混凝工艺去除合流污水中有机物及营养元素

通过系列杯罐试验混凝处理合流污水，采用硫酸铝（Al₂(SO₄)₃）、硫酸铁（Fe₂(SO₄)₃）、聚合氯化铝（PAC）和聚合氯化铝铁（PAFC）4种混凝剂均能有效去除污水中的 TP、PO^3-₄-P、SS和COD。聚合金属盐（PAC和PAFC）混凝处理效果优于金属盐（Al₂(SO₄)₃和Fe₂(SO₄)₃），达到相同的处理效果的投加量明显低于后者。助凝剂采用聚丙烯酰胺（PAM）、聚乙烯醇（PVA）、自制的高分子聚合物（AN）和活化硅酸（AS），在保持较低混凝剂投加量的条件下可明显提高污水处理效果；添加助凝剂对强化PO^3-₄-P的去除作用不明显，PO^3-₄-P的去除仅与混凝剂的投加量相关。混凝剂和助凝剂对污水中NH₃-N的去除作用相对不显著。SS去除率随混凝剂投加量的变化趋势说明混凝的机理较为复杂，可能存在多种混凝机理共同作用。     

Estrogenic and thyroid hormone activity of a series of hydroxy-polychlorinated biphenyls

A series of novel synthetic monohydroxy polychlorinated biphenyls (OH-PCBs) (5 trichloro-, 5 tetrachloro- and 5 pentachloro-compounds) have been characterized (1H and 13C NMR and high resolution MS) and their estrogenic and thyroid hormone activities assessed using a yeast two-hybrid assay, both with and without possible metabolic activation by rat liver S9 preparation. Moderate estrogenic activity was found for 2,3,4(')-trichlorobiphenyl-4-ol (compound 5) but this was eliminated when exposed to the S9 mix. 2,2('),3('),4,6-Pentachlorobiphenyl-3-ol (13) and 2('),3,3('),6-tetrachlorobiphenyl-4-ol (10) both showed weak estrogenicity in the absence of the S9 mix. The estrogenicity of compound (10) was enhanced 10-fold by exposure to S9 metabolic activation but that of compound (13) remained unchanged. 2('),4,5('),6-Tetrachlorobiphenyl-2-ol (6) showed strong thyroid hormonal activity (5% of that of T4) whereas 3('),4,6-trichlorobiphenyl-3-ol (4), compound (10) and 2,3('),4,5('),6-pentachlorobiphenyl-3-ol (14) showed moderate activity, and 2('),3,3('),5-tetrachlorobiphenyl-2-ol (8) and 3,3('),5,5('),6-pentachlorobiphenyl-2-ol (11) showed weak activity. The activity of (4) was eliminated by S9 metabolic activation whereas those of (6) and (14) were weakened and that of (10) remained unchanged.     

Heavy metal concentrations in green-lipped mussels collected from Tolo Harbour and markets in Hong Kong and Shenzhen

Green-lipped mussels, Perna viridis, were collected from Kat O, Yim Tin Tsai, Ma Liu Shui and Tap Mun around Tolo Harbour and six local markets in Hong Kong (Aberdeen, Shau Kei Wan, Kowloon City, Mongkok, Yuen Long) and Shenzhen (Dongmun) between July 1994 and February 1995 and analysed for cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn). The metal concentrations of mussels collected from the study sites were Cd (0.45-1.44 microg/g), Cr (0.82-4.89 microg/g), Cu (6.02-23.99 microg/g), Ni (3.25-6.87 microg/g), Pb (2.02-4.36 microg/g) and Zn (90-135 microg/g), while those from the markets were Cd (0.27-1.44 microg/g), Cr (1.09-3.30 microg/g), Cu (9.05-17.8 microg/g), Ni (2.44-5.25 microg/g), Pb (1.17-5 microg/g) and Zn (51-103 microg/g). The metal concentrations were below the maximum permissible levels set by the Hong Kong Government. In addition, seasonal variation of metal accumulation in mussels was investigated in Yim Tin Tsai and Ma Liu Shui and a reduction in the total heavy metal concentrations during winter was noted. The non-carcinogenic hazard index of mussels collected from Tolo Harbour and from Hong Kong markets was between 0.46 and 1.36 compared with those from Shenzhen markets (0.85-1.46), which indicated a low but possible risk in consuming the mussels.     

