Evaluation of five elements in lenses and aqueous humour of experimental rabbits after induced opacity

We evaluated the presence of Ca, Na, K, Cu and Zn in the lenses and aqueous humour of rabbits treated with an Nd:YAG laser to induce opacity of the crystalline. The mean concentrations of the elements found in control lenses were: Ca: 15.8+/-5.2 mg/kg; Na: 1.2+/-0.6 g/kg; K: 10.3+/-3.3 g/kg; Cu: 0.19+/-0.06 mg/kg; Zn: 20.6+/-3.0 mg/kg. With the exception of K and Zn, the values found in the lenses of treated eyes (Ca: 135+/-24 mg/kg; Na: 4.3+/-1.5 g/kg; K: 10.1 +/- 3.2 g/kg; Cu: 0.47+/-0.17 mg/kg; Zn: 21.8+/-4.2 mg/kg) were significantly higher than in the controls. On the other hand, the concentrations found in the aqueous humour of treated eyes (Ca: 21.7+/-4.5 mg/l; Na: 0.66+/-0.21 g/l; K: 0.29+/-0.10 g/l; Cu: 0.035+/-0.009 mg/l; Zn: 0.079+/-0.01 mg/l) were significantly lower than those of the controls. The greatest difference was observed for Na (-68.6%) and Cu (-52.7%), followed by Ca and Zn (-35.0% and -35.2%, respectively). A positive correlation was found between Ca and Na in treated lenses (r2 = 0.9226, p < 0.0001) whereas inverse correlations were found for both Ca (r2 = 0.9788, p<0.0001) and Na (r2 = 0.9491, p<0.0001) between the concentrations found in the lenses and in the aqueous humour of treated eyes.     

Heavy Metals in Sediments of the Gold Mining Impacted Pra River Basin,Ghana, West Africa

Total concentrations of Hg, Al, Fe, As, Pb, Cu, Cr, Ni, Mn, Co, V, and Zn were determined in surface sediments collected from 21 locations within the gold mining impacted Pra River basin in southwestern Ghana. Samples were collected during both the rainy and dry seasons. We hypothesized that in the rural southwestern portion of Ghana, the lack of industrial activities makes artisanal gold mining (AGM) by Hg amalgamation the main source of water resource contamination with heavy metals. Therefore, metals showing concentration trends similar to that of Hg in the studied system are likely impacted by AGM. We found that total-Hg (THg) concentrations in riverine sediments are rather low as compared to other aquatic systems that are impacted by similar mining activities. Measured THg concentrations ranged from 0.018 to 2.917 mg/kg in samples collected in the rainy season and from about 0.01 to 0.043 mg/kg in those collected during the dry season. However, the determination of the enrichment factor (EF) calculated using shale data as reference background values showed signs of severe contamination in most of the sampled sites. In the dry season, THg concentrations correlated positively and significantly to the concentrations of As (r = 0.864, p < 0.01), Cu (r = 0.691, p < 0.05), and Ni (r = 0.579, p < 0.05). Based on our previously stated hypothesis, this could then be an indication of the impact of AGM on ambient levels of these 3 elements. However, the determined concentrations of Cu, and Ni co-varied significantly with Al, suggesting that natural sources do account for the observed levels. Accordingly, both AGM and metal inputs from weathered natural deposits are likely co-responsible for the observed levels of Cu and Ni. In contrast, the lack of correlation between As and Al tends to suggest an impact of AGM on As levels. Overall, our data suggest that besides Hg and to some extent As, the impact of AGM on ambient levels of investigated metals in the gold mining impacted Pra River remains negligible. Finally, the increase in metal concentrations from the dry to the rainy season underlines the impact of changes in hydrologic conditions on levels and fate of metals in this tropical aquatic system.     

