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Purpose: This retrospective study aims to describe morphological and therapeutic peculiarities of the suprapubic incisional hernia (SIH) encountered after a Joël-Cohen laparotomy., Patients and Method: Serie-report: 9 patients had an SIH, 2 were sub-umbilical and did not concern the suprapubic scar, 3 were central, 2 on the whole length of the suprapubic scar, and 2 were bilateral in one case associated to a sub-umbilical incisional hernia., Results: SIH were wide openings, with a hernial fascia constituted from the anterior fascia, without connexion with the parietal peritoneum, in a sub-umbilical position above the suprapubic scar, or through the suprapubic scar. Rectus muscle was ruptured or sclerosed. There were 2 distinct defects, an anterior one through the anterior fascia, and a posterior one between the rectus muscles. The parietal peritoneum was retracted leaving bare the posterior side of the rectus muscles. There was an interstitial retro-fascial space, so the SIH was bisaccular. When releasing the parietal peritoneum was not feasible, the prosthesis was placed in a retro-fascial space. When the parietal peritoneum was released, the prosthesis was placed in a preperitoneal space. The anterior defect closure was not always completely feasible, fulfilled with a Vicryl prosthesis. One patient presents an abdominal wall bulging in case of efforts., Conclusion: SIH after a Joël-Cohen laparotomy is wide and dilapidating. The cure is difficult. This technique should be reserved to real emergency obstetrical procedure. We highlight the importance of the parietal peritoneum closure after gynecological or obstetric surgery., (Copyright © 2022 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

The occurrence and temporal variation of 18 perfluoroalkyl substances (PFASs) and 8 polybrominated diphenyl ethers (PBDEs) in the European Alps was investigated in a 10 m shallow firn core from Colle Gnifetti in the Monte Rosa Massif (4455 m above sea level). The firn core encompasses the years 1997-2007. Firn core sections were analyzed by liquid chromatography-tandem mass spectrometry (PFASs) and gas chromatography-mass spectrometry (PBDEs). We detected 12 PFASs and 8 PBDEs in the firn samples. Perfluorobutanoic acid (PFBA; 0.3-1.8 ng L(-1)) and perfluorooctanoic acid (PFOA; 0.2-0.6 ng L(-1)) were the major PFASs while BDE 99 (

Background: Despite the importance of the hip muscles in protecting against hip fracture and in the outcome of hip arthroplasty, the variability in their fat content has not been previously studied. Our objectives were to evaluate the variability in the fat content of the hip muscles in a population without myopathy or a need for hip surgery with the use of computed tomography (CT), to study the relationship between hip muscle fat content and physical performance, and to identify medical conditions and lifestyle habits associated with an increase in hip muscle fat content., Methods: Ten normal subjects without a relevant medical history and ninety-nine consecutive nonsurgical patients without myopathy (age, twenty-one to ninety-four years) underwent a nonenhanced CT scan of the pelvis. Patients were asked to perform physical tests (six-meter walk, repeated chair stands, and Trendelenburg test), and their level of physical activity and medical history were recorded. Evaluation of the fat content of the hip muscles was based on the analysis of four reproducible and representative CT slices with use of custom software., Results: The fat content varied among the muscles, with an anteroposterior gradient from the hip flexors (mean, 2%) to the hip extensors (mean, 10%). This gradient increased after fifty years of age. Fat content also varied considerably among patients. Higher fat content was associated with poorer performance on physical tests, even after adjustment for the cross-sectional area of the muscle (p < 0.05). Higher fat content was also associated with greater age, higher body-mass index, and lower physical activity (p < 0.001)., Conclusions: The observed variability in the fat content of individuals without myopathy or a need for hip surgery should be useful for comparison with future studies of specific populations of patients, such as those with muscle weakness secondary to hip fracture or hip surgery. Simple lifestyle changes such as dietary restriction, increased physical activity, and vitamin D supplementation may decrease muscle fat content and improve physical performance in the elderly.

