Concentrations of chlorine, bromine and iodine in Japanese rivers

Concentrations of halogens (Cl, Br and I) in 30 Japanese rivers were measured by ion chromatography and inductively coupled plasma mass spectrometry to understand their behavior in the terrestrial environment. Concentrations of Cl, Br and I in each river, obtained at 10 sampling points from the upper stream to the river mouth, tended to increase near the river mouth. The ranges of geometric means of Cl, Br and I in each river were 1.0–19.4 mg l⁻¹, 2.5–67.9 μg l⁻¹, and 0.18–8.34 μg l⁻¹, respectively. To compare halogen behavior, the concentration ratios, Br/Cl and I/Cl, were calculated. The Br/Cl range was (2.3–7.8) × 10⁻³ (geometric mean: 3.74 × 10⁻³), and it was nearly constant except for the Yoneshiro river. It was estimated that 60–80% of total Br in the middle to lower parts of this river was the excess Br. The Br chemical form in all the rivers is generally considered to be Br⁻. The I/Cl ratios had different trends in rivers flowing into the Japan Sea and Pacific Ocean, possibly due to the different geological features in the river catchments.     

Distribution of pesticides and heavy metals in trophic chain

Determination of triazines herbicides (atrazine and simazine) by high performance liquid chromatography (HPLC) in samples of trophic chain were worked out. Determination limits of 0.5 μg g⁻¹ for atrazine, 0.8 μg g⁻¹ for simazine with pesticides recovery of 70–77% in trophic chain samples were obtained. The content of simazine in soils was in range 1.72–57.89 μg g⁻¹, in grass 5–88 μg g⁻¹, in milk 2.32–15.29 μg g⁻¹, in cereals 10.98–387 μg g⁻¹, in eggs 30.14–59.48 μg g⁻¹, for fruits: 2.45–6.19 μg g⁻¹. The content of atrazine in soils was in range 0.69–19.59 μg g⁻¹, in grass 7.85–23.85 μg g⁻¹, in cereals 1.88–43.08 μg g⁻¹. Cadmium, lead and zinc were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) in the same samples as atrazine and simazine. Determination limits for cadmium 5 × 10⁻³ μg g⁻¹, for lead 1 × 10⁻² μg g⁻¹, and for zinc 0.2 × 10⁻³ μg g⁻¹, were obtained. The content of cadmium in soil was in range 0.13–5.89 μg g⁻¹, in grass 114–627.72 × 10⁻³ μg g⁻¹, in milk 8.88–61.88 × 10⁻³ μg g⁻¹, in cereals 0.20–0.31 μg g⁻¹, in eggs 0.11–0.15 μg g⁻¹, in fruits 0.23–0.59 μg g⁻¹. The content of lead in soils was in range 0.57–151.50 μg g⁻¹, in grass 0.16–136.57 μg g⁻¹, in milk 1.16–3.74 μg g⁻¹, in cereals 1.05–5.47 μg g⁻¹, in eggs 5.79–55.87 μg g⁻¹, in fruits 21.00–87.36 μg g⁻¹. Zinc content in soil was in range 9.15–424.5 μg g⁻¹, in grass 35.20–55.87 μg g⁻¹, in milk 20.00–34.38 μg g⁻¹, in cereals 14.94–28.78 μg g⁻¹, in eggs 15.67–32.01 μg g⁻¹, in fruits 14.94–18.88 μg g⁻¹.

Described below extraction and mineralization methods for particular trophic chains allowed to determine of atrazine, simazine, cadmium, lead and zinc with good repeatability and precision. Emphasis was focused on liquid–liquid extraction and solid-phase extraction of atrazine and simazine from analysed materials, as well as, on monitoring the content of herbicides and metals in soil and along trophic chain. Higher concentration of pesticides in samples from west region of Poland in comparison to that of east region is likely related to common applying them in Western Europe in relation to East Europe. The content of metals strongly depends on samples origin (industry area, vicinity of motorways).     

