The effect of soil on human health: an overview.

Soil has a considerable effect on human health, whether those effects are positive or negative, direct or indirect. Soil is an important source of nutrients in our food supply and medicines such as antibiotics. However, nutrient imbalances and the presence of human pathogens in the soil biological community can cause negative effects on health. There are also many locations where various elements or chemical compounds are found in soil at toxic levels, because of either natural conditions or anthropogenic activities. The soil of urban environments has received increased attention in the last few years, and they too pose a number of human health questions and challenges. Concepts such as soil security may provide a framework within which issues on soil and human health can be investigated using interdisciplinary and transdisciplinary approaches. It will take the contributions of experts in several different scientific, medical and social science fields to address fully soil and human health issues. Although much progress was made in understanding links between soil and human health over the last century, there is still much that we do not know about the complex interactions between them. Therefore, there is still a considerable need for research in this important area.

Runoff initiation, soil detachment and connectivity are enhanced as a consequence of vineyards plantations.

Rainfall-induced soil erosion is a major threat, especially in agricultural soils. In the Mediterranean belt, vineyards are affected by high soil loss rates, leading to land degradation. Plantation of new vines is carried out after deep ploughing, use of heavy machinery, wheel traffic, and trampling. Those works result in soil physical properties changes and contribute to enhanced runoff rates and increased soil erosion rates. The objective of this paper is to assess the impact of the plantation of vineyards on soil hydrological and erosional response under low frequency - high magnitude rainfall events, the ones that under the Mediterranean climatic conditions trigger extreme soil erosion rates. We determined time to ponding, Tp; time to runoff, Tr; time to runoff outlet, Tro; runoff rate, and soil loss under simulated rainfall (55 mm h-1, 1 h) at plot scale (0.25 m2) to characterize the runoff initiation and sediment detachment. In recent vine plantations (<1 year since plantation; R) compared to old ones (>50 years; O). Slope gradient, rock fragment cover, soil surface roughness, bulk density, soil organic matter content, soil water content and plant cover were determined. Plantation of new vineyards largely impacted runoff rates and soil erosion risk at plot scale in the short term. Tp, Tr and Tro were much shorter in R plots. Tr-Tp and Tro-Tr periods were used as connectivity indexes of water flow, and decreased to 77.5 and 33.2% in R plots compared to O plots. Runoff coefficients increased significantly from O (42.94%) to R plots (71.92%) and soil losses were approximately one order of magnitude lower (1.8 and 12.6 Mg ha-1 h-1 for O and R plots respectively). Soil surface roughness and bulk density are two key factors that determine the increase in connectivity of flows and sediments in recently planted vineyards. Our results confirm that plantation of new vineyards strongly contributes to runoff initiation and sediment detachment, and those findings confirms that soil erosion control strategies should be applied immediately after or during the plantation of vines.

Prevalence and clinical correlates of insomnia in adults with attention-deficit hyperactivity disorder.

OBJECTIVE: To investigate the prevalence of insomnia in adults with Attention-deficit hyperactivity disorder (ADHD) and its association with clinical subtypes, current ADHD symptoms, and stimulant treatment. METHOD: We obtained diagnostic information, symptom rating scales and treatment history from clinically ascertained adult ADHD patients diagnosed according to DSM-IV criteria (n = 268, mean age 38.1 years) and randomly selected population controls (n = 202, mean age 36.5 years). The Bergen Insomnia Scale (BIS) was used to measure insomnia. ADHD symptom domains were self-rated using the Adult ADHD Self-Rating Scale. RESULTS: Insomnia was far more frequent among adults with ADHD (66.8%) than in the population controls (28.8%) (P < 0.001). Insomnia was more common in adults with the combined subtype than in those with the inattentive subtype (79.7% and 55.6%, respectively) (P = 0.003). For self-reported current ADHD symptoms, inattention was strongly correlated to insomnia. Patients currently using stimulant treatment for ADHD reported a lower total insomnia score compared to patients without medication (P < 0.05). CONCLUSION: Insomnia was highly prevalent among adults with ADHD. The lower insomnia score in patients on current stimulant treatment suggests that stimulant treatment is not associated with worsening of insomnia symptoms in adult ADHD patients.

Soil organic carbon stocks assessment in Mediterranean natural areas: a comparison of entire soil profiles and soil control sections.

Soil organic carbon (SOC) is an important part of the global carbon (C) cycle. In addition, SOC is a soil property subject to changes and highly variable in space and time. Over time, some researches have analyzed entire soil profile (ESP) by pedogenetic horizons and other researches have analyzed soil control sections (SCS) to different thickness. However, very few studies compare both methods (ESP versus SCS). This research sought to analyze the SOC stock (SOCS) variability using both methods (ESP and SCS) in The Despeñaperros Natural Park, a nature reserve that consists of a 76.8 km(2) forested area in southern Spain. Thirty-four sampling points were selected in the study zone. Each sampling point was analyzed in two different ways, as ESP (by horizons) and as SCS with different depth increments (0-25, 25-50, 50-75 and 75-100 cm). The major goal of this research was to study the SOCS variability at regional scale. The soils investigated in this study included Phaeozems, Cambisols, Regosols and Leptosols. Total SOCS in the Despeñaperros Natural Park was over 28.2% greater when SCS were used compared to ESP, ranging from 0.8144 Tg C (10,604.2 Mg km(-2)) to 0.6353 Tg C (8272.1 Mg km(-2)) respectively (1 Tg = 10(12) g). However, when the topsoil (surface horizon and superficial section control) was analyzed, this difference increased to 59.8% in SCS compared to ESP. The comparison between ESP and SCS showed the effect of mixing pedogenetic horizons when depth increments were analyzed. This indicates an overestimate of T-SOCS when sampling by SCS.

