Environ Monit Assess (2015) 187:52 DOI 10.1007/s10661-015-4272-5
Assessment of the concentrations of polycyclic aromatic hydrocarbons and organochlorine pesticides in soils from the Sarno River basin, Italy, and ecotoxicological survey by Daphnia magna Michele Arienzo & Stefano Albanese & Annamaria Lima & Claudia Cannatelli & Francesco Aliberti & Flavia Cicotti & Shiuhua Qi & Benedetto De Vivo
Received: 2 September 2014 / Accepted: 2 January 2015 # Springer International Publishing Switzerland 2015
Abstract We studied the contamination level of the soils of the Sarno River basin in southwestern Italy by combined acute toxicity test with Dapnia magna and chemical extraction of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs). For the ecotoxicological assessment, 188 samples were taken and coincided with those of a previous study (2013) where heavy metals were surveyed. For the organics assessment, 21 samples were selected nearby representative areas of elevated anthropic pressure. About 10.1 % of the samples showed noticeable sign of D. magna mortality, 61–100 %, and fall along the potentially floatable areas of Sarno and Solofrana basins with high degree of contamination by Cr, As, Zn, and Hg. High levels of ecotoxicity, 61–100 %, were determined in the lower M. Arienzo (*) : S. Albanese : A. Lima : C. Cannatelli : B. De Vivo Dipartimento di Scienze della Terra, dell’Ambiente e delle Risorse, Università degli Studi di Napoli BFederico II^, Via Mezzocannone 10, 80138 Naples, Italy e-mail:
[email protected] F. Aliberti : F. Cicotti Laboratori di Igiene: Acque, Alimenti e Ambiente, Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cinthia, Edificio 7, 80126 Naples, Italy S. Qi State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
Sarno River basin in areas of moderate or low degree of contamination by Cd, Cu Hg, Pb, Sb, Sn, and Zn. Benzo(a)pyrene, indenopyrene, and benzo(g,h,i)perylene were present at concentrations of 0.32, 0.23, and 0.18 mg kg−1, respectively, 2- to 3-fold the law limits with most of the samples falling nearby the points where the ecotoxicity output was close to 100 %. Among OCPs, pp′-DDT had a mean of 0.225 mg kg−1 and hence about more than 200- and 2-fold the residential, 0.01 mg kg−1, and commercial/industrial limits, 0.1 mg kg−1 and determined mainly in the central Sarno valley in an area where elevated concentrations of benzopyrene and D. magna mortality were also observed. The study evidenced the high rate of contamination by PAHs and OCPs of the soils and the need of urgent remediation actions. Keywords Sarno basin . Polycyclic aromatic hydrocarbons . Organochlorine pesticides . Soil pollution . Ecotoxicity
Introduction Soil contamination by persistent organic pollutants (POPs) such as PAHs and organochlorine pesticides (OCPs) is an issue of great concern affecting human and environmental health in industrialized and nonindustrialized countries. The fate and behavior of PAHs and OCPs in soil is governed by many factors, including
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soil characteristics, compound properties, and environmental factors (Reid et al. 2000; Chung and Alexander 2002). Detection of such compounds may occur in a wide range of biological matrices, including blood and hair (Tsatsakis et al. 2008), and accumulate in organ tissues, without essentially undergoing metabolic degradation, thus showing long half-lives. Due to their potential for short- and long-term hazardous effects, continuous biomonitoring of the levels of PAHS and OCPs and their metabolites in humans is an essential step toward the evaluation of risk assessment and the prediction of adverse health effects in populations with either occupational or background environmental exposure to pesticides (Chrysikou et al. 2008). POPs have traditionally been studied with exhaustive extraction techniques, and these results are often coupled to risk assessment models to add a biological interpretation. However, this approach does not take into account two important processes, bioavailability and aging (Hatzinger and Alexander 1995; Laor et al. 1996). Bioavailability is a dynamic rather than a static process. As POPs persist within a soil or sediment matrix, they become increasingly resistant to desorption and thus less bioavailable (Gevao et al. 2000). Reliable and representative techniques for the assessment of the bioavailable fraction of organic contaminants are still lacking. The problem is complicated by the fact that this fraction varies depending on the physicochemical properties of the molecule; for the same contaminant, the type of soil and target organisms have also to be considered (Chung and Alexander 1998). Biological approaches use in vivo (e.g., higher plants, earthworms, and crustacean) and in vitro models (human, animal, and bacterial cells) as indicators of soil contamination (Khan et al. 2012; Sforzini et al. 2012). In view of the fact that chemical analysis require special equipments, they are expensive to perform and do not allow to evaluate the environmental toxicity; during the recent decade, large-scale investigations have been performed to study various test objects that are suitable for bioassay. The currently used methods of bioassay provide only the integral evaluation of the pollutants’ effect but not the determination of the xenobiotics’ origin (Flerov 1989). The application of a multi-criteria approach for source identification is a key point to characterize pollution levels and to locate contamination sources. There are only limited studies reporting the levels of persistent organic pollutant POPs in Italian soils, especially in southern Italy (Capuano et al. 2005).