Kinetics of nitromusk compounds degradation in water by ultraviolet radiation and hydrogen peroxide

The photodegradation of five representative nitromusk compounds in water has been performed in a stirred batch photoreactor with a UV low-pressure immersed mercury lamp, at constant temperature and different doses of hydrogen peroxide. The rate constants have been calculated on the basis of experimental data and a postulated first-order kinetic model. The rate constants, at 298 K and a dose of 1.1746 μmol l⁻¹ H₂O₂ ranges from 0.3567 × 10⁻³ s⁻¹ for musk tibetene, to 1.785 × 10⁻³ s⁻¹ for musk ambrette.     

A qualitative field method for monitoring pesticides in the edge-of-field runoff

A field method is described, which allows the qualitative estimation of pesticide contamination in the edgeof-field runoff. The method employs cheap and easy-to-use runoff sampling bottles, which were installed in an agricultural stream catchment over a period of three growing seasons. During this time 18 runoff events were detected, in nine of which insecticide contamination was measured (maximum concentrations: lindane 0.7 μg l⁻¹ and 12.7 μg kg⁻¹, parathion 20 μg l⁻¹ and 728 μg kg⁻, fenvalerate 18.4 μg 1-1 and 924 μg kg⁻¹). These insecticides were detected mainly as particle-bound chemicals. On about 80 % of the occasions the presence or absence of runoff measured in the field was in agreement with a simulation of runoff presence or absence using the runoff model KINEROS.     

Copper complexation by tannic acid in aqueous solution

The speciation of titrated copper in a dissolved tannic acid (TA) solution with an initial concentration of 4 mmol organic carbon (OC)/l was investigated in a nine-step titration experiment (Cu/OC molar ratio = 0.0030–0.0567). We differentiated between soluble and insoluble Cu species by 0.45 μm filtration. Measurements with a copper ion selective electrode (ISE) and diffusive gradients in thin films (DGT) were conducted to quantify unbound Cu(II) cations (‘free’ Cu) and labile soluble Cu complexes. For the DGT measurements, we used an APA hydrogel and a Chelex 100 chelating resin (Na form). Insoluble organic Cu complexes (>0.45 μm) was the dominant Cu species for Cu/OC = 0.0030–0.0567 with a maximum fraction of 0.96 of total Cu. At Cu/OC > 0.0100, Cu-catalysed degradation of aggregate structures resulted in a strong increase of free Cu and (labile) soluble Cu complexes with a maximum fraction of 0.28 and 0.32 of total Cu, respectively. Labile (i.e. DGT-detectable) soluble Cu complexes had a relatively high averaged diffusion coefficient (D) in the APA hydrogel (3.50 × 10⁻⁶– 5.58 × 10⁻⁶ cm² s⁻¹).     

Isoprene emission from tropical trees in Okinawa Island, Japan

This study surveyed isoprene emission from 42 indigenous and exotic tropical trees in subtropic Okinawa, Japan. Of the 42 trees studied, 4 emitted isoprene at a rate in excess of 20 μg g⁻¹ h⁻¹, and 28 showed the rates of 1–10 μg g⁻¹ h⁻¹. The remainder emitted less than 1 μg g⁻¹ h⁻¹. The majority of trees in this study may therefore fall within the lower emitting species. However, species in Moraceae that is indigenous in Okinawa emitted isoprene at relatively higher rates with an average of 14.2 μg g⁻¹ h⁻¹. The highest emission rate of 107.1 μg g⁻¹ h⁻¹ for Ficus virgata yielded the area basis rate of 47.4 nmol m⁻² s⁻¹, which is almost equivalent to the rate of high emitting species. Furthermore, a linear relationship between light intensity and isoprene emission was noted with Ficus virgata up to 1700 μmol m⁻² s⁻¹. These findings may show the potential importance of subtropical areas as sources of isoprene to the atmosphere.     

