The study characterized the biochemical changes associated with long term exposure to pesticides. Practical parameters of pesticides were collected using 500 questionnaires. Farmers having 10 years working period were invited to a private clinic for blood sampling and enzyme analysis. All participants were male farmers of different age groups, and education levels. Occupational parameters indicated that majority of farmers used manual methods for pesticide works. About 130 pesticides are currently used in Gaza. Toxicological symptoms indicated that dizziness, headache, and nausea were dominant among farmers, whereas vomiting abdominal colic and tearing were less dominant. Acetyl Cholinesterase (ACHE) cumulatively inhibited among farmers after work whereas Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST) and Alkaline Phosphatase (ALP) activities were above range after long term exposure. It can be concluded that long term exposure to pesticides may damage liver and kidney cells resulting in hepatic-toxicity and/or nephrotoxicity.
The Gaza Strip is a semi-arid region with an annual rainfall ranged from 180 - 450 mm. The population in Gaza is about 1,750,000 who live and work in an area of 365 km2. Agriculture in the Gaza Strip is highly intensive and relies on frequent application of pesticides, which results in contamination of food samples and agricultural commodities [
Moreover, long term exposure to pesticides may occur via indirect way such as ingestion of contaminated food with pesticides residues [
About 500 questionnaires were used to collect the occupational data from the field via direct contact, face to face interviews. The data collection included demographic parameters, Knowledge of pesticides hazards, occupational parameters, and toxicity symptoms
Blood sampling and analysis for enzyme activities
Farmers having long term exposure (10 years or more) to pesticides were invited to a private health clinic for voluntarily blood sampling (10 ml). The blood samples were collected in heparin containing tubes and analyzed in the same day for ACHE, ALP, AST, ALT activities and urea, uric acid, and total protein concentrations.
Acetylcholine esterase activity (ACHE) was measured by a spectrophotometer according to the method developed previously by Ellman et al. [
The activity of ALP was determined according to Bessey et al. [
The total protein content was determined by the method of Lowry et al. [
Determination of urea, creatinine and uric acid uses kit techniques.
Previous health records of the farmers having long term exposure to pesticides were collected from the health departments and personal health files. Each farmer working on pesticide spry processes should have an official medical investigation including AST, ALP, AST, ACHE, and kidney function test. The data of each farmer were saved in the particular file. This medical examination test is an obligatory for officially employed works.
The collected data were analyzed using an Excel program. Occupational exposure to pesticides were categorized into three modes as follows: mode 1, (M1) contained farmers working in pesticide application for 1 - 5 years; mode 2, M2, (6 - 10 years) and mode 3, M3, (>10 years).
The range of enzyme activities were assigned, average and standard deviation were calculated. T-test were used to detect significant differences.
The participants of the study are male Palestinian farmers from Gaza belonged to different age groups: group 1, (20 - 30) 130 farmers, group 2 (31 - 40) 185 farmers, and group 3 (41 - 60) 164 farmers. The education levels were below general secondary school (65%), General secondary schools (25%), and meddle education and above (10%).
Distribution of farmers using different pesticides type in the Gaza Strip is shown in
The scientific name, frequency of application and lethal does (LD50) of pesticides used by farmers are shown in
Type of pesticide | Farmers locations | Total | ||||
---|---|---|---|---|---|---|
Rafah | KH. Y | Gaza | North | Number | % | |
Insecticides | 25 | 71 | 54 | 71 | 221 | 44.47 |
Herbicides | 10 | 37 | 31 | 40 | 118 | 23.73 |
Nematicides | 12 | 14 | 23 | 21 | 70 | 14.1 |
Fungicides | 10 | 20 | 26 | 32 | 88 | 17.7 |
Total | 57 | 142 | 134 | 164 | 497 | 100 |
Insecticide | LD50 | Frequency | Fungicides | Frequency | LD50 |
---|---|---|---|---|---|
Chlorpyrifos1 | 135 - 165 | 156 | Mancozeb | 113 | >5000 |