Acute and chronic toxicity of veterinary antibiotics to Daphnia magna

The acute and chronic toxicity of nine antibiotics used both therapeutically and as growth promoters in intensive farming was investigated on the freshwater crustacean Daphnia magna. The effect of the antibiotics metronidazole (M), olaquindox (OL), oxolinic acid (OA), oxytetracycline (OTC), streptomycin (ST), sulfadiazine (SU), tetracycline (TC), tiamulin (TI) and tylosin (TY) was tested in accordance to the ISO (1989) and OECD (1996) standard procedures. The acute toxicities (48-h EC50 value, mg/l) in decreasing order were OA (4.6), TI (40), SU (221), ST (487), TY (680) and OTC (approximately 1000). NOECs were 340 mg/l for TC and 1000 mg/l for M and OL. Toxic effect on reproduction occurred generally at concentrations, which were one order of magnitude below the acute toxic levels. The chronic toxicity (EC50 values, mg/l) in the D. magna reproduction test in decreasing order were TI (5.4), SU (13.7), TC (44.8) and OTC (46.2). The NOECs (mg/l) obtained in the reproduction test with OA, ST, TY and M were 0.38 for OA, 32 for ST, 45 for TY and 250 for M. The observed toxicity of OA to D. magna indicates that this substance, which is a commonly used feed additive in fish farms, has a potential to cause adverse effects on the aquatic environment.     

Inorganic elemental concentrations in birch bolete mushroom (Leccinum scabrum) and top soil: contamination profiles,bioconcentation and annual variations

Abstract

Analysis of inorganic and organic contaminants in foodstuffs aids in understanding the human exposure to these compounds via consumption. In this study, an edible mushroom species (Leccinum scabrum) and top soil samples were analysed for essential and toxic substances including phosphorus and inorganic elements over a period of three fruiting seasons. Analysis of silver (Ag), aluminium (Al), barium (Ba), calcium (Ca), cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), mercury (Hg), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), nickel (Ni), phosphorus (P), lead (Pb), rubidium (Rb), strontium (Sr) and zinc (Zn) in mushrooms and topsoil were performed using inductively coupled plasma optical emission spectroscopy (ICP-OES) with ultrasonic cross flow nebulizer. Total mercury was determined by cold-vapour atomic absorption spectroscopy (CV-AAS). The results exhibited wide variation in concentrations of metals between soil and mushroom (cap and stipes) during three fruiting seasons. Positive bioconcentration factors (BFCs) indicate on bioaccumulation of several metals including, Cd, Cu, Hg, K, Mg, Na, P, Rb and Zn in caps and stipes of fruitbodies of this mushroom, while other metals such as Al, Ba, Ca, Co, Fe, Mn, Ni, Pb and Sr were not exhibiting significant positive BFCs. Over a period studied, the caps were characterised by different (p?<?0.05) concentrations of Al, Co, Cu, Hg, Mn, Ni, P, Pb and Sr. Contamination profiles, temporal fluctuations, BCFs should be taken into consideration when assessing the nutritional value of this mushroom.     

The importance of atmospheric deposition, charge and atomic mass to the dynamics of minor and rare elements in developing, ageing, and wilted leaves of beech (Fagus sylvatica L.)