Trace element and magnesium levels and superoxide dismutase activity in rheumatoid arthritis

It has been suggested that reactive oxygen metabolites and trace elements play some role in the etiology and pathogenesis of rheumatoid arthritis (RA). Superoxide dismutase (SOD) is believed to exert an important protective role against oxygen toxicity. The aim of the study was to investigate the probable changes in the levels of trace elements and SOD activity in RA. Plasma and erythrocyte copper, zinc, and magnesium levels and erythrocyte SOD activity were measured in groups of controls and RA cases. Significantly increased erythrocyte SOD activity was found in RA patients in comparison with controls(p < 0.0001). A rise in erythrocyte Zn level(p < 0.0001) and plasma Cu level(p < 0.0001) and a decrease in erythrocyte Cu level(p < 0.05) and plasma Zn level(p < 0.05) were obtained in RA patients when compared to controls. Plasma and erythrocyte Mg levels of the RA patients showed slight and statistically insignificant reductions when compared to controls(p > 0.05). In RA patients, there were positive correlations between erythrocyte SOD activity and Mg level (r = 0.4345,p < 0.01) and between erythrocyte Zn level and plasma Cu level(r = 0.4132,p < 0.01). There were negative correlations between erythrocyte SOD activity and plasma Zn level(r =-0.3605,p < 0.05) and between plasma Zn level and erythrocyte Cu level(r =-0.4578,p < 0.01) in RA patients. This work was presented at the International Congress on Free Radicals in Health and Disease, 6–10 September 1995, Istanbul, Turkey.     

Effect of pentoxifylline treatment on testicular perfusion and semen quality in Miniature horse stallions

The objective was to investigate the effects of pentoxifylline (PTX) on testicular perfusion and sperm production in stallions. In a preliminary study, six mature Miniature horse stallions were given 0, 8.5, or 17.0 mg/kg of PTX orally, twice daily, for 3 d. Total Arterial Blood Flow Rate (TABFR) was higher (P < 0.05) in all treated versus control stallions during and after treatment. Two months later (during the fall and winter), the same stallions received either 0 or 17 mg/kg of PTX orally, twice daily for 60 d. Resistance and pulsatility indices (RI and PI, respectively) decreased in PTX-treated stallions between Treatment 1 and Post-treatment periods. Arterial diameter, as well as Total Arterial Blood Flow (TABF), decreased in controls between Baseline and Treatment 1 (P < 0.05). A similar decrease in arterial diameter was delayed in Group TREATED, but reached significance during Post-treatment (P < 0.05), whereas TABF did not change in this group. Furthermore, TABFR had a transient tendency to increase during Treatment 1 (P < 0.1), whereas it steadily decreased in controls and reached significance in the Post-treatment period (P < 0.05). Both RI and PI were negatively correlated with end diastolic velocity (EDV) in both groups (P < 0.0001). There were positive correlations between RI and peak systolic velocity (PSV) in treated stallions during Treatment 1 (RI: r = 0.53, P = 0.021; PI: r = 0.59, P = 0.007). Also, there were negative correlations between Time Averaged Maximum Velocity (TAMAX) and Doppler indexes in treated stallions during Treatment 2 period (RI: r = −0.49, P = 0.006; PI: r = −0.47, P = 0.008), and during Post-treatment periods (RI: r = −0.40, P = 0.049; PI: r = −042, P = 0.039). Transient hydrocele occurred in all treated stallions (a potential complication of high-dose PTX). Semen end points were not significantly affected by PTX treatment. In conclusion, PTX delayed the seasonal decrease of testicular perfusion in stallions. Sperm quality and quantity were not significantly affected; perhaps they would have been enhanced by prolonged treatment.     

An Investigation of the Soil Property Changes and Heavy Metal Accumulation in Relation to Long-term Wastewater Irrigation in the Semi-arid Region of Iran

