was 0.6. In the recovered material, humic substances accounted for 24.2% of the total dry solids, and the amount of phosphorus (equivalent phosphorus pentoxide) was 6.2%. Heavy metals and other components all met the legal requirements for organic fertilizer. When the recovered material was applied to soybeans, the germination and growth of the seeds was significantly improved.     

Occurrence of pharmaceuticals and hormones in drinking water treated from surface waters

The levels of a wide variety of pharmaceuticals and hormones, in source and potable-water supplies of French drinking water treatment plants, were assessed. In surface waters, 27 of the 51 target compounds were determined at least once. Paracetamol, salicylic acid and carbamazepine were quantified in more than 80% of samples. The highest concentration of 71 ng/L was observed for paracetamol. Twelve other substances were widely found in the surface waters studied, contaminating between 33 and 80% of the samples. These compounds include analgesics, psychotropic drugs, antibiotics and beta-blockers consistent with the French consumption, as well as natural hormones (oestrone, progesterone and androgens) and synthetic progestatives. In drinking water supplies, 25 compounds were also present, salicylic acid being the most frequently detected. Carbamazepine and the β-blocker atenolol found at lower levels (maximum 2 ng/L), are also present in more than 30% of the contaminated drinking waters. The pharmaceuticals exhibit different reactivity towards the treatments, while progestagens and androgens seem resistant to most of them. The effectiveness of the treatments is discussed, as well as the consequences of the presence of all these compounds on human health. This is the first time that such a long list of compounds (51) is proposed to assessment, and consequently this study provides the first data on pharmaceuticals and steroids occurrences in French drinking waters and represents a basis for the assessment of risks for humans. Moreover, at the international level, this is the first time that so many substances are quantified in drinking water, due to the very low detection limits, especially in the case of the hormones.     

Der einfluß der temperatur auf thermostabilität,isoenzym-muster und reaktionskinetik der laktat-dehydrogenase aus fischen

Methodological problems complicate investigations on thermostability of lactate dehydrogenase (LDH). It is difficult to demonstrate a correlation between adaptation-temperature (AT) and LDH thermostability. Heat-inactivation characteristics change completely if diluted or undiluted tissue extracts are heated. In purified LDH (purchased from Boehringer, Mannheim, FRG), additions such as casein, bovine-serum albumin, NADH and pyruvate — even in small concentrations — can alter considerably the degree of heat resistance. It LDH activity is measured as a function of experimental temperature (ET) according to the composition of the actual test mixture (e.g. altered pyruvate concentration), a different temperature optimum is found. If tissue extracts containing unpurified enzymes are used, the accompanying substances act on the enzyme and modify its properties. Thus, possible influence of AT on enzyme properties can be concealed (suppressed, over-emphasized). In Idus idus acclimated to 10° or 20°C, brain, gill, gut and white dorsal muscle reveal identical LDH-isoenzyme patterns. However, liver-LDH shows a pattern dependent on the AT. A total of 11 bands with LDH activity were found. In 10°C fishes, the Isoenzymes 1, 3, 6 and 7 are especially active. However, 20°C fishes show marked activity of Isoenzymes 5 and 8, and a reduced activity of Isoenzyme 7. According to their electrophoretic mobility, the particular isoenzymes of LDH of white dorsal muscle of I. idus or Rhodeus amarus can be clearly distinguished. The ATs 10° or 20°C do not influence the dependence of reaction order on ET: this is not true for the velocity constant.