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The Sarno River basin in the Campania region, in the south of Italy, is known as one of the most fertile areas in Campania, where agriculture is rather intensive. There is also wide presence of dairies, paper mill and pottery industries, and 160 tanning plants between Solofra, Mercato S. Severino and Fisciano. These companies represent a serious risk for the fertility and hence to the overall quality of the soils of the basin and the water of the Sarno River, which is known as the most polluted water course of Europe (Basile et al. 1985; Arienzo et al. 2001; Adamo et al. 2006) mainly as a consequence of industrial and municipal wastewater discharges (Albanese et al. 2012). Nevertheless, the continuous use of the river water up to 1990 (prohibited since 1990), to supply water to the local intensive agriculture in its mid valley and its frequent flooding, has contaminated many agricultural lands along its course. Adamo et al. (2006) reported for the Solofrana river valley, constituting the inland portion of the Sarno plain, levels of Cr of 62–335 mg kg −1 and Cu (70– 565 mg kg−1) above the Italian regulatory levels (Cr 150, Cu 120 mg kg−1). The establishment in the lower valley of the river, close to the coastal plain, of several farms, chemicalpharmaceutical, engineering, and manufacturing industries represents an additional nonpoint source of pollution of the river and hence of the basin, thereby contributing to the final pollution of sea waters and sediments (De Pippo et al. 2006). In the present study, we determined the relationship between an acute toxicity survey by Daphnia magna from a widespread ecotoxicological screening at 188 sites of the soils of the Sarno basin with those obtained by conventional chemical extraction of PAHs and OCPs at 21 representative sites of the basin. The data from the ecotoxicological assessment were also compared with those from a parallel study on the same set of samples (Cicchella et al. 2013) determining the levels of heavy metals and their relative map distribution in the studied area.
Materials and methods Geomorphological and geology setting The Sarno River basin (Fig. 1), including the alluvial plain of the Sarno River and the valleys of the Solofrana and Cavaiola tributaries, is located between the volcanic
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Fig. 1 Geographical characterization of the Sarno River basin including the map of soil sue and of the surface hydrological network
complex of Somma-Vesuvio (NW), the Sarno Mountains (NE), the limestone Lattari Mountains (S), and the Tyrrhenian coast (W), and it is strongly urbanized (in some area, the population density goes up to about 2000 inhabitants km−2) (ISTAT 2001). The surface hydrological network and the map of soil use of the area are illustrated in Fig. 1. The basin covers about 440 km2 and is geologically composed of various types of limestone rocks. Soils of the area are mainly permeable and porous, characterized by a neutral pH, low organic matter content (OM), and cation exchange capacity (CEC) (Adamo et al. 1999). The headwater of the Sarno River is located close to the homonymous town at the base of a calcareous formation of the Campanian Apennin Mountains. The river has a daily average flow of about 61 m3 h−1 and has a relatively short straight course (24 km). The soils of the Solofrana river valley, developed from volcanic materials eroded from the surrounding mountain slopes, show moderate to high andic properties (Terribile and Di Gennaro 1996). The Cavaiola and Solofrana tributaries converge with the Sarno River crossing the heavily farmed land of S. Marzano and Scafati before discharging into the Gulf of Naples (Fig. 1). Specifically, the main reliefs are constituted by Triassic dolomite, by dolomitic limestone of the lower Jurassic-Cretaceous as well as by Cretaceous fractured and karstified limestone (De Pippo et al. 2006). Pyroclastic deposits and reworked volcanic ashes related to the Mt. Somma-Vesuvius activity (on the N–W sector of the basin) generally cover the calcareous-dolomitic rock of the Sarno Mountains and are widely spread around the Sarno River plain (Cinque et al. 1997). The high soil fertility throughout the Sarno area is the consequence of physical and
chemical actions linked to the different nature of the superficial deposits (Terribile and Di Gennaro 1996). Field sampling and sample preparation A total of 188 surface soil samples, 10-cm depth, were collected for the ecotoxicological assessment by D. magna, during the month of April 2014 across the whole study area (Fig. 2). Each sampling site was located at the center of the squared cells of an ideal grid superimposed to the study area. At each site, a composite sample of 0.5 kg of soil was collected by joining together five aliquots taken at the center and at the corners of the ideal square with a side of 5 m. Every 20 sampling site, a duplicate sample was collected in the same cell of the 20th sample in order to allow the blind control of the analytical quality. Additional 21 soil samples (Fig. 2) were taken from the 0–30-cm layer at selected sites representatives of the soil units of the study area, where the anthropic pressure was visibly high, for the conventional chemical extraction survey of PAHs and OCPs. All the samples were stored in plastic bags and kept at a temperature of 4 °C by means of a portable cooler during the transport to the laboratory. Samples for PAH and OCP analyses were packed in polystyrene boxes together with dry ice pellets and sent to the Key Laboratory of Biogeology and Environmental Geology of Ministry of Education at China University of Geosciences in Wuhan for PAH and OCP analyses. A fraction of the soils taken for conventional chemical extraction once transported to the laboratory were air dried, sieved (mesh size 2 mm), and analyzed according to the procedures published by the Ministero delle Politiche Agricole e Forestali (1997): particle-size analysis was performed by a sedimentation
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Fig. 2 Localization of the 188 sampling points (blue circles) for the ecotoxicological assessment by Daphnia magna acute toxicity test and of the 21 sampling points (red circles) for PAH and OCP conventional analysis in the Sarno River basin
procedure; pH and EC were determined in 1:2.5 (w/v) soil/water suspension; soil organic carbon (OC) content was determined by the Walkley–Black method.