Concentrations and spatial distribution of Zn, Cu, Cd, and Pb along two landscapes including a wastewater-irrigated area and a control area were determined to assess the impact of long-term wastewater irrigation and landscape properties on heavy metal contamination. Some disturbed and undisturbed soil samples were taken from soil trenches and soil cores, located on three main landscape positions (upper slope, midslope, and lower slope) in northwestern Iran. The investigation showed that the mean concentration of the heavy metals followed the order Zn > Cu > Pb > Cd in the wastewater-irrigated soil and Pb > Zn > Cu > Cd in the control soils. On average, compared to similar positions in the control region, the wastewater-irrigated regions contained 3.0 (midslope) to 4.9 (lower slope), 2.7 (midslope) to 4.6 (lower slope), 3.3 (upper slope) to 4.1 (lower slope), and 1.7 (upper slope) to 2.6 (lower slope) times higher amounts of Zn, Cu, Cd, and Pb, respectively. Significant positive relationships (P < 0.05) were recorded between the heavy metals concentration with <0.002 mm particle-size fraction and organic matter content, the fractions linked to runoff and soil erosion. It is believed that the two soil fractions play a crucial role in the distribution of the metals along the wastewater-irrigated landscape. Despite the significant increase of heavy metals (P < 0.05) in the wastewater-irrigated soils compared with control soils, the concentration of all evaluated metals was below the maximum accepted limits (Zn < 300 mg/kg, Cu < 100 mg/kg, Cd < 5 mg/kg, and Pb < 100 mg/kg), and grouped as “not-enriched” to “moderately-enriched” categories regarding the topsoil enrichment index. Overall, the lower slope was shown to be more contaminated with the heavy metals compared to the other positions.     

Assessment of Anthropogenic Influence on Heavy Metals Contamination in the Aquatic Ecosystem Components: Water,Sediment, and Fish

Heavy metals (Pb, Cd, Ni, Cr, Cu, Zn, Mn, and As) concentration was investigated in the industrial effluents, water, sediment, and fish samples collected around the Dhaka Export Processing Zone, Savar, Bangladesh, to evaluate the level of contamination. The metals concentration in the industrial effluents of DEPZ and in the water samples of Dhalaibeel (lowland cum lake) and Bangshi River were significantly higher compared to the guideline values for industrial effluents and for drinking water (WHO and USEPA), respectively. The sedimentary metal concentrations were found to be lower than the respective probable effect concentrations (PECs) following the sediment quality guidelines. Furthermore, in comparison with the fish standards, the studied fish species were not found to be contaminated by heavy metals. Principal component analysis and cluster analysis demonstrated that the wastewater from the numerous industries and the domestic sewages around the DEPZ might have a possible impact on heavy metals contamination in the study area. The Pearson correlation analysis showed significant correlations (p < 0.01 and p < 0.05) between most of the metals in the samples of effluents, water, sediments, and fish muscles. The percentage enrichment factor (EF%) and geo-accumulation index () were followed to evaluate metal contamination in the sediment samples. Dhalaibeel sediment was maximally enriched for Cr (53.55%) and Bangshi River sediment for Zn (54.37%). The geo-accumulation index values for the sediment samples were less than zero, indicating that the sediment samples were free from contamination. This study could be used as a model study to assess the impact of anthropogenic activities on heavy metals contamination in aquatic ecosystems.     

Background levels of polycyclic aromatic hydrocarbons (PAH) and selected metals in new England urban soils

Polycyclic aromatic hydrocarbons (PAH) are byproducts of combustion and are ubiquitous in the urban environment They are also present in industrial chemical wastes, such as coal tar, petroleum refinery sludges, waste oils and fuels, and wood‐treating residues. Thus, PAHs are chemicals of concern at many waste sites. Risk assessment methods will yield risk‐based cleanup levels for PAHs that range from 0.1 to 0.7 mg/kg. Given their universal presence in the urban environment, it is important to compare risk‐based cleanup levels with typical urban background levels before utilizing unrealistically low cleanup targets. However, little data exist on PAH levels in urban, nonindustrial soils. In this study, 60 samples of surficial soils from urban locations in three New England cities were analyzed for PAH compounds. In addition, all samples were analyzed for total petroleum hydrocarbons (TPH) and seven metals. The upper 95% confidence interval on the mean was 3 mg/kg for benzo(a)pyrene toxic equivalents, 12 mg/kg for total potentially carcinogenic PAH, and 25 mg/kg for total PAH. The upper 95% confidence interval was 373 mg/kg for TPH, which exceeds the target level of 100 mg/kg used by many state regulatory agencies. Metal concentrations were similar to published background levels for all metals except lead. The upper 95% confidence interval for lead was 737 mg/kg in Boston, 463 mg/kg in Providence, and 378 mg/kg in Springfield.     