Inductively coupled plasma-mass spectrometry coupled with cation exchange matrix separation has been optimised for the direct determination of platinum group element (PGE) and trace element emissions from a diesel engine car. After matrix separation method detection limits of 1.6 ng g(-1) for Pd, 0.4 ng g(-1) for Rh and 4.3 ng g(-1) for Pt were achieved, the method was validated against the certified reference material BCR 723, urban road dust. The test vehicle was fitted with new and aged catalytic converters with and without diesel particulate filters (DPF). Samples were collected after three consecutive New European Driving Cycle (NEDC) of the particulate and "soluble" phases using a home-made sampler optimised for trace element analysis. Emission factors for the PGEs ranged from 0.021 ng km(-1) for Rh to 70.5 ng km(-1) for Pt; when a DPF was fitted, the emission factors for the PGEs actually used in the catalysts dropped by up to 97% (for Pt). Trace element emission factors were found to drop by a maximum of 92% for Ni to a minimum of 18% for Y when a DPF was fitted; a new DPF was also found to cause a reduction of up to 86% in the emission of particulate matter.

The occurrence of organic pollutants in European Alpine snow/ice has been reconstructed over the past three centuries using a new online extraction method for polycyclic aromatic hydrocarbons (PAH) followed by liquid chromatographic determination. The meltwater flow from a continuous ice core melting system was split into two aliquots, with one aliquot directed to an inductively coupled plasma quadrupole mass spectrometer for continuous trace elements determinations and the second introduced into a solid phase C18 (SPE) cartridge for semicontinuous PAH extraction. The depth resolution for PAH extractions ranged from 40 to 70 cm, and corresponds to 0.7-5 years per sample. The concentrations of 11 PAH were determined in dated snow/ice samples to reconstruct the atmospheric concentration of these compounds in Europe for the last 300 years. The PAH pattern is dominated by phenanthrene (Phe), fluoranthene (Fla), and pyrene (Pyr), which represent 60-80% of the total PAH mass. Before 1875 the sum of PAH concentration (SigmaPAH) was very low with total mean concentrations less than 2 ng/kg and 0.08 ng/kg for the heavier compounds (SigmaPAH*, more than four aromatic rings). During the first phase of the industrial revolution (1770-1830) the PAH deposition showed a weak increase which became much greater from the start of the second phase of the industrial revolution at the end of 19th Century. In the 1920s, economic recession in Europe decreased PAH emissions until the 1930s when they increased again and reached a maximum concentration of 32 ng/kg from 1945 to 1955. From 1955 to 1975 the PAH concentrations decreased significantly, reflecting improvements in emission controls especially from major point sources, while from 1975 to 2003 they rose to levels equivalent to those in 1910. The Fla/(Fla+Pyr) ratio is often used for source assignment and here indicates an increase in the relative contribution of gasoline and diesel combustion with respect to coal and wood burning from 1860 to the 1980s. This trend was reversed during the last two decades.

Mercury (Hg) is an extremely toxic pollutant, and its biogeochemical cycle has been perturbed by anthropogenic emissions during recent centuries. In the atmosphere, gaseous elemental mercury (GEM; Hg degrees ) is the predominant form of mercury (up to 95%). Here we report the evolution of atmospheric levels of GEM in mid- to high-northern latitudes inferred from the interstitial air of firn (perennial snowpack) at Summit, Greenland. GEM concentrations increased rapidly after World War II from approximately 1.5 ng m(-3) reaching a maximum of approximately 3 ng m(-3) around 1970 and decreased until stabilizing at approximately 1.7 ng m(-3) around 1995. This reconstruction reproduces real-time measurements available from the Arctic since 1995 and exhibits the same general trend observed in Europe since 1990. Anthropogenic emissions caused a two-fold rise in boreal atmospheric GEM concentrations before the 1970s, which likely contributed to higher deposition of mercury in both industrialized and remotes areas. Once deposited, this toxin becomes available for methylation and, subsequently, the contamination of ecosystems. Implementation of air pollution regulations, however, enabled a large-scale decline in atmospheric mercury levels during the 1980s. The results shown here suggest that potential increases in emissions in the coming decades could have a similar large-scale impact on atmospheric Hg levels.

Snow surfaces play an important role in the biogeochemical cycle of mercury in high-latitude regions. Snowpacks act both as sources and sinks for gaseous compounds. Surprisingly, the roles of each environmental parameter that can govern the air-surface exchange over snow are not well understood owing to the lack of systematic studies. A laboratory system called the laboratory flux measurement system was used to study the emission of gaseous elemental mercury from a natural snowpack under controlled conditions. The first results from three snowpacks originating from alpine, urban and polar areas are presented. Consistent with observations in the field, we were able to reproduce gaseous mercury emissions and showed that they are mainly driven by solar radiation and especially UV-B radiation. From these laboratory experiments, we derived kinetic constants which show that divalent mercury can have a short natural lifetime of about 4-6 h in snow.