The amounts of sixty elements in developing, maturing, senescent and wilting leaves, and in the wintering dead leaves attached to the branches, are reported for a beech (Fagus sylvatica) forest on mor Podzol in south Sweden, a site with no local sources of pollution or geological anomalies. The amounts (contents per leaf) of K (potassium), Rb (rubidium), Cs (caesium), Cu (copper) and P (phosphorus) were highest in young leaves, decreasing throughout the growing season and usually in the subsequent winter. The entirely opposite pattern with a continuous, mostly even increase of the amounts was measured with Be (beryllium), Ba (barium), Hg (mercury), Al (aluminium), Tl (thallium), Pb (lead), Bi (bismuth), V (vanadium), W (tungsten), As (arsenic), Sb (antimony), and Se (selenium). Amounts of rare-earth elements and some transition metals, such as Co (cobalt), Ti (titanium), and the actinides Th (thorium) and U (uranium) were more stable during the growing season, after an initial increase in early summer, but increased greatly in the winter. This winter increase in dead attached leaves has to be accounted for by uptake from long-distance transported constituents in dry and wet deposition. It was similar to deposition rate estimates using moss carpets from the same locality. A passive uptake was positively related to ionic charge and atomic mass. However, the amounts of several, mainly non-essential elements, such as Ni (nickel), Sc (scandium), Zr (zirconium), Cr (chromium), Ag (silver), and Cd (cadmium) were not much lower in the young or maturing leaves than in the wintered dead leaves of this deciduous (hardwood) forest and a proportion apparently originated from internal translocation in the trees. Seasonal fluxes or cycling of many of the scarce or rare elements reported here have never been studied before in forest ecosystems.     

Patterns of metals and arsenic poisoning in Vibrio fischeri bacteria

The Microtox bioassay was used to establish dose-response curves for some toxic elements in aqueous solutions, namely, Zn(II), Pb(II), Cu(II), Hg(II), Ag(I), Co(II), Cd(II), Cr(VI), As(V) and As(III). Experiments were carried out at either pH 6.0 or pH 7.0 to indicate that pH may influence the measured toxicity of some elements due to pH-related changes of their chemical speciation. EC20 values, which represent a measurable threshold of toxicity, were determined for each element and were found to rank as Pb(II)>Ag(I)>Hg(II) approximately Cu(II)>Zn(II)>As(V)>Cd(II) approximately Co(II)>As(III)>Cr(VI). These values were compared to the limit concentrations allowed in industrial wastewater according to the official regulations in Catalonia (Spain). It appears that the Microtox test is sensitive enough for detecting some of the tested elements with respect to official regulations of Catalonia (Spain) dealing with pollution control, with the exception of cadmium, mercury, arsenate, arsenite and chromate.     

Qualitative and quantitative assessment of waste generation in a refrigerator-manufacturing plant based on a waste tree and mass balance

In this study, wastes originating at each production station during refrigerator manufacturing were identified and classified based on a waste tree. A mass balance study revealed a total waste production factor of 0.046 kg/kg of a product of which 75.3%, 23.9%, and 0.8% were non-hazardous wastes (NHWs), packaging wastes (PWs), and hazardous wastes (HWs), respectively. Wastes produced during refrigerator manufacturing were grouped under 35 different waste codes. Waste codes that contributed more than 5% by weight were 15 02 02 (contaminated absorbent material), 15 01 10 (contaminated packaging), 16 02 13 (electronic cards), 07 02 14 (polyol) and 08 05 01 (isocyanates), 19 08 13 (treatment sludge), 16 02 15 (capacitors), and 13 01 13 (hydraulic oil) for HWs, 12 01 01 (ferrous metal), and 16 02 16 (components) for NHWs, and, finally, 15 01 03 (wooden), 15 01 01 (paper&cardboard), and 15 01 02 (plastic) for PWs over 5 years. Scrap costs were used as a surrogate to determine production stages that generated high amounts of metal and plastic wastes. Logarithmically, increasing and decreasing trends were observed for PWs and NHWs over the study period, respectively. HW amounts did not exhibit a statistically significant trend. Twenty-eight BATs (best available techniques) were identified that could be applied in refrigerator manufacturing for waste minimization and management. Among those, 8 of them were proposed for further improvement for waste management in the facility.