Methane fluxes from tundra soils and snowpack in the maritime Antarctic

Methane fluxes were measured from three exposed tundra sites and four snowpack sites on the Fildes Peninsula in the maritime Antarctic in the summertime of 2002. The average fluxes at two normal tundra sites were −15.3 μg m⁻² h⁻¹ and −14.3 μg m⁻² h⁻¹, respectively. The fluxes from tundra site with fresh penguin dropping addition showed positive values with the average of 36.1 μg m⁻² h⁻¹, suggesting that the deposition of fresh droppings greatly enhanced CH₄ emissions from the poor Antarctic tundra during penguin breeding periods. The summertime variation in CH₄ flux was correlated with surface ground temperature and the precipitation. The correlation between the flux and PT₀, which is the product of the precipitation and surface ground temperature, was quite strong. The diurnal cycle of CH₄ flux from the tundra soils was not obtained due to local fluky weather conditions. The fluxes through four snowpack sites were also obtained by the vertical CH₄ concentration gradient and their average fluxes were −46.5 μg m⁻² h⁻¹, −28.2 μg m⁻² h⁻¹, −46.4 μg m⁻² h⁻¹ and −17.9 μg m⁻² h⁻¹, respectively, indicating that tundra soils under snowpack also consume atmospheric CH₄ in the maritime Antarctic; therefore these fluxes could constitute an important part of the annual CH₄ budget for Antarctic tundra ecosystem.     

Distribution of DDT and benzo[a]pyrene between water and dissolved organic matter in natural humic water

DDT and benzo[a]pyrene (BaP) were added both separately and as a mixture to filtered (0.22 μm) humic surface water samples. Following a contact time of 1 d, the fraction bound to dissolved organic matter and the freely dissolved part were separated by using reversed-phase octadecyl silica cartridges. The enriched solutes were analysed by gas chromatography-mass spectrometry in the selective ion monitoring (GC-MS/SIM) mode. Partition coefficients to dissolved organic matter, calculated on the basis of the recovery data, varied between 2.0 × 10⁴ and 6.6 × 10⁴ mL/g for BaP depending on the experimental conditions, whereas the corresponding values for DDT (0.6 × 10⁴ mL/g) showed no significant variation.     

Leaching and degradation of 21 pesticides in a full-scale model biobed

Filling and cleaning of pesticide sprayers presents a potential risk of pollution of soil and water. Three different solutions for handling sprayers have been suggested: Filling and cleaning in the field, filling and cleaning on hard surfaces with collection of the waste water, and filling and cleaning on a biobed, which is an excavation lined with clay and filled with a mixture of chopped straw, sphagnum and soil with turf on top, and with increased sorption capacity and microbial activity for degradation of the pesticides. In the present study the degradation and leaching of 21 pesticides (5 g of each) was followed in an established full-scale model biobed. Percolate was collected and analysed for pesticide residues, and the biobed material was sampled at three different depths and analysed by liquid chromatography double mass spectrometry (LC-MSMS). During the total study period of 563 days, no traces of 10 out of 21 applied pesticides were detected in the percolate (detection limits between 0.02 and 0.9 μg l⁻¹) and three pesticides were only detected once and at concentrations below 2 μg l⁻¹. During the first 198 days before second application, 14% of the applied herbicide bentazone was detected in the leachate with maximum and mean concentrations of 445 and 172 μg l⁻¹, respectively. About 2% of the initial mecoprop and fluazifop dose was detected in the percolate, with mean concentrations of 23 μg l⁻¹, while MCPA and dimethoate had mean concentrations of 3.5 and 4.7 μg l⁻¹, respectively. Leachate concentrations for the remaining pesticides were generally below the detection limit (0.02–0.9 μg l⁻¹, below 1% of applied). Sorption studies of five pesticides showed that compounds with a low K_d value appeared in the leachate. After 169 days, all pesticides in the biobed profile were degraded to a level below 50% of the calculated initial dose. Pesticides with K_oc values above 100 were primarily found in the uppermost 10 cm and degraded slowest due to the low bioavailability. The 11 most degradable pesticides were all degraded such that less than 3% remained in the biobed after 169 days.