Litterfall and nutrient returns in red alder stands in western Washington

Summary Litterfall was collected over 1 year from eight natural stands of red alder growing on different sites in western Washington. The stands occurred at various elevations and on different soils, and differed in age, basal area, and site index. Most litterfall was leaf litter (average 86 percent). Amounts of litterfall and leaf litter varied significantly (P<0.05) among the sites. Average weights of litterfall and leaf litter in kg ha^–1 yr^–1, were 5150 and 4440, respectively. Weight of leaf litter was not significantly (P<0.05) related to site index, stand age, or basal area. The sites varied significantly (P<0.05) in concentrations of all elements determined in the leaf litter, except Zn. Average chemical concentrations were: N, 1.98 percent; P, 0.09 percent; K, 0.44 percent; Ca, 1.01 percent; Mg, 0.21 percent; S, 0.17 percent; SO₄–S, nil; Fe, 324 ppm; Mn, 311 ppm; Zn, 53 ppm; Cu, 13 ppm; and Al, 281 ppm. There were significant correlations between some stand characteristics and concentrations of some elements, and among the different chemical components of the leaf litter. Important correlations were found between stand age and P concentration (r=–0.84,P<0.01); weight of leaf litter and P concentration (r=0.74,P<0.05); weight of leaf litter and K concentration (r=0.71,P<0.05); concentrations of N and S (r=0.81,P<0.05); and concentrations of Fe and Al (r=0.98,P<0.01). Returns of the different elements to the soil by leaf litter varied among the different sites. Average nutrient and Al returns, in kg ha^–1 yr^–1, were: N, 82; Ca, 41; K, 19; Mg, 8; S, 7; P, 4; Fe, 1; Mn, 1; Al, 1; Zn, 0.2, and Cu, <0.1.     

Enzymes and biogeochemical cycling in wetlands during a simulated drought

Possible interactions between soil enzymes and thebiogeochemistry of wetlands were investigated duringa field-based drought simulation. Under control(waterlogged) conditions, correlations were foundbetween the activity of the enzyme B-glucosidase andtwo properties associated with carbon cycling, namelyi) CH₄ release r = 0.79,p lt 0.01) and ii) dissolvedorganic carbon concentration (r= -0.81, p lt 0.01). In contrast,the transition to drought conditions resulted in correlations betweenB-glucosidase activity and certain mineralisationprocesses, namely the release of mg and Ca(r = 0.72, p lt 0.05). Sulphataseactivity correlated with changes in sulphate concentration during the droughtsimulation (r = 0.73, p lt 0.05).Further support for the suggested enzymic involvement in biogeochemicalprocesses was found in laboratory studies. Theseexperiments indicated that increasing the abundance ofB-glucosidase could stimulate trace gas emissions(p lt 0.001) and increase the concentration ofmagnesium and calcium (p lt 0.05). Increasedsulphatase abundance caused a suppression of methane emissions(p = 0.053).     