     

Evaluation of natural and anthropogenic influences on the Guadalquivir River (Spain) by dissolved heavy metals and nutrients

To evaluate both the natural and anthropogenic influences on surface waters of Guadalquivir River (SW-Spain), concentrations of dissolved trace metals (Mn, Co, Ni, Cu, Cd, Zn, and Pb), inorganic nutrients (N-NH(4)(+), N-NO(3)(-), N-NO(2)(-), and P-PO(4)(3-)) and other variables as conductivity, pH, dissolved oxygen (DO) and suspended solids (SS) were measured during a three-years period (2001-2003). Samples were taken at 26 stations twice a year, during rain and dry periods. The analysis of variance (ANOVA) suggested that temporal variations within the period of study were statistically negligible. Spatial distributions identified three different zones, mainly influenced by sewage (Eastern Zone), agriculture runoffs (Central Zone), and estuarine processes (Western Zone), respectively. Principal Component and Cluster Analysis allowed to identify the variables controlling the water quality of each zone as: N-NH(4)(+), N-NO(2)(-), Mn, and Co, (Eastern Zone), SS, and P-PO(4)(3-) (Central Zone), and Cd, pH and conductivity (Western Zone). Other variables such as Ni, Cu, Zn or N-NO(3)(-), influenced two different zones, while Pb presented a singular behavior.     

Degradation of lidocaine,tramadol, venlafaxine and the metabolites O-desmethyltramadol and O-desmethylvenlafaxine in surface waters

The photodegradation and biotic transformation of the pharmaceuticals lidocaine (LDC), tramadol (TRA) and venlafaxine (VEN), and of the metabolites O-desmethyltramadol (ODT) and O-desmethylvenlafaxine (ODV) in the aquatic environmental have been investigated. Photodegradation experiments were carried out using a medium pressure Hg lamp (laboratory experiments) and natural sunlight (field experiments). Degradation of the target compounds followed a first-order kinetic model. Rates of direct photodegradation (light absorption by the compounds itself) at pH 6.9 were very low for all of the target analytes (?0.0059 h^?1 using a Hg lamp and ?0.0027 h^?1 using natural sunlight), while rates of indirect photodegradation (degradation of the compounds through photosensitizers) in river water at pH 7.5 were approximately 59 (LDC), 5 (TRA), 8 (VEN), 15 (ODT) and 13 times (ODV) higher than the rates obtained from the experiments in ultrapure water. The accelerated photodegradation of the target compounds in natural water is attributed mainly to the formation of hydroxyl radicals through photochemical reactions. Biotic (microbial) degradation of the target compounds in surface water has been shown to occur at very low rates (?0.00029 h^?1). The half-life times determined from the field experiments were 31 (LDC), 73 (TRA), 51 (VEN), 21 (ODT) and 18 h (ODV) considering all possible mechanisms of degradation for the target compounds in river water (direct photodegradation, indirect photodegradation and biotic degradation).     

Macro, minor and toxic elemental uptake and distribution in Hypoxis hemerocallidea, "the African Potato"--an edible medicinal plant

The elemental uptake and distribution, in various parts of the admired herbal plant, Hypoxis hemerocallidea, the 'African potato' and its ability to accumulate elements in response to the growth soil quality are investigated. The total and exchangeable concentrations of twelve elements in the growth soils and their distribution in the roots, potato bulb and leaves of the plants grown under four different settings were compared. The typical concentrations of the twelve selected elements, in the bulb and leaves of the plant grown in a nursery pot (site 2) were (in microg g(-1)dry weight) Ca (8430 and 27075), Mg (2113 and 1566), Fe (66 and 150), Al (10 and 368), Zn (105 and 6.1), Mn (42 and 51), Cu (7.2 and 20.8), Ba (0.23 and 4.44), Co (0.20 and 0.42), As (2.05 and 24.56), Hg (0.92 and 1.82) and Cr (0.13 and 0.33). Except for Ca, Mg, Zn and Mn, the exchangeable cation concentrations in all the growth soils were low. Ca, Mg, Mn, Zn and As had bioaccumulation factors >1. Fe, Al and Co concentrations were high in the roots with little in the rest of the plant. High concentration of arsenic (approximately 13 microg g(-1) dry weight) with bioaccumulation factors of 7 and 20 were observed in the roots and leaves of the plant respectively (site 2), but the concentration of mercury in bulb was very low (0.92 microg g(-1) dry weight).     

