Polycyclic aromatic hydrocarbons in Syrian olive oils and their likely daily intakes

The levels of 16 US Environmental Protection Agency polycyclic aromatic hydrocarbons (16 EPA PAHs) in Syrian olive oils have been determined. Forty-two samples including commercial extra virgin and virgin olive oils, and virgin olive oils from olive mills were analyzed. Only naphthalene (NAP) was detected in all olive oil samples under investigation. Among the studied 16 EPA PAHs, the highest maximum concentration was also observed for NAP (120 μg kg^?1). Moreover, three samples exceeded the European Union (EU) maximum level of 2 μg kg^?1 for benzo[a]pyrene (BaP) in oils and fats, and only one sample exceeded the EU maximum level of 10 μg kg^?1 for the sum of benz[a]anthracene, chrysene, BaP, and benzo[b]fluoranthene (PAH4). The likely daily intakes of the total sum of 16 EPA PAHs, the sum of eight genotoxic PAHs, the sum of PAH4, the BaP, and the BaP equivalent through consumption of Syrian olive oils were estimated.     

Effects of Simulated Sulphuric Acid Deposition On Calluna Vulgaris/Peat Microcosms and Associated Soil Solutions

Calluna vulgaris/peat microcosms have been used in an outdoor simulated acid rain experiment to test a series of hypotheses about sulphuric acid deposition effects upon the growth of Calluna on peat soil, namely: (1) Initially, enhanced acid input will enhance base cation and ammonium concentrations in soil solution. This may enhance uptake of these species, increasing foliar concentrations of base cations and nitrogen, and possibly foliar chlorophyll a and b concentrations. (2) If changes are induced in nutritional status, they may influence plant growth. (3) in the longer term, enhanced ammonium and base cation solubility occurring as a consequence of cation exchange reactions will lead, especially in winter months, to enhanced leaching losses. Hence any positive effects upon plant nutrition will not be sustainable. (4) the peat will acidify significantly over two years, in the shorter term primarily as a consequence of an enhanced mobile anion effect. (5) Acidification may reduce the rate of mineralisation of organic phosphorus and, in a phosphorus-deficient peat soil, this may lead to reduced foliar phosphate concentration and possibly induce phosphorus deficiency.

Most of these hypotheses were supported to some extent by the experimental results. the peat soil solution pH fell immediately in response to the acid treatments, and longer-term acidification continued progressively over the two years of the experiment. in the first year, the treatments significantly influenced the calcium, magnesium, phosphorus and nitrogen status of the leaves from Calluna new shoots, whereas in the second year calcium, potassium and phosphorus were influenced. However, in both years foliar phosphate concentration was enhanced, rather than reduced, in response to increased acid load. Foliar carbon and nitrogen concentrations fell with increasing acidity of     

Agronomic application of olive mill wastewaters with phosphate rock in a semi-arid Mediterranean soil modifies the soil properties and decreases the extractable soil phosphorus

Olive mill wastewater (OMW), a by-product of the olive-mill industry, is produced in large amounts in Mediterranean countries. The presence of indigenous phosphate deposits in some countries like Tunisia provides an incentive for direct application or local chemical treatment at low cost to improve the solubility of low reactive phosphate rocks (PRs). The use of naturally occurring low-molecular weight organic acids (LMWOAs) that are present in OMW represents a new perspective in PR research and a possible solution for the recycling of the OMW. The present work was aimed at evaluating, under natural situations (field of olive trees), the effects of agronomic application of OMW (amounts applied: 30, 60 m(3) ha(-1)) with PR (amounts applied: 150 kg ha(-1)) on olive trees soil properties. We measured organic C, nitrogen (N), extractable phosphorus (P), exchangeable calcium (Ca), and exchangeable potassium (K), as well as other properties (pH and electrical conductivity). Our data provide evidence that agronomic application of OMW with PR has important effects on soil properties. Increases in organic C, total N, extractable P and exchangeable potassium (K) were found after the first agronomic application of OMW and PR. These increases were only temporary, following the second agronomic application of OMW and PR, significant reductions were detected in the extractable soil P (19.67 mg kg(-1) in the control soil vs. 8.99 mg kg(-1) in the amended soil). Changes in the extractable soil P could alter plant productivity and plant community structure because shifts in nutriment availability can affect the balance between limiting and non-limiting nutrients.