Polycyclic aromatic hydrocarbons and heavy metals in Kostrena coastal area

The aim of this study was to determine pollution by polycyclic aromatic hydrocarbons (PAH) and heavy metals in seawater and sediment in Kostrena coastal area, as well as their toxicity using bioluminescence based tests. Total PAH concentration in seawater ranged 1.7-155.3 ng/L. The share of carcinogenetic PAH was relatively high, ranging 22-48.3%. Nickel concentrations in seawater were beyond detection limits (< 0.1 microg/L), vanadium concentrations ranged 0.66-1.96 microg/L, chrome concentrations were beyond detection limits, and copper concentrations were also beyond detection limits or extremely low (up to 0.32 microg/L). EC50 values in seawater ranged 23.80-90.90 ng/L. Correlation between total PAH concentration and toxicity of seawater showed strong connection between them (r = 0.9579). Total PAH concentration in marine sediment ranged 58.02-1116 microg/kg dry weight (d.w.). The share of carcinogenetic PAH was extremely high ranging 10-53%. Nickel concentrations in marine sediment ranged 8-24 mg/kg d.w., vanadium concentrations ranged 24-42 mg/kg d.w., chrome concentrations ranged 11-19 mg/kg d.w., and copper concentrations ranged 7-25 mg/kg d.w. EC50 values in marine sediment ranged 818-4596 microg/kg d.w. Correlation between total PAH concentration and toxicity of marine sediment showed weak connection between them (r = 0.2590). Previous studies of seawater samples from areas of the Adriatic sea under the direct influence of oil industry did not include concentrations of heavy metals, which makes our study the first to present such comprehensive results. Our results point out the need for further evaluations and following of marine environment pollution and its consequences on living organisms and marine ecosystem in whole.     

Risk Element (As,Cd, Cu,Pb, and Zn) Contamination of Soils and Edible Vegetables in the Vicinity of Guixi Smelter,South China

Risk element (As, Cd, Cu, Pb, and Zn) contamination in soils and in two edible vegetables (Solanum melongena L. and Capsicum annum L.) was investigated in the vicinity of Guixi Smelter, South China. Soil As concentrations averaged 23.9 mg/kg. Sites near the smelter tailings recorded the highest levels of As and heavy metals in soils. The concentration order of heavy metals in soils was Cd < Pb < Zn < Cu. Cu and Cd in soils were abundant in the exchangeable and bound to carbonate fraction, while Pb and Zn were in the residual fraction, limiting their potential toxicity as pollutants. The proportions of the metals in the mobile fraction followed the order Pb < Zn < Cu < Cd. In Solanum melongena L. and Capsicum annum L., Zn concentration was the highest, followed by Cu, Cd, and Pb, different from that in soils and in the mobile fraction. Concentrations of heavy metals in the labile fractions in soils and in vegetables presented significant correlation (p < 0.05). Both of the two vegetables are not the Cu and Zn accumulators. As for Cd and As, Capsicum annum L. poses a higher risk to animal and human health than Solanum melongena L., with soil-plant transfer coefficients more than three. Root-stem is the main barrier for most of the heavy metals and As in the two vegetables, resulting in higher metal concentrations in roots relative to other plant tissues. The low stem-fruit transfer coefficients for Zn in Solanum melongena L. and for Pb in Capsicum annum L. suggested that very few of them could reach the fruits.     

Concentrations of altrenogest in plasma of mares and foals and in allantoic and amniotic fluid at parturition

Treatment with the progestin altrenogest is widely used in pregnant mares. The fact that foals born from healthy mares treated with altrenogest until term suffered from neonatal problems raises the question of direct effects of altrenogest on vital functions in the neonate. We have therefore investigated altrenogest concentrations in maternal and neonatal blood plasma and in fetal fluids. Pregnant mares were treated with altrenogest orally once daily (0,088 mg/kg bodyweight, n = 7) or left untreated (n = 8) from 280 d of gestation until foaling. Altrenogest concentration was determined in plasma of the mares, their foals and in amniotic and allantoic fluid. The concentration of altrenogest in plasma from treated mares (2.6 ± 1.0 ng/mL) was significantly lower than in plasma from their foals immediately after birth (5.6 ± 1.9 ng/mL; p < 0.05), but was significantly higher than in their fetal fluids (amniotic fluid: 0.4 ± 0.1 ng/mL; p < 0.05; allantoic fluid: 3.0 ± 1.5 ng/mL). Altrenogest was undetectable in maternal and fetal plasma and fetal fluids of control pregnancies at all times. Altrenogest concentration in plasma of foals from treated mares was strongly correlated to the altrenogest concentration in plasma of their dams (r = 0.938, p < 0.001) and in amniotic (r = 0.886, p < 0.001) and allantoic fluid (r = 0.562, p < 0.05). A significant decrease in altrenogest concentration between the time periods 0-15 min, 30-120 min, and 180-360 min after parturition was seen in the plasma from foals born to altrenogest-treated mares. In conclusion, our data demonstrate that altrenogest reaches the equine fetus at high concentrations.     