A sampling campaign was organized during spring 2004 in Spitzberg, Svalbard, in the area around the scientific base of Ny-Alesund, to characterize the snow pack bacterial population. Total bacteria counts were established by 4',6-diamino-2-phenylindole (DAPI) in the seasonal snow pack bordering the sea. On the sea shore, bacterial concentration was about 6 x 10(4) cells mL(-1), without any significant variation according to depth. In the accumulation snow layer of the glacier, concentrations were about 2 x 10(4 )cells mL(-1), except in the 2003 summer layer, where it reached 2 x 10(5) cells mL(-1), as the result of cell multiplication allowed by higher temperature and snow melting. Strains isolated from the seasonal snow pack were identified from their 16S rRNA gene sequences, and lodged in GenBank. They belong to the Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria, Firmicutes and Actinobacteria. They are closely related to cold environment bacteria, as revealed by phylogenetic tree constructions, and two appear to be of unknown affiliation. Using 1H nuclear magnetic resonance, it was shown that these isolates have the capacity to degrade organic compounds found in Arctic snow (propionate, acetate and formate), and this can allow them to develop when snow melts, and thus to be actively involved in snow chemistry.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is a hereditary arteriopathy caused by mutations of the Notch3 gene. The risk factors for cerebral microhaemorrhages (CM), their relationship to other MRI lesions in the disease and their potential clinical impact have not been previously defined. Our purpose was to examine the frequency, number and location of microhaemorrhages in a multicentre cohort study, defining predisposing factors and associated radiographic markers in CADASIL patients. We collected clinical data from 147 consecutive patients enrolled in an ongoing prospective cohort study. Degree of neurological disability and cognitive impairment were assessed by standardized scales. T(1)-weighted, FLAIR and T2*-weighted gradient-echo (GE) MRI sequences were performed. Volume and location of lacunar infarcts and white matter hyperintensity (WMH) were assessed. Number and location of CM were recorded. CM were present in 35% patients, most commonly occurring in the thalamus, brainstem and basal ganglia. The location of CM qualitatively differed from areas of lacunar infarction and WMH. There was a significant association between the presence of CM and a history of hypertension (P = 0.005), systolic blood pressure (SBP) (P = 0.014), haemoglobin A1c (HbA1c) (P = 0.004) and the volume of lacunar infarcts (P = 0.010) and WMHs (P = 0.046). The number of CM was independently associated with SBP (P = 0.005), the diagnosis of hypertension (P = 0.0004), volume of WMH (P = 0.0005) and lacunar infarcts (P = 0.004). In contrast, no association was found between blood pressure or HbA1c and the load of WMH or lacunar infarcts. The presence of CM was independently associated with increased modified Rankin scores. CM are independently associated with blood pressure and HbA1c as well as with lacunar infarct and WMH volume in CADASIL. Both the vascular risk factors and regional distribution of CM appear distinct from those associated with other MRI markers, suggesting a distinct pathological process. These lesions have a potential clinical impact in CADASIL. These findings further suggest that modulation of blood pressure and glucose levels might influence the course of the disease.

A method, based on inductively coupled plasma sector field mass spectrometry coupled with a microflow nebulizer and a desolvation system, has been developed for the direct determination of rare earth elements (REE) (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) down to the subpicogram per gram level (1 pg/g = 10(-12) g g(-1)) in approximately 1 mL of molten Antarctic ice. Contamination problems were carefully taken into account by adopting ultraclean procedures during the sample pretreatment phases. The use of a desolvation system for sample introduction during the analysis greatly reduced spectral interferences from oxide formation; the residual interfering contributions were calculated and subtracted whenever necessary. A matched calibration curve method was used for the quantification of the analytes. Instrumental detection limits ranged from 0.001 pg/g for Ho, Tm, and Lu to 0.03 pg/g for Gd. The precision, in terms of relative standard deviation on 10 replicates, ranged from 2% for La, Ce, Pr, and Lu, up to 10% for Er, Tm, and Yb. This methodology allowed the direct determination of REE in a 1-mL sample of ancient Antarctic ice with concentration ranges between 0.006 and 0.4 pg/g for Tm and 0.9-60 pg/g for Ce.