Following second pesticide application of the biobed, leachate was sampled 215 and 365 days after the treatment. This showed the same pesticides to be leached out and at concentrations comparable to those of the first treatment. The same pesticides as after the first treatment were retained in the biobed.     

Nitrous oxide emissions from tundra soil and snowpack in the maritime Antarctic

The nitrous oxide emissions were measured at three tundra sites and one snowpack on the Fildes Peninsula in the maritime Antarctic in the summertime of 2002. The average fluxes at two normal tundra sites were 1.1 ± 2.2 and 0.6 ± 1.7 μg N₂O m⁻² h⁻¹, respectively. The average flux from tundra soil site with penguin dropping addition was 3.7 ± 2.0 μg N₂O m⁻² h⁻¹, 3–6 times those from the normal tundra soils, suggesting that the deposition of fresh droppings enhanced N₂O emissions during penguin breeding period. The summer precipitation had an important effect on N₂O emissions; the flux decreased when heavy precipitation occurred. The diurnal cycle of the N₂O fluxes from Antarctic tundra soils was not obtained due to local fluky weather conditions. The N₂O fluxes through four snowpack sites were obtained by the vertical N₂O concentration gradient and their average fluxes were 0.94, 1.36, 0.81 and 0.85 μg N₂O m⁻² h⁻¹, respectively. The tundra soils under snowpack emitted N₂O in the maritime Antarctic and increased local atmospheric N₂O concentrations; therefore these fluxes could constitute an important part of the annual N₂O budget for Antarctic tundra ecosystem.     

Monoterpene emissions and carbonyl compound air concentrations during the blooming period of rape (Brassica napus)

An increasing percentage of agricultural land in Germany is used for oil seed plants. Hence, rape has become an important agricultural plant (in Saxony 1998: 12% of the farmland) in the recent years. During flowering of rape along with intensive radiation and high temperatures, a higher production and emission of biogenic VOC was observed. The emissions of terpenes were determined and more importantly, high concentrations of organic carbonyl compounds were observed during this field experiment. All measurements of interest have been carried out during two selected days with optimal weather conditions. It is found that the origin or the mechanism of formation of different group of compounds had strong influence on the day to day variation of their concentrations. The emission flux of terpenes from flowering rape plants was determined to be 16–32 μg h⁻¹ m⁻² (30–60 ng h⁻¹ per g dry plant––540–1080 ng h⁻¹ per plant), in total. Limonene, -thujene and sabinene were the most important compounds (about 60% of total terpenes). For limonene and sabinene reference emission rates (M_S) and temperature coefficients were determined: β_limonene=0.108 K⁻¹ and M_S=14.57 μg h⁻¹ m⁻²; β_sabinene=0.095 K⁻¹ and M_S=5.39 μg h⁻¹ m⁻².

The detected carbonyl compound concentrations were unexpectedly high (maximum formaldehyde concentration was 18.1 ppbv and 3.4 ppbv for butyraldehyde) for an open field. Possible reasons for these concentrations are the combination of primary emission from the plants induced by high temperature and high ozone stress, the secondary formation from biogenically and advected anthropogenically emitted VOC at high radiation intensities and furthered by the low wind speeds at this time.     

Determination and distribution characteristics of degradation products of nonylphenol polyethoxylates in the rivers of Taiwan