Effects of selenium and mercury on the enzymatic activities and lipid peroxidation in brain, liver, and blood of rats

Recent studies have reported on the toxicity and related oxidative stress of selenium and mercury. The present study compares the effects of Se as sodium selenite (Na2SeO3) and Hg as mercuric chloride (HgCl2) separately and in combination. Rats received repeated oral doses of Se (0.5 micromol/ml), Hg (0.5 micromol/ml), or Se in combination with Hg (0.5 micromol/ml of each) for 5 consecutive days. Rat serum, brain and liver samples were collected for biochemical assays. The following biochemical alterations occurred in response to Hg treatment: protein content (brain and liver), acetylcholinesterase (AChE) (brain and serum), acid and alkaline (AcP and AlP) phosphatases (plasma and liver) and glutathione S-transferase (GST) (plasma and liver) activities were significantly (P<0.05) decreased, while lactate dehydrogenase (LDH) (plasma, brain and liver), aspartate and alanine aminotransferase (AST, ALT) (serum and liver) activities were significantly increased. Thiobarbituric acid reactive substances (TBARS) was significantly increased in brain and liver. Effect of Se alone included decreased AcP, AlP and GST (serum and liver) activities. However, LDH (serum, brain and liver) and AST (liver) and TBARS (brain and liver) increased. Selenium in combination with Hg partially or totally alleviated the toxic effects of Hg on different studied enzymes. It is concluded that Se could be able to antagonize the toxic effects of mercury.     

Organohalogen contaminants and metabolites in cerebrospinal fluid and cerebellum gray matter in short-beaked common dolphins and Atlantic white-sided dolphins from the western North Atlantic

Concentrations of several congeners and classes of organohalogen contaminants (OHCs) and/or their metabolites, namely organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), hydroxylated-PCBs (OH-PCBs), methylsulfonyl-PCBs (MeSO₂-PCBs), polybrominated diphenyl ether (PBDE) flame retardants, and OH-PBDEs, were measured in cerebrospinal fluid (CSF) of short-beaked common dolphins (n = 2), Atlantic white-sided dolphins (n = 8), and gray seal (n = 1) from the western North Atlantic. In three Atlantic white-sided dolphins, cerebellum gray matter (GM) was also analyzed. The levels of OCs, PCBs, MeSO₂-PCBs, PBDEs, and OH-PBDEs in cerebellum GM were higher than the concentrations in CSF. 4-OH-2,3,3′,4′,5-pentachlorobiphenyl (4-OH-CB107) was the only detectable OH-PCB congener present in CSF. The sum (Σ) OH-PCBs/Σ PCB concentration ratio in CSF was approximately two to three orders of magnitude greater than the ratio in cerebellum GM for dolphins.     

Seasonal and vertical characteristics of particulate and elemental concentrations along diverse street canyons in South India

Environmental Science and Pollution Research - The impact of street geometries on vertical dispersion of PMs (PM2.5 and PM10) in (1) non-street canyon (NSC), (2) street canyon (SC), and (3) street...     