Cr, Cu, Zn, Co, Ni, Mo, Rh, Pd, Ag, Cd, Sb, Pt, Au, and U have been determined in clean room conditions by inductively coupled plasma sector field mass spectrometry and other analytical techniques, in various sections of two dated snow/ice cores from the high-altitude (4450 m asl) glacier saddle Colle Gnifetti, Monte Rosa massif, located in the Swiss-Italian Alps. These cores cover a 350-year time period, from 1650 to 1994. The results show highly enhanced concentrations for most metals in snow/ice dated from the second half of the 20th century, compared with concentrations in ancient ice dated from the 17th and 18th centuries. The highest increase factors from the pre-1700 period to the post-1970 period are observed for Cd (36), Zn (19), Bi (15), Cu (11), and Ni (9), confirming the importance of atmospheric pollution by heavy metals in Europe. Metal concentrations observed in Colle Gnifetti snow around 1980 appear to be quantitatively related to metal emissions from Italy, Switzerland, Germany, France, Belgium, and Austria at that time, making it possible to reconstruct past changes in metal emission in these countries during the last centuries.

V, Co, Cu, Zn, As, Rb, Sr, Ag, Cd, Ba, Pb, Bi and U have been analysed by inductively coupled plasma sector field mass spectrometry in various sections of a dated snow/ice core drilled at an altitude of 6542 m on the Sajama ice cap in Bolivia. The analysed sections were dated from the Last Glacial Stage ( approximately 22,000 years ago), the Mid-Holocene and the last centuries. The observed variations of crustal enrichment factors (EFc) for the various metals show contrasting situations. For V, Co, Rb, Sr and U, EFc values close to unity are observed for all sections, then showing that these elements are mainly derived from rock and soil dust. For the other metals, clear time trends are observed, with a pronounced increase of EFc values during the 19th and 20th centuries. This increase shows evidence of metal pollution associated with human activity in South America. For Pb an important contribution was from gasoline additives. For metals such as Cu, Zn, Ag and Cd an important contribution was from metal production activities, with a continuous increase of production during the 20th century in countries such as Peru, Chile and Bolivia.

Lead concentrations and lead isotope ratios were analyzed in two firn/ice cores covering the period from 1650 to 1994, which were obtained from the 4450 m high glacier saddle Colle Gnifetti located in the Monte Rosa massif at the Swiss-Italian border. This study presents the first glaciochemical time series with annual resolution, spanning several centuries of lead concentrations and lead isotopic compositions in precipitation in Europe. Lead concentrations in firn dated from the 1970s are approximately 25 times higher than in ice dated from the 17th century, confirming the massive rise in lead pollution in Europe during the last few centuries. A decline of the lead concentration is then observed during the last two decades, i.e., from 1975 to 1994. The lead isotope ratio 206Pb/207Pb decreased from about 1.18 in the 17th and 18th centuries to about 1.12 in the 1970s. These variations are in good agreement with available information on variations in anthropogenic lead emissions from West European countries, especially from the use of lead additives in gasoline.

To better assess the seasonality in the fallout of heavy metals to central Greenland, a continuous series of 68 snow samples has been collected at a remote site in the Summit area from a 2.7 m pit using ultraclean sampling procedures. This covers a continuous four year time period from spring 1991 to spring 1995. Co, Cu, Zn, Mo, Rh, Pd, Ag, Cd, Sb, Pt, Pb, Bi and U were determined using ultrasensitive inductively coupled plasma sector field mass spectrometry under clean room conditions. In addition we also determined Al by graphite furnace atomic absorption spectrometry and Na+, Ca2+, SO4(2-), MSA and oxalate by ion chromatography, species that will assist in the interpretation of the trace metal data. The data show pronounced inter- and intra-annual variations, with large differences in the amplitude of these variations for the element studied, with few clear seasonality patterns. Generally, high concentrations are observed in the spring snow layers, while much lower concentrations are typical of summer snow layers. Significant correlations are observed between Co, Cu, Zn, Ag and Sb, while Pt, Pd and Rh show no correlation with the other metals. Crustal enrichment factors show that while the crustal dust contribution is probably important for some metals for part of the year (spring), anthropogenic inputs are as important in many instances. Pronounced intra-annual variations are observed for some metals, in particular Pt. The variations observed for this metal parallel fairly closely changes in Russian Pt production, which points to emissions from smelters in the Russian Arctic as likely sources for Pt.

