INTRODUCTIONA dust storm is one of many air pollutants knownto humans. About 800 trillion grams of dust particlesare spread in Asia. Particulate matter (PM) is usuallysuspended in arid, semiarid, and desert areas [1].Today, dust storms are one of environmental problemsthat threaten the world [2]. The phenomenon of dustin the atmosphere causes the spread of PM around theglobe [3]. Dust phenomena can be triggered by suchfactors as environmental change, global drought, andland cover [4]. The dry currents of the Saudi air andlack of attention to the environment and desertificationin Iraq have dried up many of the marshes there andcreated dusty areas. In the past, Iran, Iraq, and SaudiArabia jointly funded the mulching of these lands duringa particular season. The Iraq war obliterated this work,resulting in a spike in western Iran, and eventuallyalmost throughout the whole country. According toHarrington et al., the United States soldiers involved inthe Iraq war had respiratory problems due to the dustphenomenon in that country [5].Biological particles, salt sprays and, in particular,dust phenomena have been reported to contain numerousheavy metals [6]. Furthermore, these metals lead toclimate change in temperature and other seasonalchanges, such as the wind speed and patterns [7].Although trace heavy metals are fundamental to livingorganisms for a normal and healthy life, excessive levelsof heavy metal contamination in the environment couldcause harm [8, 9]. To reduce environmental pollutionand mitigate the resulting degradation of soil and waterresources, it is important to precisely determine heavymetal concentrations [10, 11].Some heavy metals, for example, chrome (Cr),lead (Pb), cadmium (Cd), and mercury (Hg) inthe form of suspended particles in the air producesignificant toxicological effects on people and otherorganisms by contaminating food and drinking waterin the environment [12]. Particulate matter, whichis contaminated with heavy metals, can pollutegroundwater. It has been indicated that contaminationis transmitted from the soil to the plant. As a result,contaminated plants ingested by humans or animals cancause a toxic effect. Consequently, the concentrationof heavy metals in animal products, such as raw milk,also causes toxicity. The extent of toxicity depends ondifferent factors, such as plant processes and the amountof raw materials used [13]. Moreover, heavy metalssuch as lead, cadmium, chrome, nickel, and cobalt cancontaminate cows and their surroundings. Heavy metalsare absorbed by plant roots from the soil. As a result,this pollution causes serious problems, changing theamount and structure of milk [14].The International Agency for Research on Cancer(IARC, 2016) classifies arsenic (As) and chrome (Cr) ascarcinogenic metals and lead as a possible carcinogen.Such metals can cause different types of cancer throughdermal contact, inhalation, and ingestion [15].The western and southwestern climates of Iranare influenced by environmental conditions andmarkers such as geological, climatic, hydrological, andgeomorphological characteristics [3]. Among the factorsthat cause dust storms are the development of deserts inIraq, a decrease in volume and flow of rivers, and theTurkish dam on the rivers [16]. With a population of172 000 people, the city of Ilam is located on the westernborder of Iran (33°38′N, 46°25′E). Due to a smallpopulation and a mountainous area, the city has lowtraffic and also no air pollution industry.With the onset of spring, the phenomenon of dustcomes to Iran from Iraq. This situation was aggravatedby the Iraq war. In this study, we investigated theconcentration of suspended particles in the environmentand evaluated the effect of heavy metals on cow rawmilk in the west of the country, Ilam province.STUDY OBJECTS AND METHODSPM concentration in dust. The dust samples werecollected from four districts of Ilam province: northernand central, southern, western, and eastern (28 samplesin each). The sampling was performed on the roofsof buildings seven meters above the ground and twometers from the roof surface. During the sampling, wecomplied with all the standards of the US EnvironmentalProtection Agency. In particular, we kept the requireddistance from natural and artificial obstacles, pathways,and sources of contamination. Suspended particles PM10and PM2.5 were