Fenamiphos1 | 6 - 10 | 153 | Triadimenol | 100 | 700 |
Dimethoate1 | 387 | 67 | Penconazole | 96 | 2125 |
Imidacloprid | >5000 | 71 | Propamocarb | 34 | 2000 - 2009 |
Carbosulfan2 | 250 | 61 | Propineb | 26 | 5000 |
Cadusafos1 | 37.1 | 59 | Cymoxanil | 62 | |
Aldicarb2 | 0.93 | 57 | Chlorothalonil | 25 | 5000 |
Cypermithrin4 | 105.8 | 37 | Iprodione | 12 | 2000 |
Chlorfluazuron5 | >1000 | 67 | Bupirimate | 12 | 4000 |
Metham sodium(N) | 1800 | 29 | Herbicides | Frequency | LD50 |
Abamectin3 | 25 | 29 | Oxadiazon | 73 | 5000 |
Lufenuron5 | >2000 | 26 | Prometryn | 53 | 2000 |
Methyl bromides,(N) | 3.03 | 25* | Paraquat | 33 | 127 |
Fenpropathrin4 | 70.7 | 23 | Diquat | 32 | 408 |
Cypermethrin4 | 250 | 23 | Glyphosate | 32 | 5600 |
Methamidophos1 | 16.6 | 50 | 2, 4-D | 21 | |
DBCPs | NA | 13 | Metribuzin | 20 | 2000 |
Endosulfan5 | 70 | 16 | Pendimethalin | 20 | 1050 - 1250 |
Bromopropylate5 | >5000 | 8 | Cycloxydin | 20 | 5000 |
Chlorfenapyr | 441 | 8 | Imazapic | 20 | 5000 |
Methomoyl2 | 34 | 18 | |||
Oxydemeton methyl1 | 50 | 19 | |||
Fenazaquin | 134 | 14 |
1 = Organo-Phosphorus compounds; 2 = Oxim carbamate compounds; 3 = Bio-pesticides; 4 = Pyrothriods; 5 = Organo-Chlorine compounds; 6 = Thiazoles; 7 = Thiocarbamate; S = suspended, * = by inhalation, N = Nematicides. LD50 values obtained from Tomlin [
All chemicals listed above are synthesized and formulated in many chemical companies around the world (e.g. Bayer, Monsanto, Sigma, Makhteshim, Agan, Syngenta, Simonis, Tapazol, Sumotomo, Laid Chemicals, Niho Nohyaku, Dow Agrosciences).
It can be seen that large fraction of farmers (n = 310, 62.37%) did not use full protective clothes during pesticides application. Low fraction (n = 175, 35%) partially used protective clothes. Moreover, majority of farmers (n = 275, 55%) use their own hands to prepare pesticide solution and other related activities. In addition about 55% (n = 273) of farmers revealed body contamination with pesticide solution or its drift during application. Moreover, many farmers (n = 87, 18%) indicated that they changed application mode during the same day, resulting in increasing the exposure time and the contaminated area of the body. Furthermore, 55% of farmers revealed that they did not know the hazards of pesticide accordingly they did not use safety measures during work and claimed that skin, hand, face contamination are usually occurred during spray process. About 35%, (n = 175) of farmers have concerns about pesticides but they did not believe that pesticide can cause serious health damage to human life. About 17% (n = 84) eat or drink during work period. Moreover, 43% (n = 213) believed that pesticides are not harmful to human body accordingly they did not use protective clothes. Furthermore, about 22% (n = 109) believed that pesticides are safe for human life because they are specific chemicals for pests. Low fraction of farmers (n = 44, 9%) revealed that they used pesticide containers for domestic purposes. So far about 67% (n = 332) believed that pesticides are toxic to the human beings if they were taken orally (ingestion), whereas 77% (n = 381) believed that pesticides are not harmful to the human body through skin contamination.
Distributions of farmers according to their exposure time are shown in
Methods of pesticide works such as solution preparation, application and disposal methods are shown in
Exposure time (year) | Farmers using pesticides (locations) | Total | ||||
---|---|---|---|---|---|---|
Rafah | KH. Y | Gaza | North | Number | % | |
Mode 1 (1 - 5 y) | 22 | 45 | 54 | 69 | 190 | 38.2 |
Mode 2 (6 - 10 y) | 20 | 55 | 43 | 59 | 187 | 37.6 |
Mode 3 (>10) | 15 | 37 | 33 | 35 | 120 | 24.1 |
Total | 57 | 142 | 134 | 164 | 497 | 100 |
Location | Pesticide application | Preparation of spray solution | Disposable method | |||
---|---|---|---|---|---|---|
Manual | Mechanical | Manual | Mechanical | Manual | Mechanical | |
Rafah | 19 | 10 | 27 | 4 | 22 | 8 |
KH. Y | 87 | 55 | 107 | 25 | 122 | 5 |
Gaza | 46 | 49 | 65 | 30 | 81 | 7 |
North | 78 | 51 | 97 | 14 | 102 | 7 |
Total | 230 (58.2%) | 165 (41.8%) | 296 (80.2%) | 73 (19.8%) | 327 (92.4%) | 27 (7.6%) |
P-value between manual and mechanical pesticides application is 0.07, whereas p-value between manual and mechanical preparation of spray solution 0.019 and p-value between manual and mechanical disposable method is 0.02, indicating significant differences.
