Acute toxicity tests with Daphnia magna, Americamysis bahia, Chironomus riparius and Gammarus pulex and implications of new EU requirements for the aquatic effect assessment of insecticides

Threshold concentrations for treatment related effects of 31 insecticides, as derived from aquatic micro-/mesocosm tests, were used to calibrate the predictive value of the European Tier-1 acute effect assessment on basis of laboratory toxicity tests with Daphnia magna, Chironomus spp., Americamysis bahia and Gammarus pulex. The acute Tier-1 effect assessment on basis of Daphnia (EC(50)/100) overall was protective for organophosphates, carbamates and most pyrethroids but not for neonicotinoids and the majority of insect growth regulators (IGRs) in the database. By including the 28-day water-spiked Chironomus riparius test, the effect assessment improves but selecting the lowest value on basis of the 48-h Daphnia test (EC50/100) and the 28-day Chironomus test (NOEC/10) is not fully protective for 4 out of 23 insecticide cases. An assessment on basis of G. pulex (EC(50)/100) is sufficiently protective for 15 out of 19 insecticide cases. The Tier-1 procedure on basis of acute toxicity data (EC(50)/100) for the combination of Daphnia and A. bahia and/or Chironomus (new EU dossier requirements currently under discussion) overall is protective to pulsed insecticide exposures in micro-/mesocosms. For IGRs that affect moulting, the effect assessment on basis of the 48-h Chironomus test (EC(50)/100) may not always be protective enough to replace that of the water-spiked 28-day C. riparius test (NOEC/10) because of latency of effects.     

Second-order chlorine decay and trihalomethanes formation in a pilot-scale water distribution systems

It is well known that model-building of chlorine decay in real water distribution systems is difficult because chlorine decay is influenced by many factors (e.g., bulk water demand, pipe-wall demand, piping material, flow velocity, and residence time). In this paper, experiments were run to investigate the kinetic model of chlorine decay and the formation model of trihalomethanes (THMs) in pilot-scale water distribution systems. Experimental results show that the rate constants of chlorine decay, including wall decay and bulk decay, increasing with temperature. Moreover, the kinetic model of chlorine decay and the formation model of THMs describe experiment data of pilot-scale water distribution systems. The effect of different piping material on chlorine decay and THMs formation were also investigated. The rate constants of chlorine decay are ranked in order: stainless steel pipe, ductile iron pipe, and last, polyethelene pipe because wall decay is the largest in stainless steel pipe than that in other piping material. Correspondingly, the rate of THMs formation follows the order of stainless steel pipe, ductile iron pipe, and last, polyethelene pipe because of less chlorine in bulk water reacting with the trihalomethane formation potential (THMFP).     

Reproductive toxicity of lead,cadmium, and phthalate exposure in men

Environmental toxicants viz lead or cadmium and phthalate esters (di(2-ethylhexyl) phthalate [DEHP], dibutyl phthalate [DBP], and diethyl phthalate [DEP]) widely found in different environmental strata are linked to deteriorating male reproductive health. The objective was to assess the relationships between the seminal lead, cadmium, and phthalate (DEHP, DBP, DEP) concentrations at environmental level and serum hormone levels and semen quality in non-occupationally exposed men and specify the effect of individual and combined exposure of toxicants on semen quality. A study of 60 male partners of couples attending the Andrology Laboratory of the Reproductive Biology Department, All India Institute of Medical Sciences (AIIMS), New Delhi, India for semen analysis to assess their inability to achieve a pregnancy was selected for the study. The results of univariate and stepwise multiple regression analysis in the unadjusted model showed a significant correlation between lead or cadmium and phthalates DEHP/DBP/DEP and sperm motility, sperm concentration, and DNA damage. After adjusting for potential confounders, an association with lead or DEHP was only observed. The present data shows that lead (Pb) or cadmium (Cd) or phthalates might independently contribute to decline in semen quality and induce DNA damage. Phthalates might influence reproductive hormone testosterone. These findings are significant in light of the fact that men are exposed to a volley of chemicals; however, due to the small sample size, our finding needs to be confirmed in a larger population.     

Indication of PCDD/F formation through precursor condensation in a full-scale hazardous waste incinerator

This paper gives the PCDD/F fingerprint of boiler and fly ash of a full scale hazardous waste incinerator and demonstrates that, when the waste to be incinerated contains high concentrations of PCBs and chlorinated pesticides, heterogeneous precursor condensation is the dominant PCDD/F formation mechanism rather than de novo synthesis. This is in contrast to full-scale municipal solid waste incinerators, where de novo synthesis has been shown to be the dominant PCDD/F formation mechanism. This paper agrees with earlier predictions based on numerous lab scale experiments.     

Disappearance of dimethoate,methamidophos and pirimicarb in lettuce

Abstract

Foliar sprays of dimethoate at 150 or 300 g a.i./ha, methamidophos at 450 or 900 g a.i./ha and pirimicarb at 140 or 280 g a.i./ha were applied for control of the green peach aphid, Myzus pericae (Sulzer), and the lettuce aphid, Nasonovia ribisnigri (Mosley), about 2 weeks before the lettuce started heading, and again about 1 week from harvest. In lettuce, dimethoate partially oxidized to its oxon and pirimicarb converted to its methylamino‐ and/or formyl methylamino‐analogues. Most residues were present in the outer leaves which were exposed directly to the sprays; only traces of residues were detected in samples of the inner head leaves. Total residues disappeared rapidly. Pirimicarb was the least persistent and only traces of residues (<0.01 ppm) were detected in marketable heads. Concentrations of dimethoate, including the oxon and of methamidophos were well below their respective tolerances of 2 and 1 ppra respectively.     