Concentrations of degradation products of nonylphenol polyethoxylates (NPEOs) were analyzed in river water samples in order to determine the distribution characteristic of these alkylphenolic compounds in 18 major rivers of Taiwan. The degradation products of NPEOs were detected in all river samples, with the dicarboxylates alkylphenolic degradation products (CAPEC) being detected most frequently and at the highest concentrations. Concentrations of NP and NP1EO in rivers ranged from n.d. to 5.1 μg l⁻¹ and n.d. to 0.5 μg l⁻¹, respectively. The total concentrations of shortened carboxylates (i.e., NP1EC + NP2EC + NP3EC) and dicarboxylates alkylphenolic degradation products (CAP1EC + CAP2EC) ranged from n.d. to 63.6 μg l⁻¹ and n.d. to 94.6 μg l⁻¹, respectively. Concentrations of NP2EC, NP3EC and all CAPEC residues were determined semi-quantitatively by comparing with the internal standard. Significantly higher concentrations of CAPEC residues were detected in the river waters as compared to those of NP, NP1EO and NPEC degradation products and the average proportions of these compounds in the samples of the rivers were as follows: NP + NP1EO was 5 ± 2.5%, total NPEC was 25 ± 12%, and total CAPEC was 70 ± 12%. The high concentration ratios of CAPEC/NPEC illustrate that aerobic biodegradation plays a main route in the fate of NPEO in the rivers of Taiwan.     

Utilization and degradation of imazaquin by a naturally occurring isolate of Arthrobacter crystallopoietes

A species of bacteria that is capable of utilizing imazaquin as the sole carbon source was isolated from soil with repeated imazaquin applications, and was identified as Arthrobacter crystallopoietes (designated as strain “WWX-1”). This isolate degrades imazaquin as high as 200 μg ml⁻¹, and the estimated dissipation half-lives increased from 1.51 d for the treatment at 50 μg ml⁻¹ to 4.75 d for 200 μg ml⁻¹. Optimal growth of WWX-1 in mineral salt medium with 50 μg ml⁻¹ imazaquin was obtained at 35 °C and a pH of 5.0. Growth of WWX-1 was also observed in mineral salt medium with the addition of other imidazolinone herbicides such as imazethapyr and imazapyr, but not with different classes of herbicides such as metsulfuron-methyl. Two imazaquin metabolites were detected, and spectral analysis with HPLC–MS, ¹H NMR, and IR revealed one metabolite with a molecular weight (MW) of 199 as quinoline-2,3-dicarboxylic anhydride. We propose that A. crystallopoietes (WWX-1) could serve as an efficient biodegradation system for remediation of water and soils that are heavily contaminated with imazaquin or other structurally similar chemicals.     

TBT and TPhT persistence in a sludged soil

The persistence of tributyltin (TBT) and triphenyltin (TPhT) in soils was studied, taking into consideration the quantity of sewage sludge, TBT and TPhT concentrations in soil as well as the soil pH. The organotin compounds (OTC) were introduced into the soil via a spiked urban sludge, simulating agricultural practise. OTC speciation was achieved after acidic extraction of soil samples followed by gas chromatography–pulsed flame photometric analysis (GC–PFPD). Leaching tests conducted on a spiked sludge showed that more than 98% of TBT are sorbed on the sludge. TBT persistence in soil appeared to depend on its initial concentration in sludge. Thus, it was more important when concentration is over 1000 μg(Sn) kg⁻¹ of sludge. More than 50% of the initial TBT added into the soil were still present after 2 months, whatever the experimental conditions. The main degradation product appeared to be dibutyltin. About 90% of TPhT were initially sorbed on sludge, whatever the spiking concentration in sludge was. However, TPhT seemed to be quantitatively exchangeable at the solid/liquid interface, according to the leaching tests. It was also significantly degraded in sludged soil as only about 20% of TPhT remain present after 2 months, the monophenyltin being the main degradation product. pH had a significant positive effect on TBT and particularly TPhT persistence, according to the initial amounts introduced into the soil. Thus, at pH over 7 and triorganotin concentration over 100 μg(Sn) kg⁻¹, less than 10% of TBT but about 60% of TPhT were degraded. When the sludge was moderately contaminated by triorganotins (typically 50 μg(Sn) kg⁻¹ in our conditions) the pH had no effect on TBT and TPhT persistence.     