controls were also accomplished. Nonmotile organisms were counted after gentle shaking of the solutions and observation for 15 s and toxicity expressed as percentage of nonmotile organism relative to control.
Ecotoxicological assessment Chemicals The acute toxicity evaluation was performed by the D. magna newborn mobility inhibition test (EN ISO 6341 1999; EN ISO 6341 2013). This aquatic animal extensively used as a test organism in aquatic toxicology due to their small size, short life cycle, and amenability to lab culture. D. magna is the most sensitive test object in relation to different pollutants (OCPS, PAHS, heavy metals, etc.) among all known biological objects including experimental animals (Peters and De Bernardi 1987). The test was performed by mixing 20 g of soil with sterile distilled water 1:10w/v; the mixture was strongly shaken for 12 h, to promote the migration of potential toxic substances, linked to soil particles, to water solution. The elutrate was filtered on strainer paper disks, and the obtained solution exposed to groups of five D. magna newborns, less than 24 h old, for 24 and 48 h at 20±2 °C under dark conditions. The test was performed within 12 h from the preparation of the elutriate. The pH of the elutriate, before and after the test, was measured to ensure the optimal conditions for neonates’ survival, range of 6–9. Each sample was replicated four times, and for each batch test, four negative
Sixteen USEPA priority PAH standards (including naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno [1,2,3-cd]pyrene, dibenz[a,h]anthracene, and benzo[g,h,I]perylene) in a mixture, deuterated recovery surrogates standard consisting of naphthalene-D8, acenaphthene-D10, phenanthrene-D10, chrysene-D12, and perylene-D12, were obtained from Ultra Scientific Inc. (North Kingston, RI, USA). And, the internal standard (hexamethylbenzene) was acquired initially as a solid of 99 % purity (Aldrich Chemical, Gillingham, Dorset, UK). Organochlorine pesticide standards (including p,p′-DDT, o,p′-DDT, p,p′-DDD, o,p′-DDD, p,p ′-DDE, o,p′-DDE, α-HCH, β-HCH, γ-HCH, δ-HCH, HCB, aldrin, dieldrin, endrin, α-endosulfan, β-endosulfan, trans-chlordane, cis-chlordane, endosulfan sulfate, endrin aldehyde, endrin ketone, heptachlor, heptachlor epoxide, trans-nonachlor, cis-nonachlor, and methoxychlor) in a mixture, recovery surrogates standard
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(2,4,5,6-tetrachloro-m-xylene(TCmX) and decachlorobiphenyl (PCB209) in a mixture, and internal standard (pentachloronitrobenzene (PCNB)) in a solution were all obtained from Ultra Scientific (North Kingstown, RI, USA). Dichloromethane and n-hexane were purchased from Tedia Co., USA. Acetone was purchased from Fisher Scientific, USA. All organic solvents were better than spectrum grade and were redistilled in a glass system before use. Neutral silica gel (80–100 mesh) and alumina (100–200 mesh) were Soxhlet-extracted for 48 h in dichloromethane (DCM) solvent. Upon drying at room temperature, silica gel and alumina were baked at 180 and 240 °C for 12 h, respectively. After cooling down, purified water (3 % of the reagent weight) was added to reduce activity. Sodium sulfate was baked at 450 °C and stored in sealed containers. The glasswares were cleaned with detergent, K2Cr2O7–H2SO4 solution, tap water, and deionized water, respectively, and finally baked at 180 °C for 4 h and rinsed by some solvent two and three times before use. Extraction and cleanup In the laboratory, soil samples were homogenized and freeze-dried. Ten grams of dried soil from each sample were spiked with 1000 ng (5 μl of 200 mg l−1) of recovery surrogates (naphthalene-D8, acenaphtheneD10, phenanthrene-D10, chrysene-D12, and peryleneD12) and were Soxhlet-extracted (4–6 cycles h−1) with dichloromethane for 24 h. Elemental sulfur was removed by adding activated copper granules to the collection flasks. The analytical method for OCPs was carried out based on the method of US-EPA 8080A. In the laboratory, soil samples were homogenized and freeze-dried. Ten grams of dried soil from each sample were spiked with 20 ng (4 μl of 5 mg l−1) of TCmX and PCB209 as recovery surrogates and were Soxhletextracted with dichloromethane for 24 h. Elemental sulfur was removed by adding activated copper granules to the collection flasks. For both analytes, the sample extract was concentrated and solvent-exchanged to hexane and further reduced to 2–3 ml by a rotary evaporator (Heidolph4000). A 1:2 (v/v) alumina/silica gel column (both 3 % deactivated with H2O) was used to clean up the extract, and PAHs and OCPs were eluted with 30 ml of dichloromethane/hexane 3:7 and 2:3, respectively. The eluate was then concentrated to 0.2 ml under a gentle nitrogen stream. One thousand nanograms (5 μl
