Mercury distribution in the sediments of Ambarlı Port Area,Sea of Marmara (Turkey)

The purpose of this study is to investigate historical and current mercury (Hg) contamination in the surface and core sediments of the Ambarl? Port area. Textural parameters, total organic carbon (TOC), ²¹⁰Pb and total Hg (THg) contents were measured. Mercury contamination of the sediments was assessed on the basis of the enrichment factor (EF), anthropogenic factor (AF), index of geoaccumulation (Igeo) and corresponding sediment quality guidelines. Most surface sediment samples were also non-toxic with mercury concentrations below the effects range-low (ERL) value, but mercury levels at five stations were between ERL and effects range-median (ERM) values, where occasional adverse effects concerning risk analysis are expected. The EF and Igeo analysis showed that there was no significant mercury enrichment and contamination in the core sediment before the 1650s, but values increased from then onwards to 2009 (being especially accelerated in line with port activities from 1989), disclosing a serious ecotoxicological risk to sediment-inhabited marine organisms.     

Experimental investigation of cross-shore sandbar volumes

Sandbars are critical to the cross-shore movement of sediment. Prediction of cross-shore sandbar volumes requires knowledge about the functional relationship of sediment transport rate conditions with waves, currents, base slope, sediment property and water depth. In this study, experiments on cross- shore sediment transport were carried out in a laboratory wave channel for initial base slopes of 1/8, 1/10 and 1/15. Using regular waves with different deep-water wave steepness generated by a pedal-type wave generator, bar volumes caused by cross-shore sediment transport are investigated for beach materials with the medium diameter of d₅₀?=?0.25, 0.32, 0.45, 0.62 and 0.80 mm. A non-dimensional equation for sandbar volume was obtained by using linear and non-linear regression methods through the experimental data and was compared with previously developed equations in the literature. The results have shown that the experimental data fitted well to the proposed equation with respect to the previously developed equations.     

洱海流域农业面源污染空间分布特征及分类控制策略

作为典型的高原坝区农业型流域,洱海流域农业面源污染严重,威胁洱海水质.以洱海流域为研究对象,综合数理分析及GIS技术,开展流域农业面源污染负荷分析及评价,使用排污系数法估算了2018年洱海流域农村生活、畜禽养殖业和种植业污染中COD（化学耗氧量）、TN（总氮）、TP（总磷）的排放负荷,并通过等标污染负荷法在GIS空间分析反映流域内污染排放分布情况.结果表明:①2018年洱海流域农业面源主要污染物COD、TN、TP的排放量分别为11 188.20、2 752.56和259.33 t.COD排放量主要来自畜禽养殖,TN与TP的排放量均主要来自种植业.②洱海流域农业面源主要污染物COD、TN、TP等标污染负荷分别为559.41、2 752.56和1 296.63 m3/a.种植业等标污染负荷在总等标污染负荷中的占比最高,为36.40%,其次是畜禽养殖业,为34.44%.③各乡镇的等标污染负荷差异较大,等标污染负荷范围为（286.16±150.67）m3/a,等标污染负荷强度范围（0.13±0.067）m3/a.④聚类分析结果表明,洱海流域农业面源污染可分为种植业主导型、种植业高污染型、生活污染主导型和畜禽养殖业主导高污染型等4种类型.研究显示:来源于种植业的面源污染是洱海流域水环境保护需要控制的首要污染源,TN是需要控制的首要污染物;排放量与等标污染负荷的空间分布特征均呈流域北部乡镇污染物排放量较高,但流域西部各乡镇排放强度较大的特征;流域内各乡镇防治面源污染需要针对其污染来源特点分别采取推进种养平衡、推广绿色种植、分区控制农田径流以及推进农村生活污水治理等分类控制策略.      

Factors affecting the flux of arsenic through the mussel Mytilus galloprovincialis

Radiotracer experiments were designed to study the effects of certain environmental and biological factors on arsenic accumulation and elimination processes in the Mediterranean mussel Mytilus galloprovincialis. Arsenic (as arsenate) uptake increased with increasing arsenic concentration in the water; however, the response was not proportional, indicating that accumulation was partially suppressed at higher external arsenic concentrations. In general, approximately 80% of the ⁷⁴As taken up was associated with the soft parts, with small mussels concentrating ⁷⁴As to a greater degree than larger individuals. The highest ⁷⁴As concentrations were recorded in the byssus and the digestive gland. Increased temperature enhanced both arsenic uptake and loss. Mussels in sea water at 19 S accumulated approximately three times more ⁷⁴As than those held at 38 S. Arsenic loss was much less affected by salinity, with only a tendency for greater arsenic retention noted at lower salinities. Studies carried out in the laboratory and in situ revealed that arsenic turnover was significantly more rapid in actively growing individuals living under natural conditions. Arsenic-74 loss from the in situ group was essentially biphasic, with biological half-times of approximately 3 and 32 days for the fast and slow compartments, respectively. The active secretion of arsenic in the byssal threads contributed to the total elimination of the element from the mussels.     

Biogenic and contaminant heavy metal pollution in Estonian coniferous forests

Regional Environmental Change - Estonia is the only country in Europe that is actively mining oil shale. Oil-shale-burning power plants have been and still are the main sources of heavy metals in...     

Shift of Spawning Season and Effects of Climate Warming on Developmental Stages of a Grayling (Salmonidae)

Abstract: River‐dwelling fish, such as European graylings (Thymallus thymallus), are susceptible to changes in climate because they can often not avoid suboptimal temperatures, especially during early developmental stages. We analyzed data collected in a 62‐year‐long (1948–2009) population monitoring program. Male and female graylings were sampled about three times/week during the yearly spawning season in order to follow the development of the population. The occurrence of females bearing ripe eggs was used to approximate the timing of each spawning season. In the last years of the study, spawning season was more than 3 weeks earlier than in the first years. This shift was linked to increasing water temperatures as recorded over the last 39 years with a temperature logger at the spawning site. In early spring water temperatures rose more slowly than in later spring. Thus, embryos and larvae were exposed to increasingly colder water at a stage that is critical for sex determination and pathogen resistance in other salmonids. In summer, however, fry were exposed to increasingly warmer temperatures. The changes in water temperatures that we found embryos, larvae, and fry were exposed to could be contributing to the decline in abundance that has occurred over the last 30–40 years.     

A Device for Preventing Occupational Diseases of Lower Legs

Physiological processes characteristic of the fatigue of legs mainly appear when the worker’s activity requires standing. If the processes are intensive and regular, various diseases of legs, such as varicose veins and musculoskeletal disorders of legs and feet, can develop. Therefore, methods of reducing the fatigue of legs are important in occupational health protection. Air jet massage technology was developed and an appropriate massage device was built by the authors. The massage head turning around the lower leg and moving up and down gradually covers the leg’s surface. To determine the efficiency of the massage, fatigue processes were studied. These studies showed that jet massage effectively reduces both the subjective and objective fatigue symptoms. The device is convenient for use in industry, services, and at home.