A chemical and toxicological profile of Dutch North Sea surface sediments

Chemical and toxicological profiles were assessed in surface sediments (fraction <63 μm) from the southern North Sea. In extracts of freeze-dried samples, polybrominated biphenyl (PBB), Irgarol 1051 and phthalate concentrations were below the respective detection limits (except di(2-ethylhexyl)phthalate, which was between 170 and 3300 μg kg⁻¹ dry weight (dw)). Hexabromocyclododecane (HBCD) concentrations were between 0.8 and 6.9 μg kg⁻¹ dw, with highest concentrations at river mouths. Polybrominated diphenylethers (PBDE) concentrations were 0.4–0.6 μg kg⁻¹ dw, decabromodiphenylether (BDE209) 1–32 μg kg⁻¹ dw. The ratio BDE209/PCB153 was used as a tracer for recent emissions, and pointed towards a BDE209 source in the Western Scheldt’s upper estuary. PCBs and PAHs were between 0.19–4.7 and 2.6–200 μg kg⁻¹ dw respectively and generally had highest concentrations at near-shore locations and river mouths.

Responses in the Microtox broad-spectrum and the Mutatox genotoxicity assays were generally low, with near-shore locations giving higher responses. The umu-C genotoxicity and the ER-CALUX assay for estrogenicity showed no response, with the exception of one near-shore location (IJmuiden outer harbour, ER-CALUX).

Highest dioxin-like toxicity (DR-CALUX) was found at near-shore locations, in the outflow of the Rhine/Meuse estuary including a dumping site of harbour sludge. At the Oyster Grounds, DR-CALUX responses appeared to be linked to the occurrence of larger PAHs (4–6 rings). A new, non-destructive clean up procedure resulted in significantly higher DR-CALUX responses than the current protocol. The Dutch legislation on disposal of harbour sludge at sea, dictates the use of the conventional clean up procedure. Our results therefore indicate that probably more dioxin-like toxicity associated with harbour sludge is disposed off at sea than assumed.     

The enhancement of photodegradation efficiency using Pt-TiO2 catalyst

The residues from the extraction of lead/zinc (Pb/Zn) ores of most Pb/Zn mines are permanently stored in tailings ponds, which require revegetation to reduce their environmental impact. This can only be done if the main constraints on plant establishment are evaluated. This can readily be done by field and greenhouse studies.

To test this, the properties of different tailings from Lechang Pb/Zn mine located at the north of Guangdong Province in southern China have been studied. Physical and chemical properties including concentrations of metals (Pb, Zn, Cd and Cu) in the tailings and soils collected from different sites have been measured. The results showed that tailings contain low nitrogen (0.016–0.075%), low-organic matter (0.58–1.78%), high salt (3.55–13.85 dS/m), and high total and diethylene–tetramine–pentaacetic acid (DTPA)-extractable metal concentrations (total: 1019–1642 μg g⁻¹ Pb, 3078–6773 μg g⁻¹ Zn, 8–23 μg g⁻¹ Cd, and 85–192 μg g⁻¹ Cu; DTPA-extractable: 59–178 μg g⁻¹ Pb, 21–200 μg g⁻¹ Zn, 0.30–1.5 μg g⁻¹ Cd, and 4.3–12 μg g⁻¹ Cu). Aqueous extracts of tailings/soils (10%, 20% and 30%, w/v) from different sites were prepared for testing their effects on seed germination and root elongation of a vegetable crop Brassica chinensis and a grass species Cynodon dactylon. It was found that root elongation provided a better evaluation of toxicity than seed germination. The ranking of toxicity using root elongation was: high-sulfur tailings>tailingdam>sparsely vegetated tailings>densely vegetated tailings>mountain soil for both plants. This order was consistent with DTPA-extractable Pb contents in the tailings and soils. B. chinensis seedlings were then grown in the mixtures of different proportions of tailings and farm soil for 4 weeks, and the results (dry weights of seedlings) were in line with the root elongation test. All these demonstrated that heavy metal toxicity, especially available Pb, low content of nutrient, and poor physical structure were major constraints on plant establishment and colonization on the Pb/Zn mine tailings.     