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of 200 mg l−1) of hexamethylbenzene was added as an internal standard prior to gas chromatography–mass spectrometry (GC-MS) analysis. For OCP analysis, the eluate was concentrated to 0.2 ml under a gentle nitrogen stream 20 ng (4 μl of 5 mg l−1), and PCNB was a dd ed as a n i nte r n al s t an da r d pr i or t o g as chromatography-electron capture detector (GC-ECD) analysis. PAH analysis An HP6890N gas chromatograph equipped with mass selective detector (5975MSD) was used for detecting the levels of PAHs in the soil samples. The capillary column used for the analysis was a DB-5MS (30.0 m× 250 μm×0.25 μm film thickness). It was coupled with a HP-5975 mass selective detector operated in the electron impact mode (EI mode, 70 eV). The chromatographic conditions were as follows: injector temperature 270 °C; detector temperature 280 °C; oven temperature program was kept at 60 °C for 5 min and increased to 290 °C at a rate of 3 °C min−1 and kept at 290 °C for 40 min. The highly pure carrier gas was helium at a constant flow rate of 1.5 ml min−1. The mass spectrometer was operated in the selected ion monitoring (SIM) mode and tuned with perfluorotributylamine (PFTBA) according to the manufacturer criteria. Mass range m/z 50 and 500 were used for quantitative determinations. Data acquisition and processing were by a HP Chemstation data system. Chromatographic peaks of samples were identified by mass spectra and by comparison with the standards. A 1 μl sample was injected into the GC-MSD for analysis, in splitless/split model with a solvent delay of 5 min. A six-point response factor calibration was established to quantify the target analyses. OCP analysis An HP7890A gas chromatograph equipped with a 63Ni electron capture detector (GC-ECD) was used for detecting the levels of organochlorine pesticides in the soil samples. The capillary column used for the analysis was a HP-5 (30.0 m×320 μm×0.25 μm film thickness). Nitrogen was used as the carrier gas at 2.5 ml min−1 under the constant flow mode. Injector and detector temperatures were maintained at 290° and 300°, respectively. The temperature program used is as follows: the oven temperature began at 100 °C (equilibrium time
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1 min), rose to 200 °C at 4 °C min−1, then to 230 °C at 2 °C min−1, and at last reached 280 °C at a rate of 8 °C min−1, held for 15 min. A 2 μl sample was injected into the GC-ECD for analysis. A six-point response factor calibration was established to quantify the target analyses. Quality assurance and quality control Procedure types used for quality assurance and quality control (QA/QC) were as follows: method blank control (procedural blank samples), parallel sample control (duplicate samples), solvent blank control, and basic matter control. In order to ensure the validity of the analyses during the experiment, different reagents and procedures were used: 1. One thousand nanograms of naphthalene-D8, acenaphthene-D10, phenanthrene-D10, chryseneD12, and perylene-D12 were used as recovery surrogates, respectively, and 1000 ng hexamethylbenzene was added in extracts as the internal standard substance. The spiked recoveries of PAHs using composite standards were 49.9±14.5 % for naphthalene-D8, 74.2±9.4 % for acenaphthene-D10, 91.5±11.6 % for phenanthrene-D10, 87.1±8.5 % for chrysene-D12, and 89.2±11.0 % for perylene-D12, respectively; 20 ng TCmX and PCB-209 were used as recovery surrogates, respectively, and 20 ng PCNB was added in extracts as the internal standard substance. The spiked recoveries of OCPs using composite standards were 77.8±19.0 % for TCmX and 89.3±20.3 % for PCB209, respectively. 2. An internal standard method was used for quantification, a six-point calibration curve was established according to the results from the PAH-16 standard reagents with concentration of 10, 5, 2, 1, 0.5, and 0.2 mg l−1, and from the OCP-26 standard reagents with concentration of 200, 150, 100, 50, 20, and 10 μg l−1. For PAHs, the target compounds were identified on the basis of the retention times and selected quantitative ion, whereas for OCPs, the target compounds were identified on the basis of the retention times (previously confirmed with GC-MS). 3. During the pretreatment, a procedural blank and a parallel sample consisting of all reagents was run to check for interference and cross contamination in every set of samples (about 16 samples). Only low concentrations of few certain target compounds can
Environ Monit Assess (2015) 187:52
be detected in procedural blank samples. For more than 96 % of target compounds in parallel samples, the relative error (RE, %) of concentrations are less than 50 %, which is acceptable for Specification of Multi-purpose Regional Geochemical Survey and Guidelines for sample analysis of Multi-purpose Regional Geochemical Survey recommended by China Geological Survey (DD2005-1 and DD2005-3); 4. During the GC-MS analysis period, a solvent blank sample and a PAH-16 and OCP-26 standard reagent with concentration of 5 mg l−1 and 100μg l−1 was injected everyday before analyzing the soil samples. The target compounds were not detectable in the solvent blank samples. 5. Multi-injections were used for precision or accuracy. The samples of different concentrations were injected continually for ten times, and the relative standard deviation was calculated. RSD for all the target compounds ranged from 3.2 to 7.9 %. The final concentrations of PAHs and OCPs in all samples were corrected according to the recovery of the surrogates and were subtracted the results of blank samples.