Uptake and loss of dissolved 109Cd and 75Se in estuarine macroinvertebrates

Semaphore crabs (Heloecius cordiformis), soldier crabs (Mictyris platycheles), ghost shrimps (Trypaea australiensis), pygmy mussels (Xenostrobus securis), and polychaetes (Eunice sp.), key benthic prey items of predatory fish commonly found in estuaries throughout southeastern Australia, were exposed to dissolved (109)Cd and (75)Se for 385 h at 30 k Bq/l (uptake phase), followed by exposure to radionuclide-free water for 189 h (loss phase). The whole body uptake rates of (75)Se by pygmy mussels, semaphore crabs and soldier crabs were 1.9, 2.4 and 4.1 times higher than (109)Cd, respectively. There were no significant (P>0.05) differences between the uptake rates of (75)Se and (109)Cd for ghost shrimps and polychaetes. The uptake rates of (109)Cd and (75)Se were highest in pygmy mussels; about six times higher than in soldier crabs for (109)Cd and in polychaetes for (75)Se - the organisms with the lowest uptake rates. The loss rates of (109)Cd and (75)Se were highest in semaphore crabs; about four times higher than in polychaetes for (109)Cd and nine times higher than in ghost shrimps for (75)Se - the organisms with the lowest loss rates. The loss of (109)Cd and (75)Se in all organisms was best described by a two (i.e. short and a longer-lived) compartment model. In the short-lived, or rapidly exchanging, compartment, the biological half-lives of (75)Se (16-39 h) were about three times greater than those of (109)Cd (5-12h). In contrast, the biological half-lives of (109)Cd in the longer-lived, or slowly exchanging compartment(s), were typically greater (1370-5950 h) than those of (75)Se (161-1500 h). Semaphore crabs had the shortest biological half-lives of both radionuclides in the long-lived compartment, whereas polychaetes had the greatest biological half-life for (109)Cd (5950 h), and ghost shrimps had the greatest biological half-life for (75)Se (1500 h). This study provides the first reported data for the biological half-lives of Se in estuarine decapod crustaceans. Moreover, it emphasises the importance of determining metal(loid) accumulation and loss kinetics in keystone prey items, which consequently influences their trophic transfer potential to higher-order predators.     

Simultaneous analysis of free and sulfo-conjugated steroid estrogens in artificial urine solution and agricultural soils by high-performance liquid chromatography

A simple and robust analytical method was developed to simultaneously detect and quantify 17β-estradiol (E2), estrone (E1), 17β-estradiol-3-sulphate (E2-3S), and estrone-3-sulphate (E1-3S) in aqueous solutions (calcium chloride and artificial urine solutions) and agricultural soils using high performance liquid chromatography and UV detection. The standards for all four compounds were linear in the range of 0.01 to 1.0 μg mL(-1) (n = 6) and 1.0 to 20 μg mL(-1) (n = 6), respectively, with correlation coefficients > 0.999. The on-column limits of detection at an injection volume of 50 μL and S/N (signal: noise) ratio of 3 were: 9.0 ng mL(-1), 10 ng mL(-1), 5.0 ng mL(-1), and 7.0 ng mL(-1) for E2-3S, E1-3S, E2 and E1, respectively. The limit of detection and quantification in artificial urine solution and CaCl(2) solution was 1.0 ng mL(-1) for all four compounds. Method detection limits for the compounds in the 3 soils ranged from 2 to 2.4 ng g(-1) (E2-3S and E1-3S), and 1.0 to 2.9 ng g(-1) (E2 and E1), respectively.     

Comparison of white-footed mice and rice rats as biomonitors of polychlorinated biphenyl and metal contamination

A study was conducted to assess differences in contaminant assimilation among co-occurring white-footed mice (Peromyscus leucopus) and rice rats (Oryomys palustris) captured at a contaminated site. Rodents were collected from five areas at the Paducah Gaseous Diffusion Plant (PGDP), a uranium enrichment facility. Relatively few white-footed mice (8.7%) had quantifiable concentrations of PCBs compared to 42% of rice rats (chi2 = 6.49, d.f. = 1, P < 0.025), and seven of the 11 rice rats (64%) over 50 g body mass had quantifiable concentrations of PCBs in their livers. White-footed mice had higher mean concentrations of barium (P < 0.0001), chromium (P = 0.0010), copper (P = 0.0011), lead (P = 0.0335), and aluminum (P = 0.0006) than rice rats at all five sampling areas. Species-specific differences in accumulation of PCBs and metals were observed and attributed to differences in habitat use and foraging strategies.     