Monitoring of organotin compounds in seawater using semipermeable membrane devices (SPMDs)--tentative results.

The impact of anthropogenic pollutants on the marine ecosystem is related to the concentrations experienced by the biota in the seawater and the resulting concentration in the organism. Results from monitoring of pollutants in water samples provide snapshots that can be high or low depending on a wide range of variables. To provide more integrated information, semipermeable membrane devices, SPMDs, have been used to monitor different organic pollutants. In this survey, SPMDs were used to monitor organotin compounds in the marine environment. Time-integrated sampling using SPMDs and direct water sampling was carried out at six stations in the inner Oslofjord, Norway. The sample work-up procedure for both water and SPMDs was based on direct derivatisation using NaBEt4 and simultaneous extraction with an organic solvent. Analysis was performed using a gas chromatograph equipped with an atomic emission detector. The results show that SPMDs do accumulate organotin compounds from the water phase. Both tributyl- (TBT) and dibutyltin were detected in all of the analysed membranes while no monobutyltin was found. Levels found in SPMDs range from < 1 to 220 ng Sn SPMD(-1). Water concentrations range from 0.4 to 10 ng Sn L(-1). An investigation of relative levels of TBT showed a similar concentration gradient in the inner Oslofjord using either direct water sampling or passive sampling by SPMDs. As the membranes are able to accumulate the organotins from the water it will be possible to locate lower concentrations than with direct analyses of water samples.

Quantification of organotin compounds and determination of imposex in populations of dogwhelks (Nucella lapillus) from Norway.

Unintentional effects of the antifouling agent tributyltin (TBT) have been discovered in marine gastropods as the induction of male sex characters in females, known as imposex. The occurrence of imposex in dogwhelks (Nucella lapillus) was investigated in 41 populations sampled in 1993-1995 along the Norwegian coast. A method for quantification of organotin species using gas chromatography and atomic emission detection (GC-AED) was developed. Some degree of imposex occurred in almost all populations of dogwhelks studied, except in four from Northern Norway. The concentration of organotin compounds in the gastropods from the unaffected populations was below the detection limit (7 ng Sn/g d.w.). The concentration of TBT in dogwhelks from affected populations was in the range 48-1096 ng Sn/g d.w. A positive relation between the concentration of TBT in dogwhelks and the degree of imposex was found.

Capillary gas chromatography combined with atomic emission detection for the analysis of DDT and metabolites.

Capillary gas chromatography with atomic emission detection (GC-AED) was evaluated for the determination of DDT and metabolites in biological samples. Utilizing chlorine-selective detection at 479 nm, DDT, DDE, and DDD were quantified down to the 20 ng/g (fat weight) level (S/N = 10) in cod liver oil, while the detection, limit was 6 ng/g (S/N = 3). With splitless injection performed in the pressure programmed mode, DDT and related compounds were quantified based on a single chlorine calibration curve (universal calibration). The quantitative data obtained by GC-AED were in excellent accordance with similar results from capillary gas chromatography with electron capture detection (GC-ECD), while the procedure for calibration was simplified with the former technique.

Environmental contaminants and biochemical responses in flatfish from the Hvaler Archipelago in Norway.

The levels of several environmental contaminants, including selected polyaromatic hydrocarbons (PAH), organochlorines (DDT/DDE, hexachlorobenzene), 15 polychlorinated biphenyl (PCB) congeners, and polychlorinated dibenzofurans and dibenzo-p-dioxins, PCDF/PCDD), and heavy metals (Cd, Hg, Pb, and As) were analyzed in muscle and liver of three different flatfish species (dab, Limanda limanda; flounder, Platichthys flesus; plaice, Pleuronectes platessa) caught by gill netting at different sites in the Hvaler Archipelago. Indices of biochemical effects in liver S9-fractions were studied by measuring cytochrome P450-dependent monooxygenase and UDP-glucuronyl transferase activities, and by immunoquantitating cytochrome P450 1A1 using an indirect enzyme-linked immunosorbent assay (ELISA). Only low levels of PCDD/PCDF, Cd, and Pb were observed, whereas PCB levels were significantly elevated in fish from the inner sites of the Archipelago compared to a reference site. The contaminant gradient toward the Glomma estuary was correlated with increased cytochrome P450 1A1 activity, measured as 7-ethoxyresorufin O-deethylase (EROD), and with immunoquantitated P450 1A1. In contrast, fish from the site at Idefjorden, although containing elevated contaminant levels, did not show elevated EROD activity, but apparently elevated P450 1A1 protein. These findings may reflect different pollution histories of the sites, and indicate the applicability of biochemical effect indices (i.e., EROD and P450 1A1 immunoquantitation) to monitoring studies. The integrated chemical-biochemical approach employed in this study can obviously be expanded to give fruitful information about cause-effect relationships in other contaminant situations.