海南稻田土壤硒与重金属的含量、分布及其安全性

采集了海南省18个市(县)代表性的稻田土壤耕作层(0—20cm)样品280个,研究了硒(Se)和5种有毒重金属元素(Hg、Cd、Cr、Pb和As)的含量、分布及其相关关系,并对Se和重金属的安全性进行评价,可为合理区划清洁且富Se稻田提供理论依据。结果表明:海南稻田土壤中Hg、Cd、Cr、Pb和As平均含量均低于国家土壤环境质量一级标准值和全国土壤背景值,以绿色食品产地环境技术条件限量标准为标准,用单项污染指数法和内梅罗综合污染指数法评价海南稻田土壤重金属的污染状况,结果都是清洁的。但以海南省土壤背景值做参比值,Hakanson潜在生态危害指数达到211.54,属于强生态危害,从潜在生态危害系数来看,Hg(102.61)和Cd(98.89)达到强生态危害,分别比海南省土壤背景值增加1.56和2.3倍,今后应注意控制Hg和Cd污染源。稻田土壤Se含量从痕量到1.532mg/kg之间,平均值为0.211mg/kg,占47.5%的稻田土壤Se含量处于中等及以上水平(>0.175mg/kg)。Se含量高的稻田土壤主要集中在东北部的海口及其周边的澄迈、定安、文昌和琼海,还有东南部的万宁和保亭。由于重金属平均含量还比较低,可暂时忽略重金属污染,故可在上述Se含量高的稻田土壤上种植富Se水稻。稻田土壤Se含量与Hg、Cd和As含量呈极显著或显著正相关,因此今后应加强研究稻田土壤Se与Hg、Cd和As的有效性及其相互作用,以便生产出绿色的富Se优质大米。     

Polycyclic Aromatic Hydrocarbons in Road-Deposited Sediments and Roadside Soil in Tijuana,Mexico

Road-deposited sediment and roadside soil in the urban area of the city of Tijuana were collected and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs). The ΣPAH concentration for road-deposited sediment (RDS) ranged between 460 and 2027 µg/kg with an average of 933 µg/kg. The ΣPAH concentration in roadside soil was lower than in RDS, with a range between 54 and 1863 µg/kg and a mean value of 308 µg/kg. The diagnostic ratios showed that the PAHs originated mostly from pyrogenic sources such as gasoline and diesel combustion. The results show that PAH concentration in RDS and roadside soils is low when compared with other published studies. The low PAH levels found in this study are possibly related to differences in climate, urban features, and anthropogenic activities conducted in the studied areas. The toxicity equivalent concentrations (TEQ) of PAH calculated were also low in comparison with other studies. This is probably due to the lower concentration of total PAHs and the highly toxic high-molecular-weight PAHs.     

Concentrations of cadmium,lead, selenium,and zinc in human blood and seminal plasma

The concentrations of cadmium, lead, selenium, and zinc in blood and seminal plasma were determined in 76 Singapore males. Except for zinc, the concentrations were generally higher in blood than in seminal plasma (cadmium, 1.31 μg/L vs 0.61 μg/L; lead, 82.6 μg/L vs 12.4 μg/L, and selenium, 163.6 μg/L vs 71.5 μg/L). The mean concentration of zinc in seminal plasma was more than 30 times higher than in blood (202 mg/L vs 6.2 mg/L). Significant positive correlations were found between the concentrations in blood and seminal plasma for the two essential trace elements: selenium (r=0.45,p<0.001) and zinc (r=0.25,p<0.05). However, no relationships were found between the concentrations in blood and seminal plasma for two toxic metals (cadmium and lead). Significant inverse correlations were observed between Cd and Zn (r=−0.40,p<0.01), and Pb and Se (r=−0.32,p<0.05) in blood, whereas significant positive correlations were noted between Cd and Se (r=0.45,p<0.01), Cd and Zn (r=0.35,p<0.05), and Se and Zn (r=0.57,p<0.001) in seminal plasma. The physiological significance of these relationships are also discussed in this paper.     