Results and discussion Properties of the studied soils The soils (Table 1) appeared to have variable agricultural use with most of the soils cropped by pasture, vegetables, and fruit trees. Vineyard was observed only at two sites (S6 and S20). The pH was mainly neutral with a mean of 7.03 and with values in the subacid range only at sites S1 and S3, ~6.3. Soils appeared to be essentially of sandy type with very low content of clay and up to 83 g kg−1. With the exception of S2 and S3 which had a low OC level below 1.0 g kg−1, most of the soils displayed a medium content of OC, with a mean of 1.88 g kg−1. These data appeared to be sustained by the observations of De Pippo et al. (2006) who identified the Sarno soils as young volcanic soils, mainly formed by both colluvium material (from upslope relieves covered by well-developed andosols) and alluvial sediments. The authors identified in the Sarno area three different soil systems: soils of Phlegrean and Somma– Vesuvius pyroclastic deposits interlayered with calcareous deposits, moderately coarse texture and moderately acid; soils of the alluvial plain of the rivers Sarno and Solofrana,
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Table 1 Geographical localization, main use, and physical chemical properties of the soil samples (S1–S20) taken across the study area Soil sample
Latitude (N) Longitude (E) Land use
pH
Coarse sand Fine sand (g kg−1) (g kg−1)
Silt (g kg−1)
Clay (g kg−1)
OC (g kg−1)
S1
40.8436
14.7689
Hazelnuts
6.32
318
415
232
35
10.5
S2
40.8444
14.8094
Grass
7.35
325
395
235
45
7.5
S3
40.8236
14.8550
Fruit trees
6.31
300
429
229
42
9.5
S4
40.8096
14.5740
Vegetables
6.41
329
411
220
40
19.8
S5
40.8211
14.6155
Fruit trees
7.12
315
432
215
38
8.2
S6
40.8105
14.6731
Vineyard
7.21
332
412
220
36
16.2
S7
40.8133
14.7128
Fruit tree
7.23
456
325
154
65
20.2
S8
40.8110
14.7604
Grass
7.35
341
412
212
35
15.5
S9
40.8159
14.7979
Hazelnuts
7.64
499
336
141
24
19.7
S10
40.7781
14.5741
Fruit tree
7.44
311
452
212
25
22.1
S11
40.7777
14.6187
Vegetables
6.89
375
354
232
39
23.4
S12
40.7798
14.6676
Vegetables
6.52
325
385
254
36
23.2
S13
40.7749
14.7133
Fruit yard
7.69
189
468
260
83
24.0
S14
40.7779
14.7595
Vegetables
6.45
458
455
22
65
20.1
S15
40.7395
14.4717
Vegetables
7.54
476
450
19
55
23.2
S16
40.7365
24.5029
Vegetables
6.54
368
432
165
35
24.3
S17
40.7381
14.5370
Vegetables
7.59
352
441
171
36
19.6
S18
40.7539
14.5442
Vegetables
7.45
379
432
154
35
22.3
S19
40.7407
14.5978
Fruit trees
7.12
345
432
185
38
16.2
S20
40.7337
14.6458
Fruit trees
6.58
428
432
125
15
24.1
S21
40.7372
14.6884
Vineyard
6.96
417
440
131
12
25.3
Mean±SD
7.03±0.47
363.7±72.0
416.2±38.3
180.4±66.6
39.7±16.4
18.8±5.6
Min
6.31
189.0
325.0
19.0
12.0
7.5
Max
7.69
499.0
468.0
260.0
83.0
25.3
consisting of alluvial deposits mixed with pyroclastic material, of moderately fine texture, neutral pH; soils of the coastal plain of the River Sarno, consisting of deposits from rivers, marine and river lakes and interdunal lagoons, mixed with pyroclastic material of moderately coarse texture, moderately alkaline limestone. The ecotoxicological survey Figure 3 reports the output of the soil ecotoxicological assessment by the D. magna acute toxicity test as suggested by the current Italian environmental law 156/02 (Official Bulletin of the Italian Republic 2006) for surface water and soil/sediment. The results of the test were expressed as percentage of mortality relative to the control and partitioned in five groups of toxicity: 0, 1– 20, 21–40, 41–60, 61–80, and 81–100 %. Looking at the map of Fig. 3, it is possible to individuate that 64.8 % of
