Springer Science and Business Media LLC

This work analyses levels of particles PM10 and PM2.5 recorded at four air-quality monitoring stations located in the urban area of Valladolid (Spain) during 2015–2016. To achieve this, the evolution of particle concentrations at different time scales was determined. Average concentrations ranged from 15.3 to 17.6 µg m−3 for PM10 and between 8.9 and 14.8 µg m−3 for PM2.5. The highest monthly means were recorded in autumn and winter. The difference between mean concentrations at weekends and on weekdays for PM10 was around 3 µg m−3 at most of the measuring stations and was 1 µg m−3 for PM2.5. Two concentration peaks were found during the day, one in the morning and the other in the evening, which evidenced the influence of traffic and other anthropogenic activities on PM concentrations. Their mean values were approximately 21 and 17–21 µg m−3, respectively, for PM10. Mean maximum values for PM2.5 were 12 µg m−3, except at one of the measuring sites, with 17 µg m−3 for the morning maximum and 1 µg m−3 more for the nocturnal peak. In addition, the impact of long-distance transport of air masses in the study area was analysed by applying a HYSPLIT trajectory model, taking into account backward trajectories of European, African, and Atlantic origins as well as local conditions. In particular, high concentration events due to Saharan dust intrusions are presented. Finally, background levels of particle concentrations estimated at most sampling areas were around 15 and 7.7 µg m−3 for the PM10 and PM2.5 particle fractions, respectively.

Solid-phase microextraction combined with fast short-column liquid chromatography/electrospray ionization tandem mass spectrometry (SPME/LC/MS/MS) was used for isolating and analyzing nine N-methylcarbamate pesticides from water samples. Several SPME parameters, such as polarity of fibers, extraction time, and effect of ionic strength, were investigated and their impact on the SPME/LC/MS/MS technique was studied. The method was shown to be sensitive with detection limits between 0.3 and 1.9 μg/L and reproducible with precision between 4.5 and 12.7% RSD. The versatility of the method was exhibited by its excellent linearity in the concentration range of 2–2,000 μg/L in drinking water. A comparison of the SPME/LC/MS/MS method with LC/MS/MS methods utilizing traditional sample preparation techniques shows that the former offers similar performance in terms of precision and linearity, but is clearly easier to use and faster to perform.

We studied the toxicity and in vivo inhibition of acetylcholinesterase (AChE) by the organophosphate Nuvan (dichlorvos); Nuvan mixed with a mixed function oxidase inhibitor, piperonyl butoxide (PB); Nuvan with a pyrethroid Decis (deltamethrin); and a tertiary mixture of Nuvan, PB, and Decis in the snail Lymnaea acuminata. Nuvan was highly toxic to the snail and was a strong inhibitor of AChE activity. Both PB and Decis act synergistically with Nuvan when given together in a 1:5 and 1:46 ratio, respectively. When a tertiary mixture of Nuvan, Decis, and PB was given in a 1:46:5 ratio, the toxicity of the mixture was higher in comparision to the binary mixture of Nuvan + PB or Nuvan + Decis.

Milk samples of 14 women were analyzed for PCBs (polychlorinated biphenyls),p,p′-DDE, and HCB (hexachlorobenzene) during 11 intervals of a 120 day-lactation period. A general downward trend in residue levels was evident, and a statistically significant decline was observed for residue levels of PCBs (P<0.01) and HCB (P=0.02) on the milk fat basis. Primipara (n=9) had from 1.5 to 2.1 times higher mean residue levels than mothers nursing their second or third child (n=9). Significant declines in residue levels during lactation of the first child were found, while no pronounced changes in residue levels were observed during lactation of the second or third child. Overall, residue levels in this study were lower than corresponding levels found earlier in Norway, and within the range of the corresponding levels found in another Norwegian human milk survey done at the same time.