Ni and V have been determined in snow and ice collected at a high altitude location (Col du Dôme) near the summit of Mont Blanc on the French-Italian border; dated from the 1960s and 1990s. Ni and V were simultaneously determined by inductively coupled plasma sector field mass spectrometry. Measured concentrations range from 6 to 700 pg g(-1) and 4 to 1,100 pg g(-1) for Ni and V, respectively. The results show pronounced seasonal variations in the concentrations of both metals, with high concentration values in summer layers and much lower values for winter layers. These seasonal variations are linked especially with the existence of inversion layers during winter months. Ni and V concentrations in excess of the contributions from rock and soil dust (Ni(excess), V(excess)) appear to be mainly associated with anthropogenic inputs, with pronounced seasonal variations. Large variations in the V(excess)/Ni(excess) ratio are observed, with a higher ratio in summer than in winter. This shows differences in anthropogenic inputs at Col du Dôme during the different parts of the year. The above ratio was compared with the corresponding ratios for oil combustion from stationary sources and the exhaust from gasoline and diesel engines. It appears that Ni and V concentrations at Col du Dôme are probably the result of changing combinations of contributions from oil combustion for power generation, industrial and residential uses, on one side, and automobile and truck traffic, on the other side, with possibly a significant contribution from Ni smelters in Russia during winter months.

Fresh snow samples collected at 15 remote locations and aerosols collected at one location in the French Alps between November 1998 and April 1999 have been analyzed for Pb concentration and isotopic composition by thermal ionization mass spectrometry. The snow samples contained 19-1300 pg/g of Pb with isotopic ratios 206Pb/207Pb (208Pb/207Pb) of 1.1279-1.1607 (2.3983-2.4302). Airborne Pb concentrations at one sampling site ranged from 0.42 to 6.0 ng/m3 with isotopic ratios of 1.1321-1.1427 (2.4029-2.4160). Air mass trajectory analysis combined with isotopic compositions of potential source regions did not show discernible evidence of the long-range atmospheric transport of pollutants. Isotopic ratios in the Alpine snow samples and thus the free troposphere were generally higher than airborne Pb isotopic ratios in urban France, which coupled with the relatively high Pb concentrations suggested a regional anthropogenic Pb source, probably Italy but possibly Eastern Europe.

Recent controversies concerning the possibility of environmental contamination due to the use of uranium in classical weaponry have led us to realize that there is a lack of time series for this metal from environmental archives. We have therefore performed analysis of a dated 140 m-long ice/snow core that was drilled in 1994 at a cold high altitude site (4250 m) near the summit of Mont Blanc in the French-Italian Alps. Ultraclean analytical procedures were employed in our analyses. Uranium concentrations were determined by inductively coupled plasma sector field mass spectrometry. In ice dating from before the 1940s, uranium concentrations are found to have remained fairly constant and can be explained simply by a crustal contribution. For the post-World War II layers, on the other hand, the data show large excesses above crustal contributions. These uranium excesses are attributed to tropospheric transport of dust emitted during extensive mining and milling operations which took place in the GDR and to a smaller extent in France at that time. There is no enhancement in uranium concentrations in the ice layer in which fallout from the 1986 Chernobyl accident was previously identified from a gross beta activity vs depth profile.

Since 1976 in the United States, Canada, and Japan, and later in other countries, the exhaust system of gasoline powered cars has been equipped with catalytic converters containing Pt and/or Pd and/or Rh. This has resulted in a very significant decrease in urban air pollution for various chemical species such as NOx, CO, and hydrocarbons. There has however been concern that their ever increasing use might lead to Platinum Group Metals (PGMs) becoming widely dispersed in the environment. From the analysis of Pt, Pd, and Rh in central Greenland recent snow and ancient ice using the ultrasensitive inductively coupled plasma sector field mass spectrometry technique, we show here that the concentrations of these metals in snow dated from the mid 1990s are indeed approximately 40-120 times higher than in ice dated from 7000 years ago. The fact that such an increase is observed far away from populated areas at a high altitude location indicates there is now a large scale contamination of the troposphere of the Northern Hemisphere for PGMs. Pt/Rh mass ratio in the most recent snow samples is close to the same ratio documented for catalytic converter exhausts in a recent study, which suggests that a large fraction of the recent increase for Pt and Rh might originate from automobile catalytic converters.