the samples did not show any evidence of acute toxicity, 17.0 % of the samples manifested a low evidence of toxicity (1–20 %), about 0.53 % of the samples revealed a medium sign of ecotoxicity (21–60 %), 10.1 % of the samples showed more noticeable sign of D. magna mortality (41–61 %), whereas 8.0 % of the samples reported very high toxicity percentages (81–100 %). It is noteworthy that the samples falling in this latter class of toxicity localized mainly along the potentially floatable areas of both basins of Sarno and Solofrana. Thus, it is likely that the extensive use of rivers water for irrigation and frequent flooding (Adamo et al. 2003) might have produced widespread contamination of the soils nearby the water courses, which, unlike the water pollution, has never been well documented. It is also interesting to note that most of the samples taken in the upper Solofrana river valley and with extremely high values (100 %) of crustaceous mortality (Fig. 3) fall in
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Fig. 3 Distribution of percentual mortality of Daphnia magna as set in five different ranges (0, 1–20, 20–40, 40–60, 60–80, 80–100 %) in the Sarno River basin. The potentially floatable areas are also reported (pink color)
areas with high or very high degree of contamination for Cr, As, Zn, and Hg (Cicchella et al. 2013) and in particular along the ideal line connecting Mercato San Severino with Bracigliano. The same authors analyzing the same set of soil samples as those of the ecotoxicological assessment found that 2 % of samples contained Cr levels exceeding the action level (150 mg kg−1) set by Italian environmental law with median range of 110– 810 mg kg−1 nearby Bracigliano and Mercato San Severino. These outstanding levels of Cr have been related to the action of the tannery industry and to the use of the river water for irrigation and the frequent river overflowing (Albanese et al. 2012). By contrast, samples taken in the lower Sarno River basin and with high levels of ecotoxicity, 61–100 % of mortality (Fig. 3), lie in areas of moderate or low degree of contamination for metals and dominated by Cd, Cu Hg, Pb, Sb, Sn, and Zn from agricultural and industrial activities or heavy road traffic levels (Cicchella et al. 2013). Only one site between the town of Angri and Nocera Superiore and located hence quite distant from any possible effect from overflowing of the water of the river was placed in an area of high degree of contamination, dominated by high content of Cr and Sn (Fig. 3). Polycyclic aromatic hydrocarbons Table 2 shows the spatial distribution of the mean concentrations of PAHs of the Sarno River basin. A high
quantitative and spatial variability of the PAHs was found with the following order: Benzo(a)pyrene>chrysene > indenopyrene > benzo(b)fluoranthene > benzo(g,h,i)perylene>benzo(k)fluoranthene>pyrene> dibenzo[a,h]anthracene > benzo(a)antracene. Benzo(a)pyrene, indenopyrene, and benzo(g,h,i)perylene were present at the highest concentrations with mean values of 0.32, 0.23, and 0.18 mg kg−1, respectively. These values were about 2- to 3-fold the permitted limit for residential areas of 0.1 mg kg−1 set by the law no. 152 (Official Bulletin of the Italian Republic 2006). Benzo(a)pyrene (BaP) displayed the highest variability with a SD of 0.62 and a wider range of variability, 0.0001–2.32 mg kg−1. Figure 4 shows the spatial distribution of BaP which is also believed to be the most toxic PAH and is often considered as tracer of total PAHs concentration (Wilcke 2000). About 50 % of the samples appeared to be seriously contaminated by BaP with levels above the legal limit of 0.1 mg kg−1. The peak levels of BaP, 2.32 mg kg−1, coincided with the already described site 4 of Fig. 4 included between the town of Angri and Nocera, where a high degree of contamination Cr and Sn, and ecotoxicity, 100 % relative to the control, was observed. This site appeared also heavily polluted by indenopyrene (IndP) with a peak of 1.50 mg kg−1 as well as by all the other investigated PAHs and at levels of 2- to 15-fold the legal limit.