Heavy Metal Contamination in Urban Surface Soil of Klang District (Malaysia)

This study aimed to determine bioavailability of heavy metal concentrations (Al, Fe, Zn, Cu, Co, Cd, Pb and Cr) in 76 urban surface soil samples of Klang district (Malaysia). This study also aimed to determine health risks posed by bioavailability of heavy metals in urban soil on adults and children. For bioavailability of heavy metal concentrations, a physiologically bioavailability extraction test in vitro digestion model was used. Mean values of bioavailability heavy metal concentrations for this study were found to be the highest in Al (25.44 mg/kg) and lowest in Cr (0.10 mg/kg). Results of Spearman correlation coefficient (r) values showed significant correlations were observed for Al-Fe (r = 0.681), Cd-Co (r = 0.495), Cu-Zn (r = 0.232), Fe-Pb (r = 0.260), Fe-Zn (r = 0.239). For cluster analysis, output showed that these heavy metals could be classified into four clusters: Cluster 1 consisted of Cd, Cr, Co, and Pb; Cluster 2 consisted of Zn and Cu; Cluster 3 consisted of Fe; and Cluster 4 consisted of Al. For Clusters 1 and 2, anthropogenic sources were believed to be the sources, while for Clusters 3 and 4 the heavy metals originated from natural sources. Health risks were determined in adults and children through health risk assessment. For adults, Hazard Quotient (HQ) value was <1, indicating no non-carcinogenic risk, while for children, the HQ value was >1, indicating a non-carcinogenic risk. Meanwhile, for carcinogenic risk, heavy metal contamination in the Klang district might not pose a carcinogenic risk to adults while it may pose a carcinogenic risk to children because TR values in this study were >1.0E-04 for children. Output has identified the general health risk in the Klang district. Moreover, this study's findings will contribute to fill in the gap of knowledge on heavy metals' impacts on human health and urban development in the Klang District.     

Spatial Patterns and Risk Assessment of Heavy Metals in Soils in a Resource-Exhausted City,Northeast China

Northeast China is an intensive area of resource-exhausted city, which is facing the challenges of industry conversion and sustainable development. In order to evaluate the soil environmental quality influenced by mining activities over decades, the concentration and spatial distribution of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and Zinc (Zn) in surface soils (0-20cm) of a typical resource-exhausted city were investigated by analyzing 306 soil samples. The results showed that the average concentrations in the samples were 6.17 mg/kg for As, 0.19 mg/kg for Cd, 51.08 mg/kg for Cr, 23.27 mg/kg for Cu, 31.15 mg/kg for Ni, 22.17 mg/kg for Pb, and 54.21 mg/kg for Zn. Metals distribution maps produced by using the inverse distance weighted interpolation method and results revealed that all investigated metals showed distinct geographical patterns, and the concentrations were higher in urban and industrial areas than in farmland. Pearson correlation and principal component analysis showed that there were significant positive correlations (p<0.05) between all of the metals, and As, Cd, Cr, Mn, Ni, Pb, and Zn were closely associated with the first principal component (PC1), which explained 39.81% of the total variance. Cu and As were mainly associated with the second component (PC2). Based on the calculated Nemerow pollution index, percentage for slightly polluted (1<P ≤ 2) surface soils were reached 57.33%, while 42.65% topsoil samples are moderate polluted (2<P≤ 3). According to the results above-mentioned, different soil environmental function areas were classified and proper soil environmental management policy was proposed to decrease the environmental risks in the process of industrial city transformation.     