Riffle-dwelling crayfish populations were sampled at 16 sites in 4 tributaries of the Spring River located within the Tri-State Mining District in southwest Missouri. Crayfish density, physical habitat quality, and water quality were examined at each site to assess the ecological effects of mining-derived metals on crayfish. Metals (lead, zinc, and cadmium) were analyzed in samples of surface water, sediment, detritus, and whole crayfish. Sites were classified a posteriori into reference, mining, and downstream sites primarily based on metal concentrations in the materials analyzed. Three species of crayfish (Orconectes neglectus neglectus, O. macrus, and O. virilis) were collected during the study; however, only O. n. neglectus was collected at all sites. Mean crayfish densities were significantly lower at mining sites than at reference sites. Mean concentrations of metals were significantly correlated among the materials analyzed and were significantly greater at mining and downstream sites than at reference sites. Principal component analyses showed a separation of sites due to an inverse relationship among crayfish density, metals concentrations, and physical habitat quality variables. Sediment probable-effects quotients and surface-water toxic unit scores were significantly correlated; both indicated risk of toxicity to aquatic biota at several sites. Metals concentrations in whole crayfish at several sites exceeded concentrations known to be toxic to carnivorous wildlife. Mining-derived metals have the potential to impair ecosystem function through decreased organic matter processing and nutrient cycling in streams due to decreased crayfish densities.

The blue shark (Prionace glauca) is the most commonly caught species of Elasmobranchii at the entrance to the Gulf of California. Although fins are the primary target commodity, the entire organism is consumed. This study examined the concentration of Hg and Se in muscle and liver to understand the antagonistic process that occurs between these two elements within the organism. Twenty-two individuals were captured at the Gulf of California inlet between September 2019 and March 2021. Hg was measured by cold vapor atomic absorption, and Se by atomic absorption spectrophotometry in a graphite furnace. All individuals studied showed higher concentrations (µg g−1 wet weight) of Hg (0.69) and Se (2.49) in liver than in muscle (Hg 0.63 and Se 0.08). Although the mean Hg values were below the maximum allowable limits (Hg 1.0 µg g−1 wet weight), the molar ratio (< 1.0) and the negative health benefit value of selenium (HBVSe) in muscle show that additional caution should be taken when consuming this species. We recommend a more thorough study of the antagonistic interaction between Hg and Se to accurately assess the health risk for consumers of blue shark.

Ring Doves (Streptopelia risoria) with breeding experience were fed a control diet or one of two dosages of a mixture of DDE, PCBs, mirex, and photomirex throughout an isolation period of 90 days and one reproductive cycle. Daily observations were made of courtship and parental behaviors. Circulating levels of androgens, estrogens, progesterone, thyroxine, and prolactin were measured in the appropriate sex at selected points in the breeding cycle. The organochlorine mixture altered the nature and duration of courtship behavior in a dose-related fashion resulting in marked asynchrony in the breeding cycle. Alterations were apparently mediated through the female. Incubation and brooding behavior was altered in a dose-related fashion and the median incubation period of the high dosage group was extended by three days. Pairs receiving the high dosage spent less time feeding their young. Androgen levels of males, and the estrogen and progesterone levels of females were altered in a dose-related fashion. Thyroxine levels were increased in both sexes in a dose-related fashion and there was an alteration of prolactin levels. Correlations were obtained between behavior and some hormones. There was a marked dose-related decrease in fledging success, resulting in reductions of 15 and 50% in the number of squabs fledged per nesting attempt. Squabs of pairs receiving the high dosage were of lower weight. The results suggest that behavioral anomalies in breeding synchrony, nest construction, incubation attentiveness and parental care induced in a wild bird population by a mixture of organochlorine pollutants could alter reproductive success, increase the energetic cost to the population, and alter the reproductive fitness of contaminated individuals. These effects were seen in Herring Gulls (Larus argentatus) nesting in colonies in Lake Ontario which was highly contaminated by this same suite of organochlorine pollutants in the mid-1970's.

Twelve cotton insect scouts were monitored during an entire pesticide application season by weekly determinations ofpara-nitrophenol excretion and biweekly cholinesterase measurements. These data were compared to weekly reentry intervals and pesticide application rates to study the validity of a 48-hr minimum reentry interval for methyl parathion-treated cotton. Methyl parathion represented 54.2% of the total amount of pesticide used with toxaphene 35.3%, ethyl parathion 4.1%, and other 6.4%. A significant decrease in erythrocyte and plasma cholinesterase was observed during initial exposure but during peak exposure the cholinesterase levels had returned to normal. The maximum mean amount of methyl and ethyl parathion absorbed by calculation from PNP excretion was 0.95 mg/24hr (n=12). Twelve percent of all reentries were within two days and during one week 48% occurred during the first two days after pesticide application.