0.02833
0.01111
0.03187
0.04120
0.02031
0.05956
0.54369
0.00670
S13
S14
S15
S16
S17
S18
S19
S20
10
10
0.1
2.32126
0.00015
0.62515
0.31695
0.04965
0.05332
2.32126
0.38052
0.13972
0.21737
0.19649
0.03970
0.12744
0.09505
0.67509
0.00015
0.17698
0.07380
0.01744
0.00746
0.01681
2.03782
0.01036
0.00547
0.01412
10
0.5
1.44592
0.00472
0.39890
0.21123
0.03376
0.03560
1.44592
0.23731
0.08400
0.15499
0.13977
0.03902
0.09578
0.06690
0.43762
0.05474
0.13288
0.05543
0.01407
0.00760
0.01736
1.35914
0.00726
0.00472
0.01198
b
a
10
0.1
1.51505
0.00385
0.36354
0.17816
0.02771
0.02984
1.51505
0.20546
0.06183
0.09160
0.15135
0.01469
0.05025
0.05038
0.23945
0.13265
0.07019
0.04207
0.01760
0.00882
0.00913
0.98976
0.00853
0.00385
0.02108
10
0.5
0.92989
0.00252
0.23153
0.11989
0.02477
0.02571
0.92989
0.15985
0.04908
0.08467
0.06923
0.01298
0.04196
0.03617
0.23277
0.03274
0.08403
0.03234
0.00499
0.00466
0.00610
0.67449
0.00337
0.00252
0.00538
50
5
2.34126
0.00650
0.56012
0.28138
0.05980
0.05049
2.34126
0.32975
0.10860
0.20168
0.14697
0.02316
0.09896
0.08910
0.56711
0.07450
0.19030
0.07755
0.01243
0.01072
0.02054
1.48059
0.01022
0.00650
0.00886
10
0.1
0.25000
0.00075
0.08044
0.04728
0.00553
0.00393
0.23475
0.03398
0.01619
0.02135
0.03114
0.01200
0.01213
0.00969
0.05535
0.02477
0.01685
0.00919
0.00535
0.00144
0.25000
0.24044
0.00364
0.00075
0.00429
Limit for commercial and industrial areas according to the Italian environmental law D.Lgs.152/06. (Official Bulletin of the Italian Republic (2006))
Limit for green and residential areas according to the Italian environmental law D.Lgs.152/06 (Official Bulletin of the Italian Republic (2006))
Values exceeding the lower regulatory limit are in bold
Limitb
0.5
0.01604
S12
Limita
0.11783
S11
0.54369
0.01519
S10
Max
0.03858
S9
0.00086
0.01391
S8
0.12444
0.01296
S7
Min
0.00113
S6
SD
0.00484
S5
0.00853
0.28583
S4
0.06019
0.00156
S3
Mean±SD
0.00086
S21
0.00495
S2
5
0.1
1.51855
0.00544
0.42699
0.22681
0.02394
0.03131
1.50450
0.24830
0.08743
0.12982
0.19563
0.01838
0.08636
0.07482
0.38401
0.18385
0.10894
0.06772
0.03152
0.00675
0.01216
1.51855
0.01085
0.00544
0.03271
50
5
1.06431
0.00163
0.22887
0.09679
0.01543
0.01138
1.06431
0.09671
0.02548
0.05891
0.03693
0.00839
0.03412
0.02810
0.19690
0.02343
0.05765
0.02166
0.01312
0.00226
0.00607
0.32147
0.00261
0.00163
0.00602
Benzo(a)anthracene Benzo(a)pyrene Benzo(b)fluoranthene Benzo(g,h,i)perylene Benzo(k) fluoranthene Chrysene Dibenzo(a,h)anthracene Indenopyrene Pyrene
S1
Stations
Table 2 Mean PAH concentrations (mg kg−1) of the soils sampled in the Sarno River basin
Environ Monit Assess (2015) 187:52 Page 9 of 14 52
52
Environ Monit Assess (2015) 187:52
Page 10 of 14
Fig. 4 Distribution of the concentrations of BaP (mg kg−1) in the Sarno River basin
Other high rates of contamination by BaP, 2.04 mg kg−1, and IndP, 1.51 mg kg−1, hence 20fold the lower legal limit of 0.1 mg kg−1, were individuated in the upper central northern part of the basin nearby the town of Striano, site 19 of Fig. 4. However, most of the samples exceeding the limit of the law fall nearby the point where the ecotoxicity output was close to 100 % (see Fig. 3) and were mainly placed in the lower central Sarno basin, included between the municipalities of Nocera Superiore, Scafati, Sarno, and Mercato San Severino, an area where beside the high industrial presence, the agricultural activity is rather intensive. This area is extensively cropped by tomato (Lycopersicon lycopersicon L., CV San Marzano), which cover over 3500 ha and sustains the presence of 183 tomato plants (Albanese et al. 2012). Organochlorine pesticides Among all the investigated OCPs, o,p′-DDT, p,p′DDT, p,p′-DDE, p,p′-DDD, and dieldrin largely surpassed the limits imposed by the Italian environmental law no. 152 for residential and commercial/ industrial areas above which the site is considered potentially contaminated (Table 3). The compounds presented the following order: p,p′-DDT>p,p′-DDE> dieldrin>o,p′-DDT>p,p′-DDD. pp′-DDT had a mean of 0.225 mg kg−1 and hence about more than 200-