Toxicity symptoms among farmers observed during work periods or immediately after finishing are shown in
Effect on ACHE, ALT, AST and ALP Activity
Effects of occupational exposure to pesticides on the activity of ACHE, ALT, AST and ALP in blood serum are shown in
It can be seen that the activity range of ACHE before exposure to pesticides was 6000 - 18,200 u/l with an average and standard deviation 8867 ± 2584 u/l whereas the activity reduced to a lower range due to long term exposure to pesticides and reached 2000 - 6000 u/l with an average and standard deviation 4343 ± 1325 u/l indicating commutative toxicity.
In addition ALT range before exposure to pesticides was 4 - 35 u/l with an average of 20.9 ± 7 and dramatically increased up due to long term exposure to pesticides and reached to 35 - 567 u/l with an average of 98 ±
Toxicity symptoms | Farmer locations | |||||||
---|---|---|---|---|---|---|---|---|
Rafah | KH. Y | Gaza | North | |||||
n | % | n | % | n | % | n | % | |
Dizziness | 22 | 7.77 | 105 | 37.10 | 66 | 23.32 | 90 | 31.80 |
Headache | 23 | 8.30 | 102 | 36.82 | 64 | 23.10 | 88 | 31.77 |
Nausea | 23 | 10.18 | 78 | 34.51 | 51 | 22.57 | 74 | 32.74 |
Diarrhea | 20 | 9.52 | 89 | 42.38 | 39 | 18.57 | 62 | 29.52 |
Vomiting | 15 | 7.43 | 70 | 34.65 | 50 | 24.75 | 67 | 33.17 |
Abdominal colic | 17 | 8.25 | 77 | 37.38 | 47 | 22.82 | 65 | 31.55 |
Losing appetite | 13 | 8.02 | 59 | 36.42 | 38 | 23.46 | 52 | 32.10 |
losing conscious | 12 | 8.33 | 53 | 36.81 | 32 | 22.22 | 47 | 32.64 |
Tearing | 6 | 4.44 | 47 | 34.81 | 42 | 31.11 | 40 | 29.63 |
Tremors | 5 | 5.15 | 42 | 43.30 | 26 | 26.80 | 24 | 24.74 |
Convulsions | 4 | 5.48 | 31 | 42.47 | 18 | 24.66 | 20 | 27.40 |
Paralysis | 6 | 10.71 | 24 | 42.86 | 15 | 26.79 | 11 | 19.64 |
ACHE | ALT | AST | ALP | |||||
---|---|---|---|---|---|---|---|---|
Range | M ± S | Range | M ± S | Range | M ± S | Range | M ± S | |
Before | 6000 - 18,200 | 8867 ± 2584 | 4 - 35 | 20.9 ± 7 | 8 - 30 | 21.99 ± 6.63 | 122 - 200 | 164 ± 23 |
After | 2000 - 6000 | 4343 ± 1325 | 36 - 567 | 98 ± 131 | 31 - 802 | 209 ± 550 | 201 - 2195 | 651 ± 631 |
M and S are mean and standard deviation respectively.
131. Similarly the activities of AST and ALP followed the same trend.
Effects on cholesterol, total protein, triglyceride, urea, creatinine, and uric acid are shown in
Farmer visits to hospitals and private clinics are shown in
It is obvious that farmers have very low information about the toxicity of pesticides to human life as shown by their answers to pesticide knowledge. Lack of knowledge among farmers was most dominant among farmers. This is probably due to the low education level of farmers.
