SEAWATER INTRUSION IN COASTAL GROUNDWATER BODIES DUE TO OVEREXPLOITATION AND THE DIRECTIVE 2000/60/EC

Η θαλάσσια διείσδυση είναι ένα είδος περιβαλλοντικής ρύπανσης, που οφείλεται σε ανθρώπινες δραστηριότητες και/ή σε γεωλογικούς παράγοντες. Το πρόβλημα αυτό καταγράφεται σε πολλούς παράκτιους υδροφορείς, που αποτελούν την κύρια πηγή για την κάλυψη των υδρευτικών και αρδευτικών αναγκών. Η θαλάσσια διείσδυση που προκαλείται από υπεράντληση και πτώση της στάθμης του υπόγειου νερού είναι μεγάλης σημασίας για την Ε.Ε. Η Οδηγία πλαίσιο 2000/60/ΕΚ, ανάμεσα στα αλλά, έχει ως στόχο την αποκατάσταση θετικού ισοζυγίου μεταξύ αντλήσεων και εμπλουτισμού, καθώς και ποιοτική σύσταση που δεν θα εμφανίζει συμπτώματα εισροής θαλασσινού νερού με στόχο την αποκατάσταση της καλής χημικής κατάστασης των υπόγειων νερών έως το 2015. Για το λόγο αυτόν απαιτείται η καταγραφή της υφιστάμενης κατάστασης, η αναγνώριση των αιτιών της υφαλμύρινσης και επιπλέον η συνεργασία της επιστημονικής κοινότητας και των φορέων που χαράσσουν πολιτική στον τομέα των υδάτων με στόχο την κατάστρωση ενός σχεδίου διαχείρισης των παράκτιων υδροφορέων, το οποίο θα μειώσει την ανθρώπινη συμβολή στη θαλάσσια διείσδυση.Seawater intrusion may be considered as a type of environmental pollution, due to human activities or/and to geological factors. This problem has been widely recognized in many coastal aquifers, which constitute the main source of water for drinking and irrigation purpose. Seawater intrusion caused by anthropogenic alterations of the groundwater level is of high policy relevance due to the Water Framework Directive (2000/60/EC) which, aims to ensure a balance between abstraction and recharge and a chemical composition of the groundwater body not exhibiting the effects of saline intrusion, with the aim of achieving of good groundwater status by 2015. For this purpose, the current situation should be recorded, as well as the reasons causing seawater intrusion. The collaboration between scientific community and policy making communities is essential, in order to apply a water resources management plan, aiming at diminution of anthropogenic share in seawater intrusion

The earthworm Aporrectodea caliginosa stimulates abundance and activity of phenoxyalkanoic acid herbicide degraders

2-Methyl-4-chlorophenoxyacetic acid (MCPA) is a widely used phenoxyalkanoic acid (PAA) herbicide. Earthworms represent the dominant macrofauna and enhance microbial activities in many soils. Thus, the effect of the model earthworm Aporrectodea caliginosa (Oligochaeta, Lumbricidae) on microbial MCPA degradation was assessed in soil columns with agricultural soil. MCPA degradation was quicker in soil with earthworms than without earthworms. Quantitative PCR was inhibition-corrected per nucleic acid extract and indicated that copy numbers of tfdA-like and cadA genes (both encoding oxygenases initiating aerobic PAA degradation) in soil with earthworms were up to three and four times higher than without earthworms, respectively. tfdA-like and 16S rRNA gene transcript copy numbers in soil with earthworms were two and six times higher than without earthworms, respectively. Most probable numbers (MPNs) of MCPA degraders approximated 4 × 105 gdw−1 in soil before incubation and in soil treated without earthworms, whereas MPNs of earthworm-treated soils were approximately 150 × higher. The aerobic capacity of soil to degrade MCPA was higher in earthworm-treated soils than in earthworm-untreated soils. Burrow walls and 0–5 cm depth bulk soil displayed higher capacities to degrade MCPA than did soil from 5–10 cm depth bulk soil, expression of tfdA-like genes in burrow walls was five times higher than in bulk soil and MCPA degraders were abundant in burrow walls (MPNs of 5 × 107 gdw−1). The collective data indicate that earthworms stimulate abundance and activity of MCPA degraders endogenous to soil by their burrowing activities and might thus be advantageous for enhancing PAA degradation in soil