The performance of a double-focusing inductively coupled plasma mass spectrometer equipped with a microconcentric nebulizer was investigated for the direct simultaneous determination of Rh, Pd, and Pt in less than 1 mL of melted snow and ice samples originating from remote sites. Ultraclean procedures were adopted in the laboratories and during the pretreatment steps, to avoid possible contamination problems. Spectroscopic and nonspectroscopic interferences affecting the determination of Rh, Pd, and Pt were carefully considered. Detection limits of 0.02, 0.08, and 0.008 pg g(-)(1) for Rh, Pd, and Pt, respectively, were obtained using the following isotopes:  (103)Rh, (106)Pd, and (195)Pt. Repeatability of measurements, as RSD, was 27, 28, and 29%, for Rh, Pd, and Pt, respectively. The new method was applied to the analysis of samples coming from Greenland, Antarctica, and the Alps in order to assess the past natural background concentrations and to determine the present level of these polluting substances. The extremely low detection limits allowed the direct analysis of all samples except for two Greenland ice core sections dating from 7260 and 7760 years ago for which a preconcentration step was necessary. Concentration ranges for all snow samples were (in pg g(-)(1)) as follows:  Rh (0.0005-0.39), Pd (0.01-16.9), and Pt (0.008-2.7). The lowest concentrations were measured in the enriched Greenland ancient ice samples.

Pb, Cd, Cu, and Zn have been measured using ultraclean procedures in eight sections taken from two well-dated ice cores from Law Dome, an independent small size ice cap with high accumulation rate situated in the coastal area of East Antarctica. Seven sections were dated from the 1830s to 1940s and one was dated from three millennia ago. The data show that there are strong seasonal variations in the concentrations of Pb and Cd, with values approximately tow-to fourfold higher in winter than in spring-summer. Evaluation of the contributions from the different sources suggests that contribution from sea salt spray is relatively important, especially for Cd. Contribution from marine biogenic emissions could also be very significant. The importance of marine contributions is consistent with strong intrusions of marine air masses at this coastal site, especially during wintertime.

Vintages of French wine from 1950 to 1991 were analyzed for lead isotopes and concentrations to investigate whether they might be used to archive the isotopic composition of the anthropogenic lead in aerosols to which the vineyard was exposed. Early vintages (1950-1980) contained 78-227 ng/g of lead with 206Pb/207Pb ratios between 1.152 and 1.173, while the later vintages displayed significantly lower concentrations and a smaller range of isotopic ratios. The concentration of trimethyl lead, which is associated with automobile emissions, was found to be poorly correlated with total lead in the wines, suggesting that automobile aerosols were not a significant source of the lead. This result was supported by lead isotope data which showed a poor correlation with the available petrol and aerosol data. To identify its origin lead isotopes were measured in vineyard aerosols, soil particles, bottle caps, corks, and brass components used to dispense the wine. Although a dominant source could not be identified there was some evidence to suggest that brass which had a high lead concentration was a significant contributor. Because the lead contribution from the processing of wine was probably relatively high in the past it is unlikely that old vintages of wine will be a suitable archive for lead isotopes in aerosols.

Analysis of the Greenland ice core covering the period from 3000 to 500 years ago-the Greek, Roman, Medieval and Renaissance times-shows that lead is present at concentrations four times as great as natural values from about 2500 to 1700 years ago (500 B.C. to 300 A.D.). These results show that Greek and Roman lead and silver mining and smelting activities polluted the middle troposphere of the Northern Hemisphere on a hemispheric scale two millennia ago, long before the Industrial Revolution. Cumulative lead fallout to the Greenland Ice Sheet during these eight centuries was as high as 15 percent of that caused by the massive use of lead alkyl additives in gasoline since the 1930s. Pronounced lead pollution is also observed during Medieval and Renaissance times.