Occurrence of alternative flame retardants in indoor dust from New Zealand: indoor sources and human exposure assessment

Due to worldwide restrictions on polybrominated diphenyl ethers (PBDEs), the demand for alternative flame retardants (AFRs), such as organophosphate flame retardants (OPFRs), novel brominated FRs (NBFRs) and hexabromocyclododecanes (HBCDs), has recently increased. Little is known about human exposure to NBFRs and OPFRs and that their levels in dust have been scarcely evaluated worldwide. To increase the knowledge regarding these chemicals, we measured concentrations of five major NBFRs, ten OPFRs and three HBCD isomers in indoor dust from New Zealand homes. Dust samples were taken from living room floors (n=34) and from mattresses of the same houses (n=16). Concentrations (ngg(-1)) of NBFRs were: 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) (<2-175), decabromodiphenyl ethane (DBDPE) (<5-1430), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB) (<2-2285) and bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH) (<2-640). For OPFRs, concentrations (ngg(-1)) ranged between: tri-ethyl-phosphate (TEP) (<10-235), tri-n-butyl-phosphate (TnBP) (<20-7545), tris-(2-chloroethyl)-phosphate (TCEP) (<20-7605), tris-(1-chloro-2-propyl) phosphate (TCPP) (20-7615), tri-(2-butoxyethyl)-phosphate (TBEP) (50-27325), tris-(2,3-dichloropropyl)-phosphate (TDCPP) (20-16560), tri-phenyl-phosphate (TPhP) (20-35190), and tri-cresyl-phosphate (TCP) (<50-3760). HBCD concentrations fell in the range <2-4100ngg(-1). BTBPE, DBDPE, TBPH, TBEP, and TnBP showed significant positive correlation (p<0.05) between their concentrations in mattresses and the corresponding floor dust (n=16). These data were used to derive a range of plausible exposure scenarios. Although the estimated exposure is well below the corresponding reference doses (RfDs), caution is needed given the likely future increase in use of these FRs and the currently unknown contribution to human exposure by other pathways such as inhalation and diet.     

东莞地下水邻苯二甲酸酯分布特征及来源探讨

在广东东莞地区采集了59组地下水水样和9组地表水水样,采用气相色谱-质谱联用技术进行测定,结果表明,地下水中邻苯二甲酸酯(PAEs)的检出率为39.0％,6种PAEs的质量浓度在未检出～6.70 μg/L.其中,邻苯二甲酸双(2-乙基己基)酯(DEHP)检出率最高,为22.O％,最大值为6.20 μg/L；邻苯二甲酸二...     

In vitro evaluation of the mutagenic and cytostatic effect of Tamaron,Lannate and Manzate alone and in mixture

Pesticides are often used in agriculture, especially in floriculture. They are frequently applied in binary or ternary mixtures. Nevertheless, their impact on the genetic material has been scarcely explored. In this study, the mutagenic and cytostatic effect of three widely used pesticides, alone and combined, were analyzed. Briefly, lymphocytes cultures were obtained from peripheral blood samples of five healthy donors to determine the sister chromatid exchange and the replicative index (RI). Then, lymphocytes were exposed to Tamaron (100 ppm), Lannate (200 ppm) and Manzate (300 ppm) alone and combined. For the binary mixtures, the concentrations used were 50 ppm of Tamaron, 100 ppm of Lannate and 150 ppm of Manzate. For the ternary mixtures the following concentrations were used: Tamaron (33 ppm), Lannate (70 ppm) and Manzate (100 ppm). Finally, differential staining was performed. It was found that the frequency of SCE/cell showed a significant difference (P ≤ 0.05) between the control (2.66) and the individual treatments of Tamaron (4.87), Lannate: (5.12) and Manzate (4.23). Also, the values of the SCE in the binary mixture of Tamaron+Lannate (5.57), Tamaron+Manzate (6.06) and Lannate+Manzate (6.22) and the ternary mixture (6.63) were statistically different compared to the control. In the RI there was a significant difference between the control (1.98) and the Manzate (1.87). RI differences were also statistically significant (P ≤ 0.05) in mixtures of Tamaron+Lannate (1.64), Tamaron+Manzate (1.63), Lannate+Manzate (1.69) and total mixture (1.53). Therefore, it is suggested that these pesticides alone and in mixtures have both mutagenic and cytostatic synergistic effect in human lymphocytes in vitro.