and 2-fold the residential, 0.01 mg kg −1 , and commercial/industrial limits, 0.1 mg kg−1. This isomer of DDT was scantly detected in the upper Solofrana valley and determined mainly in the central Sarno valley with peaks of 0.69–0.96 mg kg−1 at sites S11 and S10, which is in an area where elevated concentrations of BaP and D. magna immobility have been already observed. Considerable levels of p,p′DDT, 0.047–0.224 mg kg−1, were found at S13, S14, S18, and S21, falling nearby places characterized by very elevated, 100 %, acute toxicity for D. magna (Fig. 3). The other main isomer of DDT, o,p′-DDT was detected only at few sites, S17 and S20 and at a range of 0.011–0.047 mg kg−1, up to 50- and 5-fold the legal limit for residential and commercial/ industrial areas. A similar spatial distribution as that of its parent compound p,p′-DDT was observed for p,p′-DDE, with a mean value of 0.147 mg kg−1 and a peak of 0.589 mg kg−1 at site S21, and hence 6- to 60-fold the commercial/industrial and residential limits. These data together with the calculated ratio p,p′-DDE/p,p′-DDT of 0.65 revealed for an extended use of DDT in the soils of the basin and for a slow rate of degradation of p,p′-DDT to p,p′-DDE. However, the entity of the ratio depends on the type of the soil, the irrigation practice, and the content of heavy metals (Racke et al. 1997). The medium content of OC, 18.8 g kg−1, of the studied soils and the high distribution coefficient in the organic carbon,
Environ Monit Assess (2015) 187:52 Table 3 Mean OCP concentrations (mg kg−1) of the soils sampled in the Sarno River basin
Page 11 of 14 52 Stations
o,p′-DDT
S1
0.034
p,p′-DDT
p,p′-DDE
0.028
0.285
0.023
0.02
p,p′-DDD
Dieldrin
0.15
S2 S3 S4 S5 S6 S7 S8 S9
0.016
0.014
S10
0.047
0.962
0.18
0.042
S11
0.047
0.697
0.161
0.043
S13
0.172
0.290
0.031
S14
0.212
0.103
0.012
S12
S15 S16
0.237
0.093
0.031
0.013
0.152
0.288
0.053
0.064
S18
0.047
0.589
0.021
0.029
S19
0.224
0.048
0.011
S17 Only the values exceeding the lower regulatory limit are reported a
Limit for green and residential areas according to the Italian ?environmental law D.Lgs.152/ 06 (Official Bulletin of the Italian Republic (2006))
b
Limit for commercial and industrial areas according to the ?Italian environmental law D.Lgs.152/06. (Official Bulletin of the Italian Republic (2006))
0.019
S20 S21
0.011
0.144
0.098
0.022
Mean
0.031
0.225
0.147
0.029
0.064
SD
0.015
0.248
0.150
0.017
0.034
Min
0.011
0.014
0.01
0.011
0.013
Max
0.047
0.962
0.589
0.053
0.064
Limita
0.01
0.01
0.01
0.01
0.01
Limitb
0.1
0.1
0.1
0.1
0.1
Koc, of 1.5 ×105 (Swan 1981), 5.0× 104 (Sabljic 1984), and 1.5×105 (Meylan et al. 1992) for p,p′DDT, p,p′-DDE, and p,p′-DDD, suggest a high sorption of these compounds in the studied soil and a scant temporal decrease of their concentration, as also observed by Robertson and Alexander (1998). The other metabolite of DDT, p,p′-DDD also distributed similarly to its parent compound, p,p′-DDE, and accumulated up to 0.053 mg kg−1 and hence still up to 5-fold the limit for residential areas, 0.01 mg kg−1. There are limited data on POPs in the soils of the Campania region. Thus, for comparison, the observed levels of DDT and DDE were compared with those from the sediments of Porto Marghera in Italy which is a well-known petrochemical area and appeared to be about 10–50 (Apitz et al. 2007) times more than the levels determined for this area.
Statistic of the data From the Spearman correlation matrix (Table 4), it was evident that PAHs were significantly correlated, 0.66≤ r≤0.99, which suggests a common origin. This may suggest that PAHs are probably mainly inputted by combustion of fossil fuel, biomass, and coal beside soil erosion and river transport. Among OCPs, significant correlation coefficients were found between the parent, p,p′-DDT, and its derivative product, p,p′DDT and p,p′DDE, with r>0.81. No one of the parameters appeared to be significantly (p