measured with the Enviro Check LaserSystem using the Dust Monitor Check (Grimm). Thisapparatus can directly and simultaneously measure theparticle count, PM10 and PM2.5. The system automaticallysaves the values in its memory and calculates theaverage on an hourly and a daily basis [17].On normal days, the sampling was carried outevery six days and on days with dust (a concentrationabove 150 μg/cm3), according to the MeteorologicalOrganization and satellite sites, on a daily basis. Thepeak concentrations of PM10 and PM2.5 were recordedand measured on average every hour. The dataobtained during a year were analyzed with the SPSSsoftware [18].Heavy metals in dust. Teflon and fiberglass filterswere used to investigate heavy metals in the dustphenomenon. A 100-cm section of a filter was cut andtransferred to a 100 mL beaker. Then, we added 50 mLof Aqua Regia (HNO3+ 3 HCl) and heated it to 140°Cuntil the filter section was dry. Then, we removed it andwashed the beaker with 10% nitric acid. This work wasrepeated three times. In the end, the prepared samplewas kept at room temperature until it was cooled. Then,we transferred it into a 100-mL volumetric flask anddiluted to volume with 10% HNO3. The concentrationsof heavy metals (lead, arsenic, zinc, copper, and iron)were determined by a Perkin-Elmer Analyst 800atomic absorption spectrometer, including an AS-800Autosampler equipped with Zeeman-effect backgroundcorrection. Each result was an average of three readings.Blank filters were prepared by digesting clean glassfiber filters with the same digestion method used for thedust samples. Also, the dust samples were prepared indifferent seasons [19].Heavy metals in raw milk. A total of 112 samplesof cow raw milk were collected from four districts ofIlam province: northern and central, southern, western,and eastern (28 in each), at the same places as dustsamples. All the samples were collected in nitric acidwashedpolyethylene containers. They were immediatelytransported to the laboratory in a cooler with ice packsand stored at –20°C until analysis. The raw milk sampleswere analyzed based on AOAC official methods. Theamounts of heavy metals (lead, arsenic, zinc, copper,and iron) were measured by a Perkin-Elmer Analyst 800atomic absorption spectrometer, including an AS-800Autosampler equipped with Zeeman-effect backgroundcorrection. Each sample was studied three times [20].The limit of detection and the limit of quantitation of theatomic absorption device were 0.08 ppm and 0.15 ppm,respectively.Statistical analysis. The SPSS 21 software wasused to extract the data (P < 0.05). The results of threerepetitions were analyzed by ANOVA, using an SPSSstatistics package.RESULTS AND DISCUSSIONIlam is bordered by Iraq and close to the countries ofSaudi Arabia and Kuwait, which are the main sources ofdust events in the Middle East (Fig. 1).According to Table 1, the sampling took 87 days.The average PM10 and PM2.5 were about 105.6 ± 82.9 and25.9 ± 15.4 μg/m3, respectively. The maximum particlesize of PM10 and PM2.5 was about 806.3 and 213.2 μg/m3,respectively.243Karimi E. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. 241–249Figure 1 Geographical location of Ilam province and Iraq (Google map)Table 1 Concentrations of PM10 and PM2.5 in different months of sampling in Ilam province, μg/m3Months Number ofsampling daysAverage Maximum Minimum Median Standard deviationPM10 PM2.5 PM10 PM2.5 PM10 PM2.5 PM10 PM2.5 PM10 PM2.5March-April 12 178.3 42.7 725.1 171.1 31.7 8.3 179.1 31.2 185.2 41.7April-May 9 142.4 31.3 562.3 210.4 62.7 12.5 142.3 37.1 127.5 32.4May-June 16 210.3 56.6 806.3 213.2 91.8 17.7 181.3 35.8 197.3 30.1June-July 7 112.7 27.2 351.7 98.2 51.2 10.3 125.2 29.6 110.2 12.5July-August 9 139.9 37.5 393.4 99.1 57.4 12.1 139.1 28.8 123.1 13.1August-September 6 79.8 25.1 185.2 55.3 26.6 8.7 76.6 12.5 31.5 9.2September-October 4 56.7 12.7 100.1 21.1 18.7 6.2 43.9 8.7 26.7 6.7October-November 5 58.7 13.3 110.7 20.7 19.2 6.0 45.2 8.4 27.1 7.3November-December 4 62.7 14.1 211.2 18.7 30.1 11.8 52.2 9.7 30.7 10.9December-January 4 48.4 12.2 89.6 12.9 15.2 4.4 38.3 3.5 20.3 5.2January-February 4 39.6 11.5 75.3 12.1 13.3 4.1 35.2 4.1 18.7 4.9February-March 7 137.5 26.9 300.8 121.6 41.3 9.6 127.5 11.2 97.3 10.4Study period 87 105.6 25.9 325.9 87.8 38.3 9.3 98.8 18.4 82.9 15.4Five heavy metals (lead, arsenic, zinc, copper, andiron) were measured in all the samples. Fig. 2 shows therange and mean concentrations (ng/m3) of the selectedheavy metals analyzed at the sampling stations. Inthe spring and summer, the amounts of heavy metalswere higher than in the other seasons, especially iron.Lead and copper levels were lower in all the seasonscompared to other metals.Average values of ;ead content in the raw milksamples are shown in Table 2. The highest average leadlevel was determined in the western region (57.1 μg/kg).The statistical analysis revealed a significant differencein lead concentrations between the western and southernregions compared to the east and north of Ilam province(P-value < 0.05).Average concentrations of arsenic in the milksamples are shown in Table 3. Although arsenic washigher in the south and west compared to the northernand central region or the east of the province, wefound no significant difference. The highest average***** ********040080012001600D Ph sp N Dph sp D Ph su N Dph su D Ph f N Dph f D Ph w N Dph wConcentration, ng/m3Seasons (with and without dust phenomenon)Arsenic Zinc Copper Iron Lead244Karimi E. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. 241–249arsenic level was observed in the west, amounting to12.4 mg/kg.Table 4 shows average zinc values in the rawmilk samples. The highest average amount of zincwas determined in the western region (4582.8 μg/kg). According to the statistical analysis, there was asignificant difference in zinc concentrations between thewestern and southern regions compared to the east andnorth of Ilam province (P-value < 0.05).The concentrations of copper in different regionsare shown in Table 5. As we can see, the average levelof copper in the western and southern regions wasFigure 2 Seasonal average concentrations of heavy metals (lead, arsenic, zinc, copper, iron) in dust phenomena. Dust phenomenonin spring (D Ph sp), non-dust phenomenon in spring (N Dph sp), dust phenomenon in summer (D Ph su), non-dust phenomenon insummer (N Dph su), dust phenomenon in fall (D Ph f), non-dust phenomenon in fall (N Dph f), dust phenomenon in winter(D Ph w), non-dust phenomenon in winter (N Dph w), * P-value < 0.05, ** P-value < 0.001 vs. the other group***** ********040080012001600D Ph sp N Dph sp D Ph su N Dph su D Ph f N Dph f D Ph w N Dph wConcentration, ng/m3Seasons (with and without dust phenomenon)Arsenic Zinc Copper Iron LeadTable 2 Lead contents in raw milk samplesNorthern and Central region Eastern region Southern region Western regionSample Content, μg/kg Sample Content, μg/kg Sample Content, μg/kg Sample Content, μg/kg1 29 1 31 1 49 1 482 29 2 33 2 48 2 553 23 3 35 3 53 3 494 28 4 29 4 59 4 635 27 5 37 5 57 5 616 31 6 39 6 61 6 657 25 7 38 7 55 7 59Average 27.4 Average 34.6 Average 54.6 Average 57.1Max 31 Max 39 Max 61 Max 65Min 23 Min 29 Min 48 Min 48Table 3 Arsenic contents in raw milk samplesNorthern and Central region Eastern region Southern region Western regionSample Content, μg/kg Sample Content, μg/kg Sample Content, μg/kg Sample Content, μg/kg1 11 1 10 1 13 1 122 11 2 10 2 12 2 133 12 3 12 3 12 3 124 10 4 12 4 14 4 145 10 5 13 5 10 5 126 12 6 10 6 13 6 117 11 7 9 7 12 7 13Average 11 Average 10.9 Average 12.3 Average 12.4Max 12 Max 13 Max 14 Max 14Min 10 Min 9 Min 10 Min 11245Karimi E. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. 241–249higher than in the eastern and northern regions. Thelowest average copper concentration (234.3 μg/kg) wasobserved in the northern and central region.According to Table 6, there was a significantdifference between the amounts of iron in the west andsouth compared to the east and north of the province.The highest average concentration of iron (3954 μg/kg)was found in the southern region.Typically, dust particles with a diameter of 616–660 μm remain in their places of origin. Particles sized31‒62 μm are dispersed over approximately 320 kmfrom their origin, while those sized 16‒30 μm, up to1600 kilometers. Particles below 16 μm travel longer,and particles ranging from 2‒50 μm have been reportedto mostly originate in deserts like Iraq, Saudi Arabia,and Africa [21]. The main source of dust phenomenon inthe southwest of Iran is the deserts of Iraq [22].In our study, the mean and standard deviations ofPM10 and PM2.5 were 105.69 ± 0.5 and 25.9 ± 15.4 μg/m3at the time of sampling, and