[Mercury and selenium in wild mink (Mustela vision) from Norway]. / Kvikksølv og selen i villmink (Mustela vision) fra Norge.

Levels of mercury, methylmercuri and selenium were determined in liver samples from wild mink (Mustela vision) caught in the Norwegian countries of Rogaland (38 samples), Sogn og Fjordane (15 samples) and Hedmark (18 samples). The average mercury levels from these counties were 2.6, 3.1 and 2.1 micrograms Hg/g wet weight, respectively. No significant differences in mercury levels were found. The methyl mercury levels (MeHg) were determined in 30 samples. A very strong positive correlation between total mercury (Hg) and methyl mercury (r = 0.91, P less than 0.001) was found. The average methyl mercury level was 35 per cent of total mercury. This indicates that wild mink has the ability to demethylate mercury. The selenium levels were determined in 35 samples. A strong positive correlation between the levels of total mercury and selenium (r = 0.87, P less than 0.001) was found. There was no correlation between age or nutritional condition and mercury level. In the present study mink was examined to see of it could be recommended as an indicator species for monitoring the local environment for mercury contamination. No definite answer to this question could be found. The study did reveal, however, that in all the counties studied there are individuals that are considerably contaminated with mercury.

Distribution and elimination of hexachlorobenzene (HCB) after single oral exposure in Japanese quail (Coturnix coturnix japonica).

The distribution and excretion of hexachlorobenzene (HCB) after administration to quails of a single oral dose of 4.5 microCi [14C] HCB per 100 g body weight was studied by whole-body autoradiography and liquid scintillation counting. Radiolabeled HCB was distributed throughout the body in 2 h. Peak levels were found 4-8 d after administration, with the highest concentrations in the subcutaneous and abdominal fat, uropygial gland, bone marrow, adrenals, ovarian stroma, and liver, in that order. After 3 wk, substantial amounts of radiolabeled substance were present only in the adipose tissue and the uropygial gland. The main routes of excretion were the egg yolk, uropygial gland, and bile. About 75% of the administered dose was excreted through the egg yolk and about 25% in the feces.

Organochlorines in wild mink (Mustela vison) from Norway.

Levels of PCBs, DDE, and HCB have been determined in wild mink caught in the Norwegian counties of Sogn and Fjordane, Rogaland, and Hedmark. No significant differences were founds in organochlorine levels in wild mink from these counties, and the average level, based on fat weight, in abdominal adipose tissue was about 1 ppm DDE, 0.1 ppm HCB and for PCB ranging from 1 to 15 ppm.

Organochlorine compounds in aquatic environments.

The body burdens of five organochlorine compounds were determined in several marine fishes and invertebrates from two localities in Norway. DDE, PCBs, and pentachlorobenzene showed uniform levels, especially on a fat weight basis, while hexachlorobenzene and octachlorostyrene were detected at various levels in the different species. The results are discussed with respect to the concept of accumulation through food chains, and passive partition of chemicals between water and the organism's fat. Although the results to some extent support the idea of partition, other factors may have a decisive effect on the levels found in the different species. This is true for the bottom dweller, where magnitude and circumstances of exposure may vary considerably between the different microenvironments.

Organochlorines in fish and crabs from the Kristiansand fjord in Norway.

The levels of sum-DDT, PCBs, and HCB in fish liver and crab hepatopancreas from the Kristiansand fjord area in Norway have been determined (fig. 1). The respective mean levels (fat weight basis) in stationary fish species and crabs are given in table I. The levels of PCBs and sum-DDT were about the same, and the HCB level two to one hundred times higher than corresponding levels reported for codfish (liver) from several harbours along the Norwegian coasts (Brevik et al. in press). The levels calculated on a wet weight basis, found is stationary fish from the harbour of Kristiansand and Topdals-fjord were two to three times higher than those in crabs. Calculated on a fat weight basis, however, the levels in stationary fish and crabs were much more similar (table II). The harbour area was more contaminated with PCBs and HCB than the other sites examined. It seems impossible, however, on the basis of present data to further pinpoint sources of the relatively high degree of HCB contamination in the Kristiansand fjord area.

Organochlorine compounds in Norwegian human fat and milk.

Analyses were carried out in 1975/76 of samples of human, perirenal fatty tissue and 45 samples of human milk with regard to persistent organochlorine compounds. A corresponding investigation was carried out in 1969/70. A comparison of the results suggests that a decrease in the content of DDT and its metabolites occurs. The PCB content showed a significant increase as compared with 1969/70. HCB levels of approx. 0.25 ppm and 0.0054 ppm were demonstrated in fatty tissue and in human milk, respectively. Concentrations of DDT plus metabolites, PCB and HCB in older people were significantly higher than those found in younger subjects.