The use of physiological characteristics for comparison of organic compounds phytotoxicity

The influence of intact (FLT) and photomodified (phFLT) fluoranthene (0.05, 0.5 and 5 μmol l⁻¹) and herbicide Basagran (5, 20, 35 and 50 nmol l⁻¹) on the germination, growth of seedlings and photosynthetic processes in pea plants (Pisum sativum L., cv. Garde) was investigated. The germination was significantly inhibited already by the lowest concentration (0.05 μmol l⁻¹) of FLT and phFLT, while Basagran caused inhibition only in higher concentrations (35 and 50 nmol l⁻¹). The growth of roots was significantly inhibited by higher concentration 5 μmol l⁻¹ of both FLT and phFLT and the shoot of seedlings was significantly influenced only by photomodified form. The length of root and shoot was inhibited already by concentration 5 nmol l⁻¹ of Basagran. Organic compounds applied on chloroplasts suspension influenced primary photochemical processes of photosynthesis. In chlorophyll fluorescence parameters, the significant increase of F₀ values and the decrease of F_V/F_M and Φ_II values by application of FLT (0.5 and 5 μmol l⁻¹) and phFLT (0.05, 0.5 and 5 μmol l⁻¹) was recorded. The maximum capacity of PSII (F_V/F_M) was influenced by the highest (50 nmol l⁻¹) and the effective quantum yield of PSII (Φ_II) already by the lowest (5 nmol l⁻¹) concentration of Basagran. Hill reaction activity decreased and was significantly inhibited by higher concentration (0.5 and 5 μmol l⁻¹) of FLT and phFLT and already by the lowest concentration (5 nmol l⁻¹) of Basagran.     

Determination of vapour pressures of nine organic chemicals adsorbed on silicagel

The vapour pressures of nine organic chemicals adsorbed on silicagel were determined by a method which can be standardized. They were compared with those of the non-absorbed, free compounds (range 6 × 10⁻³ – 7 × 10⁴ Pa).     

Nonylphenols in freshwaters of the hydrologic system of an Italian district: association with human activities and evaluation of human exposure

A sampling campaign for the determination of concentrations of nonylphenol isomers (NPs) in freshwaters and sediments of the hydrologic system of the Rieti district (central Italy) was conducted from 2002 to 2003. Eighteen sampling points, selected on the basis of the different human activities in the vicinity, were monitored; six series of water samples (from June 2002 to February 2003) and one of sediment samples (summer 2002) were analyzed by GC/MS.

There was a direct relationship between concentrations of NPs and the presence of urban or industrial activities near the sampling point. However, concentrations of NPs in water were in the range of <0.1–1.4 μg l⁻¹, and their presence limited to short distances from the sources of contamination. Accumulation factors in sediment samples ranged from 10² to 5 × 10³.     

Risk assessment of etofenprox (Vectron) on non-target aquatic fauna compared with other pesticides used as Simulium larvicide in a tropical environment

Within the rotational scheme developed by the Programme to fight the resistance of Simulium damnosum to chemical larvicides, there was an operational gap at discharges between 5 and 70 m³ s⁻¹ for the treatment of rivers where resistance to organophosphates was present. The use of permethrin and carbosulfan was precluded because of risk of environmental impact and, Bacillus thuringiensis ser. H-14 treatments were not envisageable due to cost and logistics constraints. Among the possible complementary groups of larvicides tested, the pseudo-pyrethroids, held promise, because of a mode of action similar to that of pyrethroids, but along with a usually lower toxicity for fish. Etofenprox, one of the pseudo-pyrethroids tested, shows a global detachment of non-target insects in 24 h close to that of pyraclofos, an organo-phosphorus compound (27 against 23%). In laboratory conditions, six times the operational dose which is 0.03 mg l⁻¹ 10 min, is needed to cause 50% mortality of Caridina sp. (a small shrimps species) and 30 times this same dose for 95% mortality. For fish species, a safety margin of 400–800 times the operational dose is observed for Oreochromis niloticus and 200–400 times for Tilapia zillii.