Dilute hydrochloric acid as an extractant for available zinc,copper and boron in rice soils

Summary Because zinc deficiency is a widespread disorder of wetland rice and copper deficiency may occur with it, 0.05M HCl was compared with 0.1M HCl, EDTA and DTPA as an extractant for available zinc and copper. It was also compared with the reflux method for boron assay.Thirty-three wetland rice soils were analyzed for zinc and copper by the four methods. Rice was grown on the flooded soils, scored visually for zinc deficiency, and the plants analyzed for zinc and copper content. In the boron study, 53 soils were extracted by the reflux method and the 0.05M HCl procedure. Rice was grown on the flooded soils, scored visually for boron toxicity, and the plants analyzed for boron content.Fourteen of the 16 soils on which rice showed zinc deficiency gave <1.0 mg/kg Zn by the 0.05M HCl method but values far in excess of the critical limits by the other methods. The r values for available and plant zinc were: 0.05M HCl (0.88^**); 0.1M HCl (0.55^**); EDTA (0.43^**); and DTPA (0.31^ns).Twelve of the zinc-deficient soils gave<0.1 mg/kg Cu by the 0.05M HCl method but values exceeding the critical limits by the EDTA and DTPA methods. The r values for available and plant copper were: 0.05M HCl (0.74^**), 0.1M HCl (0.64^**), EDTA (0.28^ns), and DTPA (0.20^ns).The critical limit of 1.0 mg/kg by the 0.05M HCl extraction was confirmed for zinc deficiency and a tentative value of 0.1 mg/kg for copper deficiency proposed.The 0.05M HCl method separated boron-toxic soils from non-toxic soils and gave a better correlation (r=0.91^**) between available and plant boron than the reflux extraction (r=0.84^**). The toxic limit by the 0.05M HCl method was provisionally set at 4 mg/kg.     

Polycyclic Aromatic Hydrocarbons in Surface Soils of Kunming,China: Concentrations,Distribution, Sources,and Potential Risk

The concentrations, distribution, possible sources, and potential risk of polycyclic aromatic hydrocarbons (PAHs) in surface soils were studied in Kunming, which is situated in a lake basin of the Yunnan-Guizhou plateau. 15 PAHs were analyzed in 40 surface soil samples (0–5 cm layer) collected from six types of land uses in the Kunming urban area. Meanwhile, the potential sources of PAHs in surface soils of Kunming were investigated by PAH composition ratios, isomer ratios, and principal component analysis (PCA). The total concentrations of 15 PAHs ranged from 101.64 to 6,208.25 ng/g (dry weight basis). The concentrations in different land uses increased in an order as: green space (541.43 ng/g) < education area (756.49 ng/g) < business area (810.17 ng/g) < residential area (1,034.36 ng/g) < industrial area (1,166.79 ng/g) < roadside greens (2,146.76 ng/g). The results of sources identification suggested that PAHs in surface soils of the Kunming urban area were greatly affected by combustion activities which came mainly from coal combustion and vehicular traffic. In addition, the toxic equivalency factors (TEFs) were used to estimate benzo[a]pyrene-equivalent concentration in surface soils of Kunming, and the risk level of PAHs in Kunming's urban surface soils was low as a whole.     

Heavy Metal Concentration in Sediments of the Nhue River and its Water-Irrigated Farmland Soil in the Suburbs of Hanoi,Vietnam

The heavy metal pollution of sediment in the Nhue River, which receives wastewater from the To Lich and Kim Nguu River system, was investigated together with the effects of use of this water for irrigation of the surrounding farmland. Eighty soil samples and 40 sediment samples were collected from six locations in the Nhue River and two locations in the To Lich River for chemical and physical analyses. The results showed that the sediments in the Nhue River are heavily polluted by metals (71–420 mg/kg for Cu, 77–433 mg/kg for Pb, 150–350 mg/kg for Zn, 0.7–8.7 mg/kg for Cd, 80– 583 mg/kg for Cr, and 32–70 mg/kg for Ni). There were positive correlations between heavy metal concentration and both clay and organic matter contents in the sediment samples. The concentrations of all metals in soil samples were much higher than the background levels in the farmland, Cd, Cu, and Pb, exceeding Vietnamese standards for agricultural grounds.