Seasonal variation of pharmaceutically active compounds in surface (Tagus River) and tap water (Central Spain)

Numerous studies have shown the presence of pharmaceutically active compounds (PhACs) in different environmental compartments, for example, in surface water or wastewater ranging from nanograms per litre to micrograms per litre. Likewise, some recent studies have pointed to seasonal variability, thus indicating that PhAcs concentrations in the aquatic environment may depend on the time of year. This work intended to find out (1) whether Tagus fluvial and drinking water were polluted with different groups of PhACs and (2) if their concentrations differed between winter and summer seasons. From the 58 substances analysed, 41 were found belonging to the main therapeutic groups. Statistical differences were seen for antibacterials, antidepressants, anxiolytics, antiepileptics, and cardiovascular drugs, with higher concentrations being detected in winter than in summer. These results might indicate that the PhACs analysed in this study undergo lower environmental degradation in winter than in summer. In order to confirm these initial results, a continuous monitoring should be performed especially on those PhACs that either because of an elevated consumption or an intrinsic chemical persistence are poorly degraded during winter months due to low temperatures and solar irradiation. It is especially important to identify which of these specific PhACs are in order to recommend their substitution by equally effective and safe substances but also environmentally friendly.     

Effects of air pollution on lung function and symptoms of asthma, rhinitis and eczema in primary school children

Health effects of ambient air pollution were studied in three groups of schoolchildren living in areas (suburban, urban and urban-traffic) with different air pollution levels in Eski?ehir, Turkey. This study involved 1,880 students aged between 9 and 13 years from 16 public primary schools. This two-season study was conducted from January 2008 through March 2009. Symptoms of asthma, rhinitis and eczema were determined by the International Study of Asthma and Allergies in Childhood questionnaire in 2008. Two lung function tests were performed by each child for summer and winter seasons with simultaneous ambient air measurements of ozone (O₃), nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) by passive sampling. Effects of air pollution on impaired lung function and symptoms in schoolchildren were estimated by multivariate logistic regression analyses. Girls with impaired lung function (only for the summer season evaluation) were more observed in suburban and urban areas when compared to urban-traffic area ([odds ratio (OR)?=?1.49; 95 % confidence interval (CI) 1.04–2.14] and [OR?=?1.69 (95 % CI 1.06–2.71)] for suburban vs. urban-traffic and urban vs. urban-traffic, respectively). Significant association between ambient ozone concentrations and impaired lung function (for an increase of 10 μg m^?3) was found only for girls for the summer season evaluation [OR?=?1.11 (95 % CI 1.03–1.19)]. No association was found for boys and for the winter season evaluation. No association was found between any of the measured air pollutants and symptoms of current wheeze, current rhinoconjunctivitis and current itchy rash. The results of this study showed that increasing ozone concentrations may cause a sub-acute impairment in lung function of school aged children.     

Application of 15N–18O double stable isotope tracer technique in an agricultural nonpoint polluted river of the Yangtze Delta Region

One strategy to combat nitrate (NO₃-N) contamination in rivers is to understand its sources. NO₃-N sources in the East Tiaoxi River of the Yangtze Delta Region were investigated by applying a ¹⁵N–¹⁸O dual isotope approach. Water samples were collected from the main channel and from the tributaries. Results show that high total N and NO₃-N are present in both the main channel and the major tributaries, and NO₃-N was one of the most important N forms in water. Analysis of isotopic compositions (δ ¹⁸O, δD) of water suggests that the river water mainly originated from three tributaries during the sampling period. There was a wide range of δ ¹⁵N-NO₃ (?1.4 to 12.4 ‰) and a narrow range of δ ¹⁸O-NO₃ (3.7 to 9.0 ‰) in the main channel waters. The δ ¹⁵N and δ ¹⁸O-NO₃ values in the upper, middle, and lower channels along the river were shifted as 8.2, 3.5, and 9.5 ‰, and 9.0, 4.2, and 6.0 ‰, respectively. In the tributary South Tiao, the δ ¹⁵N and δ ¹⁸O-NO₃ values were as high as 9.5 and 7.0 ‰, while in the tributaries Mid Tiao and North Tiao, NO₃-N in most of the samples had relatively low δ ¹⁵N and δ ¹⁸O-NO₃ values from 2.3 to 7.5 ‰ and 4.7 to 7.0 ‰, separately. Our results also suggest that the dual isotope approach can help us develop the best management practice for relieving NO₃-N pollution in the rivers at the tributary scale.     

Factors controlling phosphate interaction with iron oxides

Factors such as pH, solution ion composition, and the presence of natural organic matter (NOM) play a crucial role in the effectiveness of phosphorous adsorption by iron oxides. The interplay between these factors shows a complicated pattern and can sometimes lead to controversial results. With the help of mechanistic modeling and adsorption experiments, the net macroscopic effect of single and combined factors can be better understood and predicted. In the present work, the relative importance of the above-mentioned factors in the adsorption of phosphate was analyzed using modeling and comparison between the model prediction and experimental data. The results show that, under normal soil conditions, pH, concentration of Ca, and the presence of NOM are the most important factors that control adsorption of phosphate to iron oxides. The presence of Ca not only enhances the amount of phosphate adsorbed but also changes the pH dependency of the adsorption. An increase of dissolved organic carbon from 0.5 to 50 mg L can lead to a >50% decrease in the amount of phosphate adsorbed. Silicic acid may decrease phosphate adsorption, but this effect is only important at a very low phosphate concentration, in particular at high pH.