the maximum PM10 andPM2.5 concentrations were 806.3 and 213.2 μg/m3 in June,respectively. According to Draxler et al.,the main sources of dust phenomenon in thesouthwest and west of Iran are Kuwait, Iraq,Table 4 Zinc contents in raw milk samplesNorthern and Central region Eastern region Southern region Western regionSample Content, μg/kg Sample Content, μg/kg Sample Content, μg/kg Sample Content, μg/kg1 3120 1 3210 1 4650 1 47402 3190 2 3460 2 4770 2 44003 2870 3 3110 3 4390 3 48104 3150 4 3060 4 3880 4 50305 3210 5 2930 5 4810 5 45606 3010 6 3420 6 4230 6 43307 2460 7 3250 7 4560 7 4210Average 3001.4 Average 3205.7 Average 4470 Average 4582.8Max 3210 Max 3460 Max 4810 Max 5030Min 2460 Min 2930 Min 3880 Min 4210Table 5 Copper contents in raw milk samplesNorthern and Central region Eastern region Southern region Western regionSample Content, μg/kg Sample Content, μg/kg Sample Content, μg/kg Sample Content, μg/kg1 210 1 200 1 230 1 1702 300 2 320 2 690 2 4803 190 3 170 3 410 3 5504 180 4 350 4 520 4 4005 250 5 420 5 450 5 6706 310 6 300 6 360 6 5107 200 7 380 7 590 7 430Average 234.3 Average 305.7 Average 464.3 Average 458Max 310 Max 420 Max 690 Max 670Min 180 Min 170 Min 230 Min 170Table 6 Iron contents in raw milk samplesNorthern and Central region Eastern region Southern region Western regionSample Content, μg/kg Sample Content, μg/kg Sample Content, μg/kg Sample Content, μg/kg1 2554 1 2654 1 3865 1 38452 2129 2 2863 2 3978 2 36933 2763 3 2341 3 4762 3 42364 3327 4 3496 4 3687 4 41225 2645 5 2029 5 4831 5 35416 2431 6 2585 6 3573 6 36557 3504 7 3051 7 2985 7 4032Average 2764 Average 2717 Average 3954 Average 3874Max 3504 Max 3496 Max 4831 Max 4236Min 2129 Min 2029 Min 2985 Min 3541246Karimi E. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. 241–249and Saudi Arabia. The authors showed thatPM10 c oncentrations e xceeded 3 000 μ g/m3 [23].In the study by Shahsavani et al., which agrees withour results, the mean and standard deviations ofPM10 and PM2.5 in Ahwaz, southwest of Iran, were 407.07 ± 319.1and 83.2 ± 69.5 μg/m3, while the maximum PM10and PM2.5 c oncentrations w ere 5 337.6 a nd 9 10.9 μ g/m3 in June, respectively [24]. In another study, inthe southwest of Iran, the mean and standard PM10and PM2.5 deviations in the entire study period were 775.3 ± 598.9and 129.5 ± 114.9 μg/m3, whereas their maximumconcentrations reached 4730.1 and 774.4 μg/m3 inFebruary, respectively [17]. The difference between themaximum concentrations found by the authors and ourresults may be due to differences in geographical andatmospheric conditions and the distance from the dustsource in the period of particle measurement. Also, inanother study of 2007, the mean total concentrationof suspended particles was 282 μg/m3 and the PM10and PM2.5 concentrations were 165 and 67 μg/m3, respectively [25].Finally, a 2010 study conducted in China reportedthe mean concentrations of PM10 and PM2.5 to reach322 ± 237.4 μg/m3 and 141.5 ± 108.8 μg/m3, respectively [26].According to Jacobs et al., of 16.4 million homes inthe United States with more than one child below six,25% still had significant amounts of lead-contaminateddeteriorated paint, dust, or adjacent bare soil [27].Lu et al. detected the presence of heavy metals in soilby spectroscopic methods [28]. In another study, thevoltammetric method found cadmium (0.06 μg/L)and lead (0.65 μg/L) in soil [29]. However, the atomicabsorption technique is also very important foranalyzing heavy metals in air samples. Factors suchas high sensitivity, high performance, low cost, andaccuracy make this method a good choice. The amountof heavy metals in the atmosphere depends on the originand the distance from the source of pollution. Seasonalchanges also affect concentrations of heavy metals in theatmosphere [30]. Our results showed that the amountsof arsenic, zinc, lead, and copper were higher duringthe spring and summer. Zinc and iron had a higherlevel compared to the others. Due to high temperaturesduring the spring and summer, dust is denser than in thefall or winter, and it is easier for animals and humans toinhale them. In a study by Al-Dabbas et al., the X-raypowder diffraction method was used to detect thepresence of heavy metals (Fe, Co, Ni, Cu, Zn, and Pb)and dust particles in the streets of southern Iraq [31].Also, in Ahwaz, southwest Iran, heavy metals (Cd, Cr,Co, Ni, Pb, Zn, and Al) were identified in particles withPM10 [32].It has been well demonstrated that heavy metalssuch as cadmium, chrome, nickel, and cobalt, whichcontaminate the environment around animals, e.g. cows,penetrate into cow milk and cause tissue problems.Heavy metals can penetrate into plants through theirroots. Through contaminated drinking water andwater used in agriculture and food production, theyenter animal and human bodies [33]. As reported byRazafsha et al., plants contaminated with particlescontaining heavy metals increase the risk of raw milkcontamination [34].Dairy products are a vital part of a healthy diet, andmilk is widely used in feeding infants and children.Therefore, studying the presence of metals in milkis especially important to ensure the safety of milkproduction that is greatly reduced in a contaminated andtoxic environment [35, 36].According to the FAO/WHO guidelines and theCodex standard, the levels of lead, arsenic, zinc, andiron in milk and dairy products are 2.0, 0.050, 0.9, and0.6 μg/kg, respectively [37].We examined the amounts of heavy metals in cowmilk in Ilam, west of Iran, and found that lead levels inthe western and southern regions were higher than in theeast, center, and north. This situation was also consistentwith arsenic, zinc, copper, and iron. The averageconcentrations of arsenic and copper were generallylower than those of zinc, lead, and iron. Farm animals,which are used for milk and meat, tend to get pollutedwith heavy metals through the environment. Accordingto recent observations, the concentrations of remainingheavy metals in milk are significantly higher than thoseapproved by international authorities [38].Consistent with our study, Konuspayeva et al.reported that seasonal changes influenced the level oflead in camel milk: it was lower in the spring comparedto other seasons [39]. They also found that the presenceof arsenic in camel milk and its contamination leveldepended on the distance from the source of pollution,wind and farm topography (soil type, vegetation type),etc. [40]. Another study reported that the amount of ironand copper in the milk collected in industrial areas washigher than that of lead in traffic-intensive and industrialregions [20]. This shows the effect of the environmenton the content of heavy metals in milk. Awasthi et al.and Malhat et al. reported that the levels of cadmium,iron, and zinc in cow milk were higher in industrialareas compared to others [41,42]. A study in Egypt foundthat the amount of cadmium in cow milk produced incontaminated air was significantly higher [43].It has been shown that all the milk samples collectedfrom different governorates contained lead and iron inhigher concentrations than those recommended for milkby the IDF standard (1979). Lead is an environmentalpollutant that is toxic to humans and animals [44].Similar to our study, Kabir et al. presented theaverage concentrations of metals in 50 samples of cowmilk from contaminated environments in the followingorder: Fe > Cr > Mn > Zn > Ni > PB > Hg > Sc > Cd >As [45].CONCLUSIONWe analyzed the particle matter and the amounts247Karimi E. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. 241–249of heavy metals in the dust phenomenon in westernIran (Ilam province) over one year and also studiedthe presence of heavy metals in the raw milk samplescollected in its four regions. As a result, we can concludethat the dust phenomenon that comes from Iraq to Iranis probably one of the sources of milk contamination inwestern Iran.CONTRIBUTIONNaser Abbasi designed the work and took the lead inwriting the manuscript together with Elahe Karimi; AliAidy performed the experiments; Monireh Yari and HoriGhaneialvar derived the models and analyzed the data;Hamid Reza Kazemi and Reza Asadzadeh contributed tothe interpretation of the results.CONFLICT OF INTERESTThe authors declare that they have no conflicts ofinterest.ACKNOWLEDGEMENTSThis work was supported by the Ilam University ofMedical Sciences.ETHICAL STATEMENTThe authors confirm that they have adhered tothe journal’s ethical policies specified on its authorguidelines page, and received the approval of theappropriate ethical review committee. The authors alsoconfirm that they have followed the EU standards for theprotection of animals used for scientific purposes andfeed legislation.