Demographic and Occupational ParametersIt is obvious (
Moreover, the occupational parameters of pesticides (
Test | Cholesterol | Total protein | Triglyceride | Urea | Creatinine | Uric acid | ||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Range | M ± S | Range | M ± S | Range | M ± S | Range | M ± S | Range | M ± S | Range | M ± S | |
Before | 40 - 200 | 162.2 ± 24 | 40 - 160 | 126 ± 55 | 6 - 7.1 | 5.53 ± 1.5 | 15 - 45 | 26.37 ± 8.5 | 0.6 - 1.4 | 0.79 ± 0.3 | 2.6 - 6 | 3.92 ± 1.3 |
After | 201 - 299 | 252 ± 38 | 161 - 342 | 263 ± 83 | 7.2 - 8.6 | 7.44 ± 0.5 | 46 - 227 | 103.2 ± 50.2 | 1.41 - 16.2 | 3.36 ± 2.5 | 6.1 - 14.5 | 8.57 ± 1.9 |
Liver test | Kidney test | General hospital | ||||
---|---|---|---|---|---|---|
Before | After | Before | After | Before | After | |
Rafah | 3 | 8 | 5 | 7 | 8 | 20 |
KH. Y | 5 | 29 | 7 | 24 | 15 | 68 |
Gaza | 10 | 32 | 12 | 28 | 17 | 48 |
North | 8 | 33 | 10 | 29 | 17 | 79 |
total | 26 | 102 | 34 | 88 | 57 | 215 |
information as shown in the knowledge section above. The manual application of pesticides exposes the farmers to high potential risk. Statistical analysis shows significant differences between manual and mechanical applications of pesticides. Regardless of the statistical variations contamination of farmer skin, face and body during work indicate high potential for toxicity. This is in agreement with the toxicity symptoms (
Application of insecticides followed by fungicides or nematicides may expose the farmers to binary or tertiary pesticides mixtures and may enhance the appearance of synergisms. This hypothesis is supported by the frequent visits to hospitals or private clinic after or during the working day
So far, Chlorpyrifos, fenamiphos, imidacloprid, and methyl bromide, (highly toxic) are the most frequent insecticides whereas prometryn, paraquat, diquat, glyphosate, 2, 4-D and metribuzin are the most frequent herbicides. The frequent fungicides are pencanazole, triadimenol, and mancozeb. The high frequency of pesticide application suggests possible formation of binary or tertiary mixtures and exposure of farmers in all locations to adverse health effects. This hypothesis is in accordance with the results in
It has been shown that long term exposure to pesticides created several symptoms such as hypertension, and neurological and immunological effects [
In addition, frequent contamination of human body may result in different metabolic reactions and create hepatic damage or oxidation stress. This argument is supported by the data in
The occupational parameters (
Statistical analysis shows significant differences between the values of ALT, AST and ALP of the farmers before and after long term exposure. Our findings agree with Al-Othman et al. [
The data in
For the cases of protein content, it is suggested that long term exposures to organophosphourus insecticides disturb protein and lipid metabolism. This suggestion is supported by the toxicology symptoms (
The trend of kidney indices (urea, uric acid and creatinine)
Long-term exposure to pesticides created severe health problems. Frequent applications of pesticides exposed farmers to the possibility of binary and tertiary mixtures. Toxicity symptoms were found in all locations. Disturbance of digestive systems dominated in most farm locations. Manual application of pesticides was associated with many toxicity symptoms. Levels of ACHE decreased due to long term exposure, whereas levels of ALT, AST and ALP activities increased with exposure time and were the highest for long periods of exposure time. Kidney functions followed the same trend.
Long-term exposure to pesticides created changes in the hepatic biochemical markers, nephro-toxicity and/or cholinergic damage. ALT, ALP, AST, and kidney function indices can be taken as indicators of non-target organisms.
Special thanks to the Alexander von Humboldt foundation for a Research Fellowship at Leipzig University, Germany. I am grateful to my students at faculty of Science-IUG who helped me in data collection. Thanks also for the lab technicians at Balsam and Hunaf Laboratories, Gaza Palestine for their kind assistance in enzyme activity determinations and blood analysis.
This study was not funded by any organization.
Author declares that he has no conflict of interest. The study complies with the international ethics issues. Consent form was filled by each farmer participating with the study. Helsinki human right ethics were received before conducting the study.
Yasser El- Nahhal, (2016) Biochemical Changes Associated with Long Term Exposure to Pesticide among Farmers in the Gaza Strip. Occupational Diseases and Environmental Medicine,04,72-82. doi: 10.4236/odem.2016.43009